Patent Grant
10736919
In some aspects, the present application provides materials and methods for producing genome-edited cells engineered to express a chimeric antigen receptor (CAR) construct on the cell surface. In other aspects, the present application provides materials and methods for genome editing to modulate the expression, function, or activity of one or more immuno-oncology related genes in a cell. In yet other aspects, the present application provides materials and methods for treating a patient using the genome-edited engineered cells, both ex vivo and in vivo.
The instant application contains a Sequence Listing which has been submitted in ASCII format via EFS-Web and is hereby incorporated by reference in its entirety. Said ASCII copy, created on Jun. 3, 2019, is named SeqListing_CRTN_098CN and is 1251364 bytes in size. The Sequence Listing is being submitted by EFS Web and is hereby incorporated by reference into the specification.
Genome engineering refers to strategies and techniques for the targeted, specific modification of the genetic information (genome) of living organisms. Genome engineering is an active field of research because of the wide range of possible applications, particularly in the area of human health, e.g., to correct a gene carrying a harmful mutation or to explore the function of a gene. Early technologies developed to insert a transgene into a living cell were often limited by the random nature of the insertion location of the new sequence into the genome. Random insertions into the genome may result in disruption of normal regulation of neighboring genes leading to severe unintended effects. Furthermore, random integration technologies offer little reproducibility, as there is no guarantee that the sequence would be inserted at the same place in two different cells. Common genome engineering strategies, such as ZFNs, TALENs, HEs, and MegaTALs, allow a specific area of the DNA to be modified, thereby increasing precision of the correction or insertion compared to earlier technologies. These platforms offer a greater degree of reproducibility, but limitations remain.
Despite efforts from researchers and medical professionals worldwide to address genetic disorders, and despite the promise of previous genome engineering approaches, there remains a long-felt need to develop safe and effective universal donor cells in support of cell therapy treatments involving regenerative medicine and/or immuno-oncology related indications.
Provided herein, in some embodiments, are cells, methods, and compositions (e.g., nucleic acids, vectors, pharmaceutical compositions) used for the treatment of certain malignancies. The gene editing technology of the present disclosure, in some aspects, is used to engineer immune cell therapies targeting tumor cells that express the CD19, CD70, or BCMA antigens. Surprisingly, the immune cell therapies engineered according to the methods of the present disclosure are capable of reducing tumor volume in vivo, in some embodiments, by at least 80%, relative to untreated controls. Data from animal models, as provided herein, demonstrates that the engineered immune cell therapies, in some embodiments, eliminate the presence of detectable tumor cells just 30 days following in vivo administration, and the effect in these animal models, following a single dose of the cell therapy, persists for at least 66 days. Further, in some embodiments, the engineered immune cell therapies of the present disclosure are capable of increasing the survival rate of subject by at least 50% relative to untreated controls.
Further still, these cells are engineered to block both host-versus-graft disease and graft-versus-host disease, which renders them suitable for use as allogeneic cell transplantation therapeutics.
Moreover, genetic constructs and methods provided herein may be used, in some embodiments, to engineer immune cell populations with gene modification efficiencies high enough that the cell populations do not require purification or enrichment prior to administration in vivo. For example, at least 80% of the immune cells of an exemplary engineered cell population of the present disclosure lack surface expression of both the T cell receptor alpha constant gene and the β2 microglobulin gene, and at least 50% of the immune cells also express the particular chimeric antigen receptor of interest (e.g., targeting CD19, CD70, or BCMA).
Thus, provided herein, in some aspects, are populations of cells comprising engineered T cells that comprise a T cell receptor alpha chain constant region (TRAC) gene disrupted by insertion of a nucleic acid encoding a chimeric antigen receptor (CAR) comprising (i) an ectodomain that comprises an anti-CD19 antibody fragment, (ii) a CD8 transmembrane domain, and (iii) an endodomain that comprises a CD28 or 41BB co-stimulatory domain and optionally a CD3z co-stimulatory domain, and a disrupted beta-2-microglobulin (B2M) gene, wherein at least 70% of the engineered T cells do not express a detectable level of TCR surface protein and do not express a detectable level of B2M surface protein, and/or wherein at least 50% of the engineered T cells express a detectable level of the CAR.
Other aspects provide populations of cells comprising engineered T cells that comprise
a TRAC gene disrupted by insertion of a nucleic acid encoding a CAR comprising (i) an ectodomain that comprises an anti-CD70 antibody fragment, (ii) a CD8 transmembrane domain, and (iii) an endodomain that comprises a CD28 or 41BB co-stimulatory domain and optionally a CD3z co-stimulatory domain, and a disrupted B2M gene, wherein at least 70% of the engineered T cells do not express a detectable level of TCR surface protein and do not express a detectable level of B2M surface protein, and/or wherein at least 50% of the engineered T cells express a detectable level of the CAR.
Yet other aspects provide populations of cells comprising engineered T cells that comprise a TRAC gene disrupted by insertion of a nucleic acid encoding a CAR comprising (i) an ectodomain that comprises an anti-BCMA antibody fragment, (ii) a CD8 transmembrane domain, and (iii) an endodomain that comprises a CD28 or 41BB co-stimulatory domain and optionally a CD3z co-stimulatory domain, and a disrupted B2M gene, wherein at least 70% of the engineered T cells do not express a detectable level of TCR surface protein and do not express a detectable level of B2M surface protein, and/or wherein at least 50% of the engineered T cells express a detectable level of the CAR.
Some aspects of the present disclosure provide methods for producing an engineered T cell suitable for allogenic transplantation, the method comprising (a) delivering to a composition comprising a T cell a RNA-guided nuclease, a gRNA targeting a TRAC gene, a gRNA targeting a B2M gene, and a vector comprising a donor template that comprises a nucleic acid encoding a CAR, wherein the CAR comprises (i) an ectodomain that comprises an anti-CD19 antibody fragment, (ii) a CD8 transmembrane domain, and (iii) an endodomain that comprises a CD28 or 41BB co-stimulatory domain and optionally a CD3z co-stimulatory domain, wherein the nucleic acid encoding the CAR is flanked by left and right homology arms to the TRAC gene locus and (b) producing an engineered T cell suitable for allogeneic transplantation.
Other aspects of the present disclosure provide methods for producing an engineered T cell suitable for allogenic transplantation, the method comprising (a) delivering to a composition comprising a T cell a RNA-guided nuclease, a gRNA targeting a TRAC gene, a gRNA targeting a B2M gene, and a vector comprising a donor template that comprises a nucleic acid encoding a CAR, wherein the CAR comprises (i) an ectodomain that comprises an anti-CD70 antibody fragment, (ii) a CD8 transmembrane domain, and (iii) an endodomain that comprises a CD28 or 41BB co-stimulatory domain and optionally a CD3z co-stimulatory domain, wherein the nucleic acid encoding the CAR is flanked by left and right homology arms to the TRAC gene locus and (b) producing an engineered T cell suitable for allogeneic transplantation.
Yet other aspects of the present disclosure provide methods for producing an engineered T cell suitable for allogenic transplantation, the method comprising (a) delivering to a composition comprising a T cell a RNA-guided nuclease, a gRNA targeting a TRAC gene, a gRNA targeting a B2M gene, and a vector comprising a donor template that comprises a nucleic acid encoding a CAR, wherein the CAR comprises (i) an ectodomain that comprises an anti-BCMA antibody fragment, (ii) a CD8 transmembrane domain, and (iii) an endodomain that comprises a CD28 or 41BB co-stimulatory domain and optionally a CD3z co-stimulatory domain, wherein the nucleic acid encoding the CAR is flanked by left and right homology arms to the TRAC gene locus and (b) producing an engineered T cell suitable for allogeneic transplantation.
In some embodiments, the engineered T cells are unpurified and/or unenriched. In some embodiments, the population of cells is unpurified and/or unenriched.
In some embodiments, the anti-CD19 antibody fragment is an anti-CD19 scFv antibody fragment. In some embodiments, the anti-CD70 antibody fragment is an anti-CD70 scFv antibody fragment. In some embodiments, the anti-BCMA antibody fragment is an anti-BCMA scFv antibody fragment.
In some embodiments, the antibody fragment (e.g., scFv fragment) is humanized. In some embodiments, the humanized anti-CD19 antibody fragment is encoded by the nucleotide sequence of SEQ ID NO: 1333 and/or wherein the humanized anti-CD19 antibody fragment comprises the amino acid sequence of SEQ ID NO: 1334. In some embodiments, the humanized anti-CD19 antibody fragment comprises a heavy chain that comprises the amino acid sequence of SEQ ID NO: 1595. In some embodiments, the humanized anti-CD19 antibody fragment comprises a light chain that comprises the amino acid sequence of SEQ ID NO: 1596. In some embodiments, the humanized anti-CD70 antibody fragment is encoded by the nucleotide sequence of SEQ ID NO: 1475 or 1476 and/or wherein the humanized anti-CD70 antibody fragment comprises the amino acid sequence of SEQ ID NO: 1499 or 1500. In some embodiments, the humanized anti-CD70 antibody fragment comprises a heavy chain that comprises the amino acid sequence of SEQ ID NO: 1592. In some embodiments, the humanized anti-CD70 antibody fragment comprises a light chain that comprises the amino acid sequence of SEQ ID NO: 1593. In some embodiments, the humanized anti-BCMA antibody fragment is encoded by the nucleotide sequence of SEQ ID NO: 1479 or 1485 the humanized anti-BCMA antibody fragment comprises the amino acid sequence of SEQ ID NO: 1503 or 1509. In some embodiments, the humanized anti-BCMA antibody fragment comprises a heavy chain that comprises the amino acid sequence of SEQ ID NO: 1589 or 1524. In some embodiments, the humanized anti-BCMA antibody fragment comprises a light chain that comprises the amino acid sequence of SEQ ID NO: 1590 or 1526.
In some embodiments, the ectodomain of the CAR further comprises a signal peptide, optionally a CD8 signal peptide. In some embodiments, the CAR further comprises a hinge domain, optionally a CD8 hinge domain, located between the anti-CD19 antibody fragment and the CD8 transmembrane domain. In some embodiments, the CAR comprises the following structural arrangement from N-terminus to C-terminus: the ectodomain that comprises an anti-CD19 antibody fragment, a CD8 hinge domain, the CD8 transmembrane domain, and the endodomain that comprises a CD28 or 41BB co-stimulatory domain and a CD3z co-stimulatory domain.
In some embodiments, the CAR (anti-CD19 CAR) is encoded by the nucleotide sequence of SEQ ID NO: 1316 and/or wherein the CAR comprises the amino acid sequence of SEQ ID NO: 1338. In some embodiments, the CAR (anti-CD70 CAR) is encoded by the nucleotide sequence of SEQ ID NO: 1423, 1424, or 1275, and/or wherein the CAR comprises the amino acid sequence of SEQ ID NO: 1449, 1450, or 1276. In some embodiments, the CAR (anti-BCMA CAR) is encoded by the nucleotide sequence of SEQ ID NO: 1427, 1428, 1434, or 1435, and/or wherein the CAR comprises the amino acid sequence of SEQ ID NO: 1453, 1454, 1460, or 1461.
In some embodiments, at least 70% (e.g., at least 75%, at least 80%, at least 85%, at least 90%, or at least 95%) of the engineered T cells do not express a detectable level of TCR and/or B2M surface protein.
In some embodiments, at least 50% (e.g., at least 55%, at least 60%, at least 65%, at least 70%, or at least 75%) of the engineered T cells express a detectable level of the CAR.
In some embodiments, at least 50% (e.g., at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, or at least 80%) of the engineered T cells express a detectable level of the CAR and do not express a detectable level of TCR surface protein or B2M surface protein (e.g., detectable by flow cytometry.
In some embodiments, co-culture of the engineered T cell with CD19+ B cells results in lysis of at least 50% (e.g., at least 55%, at least 60%, at least 65%, at least 70%, or at least 75%) of the CD19+ B cells. In some embodiments, co-culture of the engineered T cell with CD70+ B cells results in lysis of at least 50% (e.g., at least 55%, at least 60%, at least 65%, at least 70%, or at least 75%) of the CD70+ B cells. In some embodiments, co-culture of the engineered T cell with BCMA+ B cells results in lysis of at least 50% (e.g., at least 55%, at least 60%, at least 65%, at least 70%, or at least 75%) of the BCMA+ B cells.
In some embodiments, the engineered T cells produce interferon gamma in the presence of CD19+ cells. In some embodiments, the engineered T cells produce interferon gamma in the presence of CD70+ cells. In some embodiments, the engineered T cells produce interferon gamma in the presence of BCMA+ cells.
In some embodiments, the engineered T cells do not proliferate in the absence of cytokine stimulation, growth factor stimulation, or antigen stimulation.
In some embodiments, the population of cells further comprises a disrupted programmed cell death protein 1 (PD1) gene. In some embodiments, at least 70% (e.g., at least 75%, at least 80%, at least 85%, or at least 90%) of the engineered T cells do not express a detectable level of PD1 surface protein.
In some embodiments, the population of cells further comprises a disrupted cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) gene. In some embodiments, at least 70% (e.g., at least 75%, at least 80%, at least 85%, or at least 90%) of the engineered T cells do not express a detectable level of CTLA-4 surface protein.
In some embodiments, the population of cells further comprises a gRNA targeting the TRAC gene, a gRNA targeting the B2M gene, and Cas9 protein (e.g., a S. pyogenes Cas9 protein).
In some embodiments, the gRNA targeting the TRAC gene comprises the nucleotide sequence of any one of SEQ ID NOs: 83-158. In some embodiments, the gRNA targeting the TRAC gene targets the nucleotide sequence of any one of SEQ ID NOs: 7-82. In some embodiments, the gRNA targeting the B2M gene comprises the nucleotide sequence of any one SEQ ID NOs: 458-506. In some embodiments, the gRNA targeting the B2M gene targets the nucleotide sequence of any one of SEQ ID NOs: 409-457. In some embodiments, the gRNA targeting the TRAC gene comprises the nucleotide sequence of SEQ ID NO: 152. In some embodiments, the gRNA targeting the TRAC gene targets the nucleotide sequence of SEQ ID NO: 76. In some embodiments, the gRNA targeting the B2M gene comprises the nucleotide sequence of SEQ ID NO: 466. In some embodiments, the gRNA targeting the B2M gene targets the nucleotide sequence of SEQ ID NO: 417.
In some embodiments, the population of cells further comprises a gRNA targeting the PD1 gene. In some embodiments, the gRNA targeting the PD1 gene comprises the nucleotide sequence of any one of SEQ ID NOs: 1083-1274 and/or targets the nucleotide sequence of any one of SEQ ID NOs: 891-1082. In some embodiments, the gRNA targeting the PD1 gene comprises the nucleotide sequence of SEQ ID NOs: 1086. In some embodiments, the gRNA targeting the PD1 gene targets the nucleotide sequence of SEQ ID NO: 894.
In some embodiments, the population of cells further comprises a gRNA targeting the CTLA-4 gene. In some embodiments, the gRNA targeting the CTLA-4 gene comprises the nucleotide sequence of any one of SEQ ID NOs: 1289-1298. In some embodiments, the gRNA targeting the CTLA-4 gene targets the nucleotide sequence of any one of SEQ ID NOs: 1278-1287. In some embodiments, the gRNA targeting the CTLA-4 gene comprises the nucleotide sequence of SEQ ID NO: 1292. In some embodiments, the gRNA targeting the CTLA-4 gene targets the nucleotide sequence of SEQ ID NO: 1281.
In some embodiments, engineered T cells of the population of cells comprise a deletion of the nucleotide sequence of SEQ ID NO: 76, relative to unmodified T cells.
In some embodiments, the disrupted B2M gene comprises an insertion of at least one nucleotide base pair and/or a deletion of at least one nucleotide base pair.
In some embodiments, a disrupted B2M gene of the engineered T cells comprises at least one nucleotide sequence selected from the group consisting of: SEQ ID NO: 1560; SEQ ID NO: 1561; SEQ ID NO: 1562; SEQ ID NO: 1563; SEQ ID NO: 1564; and SEQ ID NO: 1565.
In some embodiments, at least 16% of the cells comprise a B2M gene edited to comprise the nucleotide of SEQ ID NO: 1560; at least 6% of the cells comprise a B2M gene edited to comprise the nucleotide of SEQ ID NO: 1561; at least 4% of the cells comprise a B2M gene edited to comprise the nucleotide of SEQ ID NO: 1562; at least 2% of the cells comprise a B2M gene edited to comprise the nucleotide of SEQ ID NO: 1563; at least 2% of the cells comprise a B2M gene edited to comprise the nucleotide of SEQ ID NO: 1564; and at least 2% of the cells comprise a B2M gene edited to comprise the nucleotide of SEQ ID NO: 1565.
In some embodiments, the vector is an adeno-associated viral (AAV) vector. In some embodiments, the AAV vector is an AAV serotype 6 (AAV6) vector. In some embodiments, the AAV vector comprise the nucleotide sequence of any one of SEQ ID NOs: 1354-1357. In some embodiments, the AAV vector comprise the nucleotide sequence of SEQ ID NO: 1354. In some embodiments, the AAV vector comprise the nucleotide sequence of any one of SEQ ID NOs: 1358-1360. In some embodiments, the AAV vector comprise the nucleotide sequence of SEQ ID NO: 1360. In some embodiments, the AAV vector comprise the nucleotide sequence of any one of SEQ ID NOs: 1365, 1366, 1372, or 1373. In some embodiments, the AAV vector comprise the nucleotide sequence of SEQ ID NOs: 1366 or 1373.
In some embodiments, the donor template comprises the nucleotide sequence of any one of claims 1390-1393. In some embodiments, the donor template comprises the nucleotide sequence of SEQ ID NO: 1390. In some embodiments, the donor template comprises the nucleotide sequence of any one of SEQ ID NOs: 1394-1396. In some embodiments, the donor template comprises the nucleotide sequence of SEQ ID NO: 1396. In some embodiments, the donor template comprises the nucleotide sequence of any one of SEQ ID NOs: 1401, 1402, 1408, or 1409. In some embodiments, the donor template comprises the nucleotide sequence of SEQ ID NO: 1402 or 1409. It is understood that the inventions described in this specification are not limited to the examples summarized in this Summary. Various other aspects are described and exemplified herein.
Various aspects of materials and methods for producing genome-edited cells engineered to express a chimeric antigen receptor (CAR) construct on the cell surface, and materials and methods for treating a patient using the genome-edited engineered cells disclosed and described in this specification can be better understood by reference to the accompanying figures, in which:
SEQ ID NOs: 1-3 are sgRNA backbone sequences (Table 1).
SEQ ID NOs: 4-6 are homing endonuclease sequences.
SEQ ID NOs: 7-82 are TRAC gene target sequences (Table 4).
SEQ ID NOs: 83-158 are gRNA spacer sequences targeting the TRAC gene (Table 4).
SEQ ID NOs: 159-283 are CD3E gene target sequences (Table 5).
SEQ ID NOs: 384-408 are gRNA spacer sequences targeting the CD3E gene (Table 5).
SEQ ID NOs: 409-457 are B2M gene target sequences (Table 6).
SEQ ID NOs: 458-506 are gRNA spacer sequences targeting the B2M gene (Table 6).
SEQ ID NOs: 507-698 are CIITA gene target sequences (Table 7).
SEQ ID NOs: 699-890 are gRNA spacer sequences targeting the CIITA gene (Table 7).
SEQ ID NOs: 891-1082 are PD1 gene target sequences (Table 8).
SEQ ID NOs: 1083-1274 are gRNA spacer sequences targeting the PD1 gene (Table 8).
SEQ ID NO: 1275 is the nucleotide sequence for the CAR of CTX-145b (Table 36).
SEQ ID NO: 1276 is the amino acid sequence for the CAR of CTX-145b (Table 36).
SEQ ID NOs: 1277-1287 are CTLA-4 gene target sequences (Table 10).
SEQ ID NOs: 1288-1298 are gRNA spacer sequences targeting the CTLA-4 gene (Table 10).
SEQ ID NO: 1299 is a TRAC gene target sequence (Table 11).
SEQ ID NO: 1300 is a PD1 gene target sequence (Table 11).
SEQ ID NOs: 1301 and 1302 are AAVS1 target sequences (Table 11).
SEQ ID NOs: 1303 and 1305 are CD52 target sequences (Table 11).
SEQ ID NOs: 1305-1307 are RFX5 target sequences (Table 11).
SEQ ID NO: 1308 is a gRNA spacer sequence targeting the AAVS1 gene.
SEQ ID NOs: 1309-1311 are gRNA spacer sequences targeting the RFX5 gene.
SEQ ID NO: 1312 is a gRNA spacer sequence targeting the CD52 gene.
SEQ ID NOs: 1313-1338 are donor template component sequences for generating the anti-CD19 CAR T cells (see Table 12).
SEQ ID NO: 1339 is the nucleotide sequence for the 4-1BB co-stimulatory domain.
SEQ ID NO: 1340 is the amino acid sequence for the 4-1BB co-stimulatory domain.
SEQ ID NO: 1341 is a linker sequence.
SEQ ID NOs: 1342-1347 are chemically-modified and unmodified sgRNA sequences for B2M, TRAC, and AAVS1 (see Table 32).
SEQ ID NOs: 1348-1386 are rAAV sequences of various donor templates (see Table 34).
SEQ ID NOs: 1387-1422 are left homology arm (LHA) to right homology arm (RHA) sequences of various donor templates (see Table 35).
SEQ ID NOs: 1423-1448 are CAR nucleotide sequences of donor templates of the present disclosure (see Table 36).
SEQ ID NOs: 1449-1474 are CAR amino acid sequences encoded by donor templates of the present disclosure (see Table 37).
SEQ ID NOs: 1475-1498 are scFv nucleic acid sequences of CARs of the present disclosure (see Table 38).
SEQ ID NOs: 1499-1522 are scFv amino acid sequences encoded by CARs of the present disclosure (see Table 39).
SEQ ID NOs: 1523-1531 are anti-BCMA light chain and heavy chain sequences (see Table 39).
SEQ ID NOs: 1532-1553 are plasmid sequences of the present disclosure.
SEQ ID NOs: 1554-1559 are primer sequences used in a ddPCR assay (see Table 25).
SEQ ID NOs: 1560-1565 are gene edited sequences in the B2M gene (Table 12.3).
SEQ ID NOs: 1566-1573 are gene edited sequences in the TRAC gene (Table 12.4).
SEQ ID NOs: 1574 and 1575 are chemically-modified and unmodified sgRNA sequences for PD1 (see Table 32).
SEQ ID NOs: 1576-1577 are ITR sequences (Table 12).
SEQ ID NOs: 1578-1582 are nucleotide sequences for the left homology arms and right homology arms used for CTX-139.1-CTX-139.3 (Table 12).
SEQ ID NO: 1586 is a CD8 signal peptide sequence (Table 12).
SEQ ID NOs: 1587 and 1588 are chemically-modified and unmodified sgRNA sequences for TRAC (EXON1_T7) (see Table 32).
SEQ ID NOs: 1589-1597 are the heavy chain, light chain and linker sequences for example anti-BCMA, anti-CD70, and anti-CD19 scFv molecules (Table 39).
SEQ ID NO: 1598 is the leader peptide sequence for the anti-CD19 CAR (Table 12).
SEQ ID NO: 1599 is the CD8a transmembrane sequence without the linker (Table 12).
SEQ ID NO: 1600 is the CD8a peptide sequence.
SEQ ID NO: 1601 is the CD28 co-stimulatory domain peptide sequence.
SEQ ID NO: 1602 is the CD3-zeta co-stimulatory domain peptide sequence.
Therapeutic Approach
CRISPR edited cells such as, for example, CRISPR edited T cells, can have therapeutic uses in multiple disease states. By way of non-limiting example, the nucleic acids, vectors, cells, methods, and other materials provided in the present disclosure are useful in treating cancer, inflammatory disease and/or autoimmune disease.
Gene editing provides an important improvement over existing or potential therapies, such as introduction of target gene expression cassettes through lentivirus delivery and integration. Gene editing to modulate gene activity and/or expression has the advantage of precise genome modification and lower adverse effects, and for restoration of correct expression levels and temporal control.
The materials and methods provided herein are useful in modulating the activity of a target gene. For example, the target gene can be a gene sequence associated with host versus graft response, a gene sequence associated with graft versus host response, a gene sequence encoding an immune suppressor (e.g.: checkpoint inhibitor), or any combination thereof.
The target gene can be a gene sequence associated with a graft versus host response that is selected from the group consisting of TRAC, CD3-episolon (CD3ε), and combinations thereof. TRAC and CD3ε are components of the T cell receptor (TCR). Disrupting them by gene editing will take away the ability of the T cells to cause graft versus host disease.
The target gene can be a gene sequence associated with a host versus graft response that is selected from the group consisting of B2M, CIITA, RFX5, and combinations thereof. B2M is a common (invariant) component of MHC I complexes. Its ablation by gene editing will prevent host versus therapeutic allogeneic T cells responses leading to increased allogeneic T cell persistence. CIITA and RFX5 are components of a transcription regulatory complex that is required for the expression of MHC II genes. Distrupting them by gene editing will prevent host versus therapeutic allogeneic T cells responses leading to increased allogeneic T cell persistence.
The target gene can be a gene sequence encoding a checkpoint inhibitor that is selected from the group consisting of PD1, CTLA-4, and combinations thereof. PDCD1 (PD1) and CTLA4 are immune checkpoint molecules that are upregulated in activated T cells and serve to dampen or stop T cell responses. Disrupting them by gene editing could lead to more persistent and/or potent therapeutic T cell responses.
The target gene can be a sequence associated with pharmacological modulation of a cell. For example, CD52 is the target of the lympho-depleting therapeutic antibody alemtuzumab. Disruption of CD52 by gene editing will make therapeutic T cells resistant to alemtuzumab which may be useful in certain cancer settings.
Deletion of the above genes can be achieved with guide RNAs that have chosen from small (<5) to medium scale (>50) screens. The examples provided herein further illustrate the selection of various target regions and gRNAs useful for the creation of indels that result in disruption of a target gene, for example, reduction or elimination of gene expression and or function. The examples provided herein further illustrate the selection of various target regions and gRNAs useful for the creation of DSBs that facilitate insertion of a donor template into the genone. Examples of target genes associated with graft versus host disease, host versus graph disease and/or immune suppression. In some aspects, the guide RNA is a gRNA comprising a sequence disclosed herein.
The methods use chimeric antigen receptor constructs (CARs) that are inserted into genomic loci by using guide RNA/Cas9 to induce a double stranded break that is repaired by HDR using an AAV6 delivered donor template with homology around the cut site.
A chimeric antigen receptor (CAR) is an artificially constructed hybrid protein or polypeptide containing an antigen binding domain of an antibody (e.g., a single chain variable fragment (scFv)) linked to T-cell signaling or T-cell activation domains. CARs have the ability to redirect T-cell specificity and reactivity toward a selected target in a non-MHC-restricted manner, exploiting the antigen-binding properties of monoclonal antibodies. The non-MHC-restricted antigen recognition gives T-cells expressing CARs the ability to recognize an antigen independent of antigen processing, thus bypassing a major mechanism of tumor escape. Moreover, when expressed in T-cells, CARs advantageously do not dimerize with endogenous T-cell receptor (TCR) alpha and beta chains.
The materials and methods provided herein knock-in a nucleic acid encoding a chimeric antigen receptor (CAR) in or near a locus of a target gene by permanently deleting at least a portion of the target gene and inserting a nucleic acid encoding the CAR. The CARs used in the materials and methods provided herein include (i) an ectodomain comprising an antigen recognition region; (ii) a transmembrane domain, and (iii) an endodomain comprising at least one costimulatory domain. The nucleic acid encoding the CAR can also include a promoter, one or more gene regulatory elements, or a combination thereof. For example, the gene regulatory element can be an enhancer sequence, an intron sequence, a polyadenylation (poly(A)) sequence, and/or combinations thereof.
The donor for insertion by homology directed repair (HDR) contains the corrected sequence with small or large flanking homology arms to allow for annealing. HDR is essentially an error-free mechanism that uses a supplied homologous DNA sequence as a template during DSB repair. The rate of homology directed repair (HDR) is a function of the distance between the mutation and the cut site so choosing overlapping or nearby target sites is important. Templates can include extra sequences flanked by the homologous regions or can contain a sequence that differs from the genomic sequence, thus allowing sequence editing.
The target gene can be associated with an immune response in a subject, wherein disrupting expression of the target gene will modulate the immune response. For example, creating small insertions or deletions in the target gene, and/or permanently deleting at least a portion of the target gene and/or inserting an exogenous sequence into the target gene can disrupt expression of target gene. The target gene sequence can be associated with host versus graft response, a gene sequence associated with graft versus host response, a gene sequence encoding a checkpoint inhibitor, and/or any combination thereof.
Target genes associated with a graft versus host (GVH) response include, for example, TRAC, CD3-episolon (CD3ε), and combinations thereof. Permanently deleting at least a portion of these genes, creating small insertions or deletions in these genes, and/or inserting the nucleic acid encoding the CAR can reduce GVH response in a subject. The reduction in GVH response can be partial or complete.
Target genes associated with a host versus graft (HVG) response include, for example, B2M, CIITA, RFX5, and combinations thereof. Permanently deleting at least a portion of these genes, creating small insertions or deletions in these genes, and/or inserting the nucleic acid encoding the CAR can reduce HVG response in a subject. The reduction in HVG response can be partial or complete.
Target genes associated with immune suppression include, for example, checkpoint inhibitors such PD1, CTLA-4, and combinations thereof. Permanently deleting at least a portion of these genes, creating small insertions or deletions in these genes, and/or inserting the nucleic acid encoding the CAR can reduce immune suppression in a subject. The reduction in immune suppression can be partial or complete.
The target gene can be associated with pharmacological modulation of a cell, wherein disrupting expression of the target gene will modulate one or pharmacological characteristics of the cell.
Target genes associated with pharmacological modulation of a cell include, for example, CD52. Permanently deleting at least a portion of these genes, creating small insertions or deletions in these genes, and/or inserting the nucleic acid encoding the CAR can positively or negatively modulate one or pharmacological characteristics of the cell. The modulation of one or pharmacological characteristics of the cell can be partial or complete. For example, permanently deleting at least a portion of these genes and inserting the nucleic acid encoding the CAR can positively impact or otherwise allow the CAR T cells to survive. Alternatively, permanently deleting at least a portion of these genes and inserting the nucleic acid encoding the CAR can negatively impact or otherwise kill the CAR T cells.
The donor templates used in the nucleic acid constructs encoding the CAR can also include a minigene or cDNA. For example, the minigene or cDNA can comprise a gene sequence associated with pharmacological modulation of a cell. The gene sequence can encode Her2.
A Her2 gene sequence can be permanently inserted at a different locus in the target gene or at a different locus in the genome from where the nucleic acid encoding the CAR construct is inserted.
Provided herein are methods to DSBs that induce small insertions or deletions in a target gene resulting in the disruption (e.g.: reduction or elimination of gene expression and/or function) of the target gene.
Also, provided herein are methods to create DBSs and/or permanently delete within or near the target gene and to insert a nucleic acid construct encoding a CAR construct in the gene by inducing a double stranded break with Cas9 and a sgRNA in a target sequence (or a pair of double stranded breaks using two appropriate sgRNAs), and to provide a donor DNA template to induce Homology-Directed Repair (HDR). In some embodiments, the donor DNA template can be a short single stranded oligonucleotide, a short double stranded oligonucleotide, a long single or double stranded DNA molecule. These methods use gRNAs and donor DNA molecules for each target. In some embodiments, the donor DNA is single or double stranded DNA having homologous arms to the corresponding region. In some embodiments, the homologous arms are directed to the nuclease-targeted region of a gene selected from the group consisting of TRAC (chr14:22278151-22553663), CD3ε (chr11:118301545-118319175), B2M (chr15:44708477-44721877), CIITA (chr16:10874198-10935281), RFX5 (chr1:151337640-151350251), PD1 (chr2:241846881-241861908), CTLA-4 (chr2:203864786-203876960), CD52 (chr1:26314957-26323523), PPP1R12C (chr19:55087913-55120559), and combinations thereof.
Provided herein are methods to knock-in target cDNA or a minigene (comprised of one or more exons and introns or natural or synthetic introns) into the locus of the corresponding gene. These methods use a pair of sgRNA targeting the first exon and/or the first intron of the target gene. In some embodiments, the donor DNA is single or double stranded DNA having homologous arms to the nuclease-targeted region of a Her2 gene selected.
Provided herein are cellular methods (e.g., ex vivo or in vivo) methods for using genome engineering tools to create permanent changes to the genome by: 1) creating DSBs to induce small insertions, deletions or mutations within or near a target gene, 2) deleting within or near the target gene or other DNA sequences that encode regulatory elements of the target gene and inserting, by HDR, a nucleic acid encoding a knock-in CAR construct within or near the target gene or other DNA sequences that encode regulatory elements of the target gene, or 3) creating DSBs within or near the target gene and inserting a nucleic acid construct within or near the target gene by HDR. Such methods use endonucleases, such as CRISPR-associated (Cas9, Cpf1 and the like) nucleases, to permanently delete, insert, edit, correct, or replace one or more or exons or portions thereof (i.e., mutations within or near coding and/or splicing sequences) or insert in the genomic locus of the target gene or other DNA sequences that encode regulatory elements of the target gene. In this way, the examples set forth in the present disclosure restore the reading frame or the wild-type sequence of, or otherwise correct the gene with a single treatment (rather than deliver potential therapies for the lifetime of the patient).
Provided herein are methods for treating a patient with a medical condition. An aspect of such method is an ex vivo cell-based therapy. For example, peripheral blood mononuclear cells are isolated from the patient. Next, the chromosomal DNA of these cells is edited using the materials and methods described herein. Finally, the genome-edited cells are implanted into the patient.
Also provided herein are methods for reducing volume of a tumor in a subject, comprising administering to the subject a dose of a pharmaceutical composition comprising a population of cells (e.g., engineered T cells) of the present disclosure and reducing the volume of the tumor in the subject by at least 50% (e.g., at least 55%, at least 60%, at least 65%, at least 70%, or at least 75%) relative to control (e.g., an untreated subject).
Further provided herein are methods for increasing survival rate in a subject, comprising administering to the subject a dose of a pharmaceutical composition comprising a population of cells (e.g., engineered T cells) of the present disclosure and increasing the survival rate in the subject by at least 50% % (e.g., at least 55%, at least 60%, at least 65%, at least 70%, or at least 75%) relative to control (e.g., an untreated subject).
In some embodiments, the composition comprises at 1×105 to 1×106 cells. In some embodiments, the pharmaceutical composition comprises at 1×105 to 2×106 cells. For example, the composition may comprise 1×105, 2×105, 3×105, 4×105, 5×105, 6×105, 7×105, 8×105, 9×105, 1×106, or 2×106. In some embodiments, the pharmaceutical composition comprises 1×105 to 5×105 cells, 5×105 to 1×106 cells, or 5×105 to 1.5×106 cells.
Another aspect of an ex vivo cell-based therapy may include, for example, isolating T cells from a donor. Next, the chromosomal DNA of these cells are edited using the materials and methods described herein. Finally, the genome-edited cells are implanted into a patient.
In certain aspects, T cells are isolated from more than one donor. These cells are edited using the materials and methods described herein. Finally, the genome-edited cells are implanted into a patient.
One advantage of an ex vivo cell therapy approach is the ability to conduct a comprehensive analysis of the therapeutic prior to administration. Nuclease-based therapeutics have some level of off-target effects. Performing gene correction ex vivo allows one to fully characterize the corrected cell population prior to implantation. The present disclosure includes sequencing the entire genome of the corrected cells to ensure that the off-target effects, if any, are in genomic locations associated with minimal risk to the patient. Furthermore, populations of specific cells, including clonal populations, can be isolated prior to implantation.
Another embodiment of such methods also includes an in vivo based therapy. In this method, chromosomal DNA of the cells in the patient is edited using the materials and methods described herein. In some embodiments, the cells are T cells, such as CD4+ T-cells, CD8+ T-cells, or a combination thereof.
Also provided herein is a cellular method for editing the target gene in a cell by genome editing. For example, a cell is isolated from a patient or animal. Then, the chromosomal DNA of the cell is edited using the materials and methods described herein.
The methods provided herein, in some embodiments, involve one or a combination of the following: 1) creating indels within or near the target gene or other DNA sequences that encode regulatory elements of the target gene, 2) deleting within or near the target gene or other DNA sequences that encode regulatory elements of the target gene, 3) inserting, by HDR or NHEJ, a nucleic acid encoding a knock-in CAR construct within or near the target gene or other DNA sequences that encode regulatory elements of the target gene, or 4) deletion of at least a portion of the target gene and/or knocking-in target cDNA or a minigene (comprised of one or more exons or introns or natural or synthetic introns) or introducing exogenous target DNA or cDNA sequence or a fragment thereof into the locus of the gene.
The knock-in strategies utilize a donor DNA template in Homology-Directed Repair (HDR) or Non-Homologous End Joining (NHEJ). HDR in either strategy may be accomplished by making one or more single-stranded breaks (SSBs) or double-stranded breaks (DSBs) at specific sites in the genome by using one or more endonucleases.
For example, the knock-in strategy involves knocking-in target cDNA or a minigene (comprised of, natural or synthetic enhancer and promoter, one or more exons, and natural or synthetic introns, and natural or synthetic 3′UTR and polyadenylation signal) into the locus of the gene using a gRNA (e.g., crRNA+tracrRNA, or sgRNA) or a pair of sgRNAs targeting upstream of or in the first or other exon and/or intron of the target gene. The donor DNA can be a single or double stranded DNA having homologous arms to the nuclease-targeted region of the target gene. For example, the donor DNA can be a single or double stranded DNA having homologous arms to the nuclease-targeted region of a gene selected from the group consisting of TRAC (chr14:22278151-22553663), CD3ε (chr11:118301545-118319175), B2M (chr15:44708477-44721877), CIITA (chr16:10874198-10935281), RFX5 (chr1:151337640-151350251), PD1 (chr2:241846881-241861908), CTLA-4 (chr2:203864786-203876960), CD52 (chr1:26314957-26323523), PPP1R12C (chr19:55087913-55120559), and combinations thereof.
For example, the deletion strategy involves, in some aspects, deleting one or more introns, exons, regulatory regions, of the target gene, partial segments of the target gene or the entire target gene sequence using one or more endonucleases and one or more gRNAs or sgRNAs.
As another example, the deletion strategy involves, in some aspects, deleting one or more nucleic acids, of one or more target genes, resulting in small insertions or deletions (indels) using one or more endonucleases and one or more gRNAs or sgRNAs.
In addition to the above genome editing strategies, another example editing strategy involves modulating expression, function, or activity of a target gene by editing in the regulatory sequence.
In addition to the editing options listed above, Cas9 or similar proteins can be used to target effector domains to the same target sites that may be identified for editing, or additional target sites within range of the effector domain. A range of chromatin modifying enzymes, methylases or demethlyases may be used to alter expression of the target gene. One possibility is increasing the expression of the target protein if the mutation leads to lower activity. These types of epigenetic regulation have some advantages, particularly as they are limited in possible off-target effects.
A number of types of genomic target sites are present in addition to mutations in the coding and splicing sequences.
The regulation of transcription and translation implicates a number of different classes of sites that interact with cellular proteins or nucleotides. Often the DNA binding sites of transcription factors or other proteins can be targeted for mutation or deletion to study the role of the site, though they can also be targeted to change gene expression. Sites can be added through non-homologous end joining NHEJ or direct genome editing by homology directed repair (HDR). Increased use of genome sequencing, RNA expression and genome-wide studies of transcription factor binding have increased the ability to identify how the sites lead to developmental or temporal gene regulation. These control systems may be direct or may involve extensive cooperative regulation that can require the integration of activities from multiple enhancers. Transcription factors typically bind 6-12 bp-long degenerate DNA sequences. The low level of specificity provided by individual sites suggests that complex interactions and rules are involved in binding and the functional outcome. Binding sites with less degeneracy may provide simpler means of regulation. Artificial transcription factors can be designed to specify longer sequences that have less similar sequences in the genome and have lower potential for off-target cleavage. Any of these types of binding sites can be mutated, deleted or even created to enable changes in gene regulation or expression (Canver, M. C. et al., Nature (2015)).
Another class of gene regulatory regions having these features is microRNA (miRNA) binding sites. miRNAs are non-coding RNAs that play key roles in posttranscriptional gene regulation. miRNA may regulate the expression of 30% of all mammalian protein-encoding genes. Specific and potent gene silencing by double stranded RNA (RNAi) was discovered, plus additional small noncoding RNA (Canver, M. C. et al., Nature (2015)). The largest class of noncoding RNAs important for gene silencing are miRNAs. In mammals, miRNAs are first transcribed as long RNA transcripts, which can be separate transcriptional units, part of protein introns, or other transcripts. The long transcripts are called primary miRNA (pri-miRNA) that include imperfectly base-paired hairpin structures. These pri-miRNA are cleaved into one or more shorter precursor miRNAs (pre-miRNAs) by Microprocessor, a protein complex in the nucleus, involving Drosha.
Pre-miRNAs are short stem loops ˜70 nucleotides in length with a 2-nucleotide 3′-overhang that are exported, into the mature 19-25 nucleotide miRNA:miRNA* duplexes. The miRNA strand with lower base pairing stability (the guide strand) can be loaded onto the RNA-induced silencing complex (RISC). The passenger guide strand (marked with *), may be functional, but is usually degraded. The mature miRNA tethers RISC to partly complementary sequence motifs in target mRNAs predominantly found within the 3′ untranslated regions (UTRs) and induces posttranscriptional gene silencing (Bartel, D. P. Cell 136, 215-233 (2009); Saj, A. & Lai, E. C. Curr Opin Genet Dev 21, 504-510 (2011)).
miRNAs are important in development, differentiation, cell cycle and growth control, and in virtually all biological pathways in mammals and other multicellular organisms. miRNAs are also involved in cell cycle control, apoptosis and stem cell differentiation, hematopoiesis, hypoxia, muscle development, neurogenesis, insulin secretion, cholesterol metabolism, aging, viral replication and immune responses.
A single miRNA can target hundreds of different mRNA transcripts, while an individual transcript can be targeted by many different miRNAs. More than 28645 microRNAs have been annotated in the latest release of miRBase (v.21). Some miRNAs are encoded by multiple loci, some of which are expressed from tandemly co-transcribed clusters. The features allow for complex regulatory networks with multiple pathways and feedback controls. miRNAs are integral parts of these feedback and regulatory circuits and can help regulate gene expression by keeping protein production within limits (Herranz, H. & Cohen, S. M. Genes Dev 24, 1339-1344 (2010); Posadas, D. M. & Carthew, R. W. Curr Opin Genet Dev 27, 1-6 (2014)).
miRNAs are also important in a large number of human diseases that are associated with abnormal miRNA expression. This association underscores the importance of the miRNA regulatory pathway. Recent miRNA deletion studies have linked miRNA with regulation of the immune responses (Stern-Ginossar, N. et al., Science 317, 376-381 (2007)).
miRNAs also have a strong link to cancer and may play a role in different types of cancer. miRNAs have been found to be downregulated in a number of tumors. miRNAs are important in the regulation of key cancer-related pathways, such as cell cycle control and the DNA damage response, and are therefore used in diagnosis and are being targeted clinically. MicroRNAs delicately regulate the balance of angiogenesis, such that experiments depleting all microRNAs suppresses tumor angiogenesis (Chen, S. et al., Genes Dev 28, 1054-1067 (2014)).
As has been shown for protein coding genes, miRNA genes are also subject to epigenetic changes occurring with cancer. Many miRNA loci are associated with CpG islands increasing their opportunity for regulation by DNA methylation (Weber, B., Stresemann, C., Brueckner, B. & Lyko, F. Cell Cycle 6, 1001-1005 (2007)). The majority of studies have used treatment with chromatin remodeling drugs to reveal epigenetically silenced miRNAs.
In addition to their role in RNA silencing, miRNA can also activate translation (Posadas, D. M. & Carthew, R. W. Curr Opin Genet Dev 27, 1-6 (2014)). Knocking out these sites may lead to decreased expression of the targeted gene, while introducing these sites may increase expression.
Individual miRNAs can be knocked out most effectively by mutating the seed sequence (bases 2-8 of the microRNA), which is important for binding specificity. Cleavage in this region, followed by mis-repair by NHEJ can effectively abolish miRNA function by blocking binding to target sites. miRNA could also be inhibited by specific targeting of the special loop region adjacent to the palindromic sequence. Catalytically inactive Cas9 can also be used to inhibit shRNA expression (Zhao, Y. et al., Sci Rep 4, 3943 (2014)). In addition to targeting the miRNA, the binding sites can also be targeted and mutated to prevent the silencing by miRNA.
Chimeric Antigen Receptor (CAR) T Cells
A chimeric antigen receptor refers to an artificial immune cell receptor that is engineered to recognize and bind to an antigen expressed by tumor cells. Generally, a CAR is designed for a T cell and is a chimera of a signaling domain of the T-cell receptor (TcR) complex and an antigen-recognizing domain (e.g., a single chain fragment (scFv) of an antibody or other antibody fragment) (Enblad et al., Human Gene Therapy. 2015; 26(8):498-505). A T cell that expresses a CAR is referred to as a CAR T cell. CARs have the ability to redirect T-cell specificity and reactivity toward a selected target in a non-MHC-restricted manner. The non-MHC-restricted antigen recognition gives T-cells expressing CARs the ability to recognize an antigen independent of antigen processing, thus bypassing a major mechanism of tumor escape. Moreover, when expressed in T-cells, CARs advantageously do not dimerize with endogenous T-cell receptor (TCR) alpha and beta chains.
There are four generations of CARs, each of which contains different components. First generation CARs join an antibody-derived scFv to the CD3zeta (ζ or z) intracellular signaling domain of the T-cell receptor through hinge and transmembrane domains. Second generation CARs incorporate an additional domain, e.g., CD28, 4-1BB (41BB), or ICOS, to supply a costimulatory signal. Third-generation CARs contain two costimulatory domains fused with the TcR CD3-ζ chain. Third-generation costimulatory domains may include, e.g., a combination of CD3z, CD27, CD28, 4-1BB, ICOS, or OX40. CARs, in some embodiments, contain an ectodomain (e.g., CD3ζ), commonly derived from a single chain variable fragment (scFv), a hinge, a transmembrane domain, and an endodomain with one (first generation), two (second generation), or three (third generation) signaling domains derived from CD3Z and/or co-stimulatory molecules (Maude et al., Blood. 2015; 125(26):4017-4023; Kakarla and Gottschalk, Cancer J. 2014; 20(2):151-155).
CARs typically differ in their functional properties. The CD3ζ signaling domain of the T-cell receptor, when engaged, will activate and induce proliferation of T-cells but can lead to anergy (a lack of reaction by the body's defense mechanisms, resulting in direct induction of peripheral lymphocyte tolerance). Lymphocytes are considered anergic when they fail to respond to a specific antigen. The addition of a costimulatory domain in second-generation CARs improved replicative capacity and persistence of modified T-cells. Similar antitumor effects are observed in vitro with CD28 or 4-1BB CARs, but preclinical in vivo studies suggest that 4-1BB CARs may produce superior proliferation and/or persistence. Clinical trials suggest that both of these second-generation CARs are capable of inducing substantial T-cell proliferation in vivo, but CARs containing the 4-1BB costimulatory domain appear to persist longer. Third generation CARs combine multiple signaling domains (costimulatory) to augment potency.
In some embodiments, a chimeric antigen receptor is a first generation CAR. In other embodiments, a chimeric antigen receptor is a second generation CAR. In yet other embodiments, a chimeric antigen receptor is a third generation CAR.
A CAR, in some embodiments, comprises an extracellular (ecto) domain comprising an antigen binding domain (e.g., an antibody, such as an scFv), a transmembrane domain, and a cytoplasmic (endo) domain.
Ectodomain. The ectodomain is the region of the CAR that is exposed to the extracellular fluid and, in some embodiments, includes an antigen binding domain, and optionally a signal peptide, a spacer domain, and/or a hinge domain. In some embodiments, the antigen binding domain is a single-chain variable fragment (scFv) that include the light and heavy chains of immunoglobins connected with a short linker peptide (e.g., any one of SEQ ID NO: 1591, 1594, or 1597). The linker, in some embodiments, includes hydrophilic residues with stretches of glycine and serine for flexibility as well as stretches of glutamate and lysine for added solubility. A single-chain variable fragment (scFv) is not actually a fragment of an antibody, but instead is a fusion protein of the variable regions of the heavy (VH) and light chains (VL) of immunoglobulins, connected with a short linker peptide of ten to about 25 amino acids. The linker is usually rich in glycine for flexibility, as well as serine or threonine for solubility, and can either connect the N-terminus of the VH with the C-terminus of the VL, or vice versa. This protein retains the specificity of the original immunoglobulin, despite removal of the constant regions and the introduction of the linker. In some embodiments, the scFv of the present disclosure is humanized. In other embodiments, the scFv is fully human. In yet other embodiments, the scFv is a chimera (e.g., of mouse and human sequence). In some embodiments, the scFv is an anti-CD70 scFv (binds specifically to CD70). Non-limiting examples of anti-CD70 scFv proteins and heavy and/or light chains that may be used as provided herein include those that comprise any one of SEQ ID NOs: 1499 (scFv), 1500 (scFV), 1592 (heavy chain), or 1593 (light chain).
The signal peptide can enhance the antigen specificity of CAR binding. Signal peptides can be derived from antibodies, such as, but not limited to, CD8, as well as epitope tags such as, but not limited to, GST or FLAG. Examples of signal peptides include MLLLVTSLLLCELPHPAFLLIP (SEQ ID NO: 1598) and MALPVTALLLPLALLLHAARP (SEQ ID NO: 1586). Other signal peptides may be used.
In some embodiments, a spacer domain or hinge domain is located between an extracellular domain (comprising the antigen binding domain) and a transmembrane domain of a CAR, or between a cytoplasmic domain and a transmembrane domain of the CAR. A spacer domain is any oligopeptide or polypeptide that functions to link the transmembrane domain to the extracellular domain and/or the cytoplasmic domain in the polypeptide chain. A hinge domain is any oligopeptide or polypeptide that functions to provide flexibility to the CAR, or domains thereof, or to prevent steric hindrance of the CAR, or domains thereof. In some embodiments, a spacer domain or a hinge domain may comprise up to 300 amino acids (e.g., 10 to 100 amino acids, or 5 to 20 amino acids). In some embodiments, one or more spacer domain(s) may be included in other regions of a CAR. In some embodiments, the hinge domain is a CD8 hinge domain. Other hinge domains may be used.
Transmembrane Domain. The transmembrane domain is a hydrophobic alpha helix that spans the membrane. The transmembrane domain provides stability of the CAR. In some embodiments, the transmembrane domain of a CAR as provided herein is a CD8 transmembrane domain. In other embodiments, the transmembrane domain is a CD28 transmembrane domain. In yet other embodiments, the transmembrane domain is a chimera of a CD8 and CD28 transmembrane domain. Other transmembrane domains may be used as provided herein. In some embodiments, the transmembrane domain is a CD8a transmembrane domain, optionally including a 5′ linker.
Endodomain. The endodomain is the functional end of the receptor. Following antigen recognition, receptors cluster and a signal is transmitted to the cell. The most commonly used endodomain component is CD3-zeta, which contains three (3) ITAMs. This transmits an activation signal to the T cell after the antigen is bound. In many cases, CD3-zeta may not provide a fully competent activation signal and, thus, a co-stimulatory signaling is used. For example, CD28 and/or 4-1BB may be used with CD3-zeta (CD3ζ) to transmit a proliferative/survival signal. Thus, in some embodiments, the co-stimulatory molecule of a CAR as provided herein is a CD28 co-stimulatory molecule. In other embodiments, the co-stimulatory molecule is a 4-1BB co-stimulatory molecule. In some embodiments, a CAR includes CD3ζ and CD28. In other embodiments, a CAR includes CD3-zeta and 4-1BB. In still other embodiments, a CAR includes CD3ζ, CD28, and 4-1BB. Non-limiting examples of co-stimulatory molecules that may be used herein include those encoded by the nucleotide sequence of SEQ ID NO: 1377 (CD3-zeta), SEQ ID NO 1336 (CD28), and/or SEQ ID NO: 1339 (4-1BB).
Human Cells
As described and illustrated herein, the principal targets for gene editing are human cells. For example, primary human T cells, CD4+ and/or CD8+, can be edited. They can be isolated from peripheral blood mononuclear cell isolations.
Gene editing can be verified by alterations in target surface protein expression as well as analysis of DNA by PCR and/or sequencing.
Edited cells can have a selective advantage. MHC-I and/or MHC-II as well as PDCD1 or CTLA4 knockout T cells can persist longer in patients.
Edited cells can be assayed for off-target gene editing as well as translocations. They can also be tested for the ability to grow in cytokine free media. If edited cells display low off-target activity and minimal translocations, as well as have the inability to grow in cytokine free media, they will be deemed safe.
Primary human T cells can be isolated from peripheral blood mononuclear cells (PBMC) isolated from leukopaks. T cells can be expanded from PBMC by treatment with anti-CD3/CD28 antibody-coupled nanoparticles or beads. Activated T cells can be electroporated with RNP(s) containing Cas9 complexed to sgRNA. Cells can then be treated with AAV6 virus containing donor template DNA when HDR is needed, for example, for insertion of a nucleic acid encoding a CAR construct. Cells can then be expanded for 1-2 weeks in liquid culture. When TCR negative cells are required, edited cells can be selected for by antibody/column based methods, such as, for example, MACS.
By performing gene editing in allogeneic cells that are derived from a donor who does not have or is not suspected of having a medical condition to be treated, it is possible to generate cells that can be safely re-introduced into the patient, and effectively give rise to a population of cells that are effective in ameliorating one or more clinical conditions associated with the patient's disease.
By performing gene editing in autologous cells that are derived from and therefore already completely immunologically matched with the patient in need, it is possible to generate cells that can be safely re-introduced into the patient, and effectively give rise to a population of cells that are effective in ameliorating one or more clinical conditions associated with the patient's disease.
Progenitor cells (also referred to as stem cells herein) are capable of both proliferation and giving rise to more progenitor cells, these in turn having the ability to generate a large number of mother cells that can in turn give rise to differentiated or differentiable daughter cells. The daughter cells themselves can be induced to proliferate and produce progeny that subsequently differentiate into one or more mature cell types, while also retaining one or more cells with parental developmental potential. The term “stem cell” refers then, to a cell with the capacity or potential, under particular circumstances, to differentiate to a more specialized or differentiated phenotype, and which retains the capacity, under certain circumstances, to proliferate without substantially differentiating. In one aspect, the term progenitor or stem cell refers to a generalized mother cell whose descendants (progeny) specialize, often in different directions, by differentiation, e.g., by acquiring completely individual characters, as occurs in progressive diversification of embryonic cells and tissues. Cellular differentiation is a complex process typically occurring through many cell divisions. A differentiated cell may derive from a multipotent cell that itself is derived from a multipotent cell, and so on. While each of these multipotent cells may be considered stem cells, the range of cell types that each can give rise to may vary considerably. Some differentiated cells also have the capacity to give rise to cells of greater developmental potential. Such capacity may be natural or may be induced artificially upon treatment with various factors. In many biological instances, stem cells are also “multipotent” because they can produce progeny of more than one distinct cell type, but this is not required for “stem-ness.”
Self-renewal is another important aspect of the stem cell. In theory, self-renewal can occur by either of two major mechanisms. Stem cells may divide asymmetrically, with one daughter retaining the stem state and the other daughter expressing some distinct other specific function and phenotype. Alternatively, some of the stem cells in a population can divide symmetrically into two stems, thus maintaining some stem cells in the population as a whole, while other cells in the population give rise to differentiated progeny only. Generally, “progenitor cells” have a cellular phenotype that is more primitive (i.e., is at an earlier step along a developmental pathway or progression than is a fully differentiated cell). Often, progenitor cells also have significant or very high proliferative potential. Progenitor cells can give rise to multiple distinct differentiated cell types or to a single differentiated cell type, depending on the developmental pathway and on the environment in which the cells develop and differentiate.
In the context of cell ontogeny, the adjective “differentiated,” or “differentiating” is a relative term. A “differentiated cell” is a cell that has progressed further down the developmental pathway than the cell to which it is being compared. Thus, stem cells can differentiate into lineage-restricted precursor cells (such as a myocyte progenitor cell), which in turn can differentiate into other types of precursor cells further down the pathway (such as a myocyte precursor), and then to an end-stage differentiated cell, such as a myocyte, which plays a characteristic role in a certain tissue type, and may or may not retain the capacity to proliferate further.
The term “hematopoietic progenitor cell” refers to cells of a stem cell lineage that give rise to all the blood cell types, including erythroid (erythrocytes or red blood cells (RBCs)), myeloid (monocytes and macrophages, neutrophils, basophils, eosinophils, megakaryocytes/platelets, and dendritic cells), and lymphoid (T-cells, B-cells, NK-cells).
Isolating a Peripheral Blood Mononuclear Cell
Peripheral blood mononuclear cells may be isolated according to any method known in the art. For example, white blood cells may be isolated from a liquid sample by centrifugation and cell culturing.
Treating a Patient with GCSF
A patient may optionally be treated with granulocyte colony stimulating factor (GCSF) in accordance with any method known in the art. In some embodiments, the GCSF is administered in combination with Plerixaflor.
Animal Models
For efficacy studies, NOG or NSG mice can be used. They can be transplanted with human lymphoma cell lines and subsequently transplanted with edited human CAR−T cells. Loss/prevention of lymphoma cells can indicate the efficacy of edited T cells.
The safety of TCR edited T cells can be assessed in NOG or NSG mice. Human T cells transplanted into these mice can cause a lethal xenogeneic graft versus host disease (GVHD). Removal of the TCR by gene editing should alleviate this type of GVHD.
Genome Editing
Genome editing generally refers to the process of modifying the nucleotide sequence of a genome, preferably in a precise or pre-determined manner. Examples of methods of genome editing described herein include methods of using site-directed nucleases to cut deoxyribonucleic acid (DNA) at precise target locations in the genome, thereby creating single-strand or double-strand DNA breaks at particular locations within the genome. Such breaks may be and regularly are repaired by natural, endogenous cellular processes, such as homology-directed repair (HDR) and non-homologous end-joining (NHEJ), as recently reviewed in Cox et al., Nature Medicine 21(2), 121-31 (2015). These two main DNA repair processes consist of a family of alternative pathways. NHEJ directly joins the DNA ends resulting from a double-strand break, sometimes with the loss or addition of nucleotide sequence, which may disrupt or enhance gene expression. HDR utilizes a homologous sequence, or donor sequence, as a template for inserting a defined DNA sequence at the break point. The homologous sequence may be in the endogenous genome, such as a sister chromatid. Alternatively, the donor may be an exogenous nucleic acid, such as a plasmid, a single-strand oligonucleotide, a double-stranded oligonucleotide, a duplex oligonucleotide or a virus, that has regions of high homology with the nuclease-cleaved locus, but which may also contain additional sequence or sequence changes including deletions that may be incorporated into the cleaved target locus. A third repair mechanism is microhomology-mediated end joining (MMEJ), also referred to as “Alternative NHEJ”, in which the genetic outcome is similar to NHEJ in that small deletions and insertions can occur at the cleavage site. MMEJ makes use of homologous sequences of a few basepairs flanking the DNA break site to drive a more favored DNA end joining repair outcome, and recent reports have further elucidated the molecular mechanism of this process; see, e.g., Cho and Greenberg, Nature 518, 174-76 (2015); Kent et al., Nature Structural and Molecular Biology, Adv. Online doi:10.1038/nsmb.2961(2015); Mateos-Gomez et al., Nature 518, 254-57 (2015); Ceccaldi et al., Nature 528, 258-62 (2015). In some instances, it may be possible to predict likely repair outcomes based on analysis of potential microhomologies at the site of the DNA break.
Each of these genome editing mechanisms can be used to create desired genomic alterations. A step in the genome editing process is to create one or two DNA breaks, the latter as double-strand breaks or as two single-stranded breaks, in the target locus as close as possible to the site of intended mutation. This can be achieved via the use of site-directed polypeptides, as described and illustrated herein.
Site-directed polypeptides, such as a DNA endonuclease, can introduce double-strand breaks or single-strand breaks in nucleic acids, e.g., genomic DNA. The double-strand break can stimulate a cell's endogenous DNA-repair pathways (e.g., homology-dependent repair or non-homologous end joining or alternative non-homologous end joining (A-NHEJ) or microhomology-mediated end joining). NHEJ can repair cleaved target nucleic acid without the need for a homologous template. This can sometimes result in small deletions or insertions (indels) in the target nucleic acid at the site of cleavage, and can lead to disruption or alteration of gene expression. HDR can occur when a homologous repair template, or donor, is available. The homologous donor template comprises sequences that are homologous to sequences flanking the target nucleic acid cleavage site. The sister chromatid is generally used by the cell as the repair template. However, for the purposes of genome editing, the repair template is often supplied as an exogenous nucleic acid, such as a plasmid, duplex oligonucleotide, single-strand oligonucleotide, double-stranded oligonucleotide, or viral nucleic acid. With exogenous donor templates, it is common to introduce an additional nucleic acid sequence (such as a transgene) or modification (such as a single or multiple base change or a deletion) between the flanking regions of homology so that the additional or altered nucleic acid sequence also becomes incorporated into the target locus. MMEJ results in a genetic outcome that is similar to NHEJ in that small deletions and insertions can occur at the cleavage site. MMEJ makes use of homologous sequences of a few basepairs flanking the cleavage site to drive a favored end-joining DNA repair outcome. In some instances, it may be possible to predict likely repair outcomes based on analysis of potential microhomologies in the nuclease target regions.
Thus, in some embodiments, either non-homologous end joining or homologous recombination is used to insert an exogenous polynucleotide sequence into the target nucleic acid cleavage site. An exogenous polynucleotide sequence is termed a donor polynucleotide (or donor or donor sequence or polynucleotide donor template) herein. In some embodiments, the donor polynucleotide, a portion of the donor polynucleotide, a copy of the donor polynucleotide, or a portion of a copy of the donor polynucleotide is inserted into the target nucleic acid cleavage site. In some embodiments, the donor polynucleotide is an exogenous polynucleotide sequence, i.e., a sequence that does not naturally occur at the target nucleic acid cleavage site.
The modifications of the target DNA due to NHEJ and/or HDR can lead to, for example, mutations, deletions, alterations, integrations, gene correction, gene replacement, gene tagging, transgene insertion, nucleotide deletion, gene disruption, translocations and/or gene mutation. The processes of deleting genomic DNA and integrating non-native nucleic acid into genomic DNA are examples of genome editing.
CRISPR Endonuclease System
A CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) genomic locus can be found in the genomes of many prokaryotes (e.g., bacteria and archaea). In prokaryotes, the CRISPR locus encodes products that function as a type of immune system to help defend the prokaryotes against foreign invaders, such as virus and phage. There are three stages of CRISPR locus function: integration of new sequences into the CRISPR locus, expression of CRISPR RNA (crRNA), and silencing of foreign invader nucleic acid. Five types of CRISPR systems (e.g., Type I, Type II, Type III, Type U, and Type V) have been identified.
A CRISPR locus includes a number of short repeating sequences referred to as “repeats.” When expressed, the repeats can form secondary structures (e.g., hairpins) and/or comprise unstructured single-stranded sequences. The repeats usually occur in clusters and frequently diverge between species. The repeats are regularly interspaced with unique intervening sequences referred to as “spacers,” resulting in a repeat-spacer-repeat locus architecture. The spacers are identical to or have high homology with known foreign invader sequences. A spacer-repeat unit encodes a crisprRNA (crRNA), which is processed into a mature form of the spacer-repeat unit. A crRNA comprises a “seed” or spacer sequence that is involved in targeting a target nucleic acid (in the naturally occurring form in prokaryotes, the spacer sequence targets the foreign invader nucleic acid). A spacer sequence is located at the 5′ or 3′ end of the crRNA.
A CRISPR locus also comprises polynucleotide sequences encoding CRISPR Associated (Cas) genes. Cas genes encode endonucleases involved in the biogenesis and the interference stages of crRNA function in prokaryotes. Some Cas genes comprise homologous secondary and/or tertiary structures.
Type II CRISPR Systems
crRNA biogenesis in a Type II CRISPR system in nature requires a trans-activating CRISPR RNA (tracrRNA). The tracrRNA is modified by endogenous RNaseIII, and then hybridizes to a crRNA repeat in the pre-crRNA array. Endogenous RNaseIII is recruited to cleave the pre-crRNA. Cleaved crRNAs is subjected to exoribonuclease trimming to produce the mature crRNA form (e.g., 5′ trimming). The tracrRNA remains hybridized to the crRNA, and the tracrRNA and the crRNA associate with a site-directed polypeptide (e.g., Cas9). The crRNA of the crRNA-tracrRNA-Cas9 complex guides the complex to a target nucleic acid to which the crRNA can hybridize. Hybridization of the crRNA to the target nucleic acid activates Cas9 for targeted nucleic acid cleavage. The target nucleic acid in a Type II CRISPR system is referred to as a protospacer adjacent motif (PAM). In nature, the PAM is essential to facilitate binding of a site-directed polypeptide (e.g., Cas9) to the target nucleic acid. Type II systems (also referred to as Nmeni or CASS4) are further subdivided into Type II-A (CASS4) and II-B (CASS4a). Jinek et al., Science, 337(6096):816-821 (2012) showed that the CRISPR/Cas9 system is useful for RNA-programmable genome editing, and international patent application publication number WO2013/176772 provides numerous examples and applications of the CRISPR/Cas endonuclease system for site-specific gene editing.
Type V CRISPR Systems
Type V CRISPR systems have several important differences from Type II systems. For example, Cpf1 is a single RNA-guided endonuclease that, in contrast to Type II systems, lacks tracrRNA. In fact, Cpf1-associated CRISPR arrays are processed into mature crRNAs without the requirement of an additional trans-activating tracrRNA. The Type V CRISPR array is processed into short mature crRNAs of 42-44 nucleotides in length, with each mature crRNA beginning with 19 nucleotides of direct repeat followed by 23-25 nucleotides of spacer sequence. In contrast, mature crRNAs in Type II systems start with 20-24 nucleotides of spacer sequence followed by about 22 nucleotides of direct repeat. Also, Cpf1 utilizes a T-rich protospacer-adjacent motif such that Cpf1-crRNA complexes efficiently cleave target DNA preceded by a short T-rich PAM, which is in contrast to the G-rich PAM following the target DNA for Type II systems. Thus, Type V systems cleave at a point that is distant from the PAM, while Type II systems cleave at a point that is adjacent to the PAM. In addition, in contrast to Type II systems, Cpf1 cleaves DNA via a staggered DNA double-stranded break with a 4 or 5 nucleotide 5′ overhang. Type II systems cleave via a blunt double-stranded break. Similar to Type II systems, Cpf1 contains a predicted RuvC-like endonuclease domain, but lacks a second HNH endonuclease domain, which is in contrast to Type II systems.
Cas Genes/Polypeptides and Protospacer Adjacent Motifs
Exemplary CRISPR/Cas polypeptides include the Cas9 polypeptides in FIG. 1 of Fonfara et al., Nucleic Acids Research, 42: 2577-2590 (2014). The CRISPR/Cas gene naming system has undergone extensive rewriting since the Cas genes were discovered. FIG. 5 of Fonfara, supra, provides PAM sequences for the Cas9 polypeptides from various species.
Site-Directed Polypeptides
A site-directed polypeptide is a nuclease used in genome editing to cleave DNA. The site-directed may be administered to a cell or a patient as either: one or more polypeptides, or one or more mRNAs encoding the polypeptide.
In the context of a CRISPR/Cas or CRISPR/Cpf1 system, the site-directed polypeptide can bind to a guide RNA that, in turn, specifies the site in the target DNA to which the polypeptide is directed. In embodiments of the CRISPR/Cas or CRISPR/Cpf1 systems herein, the site-directed polypeptide is an endonuclease, such as a DNA endonuclease.
In some embodiments, a site-directed polypeptide comprises a plurality of nucleic acid-cleaving (i.e., nuclease) domains. Two or more nucleic acid-cleaving domains can be linked together via a linker. For example, the linker comprises a flexible linker. In some embodiments, linkers comprise 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 30, 35, 40 or more amino acids in length.
Naturally-occurring wild-type Cas9 enzymes comprise two nuclease domains, a HNH nuclease domain and a RuvC domain. Herein, the “Cas9” refers to both naturally-occurring and recombinant Cas9s. Cas9 enzymes contemplated herein comprises a HNH or HNH-like nuclease domain, and/or a RuvC or RuvC-like nuclease domain.
HNH or HNH-like domains comprise a McrA-like fold. HNH or HNH-like domains comprises two antiparallel β-strands and an α-helix. HNH or HNH-like domains comprises a metal binding site (e.g., a divalent cation binding site). HNH or HNH-like domains can cleave one strand of a target nucleic acid (e.g., the complementary strand of the crRNA targeted strand).
RuvC or RuvC-like domains comprise an RNaseH or RNaseH-like fold. RuvC/RNaseH domains are involved in a diverse set of nucleic acid-based functions including acting on both RNA and DNA. The RNaseH domain comprises 5 β-strands surrounded by a plurality of α-helices. RuvC/RNaseH or RuvC/RNaseH-like domains comprise a metal binding site (e.g., a divalent cation binding site). RuvC/RNaseH or RuvC/RNaseH-like domains can cleave one strand of a target nucleic acid (e.g., the non-complementary strand of a double-stranded target DNA).
Site-directed polypeptides can introduce double-strand breaks or single-strand breaks in nucleic acids, e.g., genomic DNA. The double-strand break can stimulate a cell's endogenous DNA-repair pathways (e.g., homology-dependent repair (HDR) or non-homologous end-joining (NHEJ) or alternative non-homologous end joining (A-NHEJ) or microhomology-mediated end joining (MMEJ)). NHEJ can repair cleaved target nucleic acid without the need for a homologous template. This can sometimes result in small deletions or insertions (indels) in the target nucleic acid at the site of cleavage, and can lead to disruption or alteration of gene expression. HDR can occur when a homologous repair template, or donor, is available. The homologous donor template comprises sequences that are homologous to sequences flanking the target nucleic acid cleavage site. The sister chromatid is generally used by the cell as the repair template. However, for the purposes of genome editing, the repair template is often supplied as an exogenous nucleic acid, such as a plasmid, duplex oligonucleotide, single-strand oligonucleotide or viral nucleic acid. With exogenous donor templates, it is common to introduce an additional nucleic acid sequence (such as a transgene) or modification (such as a single or multiple base change or a deletion) between the flanking regions of homology so that the additional or altered nucleic acid sequence also becomes incorporated into the target locus. MMEJ results in a genetic outcome that is similar to NHEJ in that small deletions and insertions can occur at the cleavage site. MMEJ makes use of homologous sequences of a few basepairs flanking the cleavage site to drive a favored end-joining DNA repair outcome. In some instances, it may be possible to predict likely repair outcomes based on analysis of potential microhomologies in the nuclease target regions.
Thus, in some embodiments, homologous recombination is used to insert an exogenous polynucleotide sequence into the target nucleic acid cleavage site. An exogenous polynucleotide sequence is termed a donor polynucleotide (or donor or donor sequence) herein. In some embodiments, the donor polynucleotide, a portion of the donor polynucleotide, a copy of the donor polynucleotide, or a portion of a copy of the donor polynucleotide is inserted into the target nucleic acid cleavage site. In some embodiments, the donor polynucleotide is an exogenous polynucleotide sequence, i.e., a sequence that does not naturally occur at the target nucleic acid cleavage site.
The modifications of the target DNA due to NHEJ and/or HDR can lead to, for example, mutations, deletions, alterations, integrations, gene correction, gene replacement, gene tagging, transgene insertion, nucleotide deletion, gene disruption, translocations and/or gene mutation. The processes of deleting genomic DNA and integrating non-native nucleic acid into genomic DNA are examples of genome editing.
In some embodiments, the site-directed polypeptide comprises an amino acid sequence having at least 10%, at least 15%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 99%, or 100% amino acid sequence identity to a wild-type exemplary site-directed polypeptide [e.g., Cas9 from S. pyogenes, US2014/0068797 Sequence ID No. 8 or Sapranauskas et al., Nucleic Acids Res, 39(21): 9275-9282 (2010], and various other site-directed polypeptides. In some embodiments, the site-directed polypeptide comprises at least 70, 75, 80, 85, 90, 95, 97, 99, or 100% identity to a wild-type site-directed polypeptide (e.g., Cas9 from S. pyogenes, supra) over 10 contiguous amino acids.
In some embodiments, the site-directed polypeptide comprises an amino acid sequence having at least 10%, at least 15%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 99%, or 100% amino acid sequence identity to the nuclease domain of a wild-type exemplary site-directed polypeptide (e.g., Cas9 from S. pyogenes, supra).
In some embodiments, the site-directed polypeptide comprises at most: 70, 75, 80, 85, 90, 95, 97, 99, or 100% identity to a wild-type site-directed polypeptide (e.g., Cas9 from S. pyogenes, supra) over 10 contiguous amino acids. In some embodiments, the site-directed polypeptide comprises at least: 70, 75, 80, 85, 90, 95, 97, 99, or 100% identity to a wild-type site-directed polypeptide (e.g., Cas9 from S. pyogenes, supra) over 10 contiguous amino acids in a HNH nuclease domain of the site-directed polypeptide. In some embodiments, the site-directed polypeptide comprises at most: 70, 75, 80, 85, 90, 95, 97, 99, or 100% identity to a wild-type site-directed polypeptide (e.g., Cas9 from S. pyogenes, supra) over 10 contiguous amino acids in a HNH nuclease domain of the site-directed polypeptide. In some embodiments, the site-directed polypeptide comprises at least: 70, 75, 80, 85, 90, 95, 97, 99, or 100% identity to a wild-type site-directed polypeptide (e.g., Cas9 from S. pyogenes, supra) over 10 contiguous amino acids in a RuvC nuclease domain of the site-directed polypeptide. In some embodiments, the site-directed polypeptide comprises at most: 70, 75, 80, 85, 90, 95, 97, 99, or 100% identity to a wild-type site-directed polypeptide (e.g., Cas9 from S. pyogenes, supra) over 10 contiguous amino acids in a RuvC nuclease domain of the site-directed polypeptide.
In some embodiments, the site-directed polypeptide comprises a modified form of a wild-type exemplary site-directed polypeptide. In some embodiments, the modified form of the wild-type exemplary site-directed polypeptide comprises a mutation that reduces the nucleic acid-cleaving activity of the site-directed polypeptide. In some embodiments, the modified form of the wild-type exemplary site-directed polypeptide has less than 90%, less than 80%, less than 70%, less than 60%, less than 50%, less than 40%, less than 30%, less than 20%, less than 10%, less than 5%, or less than 1% of the nucleic acid-cleaving activity of the wild-type exemplary site-directed polypeptide (e.g., Cas9 from S. pyogenes, supra). In some embodiments, the modified form of the site-directed polypeptide has no substantial nucleic acid-cleaving activity. When a site-directed polypeptide is a modified form that has no substantial nucleic acid-cleaving activity, it is referred to herein as “enzymatically inactive.”
In some embodiments, the modified form of the site-directed polypeptide comprises a mutation such that it can induce a single-strand break (SSB) on a target nucleic acid (e.g., by cutting only one of the sugar-phosphate backbones of a double-strand target nucleic acid). In some embodiments, the mutation results in less than 90%, less than 80%, less than 70%, less than 60%, less than 50%, less than 40%, less than 30%, less than 20%, less than 10%, less than 5%, or less than 1% of the nucleic acid-cleaving activity in one or more of the plurality of nucleic acid-cleaving domains of the wild-type site directed polypeptide (e.g., Cas9 from S. pyogenes, supra). In some embodiments, the mutation results in one or more of the plurality of nucleic acid-cleaving domains retaining the ability to cleave the complementary strand of the target nucleic acid, but reducing its ability to cleave the non-complementary strand of the target nucleic acid. In some embodiments, the mutation results in one or more of the plurality of nucleic acid-cleaving domains retaining the ability to cleave the non-complementary strand of the target nucleic acid, but reducing its ability to cleave the complementary strand of the target nucleic acid. For example, residues in the wild-type exemplary S. pyogenes Cas9 polypeptide, such as Asp10, His840, Asn854 and Asn856, are mutated to inactivate one or more of the plurality of nucleic acid-cleaving domains (e.g., nuclease domains). The residues to be mutated can correspond to residues Asp10, His840, Asn854 and Asn856 in the wild-type exemplary S. pyogenes Cas9 polypeptide (e.g., as determined by sequence and/or structural alignment). Non-limiting examples of mutations include D10A, H840A, N854A or N856A. One skilled in the art will recognize that mutations other than alanine substitutions can be suitable.
In some embodiments, a D10A mutation is combined with one or more of H840A, N854A, or N856A mutations to produce a site-directed polypeptide substantially lacking DNA cleavage activity. In some embodiments, a H840A mutation is combined with one or more of D10A, N854A, or N856A mutations to produce a site-directed polypeptide substantially lacking DNA cleavage activity. In some embodiments, a N854A mutation is combined with one or more of H840A, D10A, or N856A mutations to produce a site-directed polypeptide substantially lacking DNA cleavage activity. In some embodiments, aN856A mutation is combined with one or more of H840A, N854A, or D10A mutations to produce a site-directed polypeptide substantially lacking DNA cleavage activity. Site-directed polypeptides that comprise one substantially inactive nuclease domain are referred to as “nickases”.
Nickase variants of RNA-guided endonucleases, for example Cas9, can be used to increase the specificity of CRISPR-mediated genome editing. Wild type Cas9 is typically guided by a single guide RNA designed to hybridize with a specified ˜20 nucleotide sequence in the target sequence (such as an endogenous genomic locus). However, several mismatches can be tolerated between the guide RNA and the target locus, effectively reducing the length of required homology in the target site to, for example, as little as 13 nt of homology, and thereby resulting in elevated potential for binding and double-strand nucleic acid cleavage by the CRISPR/Cas9 complex elsewhere in the target genome—also known as off-target cleavage. Because nickase variants of Cas9 each only cut one strand, in order to create a double-strand break it is necessary for a pair of nickases to bind in close proximity and on opposite strands of the target nucleic acid, thereby creating a pair of nicks, which is the equivalent of a double-strand break. This requires that two separate guide RNAs—one for each nickase—must bind in close proximity and on opposite strands of the target nucleic acid. This requirement essentially doubles the minimum length of homology needed for the double-strand break to occur, thereby reducing the likelihood that a double-strand cleavage event will occur elsewhere in the genome, where the two guide RNA sites—if they exist—are unlikely to be sufficiently close to each other to enable the double-strand break to form. As described in the art, nickases can also be used to promote HDR versus NHEJ. HDR can be used to introduce selected changes into target sites in the genome through the use of specific donor sequences that effectively mediate the desired changes. Descriptions of various CRISPR/Cas systems for use in gene editing can be found, e.g., in international patent application publication number WO2013/176772, and in Nature Biotechnology 32, 347-355 (2014), and references cited therein.
Mutations contemplated include substitutions, additions, and deletions, or any combination thereof. In some embodiments, the mutation converts the mutated amino acid to alanine. In some embodiments, the mutation converts the mutated amino acid to another amino acid (e.g., glycine, serine, threonine, cysteine, valine, leucine, isoleucine, methionine, proline, phenylalanine, tyrosine, tryptophan, aspartic acid, glutamic acid, asparagines, glutamine, histidine, lysine, or arginine). In some embodiments, the mutation converts the mutated amino acid to a non-natural amino acid (e.g., selenomethionine). In some embodiments, the mutation converts the mutated amino acid to amino acid mimics (e.g., phosphomimics). In some embodiments, the mutation is a conservative mutation. For example, the mutation converts the mutated amino acid to amino acids that resemble the size, shape, charge, polarity, conformation, and/or rotamers of the mutated amino acids (e.g., cysteine/serine mutation, lysine/asparagine mutation, histidine/phenylalanine mutation). In some embodiments, the mutation causes a shift in reading frame and/or the creation of a premature stop codon. In some embodiments, mutations cause changes to regulatory regions of genes or loci that affect expression of one or more genes.
In some embodiments, the site-directed polypeptide (e.g., variant, mutated, enzymatically inactive and/or conditionally enzymatically inactive site-directed polypeptide) targets nucleic acid. In some embodiments, the site-directed polypeptide (e.g., variant, mutated, enzymatically inactive and/or conditionally enzymatically inactive endoribonuclease) targets DNA. In some embodiments, the site-directed polypeptide (e.g., variant, mutated, enzymatically inactive and/or conditionally enzymatically inactive endoribonuclease) targets RNA.
In some embodiments, the site-directed polypeptide comprises one or more non-native sequences (e.g., the site-directed polypeptide is a fusion protein).
In some embodiments, the site-directed polypeptide comprises an amino acid sequence comprising at least 15% amino acid identity to a Cas9 from a bacterium (e.g., S. pyogenes), a nucleic acid binding domain, and two nucleic acid cleaving domains (i.e., a HNH domain and a RuvC domain).
In some embodiments, the site-directed polypeptide comprises an amino acid sequence comprising at least 15% amino acid identity to a Cas9 from a bacterium (e.g., S. pyogenes), and two nucleic acid cleaving domains (i.e., a HNH domain and a RuvC domain).
In some embodiments, the site-directed polypeptide comprises an amino acid sequence comprising at least 15% amino acid identity to a Cas9 from a bacterium (e.g., S. pyogenes), and two nucleic acid cleaving domains, wherein one or both of the nucleic acid cleaving domains comprise at least 50% amino acid identity to a nuclease domain from Cas9 from a bacterium (e.g., S. pyogenes).
In some embodiments, the site-directed polypeptide comprises an amino acid sequence comprising at least 15% amino acid identity to a Cas9 from a bacterium (e.g., S. pyogenes), two nucleic acid cleaving domains (i.e., a HNH domain and a RuvC domain), and non-native sequence (for example, a nuclear localization signal) or a linker linking the site-directed polypeptide to a non-native sequence.
In some embodiments, the site-directed polypeptide comprises an amino acid sequence comprising at least 15% amino acid identity to a Cas9 from a bacterium (e.g., S. pyogenes), two nucleic acid cleaving domains (i.e., a HNH domain and a RuvC domain), wherein the site-directed polypeptide comprises a mutation in one or both of the nucleic acid cleaving domains that reduces the cleaving activity of the nuclease domains by at least 50%.
In some embodiments, the site-directed polypeptide comprises an amino acid sequence comprising at least 15% amino acid identity to a Cas9 from a bacterium (e.g., S. pyogenes), and two nucleic acid cleaving domains (i.e., a HNH domain and a RuvC domain), wherein one of the nuclease domains comprises mutation of aspartic acid 10, and/or wherein one of the nuclease domains comprises a mutation of histidine 840, and wherein the mutation reduces the cleaving activity of the nuclease domain(s) by at least 50%.
In some embodiments, the one or more site-directed polypeptides, e.g. DNA endonucleases, comprises two nickases that together effect one double-strand break at a specific locus in the genome, or four nickases that together effect or cause two double-strand breaks at specific loci in the genome. Alternatively, one site-directed polypeptide, e.g. DNA endonuclease, effects one double-strand break at a specific locus in the genome.
Genome-Targeting Nucleic Acid
The present disclosure provides a genome-targeting nucleic acid that can direct the activities of an associated polypeptide (e.g., a site-directed polypeptide) to a specific target sequence within a target nucleic acid. The genome-targeting nucleic acid can be an RNA. A genome-targeting RNA is referred to as a “guide RNA” or “gRNA” herein. A guide RNA comprises at least a spacer sequence that hybridizes to a target nucleic acid sequence of interest, and a CRISPR repeat sequence. In Type II systems, the gRNA also comprises a second RNA called the tracrRNA sequence. In the Type II guide RNA (gRNA), the CRISPR repeat sequence and tracrRNA sequence hybridize to each other to form a duplex. In the Type V guide RNA (gRNA), the crRNA forms a duplex. In both systems, the duplex binds a site-directed polypeptide, such that the guide RNA and site-direct polypeptide form a complex. In some embodiments, the genome-targeting nucleic acid provides target specificity to the complex by virtue of its association with the site-directed polypeptide. The genome-targeting nucleic acid thus directs the activity of the site-directed polypeptide.
Exemplary guide RNAs include the spacer sequences in SEQ ID NOs: 83-158, 284-408, 458-506, 699-890, 1083-1276, 1288-1298, and 1308-1312 with the genome location of their target sequence and the associated endonuclease (e.g., Cas9) cut site. As is understood by the person of ordinary skill in the art, each guide RNA is designed to include a spacer sequence complementary to its genomic target sequence. For example, each of the spacer sequences in SEQ ID NOs: 83-158, 284-408, 458-506, 699-890, 1083-1276, 1288-1298, and 1308-1312 can be put into a single RNA chimera or a crRNA (along with a corresponding tracrRNA). See Jinek et al., Science, 337, 816-821 (2012) and Deltcheva et al., Nature, 471, 602-607 (2011).
In some embodiments, the genome-targeting nucleic acid is a double-molecule guide RNA. In some embodiments, the genome-targeting nucleic acid is a single-molecule guide RNA.
A double-molecule guide RNA comprises two strands of RNA. The first strand comprises in the 5′ to 3′ direction, an optional spacer extension sequence, a spacer sequence and a minimum CRISPR repeat sequence. The second strand comprises a minimum tracrRNA sequence (complementary to the minimum CRISPR repeat sequence), a 3′ tracrRNA sequence and an optional tracrRNA extension sequence.
A single-molecule guide RNA (sgRNA) in a Type II system comprises, in the 5′ to 3′ direction, an optional spacer extension sequence, a spacer sequence, a minimum CRISPR repeat sequence, a single-molecule guide linker, a minimum tracrRNA sequence, a 3′ tracrRNA sequence and an optional tracrRNA extension sequence. The optional tracrRNA extension may comprise elements that contribute additional functionality (e.g., stability) to the guide RNA. The single-molecule guide linker links the minimum CRISPR repeat and the minimum tracrRNA sequence to form a hairpin structure. The optional tracrRNA extension comprises one or more hairpins.
A single-molecule guide RNA (sgRNA) in a Type V system comprises, in the 5′ to 3′ direction, a minimum CRISPR repeat sequence and a spacer sequence.
The sgRNA can comprise a 20 nucleotide spacer sequence at the 5′ end of the sgRNA sequence. The sgRNA can comprise a less than a 20 nucleotide spacer sequence at the 5′ end of the sgRNA sequence. The sgRNA can comprise a more than 20 nucleotide spacer sequence at the 5′ end of the sgRNA sequence. The sgRNA can comprise a variable length spacer sequence with 17-30 nucleotides at the 5′ end of the sgRNA sequence (see Table 1).
The sgRNA can comprise no uracil at the 3′ end of the sgRNA sequence, such as in SEQ ID NO: 1 of Table 1. The sgRNA can comprise one or more uracil at the 3′ end of the sgRNA sequence, such as in SEQ ID NOs: 1, 2, or 3 in Table 1. For example, the sgRNA can comprise 1 uracil (U) at the 3′ end of the sgRNA sequence. The sgRNA can comprise 2 uracil (UU) at the 3′ end of the sgRNA sequence. The sgRNA can comprise 3 uracil (UUU) at the 3′ end of the sgRNA sequence. The sgRNA can comprise 4 uracil (UUUU) at the 3′ end of the sgRNA sequence. The sgRNA can comprise 5 uracil (UUUUU) at the 3′ end of the sgRNA sequence. The sgRNA can comprise 6 uracil (UUUUUU) at the 3′ end of the sgRNA sequence. The sgRNA can comprise 7 uracil (UUUUUUU) at the 3′ end of the sgRNA sequence. The sgRNA can comprise 8 uracil (UUUUUUUU) at the 3′ end of the sgRNA sequence.
The sgRNA can be unmodified or modified. For example, modified sgRNAs can comprise one or more 2′-O-methyl phosphorothioate nucleotides.
By way of illustration, guide RNAs used in the CRISPR/Cas/Cpf1 system, or other smaller RNAs can be readily synthesized by chemical means, as illustrated below and described in the art. While chemical synthetic procedures are continually expanding, purifications of such RNAs by procedures such as high performance liquid chromatography (HPLC, which avoids the use of gels such as PAGE) tends to become more challenging as polynucleotide lengths increase significantly beyond a hundred or so nucleotides. One approach used for generating RNAs of greater length is to produce two or more molecules that are ligated together. Much longer RNAs, such as those encoding a Cas9 or Cpf1 endonuclease, are more readily generated enzymatically. Various types of RNA modifications can be introduced during or after chemical synthesis and/or enzymatic generation of RNAs, e.g., modifications that enhance stability, reduce the likelihood or degree of innate immune response, and/or enhance other attributes, as described in the art.
Spacer Extension Sequence
In some examples of genome-targeting nucleic acids, a spacer extension sequence may modify activity, provide stability and/or provide a location for modifications of a genome-targeting nucleic acid. A spacer extension sequence may modify on- or off-target activity or specificity. In some embodiments, a spacer extension sequence is provided. A spacer extension sequence may have a length of more than 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 120, 140, 160, 180, 200, 220, 240, 260, 280, 300, 320, 340, 360, 380, 400, 1000, 2000, 3000, 4000, 5000, 6000, or 7000 or more nucleotides. The spacer extension sequence may have a length of less than 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 120, 140, 160, 180, 200, 220, 240, 260, 280, 300, 320, 340, 360, 380, 400, 1000, 2000, 3000, 4000, 5000, 6000, 7000 or more nucleotides. In some embodiments, the spacer extension sequence is less than 10 nucleotides in length. In some embodiments, the spacer extension sequence is between 10-30 nucleotides in length. In some embodiments, the spacer extension sequence is between 30-70 nucleotides in length.
In some embodiments, the spacer extension sequence comprises another moiety (e.g., a stability control sequence, an endoribonuclease binding sequence, a ribozyme). In some embodiments, the moiety decreases or increases the stability of a nucleic acid targeting nucleic acid. In some embodiments, the moiety is a transcriptional terminator segment (i.e., a transcription termination sequence). In some embodiments, the moiety functions in a eukaryotic cell. In some embodiments, the moiety functions in a prokaryotic cell. In some embodiments, the moiety functions in both eukaryotic and prokaryotic cells. Non-limiting examples of suitable moieties include: a 5′ cap (e.g., a 7-methylguanylate cap (m7 G)), a riboswitch sequence (e.g., to allow for regulated stability and/or regulated accessibility by proteins and protein complexes), a sequence that forms a dsRNA duplex (i.e., a hairpin), a sequence that targets the RNA to a subcellular location (e.g., nucleus, mitochondria, chloroplasts, and the like), a modification or sequence that provides for tracking (e.g., direct conjugation to a fluorescent molecule, conjugation to a moiety that facilitates fluorescent detection, a sequence that allows for fluorescent detection, etc.), and/or a modification or sequence that provides a binding site for proteins (e.g., proteins that act on DNA, including transcriptional activators, transcriptional repressors, DNA methyltransferases, DNA demethylases, histone acetyltransferases, histone deacetylases, and the like).
Spacer Sequence
A gRNA comprises a spacer sequence. A spacer sequence is a sequence (e.g., a 20 base pair sequence) that defines the target sequence (e.g., a DNA target sequences, such as a genomic target sequence) of a target nucleic acid of interest. The “target sequence” is adjacent to a PAM sequence and is the sequence modified by an RNA-guided nuclease (e.g., Cas9). The “target nucleic acid” is a double-stranded molecule: one strand comprises the target sequence and is referred to as the “PAM strand,” and the other complementary strand is referred to as the “non-PAM strand.” One of skill in the art recognizes that the gRNA spacer sequence hybridizes to the reverse complement of the target sequence, which is located in the non-PAM strand of the target nucleic acid of interest. Thus, the gRNA spacer sequence is the RNA equivalent of the target sequence. For example, if the target sequence is 5′-AGAGCAACAGTGCTGTGGCC-3′ (SEQ ID NO: 76), then the gRNA spacer sequence is 5′-AGAGCAACAGUGCUGUGGCC-3′ (SEQ ID NO: 152). The spacer of a gRNA interacts with a target nucleic acid of interest in a sequence-specific manner via hybridization (i.e., base pairing). The nucleotide sequence of the spacer thus varies depending on the target sequence of the target nucleic acid of interest.
In a CRISPR/Cas system herein, the spacer sequence is designed to hybridize to a region of the target nucleic acid that is located 5′ of a PAM of the Cas9 enzyme used in the system. The spacer may perfectly match the target sequence or may have mismatches. Each Cas9 enzyme has a particular PAM sequence that it recognizes in a target DNA. For example, S. pyogenes recognizes in a target nucleic acid a PAM that comprises the sequence 5′-NRG-3′, where R comprises either A or G, where N is any nucleotide and N is immediately 3′ of the target nucleic acid sequence targeted by the spacer sequence.
In some embodiments, the target nucleic acid sequence comprises 20 nucleotides. In some embodiments, the target nucleic acid comprises less than 20 nucleotides. In some embodiments, the target nucleic acid comprises more than 20 nucleotides. In some embodiments, the target nucleic acid comprises at least: 5, 10, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 30 or more nucleotides. In some embodiments, the target nucleic acid comprises at most: 5, 10, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 30 or more nucleotides. In some embodiments, the target nucleic acid sequence comprises 20 bases immediately 5′ of the first nucleotide of the PAM. For example, in a sequence comprising 5′-NNNNNNNNNNNNNNNNNNNNNRG-3′, the target nucleic acid comprises the sequence that corresponds to the Ns, wherein N is any nucleotide, and the underlined NRG sequence is the S. pyogenes PAM.
In some embodiments, the spacer sequence that hybridizes to the target nucleic acid has a length of at least about 6 nucleotides (nt). The spacer sequence can be at least about 6 nt, at least about 10 nt, at least about 15 nt, at least about 18 nt, at least about 19 nt, at least about 20 nt, at least about 25 nt, at least about 30 nt, at least about 35 nt or at least about 40 nt, from about 6 nt to about 80 nt, from about 6 nt to about 50 nt, from about 6 nt to about 45 nt, from about 6 nt to about 40 nt, from about 6 nt to about 35 nt, from about 6 nt to about 30 nt, from about 6 nt to about 25 nt, from about 6 nt to about 20 nt, from about 6 nt to about 19 nt, from about 10 nt to about 50 nt, from about 10 nt to about 45 nt, from about 10 nt to about 40 nt, from about 10 nt to about 35 nt, from about 10 nt to about 30 nt, from about 10 nt to about 25 nt, from about 10 nt to about 20 nt, from about 10 nt to about 19 nt, from about 19 nt to about 25 nt, from about 19 nt to about 30 nt, from about 19 nt to about 35 nt, from about 19 nt to about 40 nt, from about 19 nt to about 45 nt, from about 19 nt to about 50 nt, from about 19 nt to about 60 nt, from about 20 nt to about 25 nt, from about 20 nt to about 30 nt, from about 20 nt to about 35 nt, from about 20 nt to about 40 nt, from about 20 nt to about 45 nt, from about 20 nt to about 50 nt, or from about 20 nt to about 60 nt. In some embodiments, the spacer sequence comprises 20 nucleotides. In some embodiments, the spacer comprises 19 nucleotides.
In some embodiments, the percent complementarity between the spacer sequence and the target nucleic acid is at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 97%, at least about 98%, at least about 99%, or 100%. In some embodiments, the percent complementarity between the spacer sequence and the target nucleic acid is at most about 30%, at most about 40%, at most about 50%, at most about 60%, at most about 65%, at most about 70%, at most about 75%, at most about 80%, at most about 85%, at most about 90%, at most about 95%, at most about 97%, at most about 98%, at most about 99%, or 100%. In some embodiments, the percent complementarity between the spacer sequence and the target nucleic acid is 100% over the six contiguous 5′-most nucleotides of the target sequence of the complementary strand of the target nucleic acid. In some embodiments, the percent complementarity between the spacer sequence and the target nucleic acid is at least 60% over about 20 contiguous nucleotides. In some embodiments, the length of the spacer sequence and the target nucleic acid differs by 1 to 6 nucleotides, which may be thought of as a bulge or bulges.
In some embodiments, the spacer sequence can be designed using a computer program. The computer program can use variables, such as predicted melting temperature, secondary structure formation, predicted annealing temperature, sequence identity, genomic context, chromatin accessibility, % GC, frequency of genomic occurrence (e.g., of sequences that are identical or are similar but vary in one or more spots as a result of mismatch, insertion or deletion), methylation status, presence of SNPs, and the like.
Minimum CRISPR Repeat Sequence
In some embodiments, a minimum CRISPR repeat sequence is a sequence with at least about 30%, about 40%, about 50%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, or 100% sequence identity to a reference CRISPR repeat sequence (e.g., crRNA from S. pyogenes).
A minimum CRISPR repeat sequence comprises nucleotides that can hybridize to a minimum tracrRNA sequence in a cell. The minimum CRISPR repeat sequence and a minimum tracrRNA sequence form a duplex, i.e. a base-paired double-stranded structure. Together, the minimum CRISPR repeat sequence and the minimum tracrRNA sequence bind to the site-directed polypeptide. At least a part of the minimum CRISPR repeat sequence hybridizes to the minimum tracrRNA sequence. In some embodiments, at least a part of the minimum CRISPR repeat sequence comprises at least about 30%, about 40%, about 50%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, or 100% complementary to the minimum tracrRNA sequence. In some embodiments, at least a part of the minimum CRISPR repeat sequence comprises at most about 30%, about 40%, about 50%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, or 100% complementary to the minimum tracrRNA sequence.
The minimum CRISPR repeat sequence can have a length from about 7 nucleotides to about 100 nucleotides. For example, the length of the minimum CRISPR repeat sequence is from about 7 nucleotides (nt) to about 50 nt, from about 7 nt to about 40 nt, from about 7 nt to about 30 nt, from about 7 nt to about 25 nt, from about 7 nt to about 20 nt, from about 7 nt to about 15 nt, from about 8 nt to about 40 nt, from about 8 nt to about 30 nt, from about 8 nt to about 25 nt, from about 8 nt to about 20 nt, from about 8 nt to about 15 nt, from about 15 nt to about 100 nt, from about 15 nt to about 80 nt, from about 15 nt to about 50 nt, from about 15 nt to about 40 nt, from about 15 nt to about 30 nt, or from about 15 nt to about 25 nt. In some embodiments, the minimum CRISPR repeat sequence is approximately 9 nucleotides in length. In some embodiments, the minimum CRISPR repeat sequence is approximately 12 nucleotides in length.
In some embodiments, the minimum CRISPR repeat sequence is at least about 60% identical to a reference minimum CRISPR repeat sequence (e.g., wild-type crRNA from S. pyogenes) over a stretch of at least 6, 7, or 8 contiguous nucleotides. For example, the minimum CRISPR repeat sequence is at least about 65% identical, at least about 70% identical, at least about 75% identical, at least about 80% identical, at least about 85% identical, at least about 90% identical, at least about 95% identical, at least about 98% identical, at least about 99% identical or 100% identical to a reference minimum CRISPR repeat sequence over a stretch of at least 6, 7, or 8 contiguous nucleotides.
Minimum tracrRNA Sequence
In some embodiments, a minimum tracrRNA sequence is a sequence with at least about 30%, about 40%, about 50%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, or 100% sequence identity to a reference tracrRNA sequence (e.g., wild type tracrRNA from S. pyogenes).
A minimum tracrRNA sequence comprises nucleotides that hybridize to a minimum CRISPR repeat sequence in a cell. A minimum tracrRNA sequence and a minimum CRISPR repeat sequence form a duplex, i.e. a base-paired double-stranded structure. Together, the minimum tracrRNA sequence and the minimum CRISPR repeat bind to a site-directed polypeptide. At least a part of the minimum tracrRNA sequence can hybridize to the minimum CRISPR repeat sequence. In some embodiments, the minimum tracrRNA sequence is at least about 30%, about 40%, about 50%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, or 100% complementary to the minimum CRISPR repeat sequence.
The minimum tracrRNA sequence can have a length from about 7 nucleotides to about 100 nucleotides. For example, the minimum tracrRNA sequence can be from about 7 nucleotides (nt) to about 50 nt, from about 7 nt to about 40 nt, from about 7 nt to about 30 nt, from about 7 nt to about 25 nt, from about 7 nt to about 20 nt, from about 7 nt to about 15 nt, from about 8 nt to about 40 nt, from about 8 nt to about 30 nt, from about 8 nt to about 25 nt, from about 8 nt to about 20 nt, from about 8 nt to about 15 nt, from about 15 nt to about 100 nt, from about 15 nt to about 80 nt, from about 15 nt to about 50 nt, from about 15 nt to about 40 nt, from about 15 nt to about 30 nt or from about 15 nt to about 25 nt long. In some embodiments, the minimum tracrRNA sequence is approximately 9 nucleotides in length. In some embodiments, the minimum tracrRNA sequence is approximately 12 nucleotides. In some embodiments, the minimum tracrRNA consists of tracrRNA nt 23-48 described in Jinek et al., supra.
In some embodiments, the minimum tracrRNA sequence is at least about 60% identical to a reference minimum tracrRNA (e.g., wild type, tracrRNA from S. pyogenes) sequence over a stretch of at least 6, 7, or 8 contiguous nucleotides. For example, the minimum tracrRNA sequence is at least about 65% identical, about 70% identical, about 75% identical, about 80% identical, about 85% identical, about 90% identical, about 95% identical, about 98% identical, about 99% identical or 100% identical to a reference minimum tracrRNA sequence over a stretch of at least 6, 7, or 8 contiguous nucleotides.
In some embodiments, the duplex between the minimum CRISPR RNA and the minimum tracrRNA comprises a double helix. In some embodiments, the duplex between the minimum CRISPR RNA and the minimum tracrRNA comprises at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 or more nucleotides. In some embodiments, the duplex between the minimum CRISPR RNA and the minimum tracrRNA comprises at most about 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 or more nucleotides.
In some embodiments, the duplex comprises a mismatch (i.e., the two strands of the duplex are not 100% complementary). In some embodiments, the duplex comprises at least about 1, 2, 3, 4, or 5 or mismatches. In some embodiments, the duplex comprises at most about 1, 2, 3, 4, or 5 or mismatches. In some embodiments, the duplex comprises no more than 2 mismatches.
Bulges
In some embodiments, there is a “bulge” in the duplex between the minimum CRISPR RNA and the minimum tracrRNA. A bulge is an unpaired region of nucleotides within the duplex. In some embodiments, the bulge contributes to the binding of the duplex to the site-directed polypeptide. In some embodiments, the bulge comprises, on one side of the duplex, an unpaired 5′-XXXY-3′ where X is any purine and Y comprises a nucleotide that can form a wobble pair with a nucleotide on the opposite strand, and an unpaired nucleotide region on the other side of the duplex. The number of unpaired nucleotides on the two sides of the duplex can be different.
In some embodiments, the bulge comprises an unpaired purine (e.g., adenine) on the minimum CRISPR repeat strand of the bulge. In some embodiments, the bulge comprises an unpaired 5′-AAGY-3′ of the minimum tracrRNA sequence strand of the bulge, where Y comprises a nucleotide that can form a wobble pairing with a nucleotide on the minimum CRISPR repeat strand.
In some embodiments, a bulge on the minimum CRISPR repeat side of the duplex comprises at least 1, 2, 3, 4, or 5 or more unpaired nucleotides. In some embodiments, a bulge on the minimum CRISPR repeat side of the duplex comprises at most 1, 2, 3, 4, or 5 or more unpaired nucleotides. In some embodiments, a bulge on the minimum CRISPR repeat side of the duplex comprises 1 unpaired nucleotide.
In some embodiments, a bulge on the minimum tracrRNA sequence side of the duplex comprises at least 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 or more unpaired nucleotides. In some embodiments, a bulge on the minimum tracrRNA sequence side of the duplex comprises at most 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 or more unpaired nucleotides. In some embodiments, a bulge on a second side of the duplex (e.g., the minimum tracrRNA sequence side of the duplex) comprises 4 unpaired nucleotides.
In some embodiments, a bulge comprises at least one wobble pairing. In some embodiments, a bulge comprises at most one wobble pairing. In some embodiments, a bulge comprises at least one purine nucleotide. In some embodiments, a bulge comprises at least 3 purine nucleotides. In some embodiments, a bulge sequence comprises at least 5 purine nucleotides. In some embodiments, a bulge sequence comprises at least one guanine nucleotide. In some embodiments, a bulge sequence comprises at least one adenine nucleotide.
Hairpins
In various embodiments, one or more hairpins are located 3′ to the minimum tracrRNA in the 3′ tracrRNA sequence.
In some embodiments, the hairpin starts at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, or 20 or more nucleotides 3′ from the last paired nucleotide in the minimum CRISPR repeat and minimum tracrRNA sequence duplex. In some embodiments, the hairpin starts at most about 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 or more nucleotides 3′ of the last paired nucleotide in the minimum CRISPR repeat and minimum tracrRNA sequence duplex.
In some embodiments, the hairpin comprises at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, or 20 or more consecutive nucleotides. In some embodiments, the hairpin comprises at most about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, or more consecutive nucleotides.
In some embodiments, the hairpin comprises a CC dinucleotide (i.e., two consecutive cytosine nucleotides).
In some embodiments, the hairpin comprises duplexed nucleotides (e.g., nucleotides in a hairpin, hybridized together). For example, a hairpin comprises a CC dinucleotide that is hybridized to a GG dinucleotide in a hairpin duplex of the 3′ tracrRNA sequence.
One or more of the hairpins can interact with guide RNA-interacting regions of a site-directed polypeptide.
In some embodiments, there are two or more hairpins, and in other embodiments there are three or more hairpins.
3′ tracrRNA Sequence
In some embodiments, a 3′ tracrRNA sequence comprises a sequence with at least about 30%, about 40%, about 50%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, or 100% sequence identity to a reference tracrRNA sequence (e.g., a tracrRNA from S. pyogenes).
The 3′ tracrRNA sequence has a length from about 6 nucleotides to about 100 nucleotides. For example, the 3′ tracrRNA sequence can have a length from about 6 nucleotides (nt) to about 50 nt, from about 6 nt to about 40 nt, from about 6 nt to about 30 nt, from about 6 nt to about 25 nt, from about 6 nt to about 20 nt, from about 6 nt to about 15 nt, from about 8 nt to about 40 nt, from about 8 nt to about 30 nt, from about 8 nt to about 25 nt, from about 8 nt to about 20 nt, from about 8 nt to about 15 nt, from about 15 nt to about 100 nt, from about 15 nt to about 80 nt, from about 15 nt to about 50 nt, from about 15 nt to about 40 nt, from about 15 nt to about 30 nt, or from about 15 nt to about 25 nt. In some embodiments, the 3′ tracrRNA sequence has a length of approximately 14 nucleotides.
In some embodiments, the 3′ tracrRNA sequence is at least about 60% identical to a reference 3′ tracrRNA sequence (e.g., wild type 3′ tracrRNA sequence from S. pyogenes) over a stretch of at least 6, 7, or 8 contiguous nucleotides. For example, the 3′ tracrRNA sequence is at least about 60% identical, about 65% identical, about 70% identical, about 75% identical, about 80% identical, about 85% identical, about 90% identical, about 95% identical, about 98% identical, about 99% identical, or 100% identical, to a reference 3′ tracrRNA sequence (e.g., wild type 3′ tracrRNA sequence from S. pyogenes) over a stretch of at least 6, 7, or 8 contiguous nucleotides.
In some embodiments, the 3′ tracrRNA sequence comprises more than one duplexed region (e.g., hairpin, hybridized region). In some embodiments, the 3′ tracrRNA sequence comprises two duplexed regions.
In some embodiments, the 3′ tracrRNA sequence comprises a stem loop structure. In some embodiments, the stem loop structure in the 3′ tracrRNA comprises at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15 or 20 or more nucleotides. In some embodiments, the stem loop structure in the 3′ tracrRNA comprises at most 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 or more nucleotides. In some embodiments, the stem loop structure comprises a functional moiety. For example, the stem loop structure may comprise an aptamer, a ribozyme, a protein-interacting hairpin, a CRISPR array, an intron, or an exon. In some embodiments, the stem loop structure comprises at least about 1, 2, 3, 4, or 5 or more functional moieties. In some embodiments, the stem loop structure comprises at most about 1, 2, 3, 4, or 5 or more functional moieties.
In some embodiments, the hairpin in the 3′ tracrRNA sequence comprises a P-domain. In some embodiments, the P-domain comprises a double-stranded region in the hairpin.
tracrRNA Extension Sequence
In some embodiments, a tracrRNA extension sequence is provided whether the tracrRNA is in the context of single-molecule guides or double-molecule guides. In some embodiments, the tracrRNA extension sequence has a length from about 1 nucleotide to about 400 nucleotides. In some embodiments, the tracrRNA extension sequence has a length of more than 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 120, 140, 160, 180, 200, 220, 240, 260, 280, 300, 320, 340, 360, 380, or 400 nucleotides. In some embodiments, the tracrRNA extension sequence has a length from about 20 to about 5000 or more nucleotides. In some embodiments, the tracrRNA extension sequence has a length of more than 1000 nucleotides. In some embodiments, the tracrRNA extension sequence has a length of less than 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 120, 140, 160, 180, 200, 220, 240, 260, 280, 300, 320, 340, 360, 380, 400 or more nucleotides. In some embodiments, the tracrRNA extension sequence has a length of less than 1000 nucleotides. In some embodiments, the tracrRNA extension sequence comprises less than 10 nucleotides in length. In some embodiments, the tracrRNA extension sequence is 10-30 nucleotides in length. In some embodiments, the tracrRNA extension sequence is 30-70 nucleotides in length.
In some embodiments, the tracrRNA extension sequence comprises a functional moiety (e.g., a stability control sequence, ribozyme, endoribonuclease binding sequence). In some embodiments, the functional moiety comprises a transcriptional terminator segment (i.e., a transcription termination sequence). In some embodiments, the functional moiety has a total length from about 10 nucleotides (nt) to about 100 nucleotides, from about 10 nt to about 20 nt, from about 20 nt to about 30 nt, from about 30 nt to about 40 nt, from about 40 nt to about 50 nt, from about 50 nt to about 60 nt, from about 60 nt to about 70 nt, from about 70 nt to about 80 nt, from about 80 nt to about 90 nt, or from about 90 nt to about 100 nt, from about 15 nt to about 80 nt, from about 15 nt to about 50 nt, from about 15 nt to about 40 nt, from about 15 nt to about 30 nt, or from about 15 nt to about 25 nt. In some embodiments, the functional moiety functions in a eukaryotic cell. In some embodiments, the functional moiety functions in a prokaryotic cell. In some embodiments, the functional moiety functions in both eukaryotic and prokaryotic cells.
Non-limiting examples of suitable tracrRNA extension functional moieties include a 3′ poly-adenylated tail, a riboswitch sequence (e.g., to allow for regulated stability and/or regulated accessibility by proteins and protein complexes), a sequence that forms a dsRNA duplex (i.e., a hairpin), a sequence that targets the RNA to a subcellular location (e.g., nucleus, mitochondria, chloroplasts, and the like), a modification or sequence that provides for tracking (e.g., direct conjugation to a fluorescent molecule, conjugation to a moiety that facilitates fluorescent detection, a sequence that allows for fluorescent detection, etc.), and/or a modification or sequence that provides a binding site for proteins (e.g., proteins that act on DNA, including transcriptional activators, transcriptional repressors, DNA methyltransferases, DNA demethylases, histone acetyltransferases, histone deacetylases, and the like). In some embodiments, the tracrRNA extension sequence comprises a primer binding site or a molecular index (e.g., barcode sequence). In some embodiments, the tracrRNA extension sequence comprises one or more affinity tags.
Single-Molecule Guide Linker Sequence
In some embodiments, the linker sequence of a single-molecule guide nucleic acid has a length from about 3 nucleotides to about 100 nucleotides. In Jinek et al., supra, for example, a simple 4 nucleotide “tetraloop” (-GAAA-) was used, Science, 337(6096):816-821 (2012). An illustrative linker has a length from about 3 nucleotides (nt) to about 90 nt, from about 3 nt to about 80 nt, from about 3 nt to about 70 nt, from about 3 nt to about 60 nt, from about 3 nt to about 50 nt, from about 3 nt to about 40 nt, from about 3 nt to about 30 nt, from about 3 nt to about 20 nt, from about 3 nt to about 10 nt. For example, the linker can have a length from about 3 nt to about 5 nt, from about 5 nt to about 10 nt, from about 10 nt to about 15 nt, from about 15 nt to about 20 nt, from about 20 nt to about 25 nt, from about 25 nt to about 30 nt, from about 30 nt to about 35 nt, from about 35 nt to about 40 nt, from about 40 nt to about 50 nt, from about 50 nt to about 60 nt, from about 60 nt to about 70 nt, from about 70 nt to about 80 nt, from about 80 nt to about 90 nt, or from about 90 nt to about 100 nt. In some embodiments, the linker of a single-molecule guide nucleic acid is between 4 and 40 nucleotides. In some embodiments, the linker is at least about 100, 500, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500, 5000, 5500, 6000, 6500, or 7000 or more nucleotides. In some embodiments, the linker is at most about 100, 500, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500, 5000, 5500, 6000, 6500, or 7000 or more nucleotides.
Linkers comprise any of a variety of sequences, although in some examples the linker will not comprise sequences that have extensive regions of homology with other portions of the guide RNA, which might cause intramolecular binding that could interfere with other functional regions of the guide. In Jinek et al., supra, a simple 4 nucleotide sequence -GAAA- was used, Science, 337(6096):816-821 (2012), but numerous other sequences, including longer sequences can likewise be used.
In some embodiments, the linker sequence comprises a functional moiety. For example, the linker sequence may comprise one or more features, including an aptamer, a ribozyme, a protein-interacting hairpin, a protein binding site, a CRISPR array, an intron, or an exon. In some embodiments, the linker sequence comprises at least about 1, 2, 3, 4, or 5 or more functional moieties. In some embodiments, the linker sequence comprises at most about 1, 2, 3, 4, or 5 or more functional moieties.
Genome Engineering Strategies to Edit Cells by Deletion, Insertion, or Modulation of One or More Nucleic Acids or Exons within or Near a Target Gene, and by Knocking-in cDNA, an Expression Vector, or Minigene into the Locus of the Corresponding Target Gene
Some genome engineering strategies involve deleting the target DNA and/or knocking-in cDNA, expression vector, or a minigene (comprised of one or more exons and introns or natural or synthetic introns) and/or knocking-in a cDNA interrupted by some or all target introns into the locus of the corresponding gene. These strategies treat, and/or mitigate the diseased state. These strategies may require a more custom approach. This is advantageous, as HDR efficiencies may be inversely related to the size of the donor molecule. Also, it is expected that the donor templates can fit into size constrained viral vector molecules, e.g., adeno-associated virus (AAV) molecules, which have been shown to be an effective means of donor template delivery. Also, it is expected that the donor templates can fit into other size constrained molecules, including, by way of non-limiting example, platelets and/or exosomes or other microvesicles.
Homology direct repair is a cellular mechanism for repairing double-stranded breaks (DSBs). The most common form is homologous recombination. There are additional pathways for HDR, including single-strand annealing and alternative-HDR. Genome engineering tools allow researchers to manipulate the cellular homologous recombination pathways to create site-specific modifications to the genome. It has been found that cells can repair a double-stranded break using a synthetic donor molecule provided in trans. Therefore, by introducing a double-stranded break near a specific mutation and providing a suitable donor, targeted changes can be made in the genome. Specific cleavage increases the rate of HDR more than 1,000 fold above the rate of 1 in 106 cells receiving a homologous donor alone. The rate of homology directed repair (HDR) at a particular nucleotide is a function of the distance to the cut site, so choosing overlapping or nearest target sites is important. Gene editing offers the advantage over gene addition, as correcting in situ leaves the rest of the genome unperturbed.
Supplied donors for editing by HDR vary markedly but generally contain the intended sequence with small or large flanking homology arms to allow annealing to the genomic DNA. The homology regions flanking the introduced genetic changes can be 30 bp or smaller or as large as a multi-kilobase cassette that can contain promoters, cDNAs, etc. Both single-stranded and double-stranded oligonucleotide donors have been used. These oligonucleotides range in size from less than 100 nt to over many kb, though longer ssDNA can also be generated and used. Double-stranded donors are often used, including PCR amplicons, plasmids, and mini-circles. In general, it has been found that an AAV vector is a very effective means of delivery of a donor template, though the packaging limits for individual donors is <5 kb. Active transcription of the donor increased HDR three-fold, indicating the inclusion of promoter may increase conversion. Conversely, CpG methylation of the donor decreased gene expression and HDR.
In addition to wildtype endonucleases, such as Cas9, nickase variants exist that have one or the other nuclease domain inactivated resulting in cutting of only one DNA strand. HDR can be directed from individual Cas nickases or using pairs of nickases that flank the target area. Donors can be single-stranded, nicked, or dsDNA.
The donor DNA can be supplied with the nuclease or independently by a variety of different methods, for example by transfection, nano-particle, micro-injection, or viral transduction. A range of tethering options has been proposed to increase the availability of the donors for HDR. Examples include attaching the donor to the nuclease, attaching to DNA binding proteins that bind nearby, or attaching to proteins that are involved in DNA end binding or repair.
The repair pathway choice can be guided by a number of culture conditions, such as those that influence cell cycling, or by targeting of DNA repair and associated proteins. For example, to increase HDR, key NHEJ molecules can be suppressed, such as KU70, KU80 or DNA ligase IV.
Without a donor present, the ends from a DNA break or ends from different breaks can be joined using the several nonhomologous repair pathways in which the DNA ends are joined with little or no base-pairing at the junction. In addition to canonical NHEJ, there are similar repair mechanisms, such as alt-NHEJ. If there are two breaks, the intervening segment can be deleted or inverted. NHEJ repair pathways can lead to insertions, deletions or mutations at the joints.
NHEJ was used to insert a gene expression cassette into a defined locus in human cell lines after nuclease cleavage of both the chromosome and the donor molecule. (Cristea, et al., Biotechnology and Bioengineering 110:871-880 (2012); Maresca, M., Lin, V. G., Guo, N. & Yang, Y., Genome Res 23, 539-546 (2013)).
In addition to genome editing by NHEJ or HDR, site-specific gene insertions have been conducted that use both the NHEJ pathway and HR. A combination approach may be applicable in certain settings, possibly including intron/exon borders. NHEJ may prove effective for ligation in the intron, while the error-free HDR may be better suited in the coding region.
The target gene contains a number of exons. Any one or more of the exons or nearby introns may be targeted. Alternatively, there are various mutations associated with various medical conditions, which are a combination of insertions, deletions, missense, nonsense, frameshift and other mutations, with the common effect of inactivating target. Any one or more of the mutations may be repaired in order to restore the inactive target. As a further alternative, a cDNA construct, expression vector, or minigene (comprised of, natural or synthetic enhancer and promoter, one or more exons, and natural or synthetic introns, and natural or synthetic 3′UTR and polyadenylation signal) may be knocked-in to the genome or a target gene. In some embodiments, the methods can provide one gRNA or a pair of gRNAs that can be used to facilitate incorporation of a new sequence from a polynucleotide donor template to knock-in a cDNA construct, expression vector, or minigene
Some embodiments of the methods provide gRNA pairs that make a deletion by cutting the gene twice, one gRNA cutting at the 5′ end of one or more mutations and the other gRNA cutting at the 3′ end of one or more mutations that facilitates insertion of a new sequence from a polynucleotide donor template to replace the one or more mutations, or deletion may exclude mutant amino acids or amino acids adjacent to it (e.g., premature stop codon) and lead to expression of a functional protein, or restore an open reading frame. The cutting may be accomplished by a pair of DNA endonucleases that each makes a DSB in the genome, or by multiple nickases that together make a DSB in the genome.
Alternatively, some embodiments of the methods provide one gRNA to make one double-strand cut around one or more mutations that facilitates insertion of a new sequence from a polynucleotide donor template to replace the one or more mutations. The double-strand cut may be made by a single DNA endonuclease or multiple nickases that together make a DSB in the genome, or single gRNA may lead to deletion (MMEJ), which may exclude mutant amino acid (e.g., premature stop codon) and lead to expression of a functional protein, or restore an open reading frame.
Illustrative modifications within the target gene include replacements within or near (proximal) to the mutations referred to above, such as within the region of less than 3 kb, less than 2 kb, less than 1 kb, less than 0.5 kb upstream or downstream of the specific mutation. Given the relatively wide variations of mutations in the target gene, it will be appreciated that numerous variations of the replacements referenced above (including without limitation larger as well as smaller deletions), would be expected to result in restoration of the target gene.
Such variants include replacements that are larger in the 5′ and/or 3′ direction than the specific mutation in question, or smaller in either direction. Accordingly, by “near” or “proximal” with respect to specific replacements, it is intended that the SSB or DSB locus associated with a desired replacement boundary (also referred to herein as an endpoint) may be within a region that is less than about 3 kb from the reference locus noted. In some embodiments, the SSB or DSB locus is more proximal and within 2 kb, within 1 kb, within 0.5 kb, or within 0.1 kb. In the case of small replacement, the desired endpoint is at or “adjacent to” the reference locus, by which it is intended that the endpoint is within 100 bp, within 50 bp, within 25 bp, or less than about 10 bp to 5 bp from the reference locus.
Embodiments comprising larger or smaller replacements is expected to provide the same benefit, as long as the target protein activity is restored. It is thus expected that many variations of the replacements described and illustrated herein will be effective for ameliorating a medical condition.
Another genome engineering strategy involves exon deletion. Targeted deletion of specific exons is an attractive strategy for treating a large subset of patients with a single therapeutic cocktail. Deletions can either be single exon deletions or multi-exon deletions. While multi-exon deletions can reach a larger number of patients, for larger deletions the efficiency of deletion greatly decreases with increased size. Therefore, deletions range can be from 40 to 10,000 base pairs (bp) in size. For example, deletions may range from 40-100; 100-300; 300-500; 500-1,000; 1,000-2,000; 2,000-3,000; 3,000-5,000; or 5,000-10,000 base pairs in size.
Deletions can occur in enhancer, promoter, 1st intron, and/or 3′UTR leading to upregulation of the gene expression, and/or through deletion of the regulatory elements.
In order to ensure that the pre-mRNA is properly processed following deletion, the surrounding splicing signals can be deleted. Splicing donor and acceptors are generally within 100 base pairs of the neighboring intron. Therefore, in some embodiments, methods can provide all gRNAs that cut approximately +/−100-3100 bp with respect to each exon/intron junction of interest.
For any of the genome editing strategies, gene editing can be confirmed by sequencing or PCR analysis.
Target Sequence Selection
Shifts in the location of the 5′ boundary and/or the 3′ boundary relative to particular reference loci are used to facilitate or enhance particular applications of gene editing, which depend in part on the endonuclease system selected for the editing, as further described and illustrated herein.
In a first, nonlimiting example of such target sequence selection, many endonuclease systems have rules or criteria that guide the initial selection of potential target sites for cleavage, such as the requirement of a PAM sequence motif in a particular position adjacent to the DNA cleavage sites in the case of CRISPR Type II or Type V endonucleases.
In another nonlimiting example of target sequence selection or optimization, the frequency of off-target activity for a particular combination of target sequence and gene editing endonuclease (i.e. the frequency of DSBs occurring at sites other than the selected target sequence) is assessed relative to the frequency of on-target activity. In some embodiments, cells that have been correctly edited at the desired locus may have a selective advantage relative to other cells. Illustrative, but nonlimiting, examples of a selective advantage include the acquisition of attributes such as enhanced rates of replication, persistence, resistance to certain conditions, enhanced rates of successful engraftment or persistence in vivo following introduction into a patient, and other attributes associated with the maintenance or increased numbers or viability of such cells. In other embodiments, cells that have been correctly edited at the desired locus may be positively selected for by one or more screening methods used to identify, sort or otherwise select for cells that have been correctly edited. Both selective advantage and directed selection methods may take advantage of the phenotype associated with the correction. In some embodiments, cells may be edited two or more times in order to create a second modification that creates a new phenotype that is used to select or purify the intended population of cells. Such a second modification could be created by adding a second gRNA for a selectable or screenable marker. In some embodiments, cells can be correctly edited at the desired locus using a DNA fragment that contains the cDNA and also a selectable marker.
Whether any selective advantage is applicable or any directed selection is to be applied in a particular case, target sequence selection is also guided by consideration of off-target frequencies in order to enhance the effectiveness of the application and/or reduce the potential for undesired alterations at sites other than the desired target. As described further and illustrated herein and in the art, the occurrence of off-target activity is influenced by a number of factors including similarities and dissimilarities between the target site and various off-target sites, as well as the particular endonuclease used. Bioinformatics tools are available that assist in the prediction of off-target activity, and frequently such tools can also be used to identify the most likely sites of off-target activity, which can then be assessed in experimental settings to evaluate relative frequencies of off-target to on-target activity, thereby allowing the selection of sequences that have higher relative on-target activities. Illustrative examples of such techniques are provided herein, and others are known in the art.
Another aspect of target sequence selection relates to homologous recombination events. Sequences sharing regions of homology can serve as focal points for homologous recombination events that result in deletion of intervening sequences. Such recombination events occur during the normal course of replication of chromosomes and other DNA sequences, and also at other times when DNA sequences are being synthesized, such as in the case of repairs of double-strand breaks (DSBs), which occur on a regular basis during the normal cell replication cycle but may also be enhanced by the occurrence of various events (such as UV light and other inducers of DNA breakage) or the presence of certain agents (such as various chemical inducers). Many such inducers cause DSBs to occur indiscriminately in the genome, and DSBs are regularly being induced and repaired in normal cells. During repair, the original sequence may be reconstructed with complete fidelity, however, in some embodiments, small insertions or deletions (referred to as “indels”) are introduced at the DSB site.
DSBs may also be specifically induced at particular locations, as in the case of the endonucleases systems described herein, which can be used to cause directed or preferential gene modification events at selected chromosomal locations. The tendency for homologous sequences to be subject to recombination in the context of DNA repair (as well as replication) can be taken advantage of in a number of circumstances, and is the basis for one application of gene editing systems, such as CRISPR, in which homology directed repair is used to insert a sequence of interest, provided through use of a “donor” polynucleotide, into a desired chromosomal location.
Regions of homology between particular sequences, which can be small regions of “microhomology” that may comprise as few as ten basepairs or less, can also be used to bring about desired deletions. For example, a single DSB is introduced at a site that exhibits microhomology with a nearby sequence. During the normal course of repair of such DSB, a result that occurs with high frequency is the deletion of the intervening sequence as a result of recombination being facilitated by the DSB and concomitant cellular repair process.
In some circumstances, however, selecting target sequences within regions of homology can also give rise to much larger deletions, including gene fusions (when the deletions are in coding regions), which may or may not be desired given the particular circumstances.
The examples provided herein further illustrate the selection of various target regions for the creation of DSBs designed to induce replacements that result in modulation of target protein activity, as well as the selection of specific target sequences within such regions that are designed to minimize off-target events relative to on-target events.
Nucleic Acid Modifications
In some embodiments, polynucleotides introduced into cells comprise one or more modifications that can be used individually or in combination, for example, to enhance activity, stability or specificity, alter delivery, reduce innate immune responses in host cells, or for other enhancements, as further described herein and known in the art.
In some embodiments, modified polynucleotides are used in the CRISPR/Cas9/Cpf1 system, in which case the guide RNAs (either single-molecule guides or double-molecule guides) and/or a DNA or an RNA encoding a Cas or Cpf1 endonuclease introduced into a cell can be modified, as described and illustrated below. Such modified polynucleotides can be used in the CRISPR/Cas9/Cpf1 system to edit any one or more genomic loci.
Using the CRISPR/Cas9/Cpf1 system for purposes of nonlimiting illustrations of such uses, modifications of guide RNAs can be used to enhance the formation or stability of the CRISPR/Cas9/Cpf1 genome editing complex comprising guide RNAs, which may be single-molecule guides or double-molecule, and a Cas or Cpf1 endonuclease. Modifications of guide RNAs can also or alternatively be used to enhance the initiation, stability or kinetics of interactions between the genome editing complex with the target sequence in the genome, which can be used, for example, to enhance on-target activity. Modifications of guide RNAs can also or alternatively be used to enhance specificity, e.g., the relative rates of genome editing at the on-target site as compared to effects at other (off-target) sites.
Modifications can also or alternatively be used to increase the stability of a guide RNA, e.g., by increasing its resistance to degradation by ribonucleases (RNases) present in a cell, thereby causing its half-life in the cell to be increased. Modifications enhancing guide RNA half-life can be particularly useful in aspects in which a Cas or Cpf1 endonuclease is introduced into the cell to be edited via an RNA that needs to be translated in order to generate endonuclease, because increasing the half-life of guide RNAs introduced at the same time as the RNA encoding the endonuclease can be used to increase the time that the guide RNAs and the encoded Cas or Cpf1 endonuclease co-exist in the cell.
Modifications can also or alternatively be used to decrease the likelihood or degree to which RNAs introduced into cells elicit innate immune responses. Such responses, which have been well characterized in the context of RNA interference (RNAi), including small-interfering RNAs (siRNAs), as described below and in the art, tend to be associated with reduced half-life of the RNA and/or the elicitation of cytokines or other factors associated with immune responses.
One or more types of modifications can also be made to RNAs encoding an endonuclease that are introduced into a cell, including, without limitation, modifications that enhance the stability of the RNA (such as by increasing its degradation by RNAses present in the cell), modifications that enhance translation of the resulting product (i.e. the endonuclease), and/or modifications that decrease the likelihood or degree to which the RNAs introduced into cells elicit innate immune responses.
Combinations of modifications, such as the foregoing and others, can likewise be used. In the case of CRISPR/Cas9/Cpf1, for example, one or more types of modifications can be made to guide RNAs (including those exemplified above), and/or one or more types of modifications can be made to RNAs encoding Cas endonuclease (including those exemplified above).
By way of illustration, guide RNAs used in the CRISPR/Cas9/Cpf1 system, or other smaller RNAs can be readily synthesized by chemical means, enabling a number of modifications to be readily incorporated, as illustrated below and described in the art. While chemical synthetic procedures are continually expanding, purifications of such RNAs by procedures such as high performance liquid chromatography (HPLC, which avoids the use of gels such as PAGE) tends to become more challenging as polynucleotide lengths increase significantly beyond a hundred or so nucleotides. One approach used for generating chemically-modified RNAs of greater length is to produce two or more molecules that are ligated together. Much longer RNAs, such as those encoding a Cas9 endonuclease, are more readily generated enzymatically. While fewer types of modifications are generally available for use in enzymatically produced RNAs, there are still modifications that can be used to, e.g., enhance stability, reduce the likelihood or degree of innate immune response, and/or enhance other attributes, as described further below and in the art; and new types of modifications are regularly being developed.
By way of illustration of various types of modifications, especially those used frequently with smaller chemically synthesized RNAs, modifications can comprise one or more nucleotides modified at the 2′ position of the sugar, in some embodiments, a 2′-O-alkyl, 2′-O-alkyl-O-alkyl, or 2′-fluoro-modified nucleotide. In some embodiments, RNA modifications comprise 2′-fluoro, 2′-amino or 2′ O-methyl modifications on the ribose of pyrimidines, abasic residues, or an inverted base at the 3′ end of the RNA. Such modifications are routinely incorporated into oligonucleotides and these oligonucleotides have been shown to have a higher Tm (i.e., higher target binding affinity) than 2′-deoxyoligonucleotides against a given target.
A number of nucleotide and nucleoside modifications have been shown to make the oligonucleotide into which they are incorporated more resistant to nuclease digestion than the native oligonucleotide; these modified oligos survive intact for a longer time than unmodified oligonucleotides. Specific examples of modified oligonucleotides include those comprising modified backbones, for example, phosphorothioates, phosphotriesters, methyl phosphonates, short chain alkyl or cycloalkyl intersugar linkages or short chain heteroatomic or heterocyclic intersugar linkages. Some oligonucleotides are oligonucleotides with phosphorothioate backbones and those with heteroatom backbones, particularly CH2—NH—O—CH2, CH, ˜N(CH3)˜O˜CH2 (known as a methylene(methylimino) or MMI backbone), CH2—O—N (CH3)—CH2, CH2—N(CH3)—N(CH3)—CH2 and O—N(CH3)—CH2—CH2 backbones, wherein the native phosphodiester backbone is represented as O—P—O—CH); amide backbones [see De Mesmaeker et al., Ace. Chem. Res., 28:366-374 (1995)]; morpholino backbone structures (see Summerton and Weller, U.S. Pat. No. 5,034,506); peptide nucleic acid (PNA) backbone (wherein the phosphodiester backbone of the oligonucleotide is replaced with a polyamide backbone, the nucleotides being bound directly or indirectly to the aza nitrogen atoms of the polyamide backbone, see Nielsen et al., Science 1991, 254, 1497). Phosphorus-containing linkages include, but are not limited to, phosphorothioates, chiral phosphorothioates, phosphorodithioates, phosphotriesters, aminoalkylphosphotriesters, methyl and other alkyl phosphonates comprising 3′alkylene phosphonates and chiral phosphonates, phosphinates, phosphoramidates comprising 3′-amino phosphoramidate and aminoalkylphosphoramidates, thionophosphoramidates, thionoalkylphosphonates, thionoalkylphosphotriesters, and boranophosphates having normal 3′-5′ linkages, 2′-5′ linked analogs of these, and those having inverted polarity wherein the adjacent pairs of nucleoside units are linked 3′-5′ to 5′-3′ or 2′-5′ to 5′-2′; see U.S. Pat. Nos. 3,687,808; 4,469,863; 4,476,301; 5,023,243; 5,177,196; 5,188,897; 5,264,423; 5,276,019; 5,278,302; 5,286,717; 5,321,131; 5,399,676; 5,405,939; 5,453,496; 5,455,233; 5,466,677; 5,476,925; 5,519,126; 5,536,821; 5,541,306; 5,550,111; 5,563,253; 5,571,799; 5,587,361; and 5,625,050, each of which is herein incorporated by reference.
Morpholino-based oligomeric compounds are described in Braasch and David Corey, Biochemistry, 41(14): 4503-4510 (2002); Genesis, Volume 30, Issue 3, (2001); Heasman, Dev. Biol., 243: 209-214 (2002); Nasevicius et al., Nat. Genet., 26:216-220 (2000); Lacerra et al., Proc. Natl. Acad. Sci., 97: 9591-9596 (2000); and U.S. Pat. No. 5,034,506, issued Jul. 23, 1991.
Cyclohexenyl nucleic acid oligonucleotide mimetics are described in Wang et al., J. Am. Chem. Soc., 122: 8595-8602 (2000).
Modified oligonucleotide backbones that do not include a phosphorus atom therein have backbones that are formed by short chain alkyl or cycloalkyl internucleoside linkages, mixed heteroatom and alkyl or cycloalkyl internucleoside linkages, or one or more short chain heteroatomic or heterocyclic internucleoside linkages. These comprise those having morpholino linkages (formed in part from the sugar portion of a nucleoside); siloxane backbones; sulfide, sulfoxide and sulfone backbones; formacetyl and thioformacetyl backbones; methylene formacetyl and thioformacetyl backbones; alkene containing backbones; sulfamate backbones; methyleneimino and methylenehydrazino backbones; sulfonate and sulfonamide backbones; amide backbones; and others having mixed N, O, S, and CH2 component parts; see U.S. Pat. Nos. 5,034,506; 5,166,315; 5,185,444; 5,214,134; 5,216,141; 5,235,033; 5,264,562; 5,264,564; 5,405,938; 5,434,257; 5,466,677; 5,470,967; 5,489,677; 5,541,307; 5,561,225; 5,596,086; 5,602,240; 5,610,289; 5,602,240; 5,608,046; 5,610,289; 5,618,704; 5,623,070; 5,663,312; 5,633,360; 5,677,437; and 5,677,439, each of which is herein incorporated by reference.
One or more substituted sugar moieties can also be included, e.g., one of the following at the 2′ position: OH, SH, SCH3, F, OCN, OCH3, OCH3 O(CH2)n CH3, O(CH2)n NH2, or O(CH2)n CH3, where n is from 1 to about 10; C1 to C10 lower alkyl, alkoxyalkoxy, substituted lower alkyl, alkaryl or aralkyl; Cl; Br; CN; CF3; OCF3; O-, S-, or N-alkyl; O-, S-, or N-alkenyl; SOCH3; SO2 CH3; ONO2; NO2; N3; NH2; heterocycloalkyl; heterocycloalkaryl; aminoalkylamino; polyalkylamino; substituted silyl; an RNA cleaving group; a reporter group; an intercalator; a group for improving the pharmacokinetic properties of an oligonucleotide; or a group for improving the pharmacodynamic properties of an oligonucleotide and other substituents having similar properties. In some embodiments, a modification includes 2′-methoxyethoxy (2′-O—CH2CH2OCH3, also known as 2′-O-(2-methoxyethyl)) (Martin et al, Helv. Chim. Acta, 1995, 78, 486). Other modifications include 2′-methoxy (2′-O—CH3), 2′-propoxy (2′-OCH2 CH2CH3) and 2′-fluoro (2′-F). Similar modifications may also be made at other positions on the oligonucleotide, particularly the 3′ position of the sugar on the 3′ terminal nucleotide and the 5′ position of 5′ terminal nucleotide. Oligonucleotides may also have sugar mimetics, such as cyclobutyls in place of the pentofuranosyl group.
In some embodiments, both a sugar and an internucleoside linkage, i.e., the backbone, of the nucleotide units are replaced with novel groups. The base units are maintained for hybridization with an appropriate nucleic acid target compound. One such oligomeric compound, an oligonucleotide mimetic that has been shown to have excellent hybridization properties, is referred to as a peptide nucleic acid (PNA). In PNA compounds, the sugar-backbone of an oligonucleotide is replaced with an amide containing backbone, for example, an aminoethylglycine backbone. The nucleobases are retained and are bound directly or indirectly to aza nitrogen atoms of the amide portion of the backbone. Representative United States patents that teach the preparation of PNA compounds comprise, but are not limited to, U.S. Pat. Nos. 5,539,082; 5,714,331; and 5,719,262. Further teaching of PNA compounds can be found in Nielsen et al, Science, 254: 1497-1500 (1991).
Guide RNAs can also include, additionally or alternatively, nucleobase (often referred to in the art simply as “base”) modifications or substitutions. As used herein, “unmodified” or “natural” nucleobases include adenine (A), guanine (G), thymine (T), cytosine (C), and uracil (U). Modified nucleobases include nucleobases found only infrequently or transiently in natural nucleic acids, e.g., hypoxanthine, 6-methyladenine, 5-Me pyrimidines, particularly 5-methylcytosine (also referred to as 5-methyl-2′ deoxycytosine and often referred to in the art as 5-Me-C), 5-hydroxymethylcytosine (HMC), glycosyl HMC and gentobiosyl HMC, as well as synthetic nucleobases, e.g., 2-aminoadenine, 2-(methylamino)adenine, 2-(imidazolylalkyl)adenine, 2-(aminoalklyamino)adenine or other heterosubstituted alkyladenines, 2-thiouracil, 2-thiothymine, 5-bromouracil, 5-hydroxymethyluracil, 8-azaguanine, 7-deazaguanine, N6 (6-aminohexyl)adenine, and 2,6-diaminopurine. Kornberg, A., DNA Replication, W. H. Freeman & Co., San Francisco, pp 75-77 (1980); Gebeyehu et al., Nucl. Acids Res. 15:4513 (1997). A “universal” base known in the art, e.g., inosine, can also be included. 5-Me-C substitutions have been shown to increase nucleic acid duplex stability by 0.6-1.2° C. (Sanghvi, Y. S., in Crooke, S. T. and Lebleu, B., eds., Antisense Research and Applications, CRC Press, Boca Raton, 1993, pp. 276-278) and are embodiments of base substitutions.
Modified nucleobases comprise other synthetic and natural nucleobases, such as 5-methylcytosine (5-me-C), 5-hydroxymethyl cytosine, xanthine, hypoxanthine, 2-aminoadenine, 6-methyl and other alkyl derivatives of adenine and guanine, 2-propyl and other alkyl derivatives of adenine and guanine, 2-thiouracil, 2-thiothymine and 2-thiocytosine, 5-halouracil and cytosine, 5-propynyl uracil and cytosine, 6-azo uracil, cytosine and thymine, 5-uracil (pseudo-uracil), 4-thiouracil, 8-halo, 8-amino, 8-thiol, 8-thioalkyl, 8-hydroxyl and other 8-substituted adenines and guanines, 5-halo particularly 5-bromo, 5-trifluoromethyl and other 5-substituted uracils and cytosines, 7-methylquanine and 7-methyladenine, 8-azaguanine and 8-azaadenine, 7-deazaguanine and 7-deazaadenine, and 3-deazaguanine and 3-deazaadenine.
Further, nucleobases comprise those disclosed in U.S. Pat. No. 3,687,808, those disclosed in ‘The Concise Encyclopedia of Polymer Science And Engineering’, pages 858-859, Kroschwitz, J. I., ed. John Wiley & Sons, 1990, those disclosed by Englisch et al., Angewandle Chemie, International Edition', 1991, 30, page 613, and those disclosed by Sanghvi, Y. S., Chapter 15, Antisense Research and Applications', pages 289-302, Crooke, S. T. and Lebleu, B. ea., CRC Press, 1993. Certain of these nucleobases are particularly useful for increasing the binding affinity of the oligomeric compounds of the disclosure. These include 5-substituted pyrimidines, 6-azapyrimidines and N-2, N-6 and 0-6 substituted purines, comprising 2-aminopropyladenine, 5-propynyluracil and 5-propynylcytosine. 5-methylcytosine substitutions have been shown to increase nucleic acid duplex stability by 0.6-1.2° C. (Sanghvi, Y. S., Crooke, S. T. and Lebleu, B., eds, ‘Antisense Research and Applications’, CRC Press, Boca Raton, 1993, pp. 276-278) and are aspects of base substitutions, even more particularly when combined with 2′-O-methoxyethyl sugar modifications. Modified nucleobases are described in U.S. Pat. No. 3,687,808, as well as U.S. Pat. Nos. 4,845,205; 5,130,302; 5,134,066; 5,175,273; 5,367,066; 5,432,272; 5,457,187; 5,459,255; 5,484,908; 5,502,177; 5,525,711; 5,552,540; 5,587,469; 5,596,091; 5,614,617; 5,681,941; 5,750,692; 5,763,588; 5,830,653; 6,005,096; and US Patent Application Publication 2003/0158403.
Thus, the term “modified” refers to a non-natural sugar, phosphate, or base that is incorporated into a guide RNA, an endonuclease, or both a guide RNA and an endonuclease. It is not necessary for all positions in a given oligonucleotide to be uniformly modified, and in fact more than one of the aforementioned modifications may be incorporated in a single oligonucleotide, or even in a single nucleoside within an oligonucleotide.
In some embodiments, the guide RNAs and/or mRNA (or DNA) encoding an endonuclease are chemically linked to one or more moieties or conjugates that enhance the activity, cellular distribution, or cellular uptake of the oligonucleotide. Such moieties comprise, but are not limited to, lipid moieties such as a cholesterol moiety [Letsinger et al., Proc. Natl. Acad. Sci. USA, 86: 6553-6556 (1989)]; cholic acid [Manoharan et al., Bioorg. Med. Chem. Let., 4: 1053-1060 (1994)]; a thioether, e.g., hexyl-S-tritylthiol [Manoharan et al, Ann. N. Y. Acad. Sci., 660: 306-309 (1992) and Manoharan et al., Bioorg. Med. Chem. Let., 3: 2765-2770 (1993)]; a thiocholesterol [Oberhauser et al., Nucl. Acids Res., 20: 533-538 (1992)]; an aliphatic chain, e.g., dodecandiol or undecyl residues [Kabanov et al., FEBS Lett., 259: 327-330 (1990) and Svinarchuk et al., Biochimie, 75: 49-54 (1993)]; a phospholipid, e.g., di-hexadecyl-rac-glycerol or triethylammonium 1,2-di-O-hexadecyl-rac-glycero-3-H-phosphonate [Manoharan et al., Tetrahedron Lett., 36: 3651-3654 (1995) and Shea et al., Nucl. Acids Res., 18: 3777-3783 (1990)]; a polyamine or a polyethylene glycol chain [Mancharan et al., Nucleosides & Nucleotides, 14: 969-973 (1995)]; adamantane acetic acid [Manoharan et al., Tetrahedron Lett., 36: 3651-3654 (1995)]; a palmityl moiety [(Mishra et al., Biochim. Biophys. Acta, 1264: 229-237 (1995)]; or an octadecylamine or hexylamino-carbonyl-t oxycholesterol moiety [Crooke et al., J. Pharmacol. Exp. Ther., 277: 923-937 (1996)]. See also U.S. Pat. Nos. 4,828,979; 4,948,882; 5,218,105; 5,525,465; 5,541,313; 5,545,730; 5,552,538; 5,578,717, 5,580,731; 5,580,731; 5,591,584; 5,109,124; 5,118,802; 5,138,045; 5,414,077; 5,486,603; 5,512,439; 5,578,718; 5,608,046; 4,587,044; 4,605,735; 4,667,025; 4,762,779; 4,789,737; 4,824,941; 4,835,263; 4,876,335; 4,904,582; 4,958,013; 5,082,830; 5,112,963; 5,214,136; 5,082,830; 5,112,963; 5,214,136; 5,245,022; 5,254,469; 5,258,506; 5,262,536; 5,272,250; 5,292,873; 5,317,098; 5,371,241, 5,391,723; 5,416,203, 5,451,463; 5,510,475; 5,512,667; 5,514,785; 5,565,552; 5,567,810; 5,574,142; 5,585,481; 5,587,371; 5,595,726; 5,597,696; 5,599,923; 5,599, 928 and 5,688,941.
Sugars and other moieties can be used to target proteins and complexes comprising nucleotides, such as cationic polysomes and liposomes, to particular sites. For example, hepatic cell directed transfer can be mediated via asialoglycoprotein receptors (ASGPRs); see, e.g., Hu, et al., Protein Pept Lett. 21(10):1025-30 (2014). Other systems known in the art and regularly developed can be used to target biomolecules of use in the present case and/or complexes thereof to particular target cells of interest.
These targeting moieties or conjugates can include conjugate groups covalently bound to functional groups, such as primary or secondary hydroxyl groups. Conjugate groups of the disclosure include intercalators, reporter molecules, polyamines, polyamides, polyethylene glycols, polyethers, groups that enhance the pharmacodynamic properties of oligomers, and groups that enhance the pharmacokinetic properties of oligomers. Typical conjugate groups include cholesterols, lipids, phospholipids, biotin, phenazine, folate, phenanthridine, anthraquinone, acridine, fluoresceins, rhodamines, coumarins, and dyes. Groups that enhance the pharmacodynamic properties, in the context of this disclosure, include groups that improve uptake, enhance resistance to degradation, and/or strengthen sequence-specific hybridization with the target nucleic acid. Groups that enhance the pharmacokinetic properties, in the context of this disclosure, include groups that improve uptake, distribution, metabolism or excretion of the compounds of the present disclosure. Representative conjugate groups are disclosed in International Patent Application No. PCT/US92/09196, filed Oct. 23, 1992, and U.S. Pat. No. 6,287,860, which are incorporated herein by reference. Conjugate moieties include, but are not limited to, lipid moieties such as a cholesterol moiety, cholic acid, a thioether, e.g., hexyl-5-tritylthiol, a thiocholesterol, an aliphatic chain, e.g., dodecandiol or undecyl residues, a phospholipid, e.g., di-hexadecyl-rac-glycerol or triethylammonium 1,2-di-O-hexadecyl-rac-glycero-3-H-phosphonate, a polyamine or a polyethylene glycol chain, or adamantane acetic acid, a palmityl moiety, or an octadecylamine or hexylamino-carbonyl-oxy cholesterol moiety. See, e.g., U.S. Pat. Nos. 4,828,979; 4,948,882; 5,218,105; 5,525,465; 5,541,313; 5,545,730; 5,552,538; 5,578,717, 5,580,731; 5,580,731; 5,591,584; 5,109,124; 5,118,802; 5,138,045; 5,414,077; 5,486,603; 5,512,439; 5,578,718; 5,608,046; 4,587,044; 4,605,735; 4,667,025; 4,762,779; 4,789,737; 4,824,941; 4,835,263; 4,876,335; 4,904,582; 4,958,013; 5,082,830; 5,112,963; 5,214,136; 5,082,830; 5,112,963; 5,214,136; 5,245,022; 5,254,469; 5,258,506; 5,262,536; 5,272,250; 5,292,873; 5,317,098; 5,371,241, 5,391,723; 5,416,203, 5,451,463; 5,510,475; 5,512,667; 5,514,785; 5,565,552; 5,567,810; 5,574,142; 5,585,481; 5,587,371; 5,595,726; 5,597,696; 5,599,923; 5,599,928 and 5,688,941.
Longer polynucleotides that are less amenable to chemical synthesis and are typically produced by enzymatic synthesis can also be modified by various means. Such modifications can include, for example, the introduction of certain nucleotide analogs, the incorporation of particular sequences or other moieties at the 5′ or 3′ ends of molecules, and other modifications. By way of illustration, the mRNA encoding Cas9 is approximately 4 kb in length and can be synthesized by in vitro transcription. Modifications to the mRNA can be applied to, e.g., increase its translation or stability (such as by increasing its resistance to degradation with a cell), or to reduce the tendency of the RNA to elicit an innate immune response that is often observed in cells following introduction of exogenous RNAs, particularly longer RNAs such as that encoding Cas9.
Numerous such modifications have been described in the art, such as polyA tails, 5′ cap analogs (e.g., Anti Reverse Cap Analog (ARCA) or m7G(5′)ppp(5′)G (mCAP)), modified 5′ or 3′ untranslated regions (UTRs), use of modified bases (such as Pseudo-UTP, 2-Thio-UTP, 5-Methylcytidine-5′-Triphosphate (5-Methyl-CTP) or N6-Methyl-ATP), or treatment with phosphatase to remove 5′ terminal phosphates. These and other modifications are known in the art, and new modifications of RNAs are regularly being developed.
There are numerous commercial suppliers of modified RNAs, including for example, TriLink Biotech, AxoLabs, Bio-Synthesis Inc., Dharmacon and many others. As described by TriLink, for example, 5-Methyl-CTP can be used to impart desirable characteristics, such as increased nuclease stability, increased translation or reduced interaction of innate immune receptors with in vitro transcribed RNA. 5-Methylcytidine-5′-Triphosphate (5-Methyl-CTP), N6-Methyl-ATP, as well as Pseudo-UTP and 2-Thio-UTP, have also been shown to reduce innate immune stimulation in culture and in vivo while enhancing translation, as illustrated in publications by Kormann et al. and Warren et al. referred to below.
It has been shown that chemically modified mRNA delivered in vivo can be used to achieve improved therapeutic effects; see, e.g., Kormann et al., Nature Biotechnology 29, 154-157 (2011). Such modifications can be used, for example, to increase the stability of the RNA molecule and/or reduce its immunogenicity. Using chemical modifications such as Pseudo-U, N6-Methyl-A, 2-Thio-U and 5-Methyl-C, it was found that substituting just one quarter of the uridine and cytidine residues with 2-Thio-U and 5-Methyl-C respectively resulted in a significant decrease in toll-like receptor (TLR) mediated recognition of the mRNA in mice. By reducing the activation of the innate immune system, these modifications can be used to effectively increase the stability and longevity of the mRNA in vivo; see, e.g., Kormann et al., supra.
It has also been shown that repeated administration of synthetic messenger RNAs incorporating modifications designed to bypass innate anti-viral responses can reprogram differentiated human cells to pluripotency. See, e.g., Warren, et al., Cell Stem Cell, 7(5):618-30 (2010). Such modified mRNAs that act as primary reprogramming proteins can be an efficient means of reprogramming multiple human cell types. Such cells are referred to as induced pluripotency stem cells (iPSCs), and it was found that enzymatically synthesized RNA incorporating 5-Methyl-CTP, Pseudo-UTP and an Anti Reverse Cap Analog (ARCA) could be used to effectively evade the cell's antiviral response; see, e.g., Warren et al., supra.
Other modifications of polynucleotides described in the art include, for example, the use of polyA tails, the addition of 5′ cap analogs (such as m7G(5′)ppp(5′)G (mCAP)), modifications of 5′ or 3′ untranslated regions (UTRs), or treatment with phosphatase to remove 5′ terminal phosphates—and new approaches are regularly being developed.
A number of compositions and techniques applicable to the generation of modified RNAs for use herein have been developed in connection with the modification of RNA interference (RNAi), including small-interfering RNAs (siRNAs). siRNAs present particular challenges in vivo because their effects on gene silencing via mRNA interference are generally transient, which can require repeat administration. In addition, siRNAs are double-stranded RNAs (dsRNA) and mammalian cells have immune responses that have evolved to detect and neutralize dsRNA, which is often a by-product of viral infection. Thus, there are mammalian enzymes such as PKR (dsRNA-responsive kinase), and potentially retinoic acid-inducible gene I (RIG-I), that can mediate cellular responses to dsRNA, as well as Toll-like receptors (such as TLR3, TLR7 and TLR8) that can trigger the induction of cytokines in response to such molecules; see, e.g., the reviews by Angart et al., Pharmaceuticals (Basel) 6(4): 440-468 (2013); Kanasty et al., Molecular Therapy 20(3): 513-524 (2012); Burnett et al., Biotechnol J. 6(9):1130-46 (2011); Judge and MacLachlan, Hum Gene Ther 19(2):111-24 (2008); and references cited therein.
A large variety of modifications have been developed and applied to enhance RNA stability, reduce innate immune responses, and/or achieve other benefits that can be useful in connection with the introduction of polynucleotides into human cells, as described herein; see, e.g., the reviews by Whitehead K A et al., Annual Review of Chemical and Biomolecular Engineering, 2: 77-96 (2011); Gaglione and Messere, Mini Rev Med Chem, 10(7):578-95 (2010); Chernolovskaya et al, Curr Opin Mol Ther., 12(2):158-67 (2010); Deleavey et al., Curr Protoc Nucleic Acid Chem Chapter 16:Unit 16.3 (2009); Behlke, Oligonucleotides 18(4):305-19 (2008); Fucini et al., Nucleic Acid Ther 22(3): 205-210 (2012); Bremsen et al., Front Genet 3:154 (2012).
As noted above, there are a number of commercial suppliers of modified RNAs, many of which have specialized in modifications designed to improve the effectiveness of siRNAs. A variety of approaches are offered based on various findings reported in the literature. For example, Dharmacon notes that replacement of a non-bridging oxygen with sulfur (phosphorothioate, PS) has been extensively used to improve nuclease resistance of siRNAs, as reported by Kole, Nature Reviews Drug Discovery 11:125-140 (2012). Modifications of the 2′-position of the ribose have been reported to improve nuclease resistance of the internucleotide phosphate bond while increasing duplex stability (Tm), which has also been shown to provide protection from immune activation. A combination of moderate PS backbone modifications with small, well-tolerated 2′-substitutions (2′-O-Methyl, 2′-Fluoro, 2′-Hydro) have been associated with highly stable siRNAs for applications in vivo, as reported by Soutschek et al. Nature 432:173-178 (2004); and 2′-O-Methyl modifications have been reported to be effective in improving stability as reported by Volkov, Oligonucleotides 19:191-202 (2009). With respect to decreasing the induction of innate immune responses, modifying specific sequences with 2′-O-Methyl, 2′-Fluoro, 2′-Hydro have been reported to reduce TLR7/TLR8 interaction while generally preserving silencing activity; see, e.g., Judge et al., Mol. Ther. 13:494-505 (2006); and Cekaite et al., J. Mol. Biol. 365:90-108 (2007). Additional modifications, such as 2-thiouracil, pseudouracil, 5-methylcytosine, 5-methyluracil, and N6-methyladenosine have also been shown to minimize the immune effects mediated by TLR3, TLR7, and TLR8; see, e.g., Kariko, K. et al., Immunity 23:165-175 (2005).
As is also known in the art, and commercially available, a number of conjugates can be applied to polynucleotides, such as RNAs, for use herein that can enhance their delivery and/or uptake by cells, including for example, cholesterol, tocopherol and folic acid, lipids, peptides, polymers, linkers and aptamers; see, e.g., the review by Winkler, Ther. Deliv. 4:791-809 (2013), and references cited therein.
Codon-Optimization
In some embodiments, a polynucleotide encoding a site-directed polypeptide is codon-optimized according to methods standard in the art for expression in the cell containing the target DNA of interest. For example, if the intended target nucleic acid is in a human cell, a human codon-optimized polynucleotide encoding Cas9 is contemplated for use for producing the Cas9 polypeptide.
Complexes of a Genome-targeting Nucleic Acid and a Site-Directed Polypeptide
A genome-targeting nucleic acid interacts with a site-directed polypeptide (e.g., a nucleic acid-guided nuclease such as Cas9), thereby forming a complex. The genome-targeting nucleic acid guides the site-directed polypeptide to a target nucleic acid.
RNPs
The site-directed polypeptide and genome-targeting nucleic acid may each be administered separately to a cell or a patient. On the other hand, the site-directed polypeptide may be pre-complexed with one or more guide RNAs, or one or more crRNA together with a tracrRNA. The pre-complexed material may then be administered to a cell or a patient. Such pre-complexed material is known as a ribonucleoprotein particle (RNP).
Nucleic Acids Encoding System Components
The present disclosure provides a nucleic acid comprising a nucleotide sequence encoding a genome-targeting nucleic acid of the disclosure, a site-directed polypeptide of the disclosure, and/or any nucleic acid or proteinaceous molecule necessary to carry out the aspects of the methods of the disclosure.
The nucleic acid encoding a genome-targeting nucleic acid of the disclosure, a site-directed polypeptide of the disclosure, and/or any nucleic acid or proteinaceous molecule necessary to carry out the aspects of the methods of the disclosure comprises a vector (e.g., a recombinant expression vector).
The term “vector” refers to a nucleic acid molecule capable of transporting another nucleic acid to which it has been linked. One type of vector is a “plasmid”, which refers to a circular double-stranded DNA loop into which additional nucleic acid segments can be ligated. Another type of vector is a viral vector (e.g., AAV), wherein additional nucleic acid segments can be ligated into the viral genome. Certain vectors are capable of autonomous replication in a host cell into which they are introduced (e.g., bacterial vectors having a bacterial origin of replication and episomal mammalian vectors). Other vectors (e.g., non-episomal mammalian vectors) are integrated into the genome of a host cell upon introduction into the host cell, and thereby are replicated along with the host genome.
In some embodiments, vectors are capable of directing the expression of nucleic acids to which they are operatively linked. Such vectors are referred to herein as “recombinant expression vectors”, or more simply “expression vectors”, which serve equivalent functions.
The term “operably linked” means that the nucleotide sequence of interest is linked to regulatory sequence(s) in a manner that allows for expression of the nucleotide sequence. The term “regulatory sequence” is intended to include, for example, promoters, enhancers and other expression control elements (e.g., polyadenylation signals). Such regulatory sequences are well known in the art and are described, for example, in Goeddel; Gene Expression Technology: Methods in Enzymology 185, Academic Press, San Diego, Calif. (1990). Regulatory sequences include those that direct constitutive expression of a nucleotide sequence in many types of host cells, and those that direct expression of the nucleotide sequence only in certain host cells (e.g., tissue-specific regulatory sequences). It will be appreciated by those skilled in the art that the design of the expression vector can depend on such factors as the choice of the target cell, the level of expression desired, and the like.
Expression vectors contemplated include, but are not limited to, viral vectors based on vaccinia virus, poliovirus, adenovirus, adeno-associated virus, SV40, herpes simplex virus, human immunodeficiency virus, retrovirus (e.g., Murine Leukemia Virus, spleen necrosis virus, and vectors derived from retroviruses such as Rous Sarcoma Virus, Harvey Sarcoma Virus, avian leukosis virus, a lentivirus, human immunodeficiency virus, myeloproliferative sarcoma virus, and mammary tumor virus) and other recombinant vectors. Other vectors contemplated for eukaryotic target cells include, but are not limited to, the vectors pXT1, pSG5, pSVK3, pBPV, pMSG, and pSVLSV40 (Pharmacia). Additional vectors contemplated for eukaryotic target cells include, but are not limited to, the vectors. Other vectors may be used so long as they are compatible with the host cell.
In some embodiments, a vector comprises one or more transcription and/or translation control elements. Depending on the host/vector system utilized, any of a number of suitable transcription and translation control elements, including constitutive and inducible promoters, transcription enhancer elements, transcription terminators, etc. may be used in the expression vector. In some embodiments, the vector is a self-inactivating vector that either inactivates the viral sequences or the components of the CRISPR machinery or other elements.
Non-limiting examples of suitable eukaryotic promoters (i.e., promoters functional in a eukaryotic cell) include those from cytomegalovirus (CMV) immediate early, herpes simplex virus (HSV) thymidine kinase, early and late SV40, long terminal repeats (LTRs) from retrovirus, human elongation factor-1 promoter (EF1), a hybrid construct comprising the cytomegalovirus (CMV) enhancer fused to the chicken beta-actin promoter (CAG), murine stem cell virus promoter (MSCV), phosphoglycerate kinase-1 locus promoter (PGK), and mouse metallothionein-I.
For expressing small RNAs, including guide RNAs used in connection with Cas endonuclease, various promoters such as RNA polymerase III promoters, including for example U6 and H1, can be advantageous. Descriptions of and parameters for enhancing the use of such promoters are known in art, and additional information and approaches are regularly being described; see, e.g., Ma, H. et al., Molecular Therapy-Nucleic Acids 3, e161 (2014) doi:10.1038/mtna.2014.12.
The expression vector may also contain a ribosome binding site for translation initiation and a transcription terminator. The expression vector may also comprise appropriate sequences for amplifying expression. The expression vector may also include nucleotide sequences encoding non-native tags (e.g., histidine tag, hemagglutinin tag, green fluorescent protein, etc.) that are fused to the site-directed polypeptide, thus resulting in a fusion protein.
In some embodiments, a promoter is an inducible promoter (e.g., a heat shock promoter, tetracycline-regulated promoter, steroid-regulated promoter, metal-regulated promoter, estrogen receptor-regulated promoter, etc.). In some embodiments, the promoter is a constitutive promoter (e.g., CMV promoter, UBC promoter). In some embodiments, the promoter is a spatially restricted and/or temporally restricted promoter (e.g., a tissue specific promoter, a cell type specific promoter, etc.).
In some embodiments, the nucleic acid encoding a genome-targeting nucleic acid of the disclosure and/or a site-directed polypeptide is packaged into or on the surface of delivery vehicles for delivery to cells. Delivery vehicles contemplated include, but are not limited to, nanospheres, liposomes, quantum dots, nanoparticles, polyethylene glycol particles, hydrogels, and micelles. As described in the art, a variety of targeting moieties can be used to enhance the preferential interaction of such vehicles with desired cell types or locations.
Introduction of the complexes, polypeptides, and nucleic acids of the disclosure into cells can occur by viral or bacteriophage infection, transfection, conjugation, protoplast fusion, lipofection, electroporation, nucleofection, calcium phosphate precipitation, polyethyleneimine (PEI)-mediated transfection, DEAE-dextran mediated transfection, liposome-mediated transfection, particle gun technology, calcium phosphate precipitation, direct micro-injection, nanoparticle-mediated nucleic acid delivery, and the like.
Delivery
Guide RNA polynucleotides (RNA or DNA) and/or endonuclease polynucleotide(s) (RNA or DNA) can be delivered by viral or non-viral delivery vehicles known in the art. Alternatively, endonuclease polypeptide(s) may be delivered by viral or non-viral delivery vehicles known in the art, such as electroporation or lipid nanoparticles. In some embodiments, the DNA endonuclease may be delivered as one or more polypeptides, either alone or pre-complexed with one or more guide RNAs, or one or more crRNA together with a tracrRNA.
Polynucleotides may be delivered by non-viral delivery vehicles including, but not limited to, nanoparticles, liposomes, ribonucleoproteins, positively charged peptides, small molecule RNA-conjugates, aptamer-RNA chimeras, and RNA-fusion protein complexes. Some exemplary non-viral delivery vehicles are described in Peer and Lieberman, Gene Therapy, 18: 1127-1133 (2011) (which focuses on non-viral delivery vehicles for siRNA that are also useful for delivery of other polynucleotides).
Polynucleotides, such as guide RNA, sgRNA, and mRNA encoding an endonuclease, may be delivered to a cell or a patient by a lipid nanoparticle (LNP).
A LNP refers to any particle having a diameter of less than 1000 nm, 500 nm, 250 nm, 200 nm, 150 nm, 100 nm, 75 nm, 50 nm, or 25 nm. Alternatively, a nanoparticle may range in size from 1-1000 nm, 1-500 nm, 1-250 nm, 25-200 nm, 25-100 nm, 35-75 nm, or 25-60 nm.
LNPs may be made from cationic, anionic, or neutral lipids. Neutral lipids, such as the fusogenic phospholipid DOPE or the membrane component cholesterol, may be included in LNPs as ‘helper lipids’ to enhance transfection activity and nanoparticle stability. Limitations of cationic lipids include low efficacy owing to poor stability and rapid clearance, as well as the generation of inflammatory or anti-inflammatory responses.
LNPs may also be comprised of hydrophobic lipids, hydrophilic lipids, or both hydrophobic and hydrophilic lipids.
Any lipid or combination of lipids that are known in the art may be used to produce a LNP. Examples of lipids used to produce LNPs are: DOTMA, DOSPA, DOTAP, DMRIE, DC-cholesterol, DOTAP-cholesterol, GAP-DMORIE-DPyPE, and GL67A-DOPE-DMPE-polyethylene glycol (PEG). Examples of cationic lipids are: 98N12-5, C12-200, DLin-KC2-DMA (KC2), DLin-MC3-DMA (MC3), XTC, MD1, and 7C1. Examples of neutral lipids are: DPSC, DPPC, POPC, DOPE, and SM. Examples of PEG-modified lipids are: PEG-DMG, PEG-CerC14, and PEG-CerC20.
The lipids may be combined in any number of molar ratios to produce a LNP. In addition, the polynucleotide(s) may be combined with lipid(s) in a wide range of molar ratios to produce a LNP.
As stated previously, the site-directed polypeptide and genome-targeting nucleic acid may each be administered separately to a cell or a patient. On the other hand, the site-directed polypeptide may be pre-complexed with one or more guide RNAs, or one or more crRNA together with a tracrRNA. The pre-complexed material may then be administered to a cell or a patient. Such pre-complexed material is known as a ribonucleoprotein particle (RNP).
RNA is capable of forming specific interactions with RNA or DNA. While this property is exploited in many biological processes, it also comes with the risk of promiscuous interactions in a nucleic acid-rich cellular environment. One solution to this problem is the formation of ribonucleoprotein particles (RNPs), in which the RNA is pre-complexed with an endonuclease. Another benefit of the RNP is protection of the RNA from degradation.
The endonuclease in the RNP may be modified or unmodified. Likewise, the gRNA, crRNA, tracrRNA, or sgRNA may be modified or unmodified. Numerous modifications are known in the art and may be used.
The endonuclease and sgRNA may be generally combined in a 1:1 molar ratio. Alternatively, the endonuclease, crRNA and tracrRNA may be generally combined in a 1:1:1 molar ratio. However, a wide range of molar ratios may be used to produce a RNP.
A recombinant adeno-associated virus (AAV) vector may be used for delivery. Techniques to produce rAAV particles, in which an AAV genome to be packaged that includes the polynucleotide to be delivered, rep and cap genes, and helper virus functions are provided to a cell are standard in the art. Production of rAAV requires that the following components are present within a single cell (denoted herein as a packaging cell): a rAAV genome, AAV rep and cap genes separate from (i.e., not in) the rAAV genome, and helper virus functions. The AAV rep and cap genes may be from any AAV serotype for which recombinant virus can be derived, and may be from a different AAV serotype than the rAAV genome ITRs, including, but not limited to, AAV serotypes AAV-1, AAV-2, AAV-3, AAV-4, AAV-5, AAV-6, AAV-7, AAV-8, AAV-9, AAV-10, AAV-11, AAV-12, AAV-13 and AAV rh.74. Production of pseudotyped rAAV is disclosed in, for example, international patent application publication number WO 01/83692. See Table 2.
A method of generating a packaging cell involves creating a cell line that stably expresses all of the necessary components for AAV particle production. For example, a plasmid (or multiple plasmids) comprising a rAAV genome lacking AAV rep and cap genes, AAV rep and cap genes separate from the rAAV genome, and a selectable marker, such as a neomycin resistance gene, are integrated into the genome of a cell. AAV genomes have been introduced into bacterial plasmids by procedures such as GC tailing (Samulski et al., 1982, Proc. Natl. Acad. S6. USA, 79:2077-2081), addition of synthetic linkers containing restriction endonuclease cleavage sites (Laughlin et al., 1983, Gene, 23:65-73) or by direct, blunt-end ligation (Senapathy & Carter, 1984, J. Biol. Chem., 259:4661-4666). The packaging cell line is then infected with a helper virus, such as adenovirus. The advantages of this method are that the cells are selectable and are suitable for large-scale production of rAAV. Other examples of suitable methods employ adenovirus or baculovirus, rather than plasmids, to introduce rAAV genomes and/or rep and cap genes into packaging cells.
General principles of rAAV production are reviewed in, for example, Carter, 1992, Current Opinions in Biotechnology, 1533-539; and Muzyczka, 1992, Curr. Topics in Microbial. and Immunol., 158:97-129). Various approaches are described in Ratschin et al., Mol. Cell. Biol. 4:2072 (1984); Hermonat et al., Proc. Natl. Acad. Sci. USA, 81:6466 (1984); Tratschin et al., Mol. Cell. Biol. 5:3251 (1985); McLaughlin et al., J. Virol., 62:1963 (1988); and Lebkowski et al., 1988 Mol. Cell. Biol., 7:349 (1988). Samulski et al. (1989, J. Virol., 63:3822-3828); U.S. Pat. No. 5,173,414; WO 95/13365 and corresponding U.S. Pat. No. 5,658,776; WO 95/13392; WO 96/17947; PCT/US98/18600; WO 97/09441 (PCT/US96/14423); WO 97/08298 (PCT/US96/13872); WO 97/21825 (PCT/US96/20777); WO 97/06243 (PCT/FR96/01064); WO 99/11764; Perrin et al. (1995) Vaccine 13:1244-1250; Paul et al. (1993) Human Gene Therapy 4:609-615; Clark et al. (1996) Gene Therapy 3:1124-1132; U.S. Pat. Nos. 5,786,211; 5,871,982; and 6,258,595.
AAV vector serotypes can be matched to target cell types. For example, the following exemplary cell types may be transduced by the indicated AAV serotypes among others. See Table 3.
In addition to adeno-associated viral vectors, other viral vectors can be used. Such viral vectors include, but are not limited to, lentivirus, alphavirus, enterovirus, pestivirus, baculovirus, herpesvirus, Epstein Barr virus, papovavirusr, poxvirus, vaccinia virus, and herpes simplex virus.
In some embodiments, Cas9 mRNA, sgRNA targeting one or two loci in target gene, and donor DNA is each separately formulated into lipid nanoparticles, or are all co-formulated into one lipid nanoparticle, or co-formulated into two or more lipid nanoparticles.
In some embodiments, Cas9 mRNA is formulated in a lipid nanoparticle, while sgRNA and donor DNA are delivered in an AAV vector. In some embodiments, Cas9 mRNA and sgRNA are co-formulated in a lipid nanoparticle, while donor DNA is delivered in an AAV vector.
Options are available to deliver the Cas9 nuclease as a DNA plasmid, as mRNA or as a protein. The guide RNA can be expressed from the same DNA, or can also be delivered as an RNA. The RNA can be chemically modified to alter or improve its half-life, or decrease the likelihood or degree of immune response. The endonuclease protein can be complexed with the gRNA prior to delivery. Viral vectors allow efficient delivery; split versions of Cas9 and smaller orthologs of Cas9 can be packaged in AAV, as can donors for HDR. A range of non-viral delivery methods also exist that can deliver each of these components, or non-viral and viral methods can be employed in tandem. For example, nano-particles can be used to deliver the protein and guide RNA, while AAV can be used to deliver a donor DNA.
Exosomes
Exosomes, a type of microvesicle bound by phospholipid bilayer, can be used to deliver nucleic acids to specific tissue. Many different types of cells within the body naturally secrete exosomes. Exosomes form within the cytoplasm when endosomes invaginate and form multivesicular-endosomes (MVE). When the MVE fuses with the cellular membrane, the exosomes are secreted in the extracellular space. Ranging between 30-120 nm in diameter, exosomes can shuttle various molecules from one cell to another in a form of cell-to-cell communication. Cells that naturally produce exosomes, such as mast cells, can be genetically altered to produce exosomes with surface proteins that target specific tissues, alternatively exosomes can be isolated from the bloodstream. Specific nucleic acids can be placed within the engineered exosomes with electroporation. When introduced systemically, the exosomes can deliver the nucleic acids to the specific target tissue.
Genetically Modified Cells
The term “genetically modified cell” refers to a cell that comprises at least one genetic modification introduced by genome editing (e.g., using the CRISPR/Cas9/Cpf1 system). In some examples, (e.g., ex vivo examples) herein, the genetically modified cell is genetically modified progenitor cell. In some examples herein, the genetically modified cell is genetically modified T cell. A genetically modified cell comprising an exogenous genome-targeting nucleic acid and/or an exogenous nucleic acid encoding a genome-targeting nucleic acid is contemplated herein.
The term “control treated population” describes a population of cells that has been treated with identical media, viral induction, nucleic acid sequences, temperature, confluency, flask size, pH, etc., with the exception of the addition of the genome editing components. Any method known in the art can be used to measure restoration of target gene or protein expression or activity, for example Western Blot analysis of the target protein or quantifying target mRNA.
The term “isolated cell” refers to a cell that has been removed from an organism in which it was originally found, or a descendant of such a cell. Optionally, the cell is cultured in vitro, e.g., under defined conditions or in the presence of other cells. Optionally, the cell is later introduced into a second organism or re-introduced into the organism from which it (or the cell from which it is descended) was isolated.
The term “isolated population” with respect to an isolated population of cells refers to a population of cells that has been removed and separated from a mixed or heterogeneous population of cells. In some embodiments, the isolated population is a substantially pure population of cells, as compared to the heterogeneous population from which the cells were isolated or enriched. In some embodiments, the isolated population is an isolated population of human progenitor cells, e.g., a substantially pure population of human progenitor cells, as compared to a heterogeneous population of cells comprising human progenitor cells and cells from which the human progenitor cells were derived.
The term “substantially enhanced,” with respect to a particular cell population, refers to a population of cells in which the occurrence of a particular type of cell is increased relative to pre-existing or reference levels, by at least 2-fold, at least 3-, at least 4-, at least 5-, at least 6-, at least 7-, at least 8-, at least 9, at least 10-, at least 20-, at least 50-, at least 100-, at least 400-, at least 1000-, at least 5000-, at least 20000-, at least 100000- or more fold depending, e.g., on the desired levels of such cells for ameliorating a medical condition.
The term “substantially enriched” with respect to a particular cell population, refers to a population of cells that is at least about 10%, about 20%, about 30%, about 40%, about 50%, about 60%, about 70% or more with respect to the cells making up a total cell population.
The terms “substantially enriched” or “substantially pure” with respect to a particular cell population, refers to a population of cells that is at least about 75%, at least about 85%, at least about 90%, or at least about 95% pure, with respect to the cells making up a total cell population. That is, the terms “substantially pure” or “essentially purified,” with regard to a population of progenitor cells, refers to a population of cells that contain fewer than about 20%, about 15%, about 10%, about 9%, about 8%, about 7%, about 6%, about 5%, about 4%, about 3%, about 2%, about 1%, or less than 1%, of cells that are not progenitor cells as defined by the terms herein.
Implanting Cells into Patients
Another step of the ex vivo methods of the present disclosure comprises implanting the cells into patients. This implanting step may be accomplished using any method of implantation known in the art. For example, the genetically modified cells may be injected directly in the patient's blood or otherwise administered to the patient. The genetically modified cells may be purified ex vivo using a selected marker.
Pharmaceutically Acceptable Carriers
The ex vivo methods of administering progenitor cells to a subject contemplated herein involve the use of therapeutic compositions comprising progenitor cells.
Therapeutic compositions contain a physiologically tolerable carrier together with the cell composition, and optionally at least one additional bioactive agent as described herein, dissolved or dispersed therein as an active ingredient. In some embodiments, the therapeutic composition is not substantially immunogenic when administered to a mammal or human patient for therapeutic purposes, unless so desired.
In general, the progenitor cells described herein are administered as a suspension with a pharmaceutically acceptable carrier. One of skill in the art will recognize that a pharmaceutically acceptable carrier to be used in a cell composition will not include buffers, compounds, cryopreservation agents, preservatives, or other agents in amounts that substantially interfere with the viability of the cells to be delivered to the subject. A formulation comprising cells can include e.g., osmotic buffers that permit cell membrane integrity to be maintained, and optionally, nutrients to maintain cell viability or enhance engraftment upon administration. Such formulations and suspensions are known to those of skill in the art and/or can be adapted for use with the progenitor cells, as described herein, using routine experimentation.
A cell composition can also be emulsified or presented as a liposome composition, provided that the emulsification procedure does not adversely affect cell viability. The cells and any other active ingredient can be mixed with excipients that are pharmaceutically acceptable and compatible with the active ingredient, and in amounts suitable for use in the therapeutic methods described herein.
Additional agents included in a cell composition can include pharmaceutically acceptable salts of the components therein. Pharmaceutically acceptable salts include the acid addition salts (formed with the free amino groups of the polypeptide) that are formed with inorganic acids, such as, for example, hydrochloric or phosphoric acids, or such organic acids as acetic, tartaric, mandelic and the like. Salts formed with the free carboxyl groups can also be derived from inorganic bases, such as, for example, sodium, potassium, ammonium, calcium or ferric hydroxides, and such organic bases as isopropylamine, trimethylamine, 2-ethylamino ethanol, histidine, procaine and the like.
Physiologically tolerable carriers are well known in the art. Exemplary liquid carriers are sterile aqueous solutions that contain no materials in addition to the active ingredients and water, or contain a buffer such as sodium phosphate at physiological pH value, physiological saline or both, such as phosphate-buffered saline. Still further, aqueous carriers can contain more than one buffer salt, as well as salts such as sodium and potassium chlorides, dextrose, polyethylene glycol and other solutes. Liquid compositions can also contain liquid phases in addition to and to the exclusion of water. Exemplary of such additional liquid phases are glycerin, vegetable oils such as cottonseed oil, and water-oil emulsions. The amount of an active compound used in the cell compositions that is effective in the treatment of a particular disorder or condition will depend on the nature of the disorder or condition, and can be determined by standard clinical techniques.
Administration & Efficacy
The terms “administering,” “introducing” and “transplanting” are used interchangeably in the context of the placement of cells, e.g., progenitor cells, into a subject, by a method or route that results in at least partial localization of the introduced cells at a desired site, such as a site of injury or repair, such that a desired effect(s) is produced. The cells e.g., progenitor cells, or their differentiated progeny can be administered by any appropriate route that results in delivery to a desired location in the subject where at least a portion of the implanted cells or components of the cells remain viable. The period of viability of the cells after administration to a subject can be as short as a few hours, e.g., twenty-four hours, to a few days, to as long as several years, or even the life time of the patient, i.e., long-term engraftment. For example, in some aspects described herein, an effective amount of myogenic progenitor cells is administered via a systemic route of administration, such as an intraperitoneal or intravenous route.
The terms “individual”, “subject,” “host” and “patient” are used interchangeably herein and refer to any subject for whom diagnosis, treatment or therapy is desired. In some aspects, the subject is a mammal. In some aspects, the subject is a human being.
The term “donor” is used to refer to an individual that is not the patient. In some embodiments, the donor is an individual who does not have or is not suspected of having the medical condition to be treated. In some embodiments, multiple donors, e.g., two or more donors, can be used. In some embodiments, each donor used is an individual who does not have or is not suspected of having the medical condition to be treated.
When provided prophylactically, progenitor cells described herein can be administered to a subject in advance of any symptom of a medical condition, e.g., prior to the development of alpha/beta T-cell lymphopenia with gamma/delta T-cell expansion, severe cytomegalovirus (CMV) infection, autoimmunity, chronic inflammation of the skin, eosinophilia, failure to thrive, swollen lymph nodes, swollen spleen, diarrhea and enlarged liver. Accordingly, the prophylactic administration of a hematopoietic progenitor cell population serves to prevent a medical condition.
When provided therapeutically, hematopoietic progenitor cells are provided at (or after) the onset of a symptom or indication of a medical condition, e.g., upon the onset of disease.
In some embodiments, the T cell population being administered according to the methods described herein comprises allogeneic T cells obtained from one or more donors. In some embodiments, the cell population being administered can be allogeneic blood cells, hematopoietic stem cells, hematopoietic progenitor cells, embryonic stem cells, or induced embryonic stem cells. “Allogeneic” refers to a cell, cell population, or biological samples comprising cells, obtained from one or more different donors of the same species, where the genes at one or more loci are not identical to the recipient. For example, a hematopoietic progenitor cell population, or T cell population, being administered to a subject can be derived from one or more unrelated donors, or from one or more non-identical siblings. In some embodiments, syngeneic cell populations may be used, such as those obtained from genetically identical donors, (e.g., identical twins). In some embodiments, the cells are autologous cells; that is, the cells (e.g.: hematopoietic progenitor cells, or T cells) are obtained or isolated from a subject and administered to the same subject, i.e., the donor and recipient are the same.
The term “effective amount” refers to the amount of a population of progenitor cells or their progeny needed to prevent or alleviate at least one or more signs or symptoms of a medical condition, and relates to a sufficient amount of a composition to provide the desired effect, e.g., to treat a subject having a medical condition. The term “therapeutically effective amount” therefore refers to an amount of progenitor cells or a composition comprising progenitor cells that is sufficient to promote a particular effect when administered to a typical subject, such as one who has or is at risk for a medical condition. An effective amount would also include an amount sufficient to prevent or delay the development of a symptom of the disease, alter the course of a symptom of the disease (for example but not limited to, slow the progression of a symptom of the disease), or reverse a symptom of the disease. It is understood that for any given case, an appropriate “effective amount” can be determined by one of ordinary skill in the art using routine experimentation.
For use in the various aspects described herein, an effective amount of progenitor cells comprises at least 102 progenitor cells, at least 5×102 progenitor cells, at least 103 progenitor cells, at least 5×103 progenitor cells, at least 104 progenitor cells, at least 5×104 progenitor cells, at least 105 progenitor cells, at least 2×105 progenitor cells, at least 3×105 progenitor cells, at least 4×105 progenitor cells, at least 5×105 progenitor cells, at least 6×105 progenitor cells, at least 7×105 progenitor cells, at least 8×105 progenitor cells, at least 9×105 progenitor cells, at least 1×106 progenitor cells, at least 2×106 progenitor cells, at least 3×106 progenitor cells, at least 4×106 progenitor cells, at least 5×106 progenitor cells, at least 6×106 progenitor cells, at least 7×106 progenitor cells, at least 8×106 progenitor cells, at least 9×106 progenitor cells, or multiples thereof. The progenitor cells are derived from one or more donors, or are obtained from an autologous source. In some examples described herein, the progenitor cells are expanded in culture prior to administration to a subject in need thereof.
Modest and incremental increases in the levels of functional target expressed in cells of patients having a medical condition can be beneficial for ameliorating one or more symptoms of the disease, for increasing long-term survival, and/or for reducing side effects associated with other treatments. Upon administration of such cells to human patients, the presence of hematopoietic progenitors that are producing increased levels of functional target is beneficial. In some embodiments, effective treatment of a subject gives rise to at least about 3%, 5% or 7% functional target relative to total target in the treated subject. In some embodiments, functional target will be at least about 10% of total target. In some embodiments, functional target will be at least about 20% to 30% of total target. Similarly, the introduction of even relatively limited subpopulations of cells having significantly elevated levels of functional target can be beneficial in various patients because in some situations normalized cells will have a selective advantage relative to diseased cells. However, even modest levels of hematopoietic progenitors with elevated levels of functional target can be beneficial for ameliorating one or more aspects of a medical condition in patients. In some embodiments, about 10%, about 20%, about 30%, about 40%, about 50%, about 60%, about 70%, about 80%, about 90% or more of the hematopoietic progenitors in patients to whom such cells are administered are producing increased levels of functional target.
“Administered” refers to the delivery of a progenitor cell composition into a subject by a method or route that results in at least partial localization of the cell composition at a desired site. A cell composition can be administered by any appropriate route that results in effective treatment in the subject, i.e. administration results in delivery to a desired location in the subject where at least a portion of the composition delivered, i.e. at least 1×104 cells are delivered to the desired site for a period of time. Modes of administration include injection, infusion, instillation, or ingestion. “Injection” includes, without limitation, intravenous, intramuscular, intra-arterial, intrathecal, intraventricular, intracapsular, intraorbital, intracardiac, intradermal, intraperitoneal, transtracheal, subcutaneous, subcuticular, intraarticular, sub capsular, subarachnoid, intraspinal, intracerebro spinal, and intrasternal injection and infusion. In some embodiments, the route is intravenous. For the delivery of cells, administration by injection or infusion can be made.
The cells are administered systemically. The phrases “systemic administration,” “administered systemically”, “peripheral administration” and “administered peripherally” refer to the administration of a population of progenitor cells other than directly into a target site, tissue, or organ, such that it enters, instead, the subject's circulatory system and, thus, is subject to metabolism and other like processes.
The efficacy of a treatment comprising a composition for the treatment of a medical condition can be determined by the skilled clinician. However, a treatment is considered “effective treatment,” if any one or all of the signs or symptoms of, as but one example, levels of functional target are altered in a beneficial manner (e.g., increased by at least 10%), or other clinically accepted symptoms or markers of disease are improved or ameliorated. Efficacy can also be measured by failure of an individual to worsen as assessed by hospitalization or need for medical interventions (e.g., progression of the disease is halted or at least slowed). Methods of measuring these indicators are known to those of skill in the art and/or described herein. Treatment includes any treatment of a disease in an individual or an animal (some non-limiting examples include a human, or a mammal) and includes: (1) inhibiting the disease, e.g., arresting, or slowing the progression of symptoms; or (2) relieving the disease, e.g., causing regression of symptoms; and (3) preventing or reducing the likelihood of the development of symptoms.
The treatment according to the present disclosure ameliorates one or more symptoms associated with a medical condition by increasing the amount of functional target in the individual. Early signs typically associated with a medical condition include for example, development of alpha/beta T-cell lymphopenia with gamma/delta T-cell expansion, severe cytomegalovirus (CMV) infection, autoimmunity, chronic inflammation of the skin, eosinophilia, failure to thrive, swollen lymph nodes, swollen spleen, diarrhea and enlarged liver.
Kits
The present disclosure provides kits for carrying out the methods described herein. A kit can include one or more of a genome-targeting nucleic acid, a polynucleotide encoding a genome-targeting nucleic acid, a site-directed polypeptide, a polynucleotide encoding a site-directed polypeptide, and/or any nucleic acid or proteinaceous molecule necessary to carry out the aspects of the methods described herein, or any combination thereof.
In some embodiments, a kit comprises: (1) a vector comprising a nucleotide sequence encoding a genome-targeting nucleic acid, (2) the site-directed polypeptide or a vector comprising a nucleotide sequence encoding the site-directed polypeptide, and (3) a reagent for reconstitution and/or dilution of the vector(s) and or polypeptide.
In some embodiments, a kit comprises: (1) a vector comprising (i) a nucleotide sequence encoding a genome-targeting nucleic acid, and (ii) a nucleotide sequence encoding the site-directed polypeptide; and (2) a reagent for reconstitution and/or dilution of the vector.
In some embodiments of any of the above kits, the kit comprises a single-molecule guide genome-targeting nucleic acid. In some embodiments of any of the above kits, the kit comprises a double-molecule genome-targeting nucleic acid. In some embodiments of any of the above kits, the kit comprises two or more double-molecule guides or single-molecule guides. In some embodiments, the kits comprise a vector that encodes the nucleic acid targeting nucleic acid.
In any of the above kits, the kit further comprises a polynucleotide to be inserted to affect the desired genetic modification.
Components of a kit may be in separate containers, or combined in a single container.
Any kit described above can further comprise one or more additional reagents, where such additional reagents are selected from a buffer, a buffer for introducing a polypeptide or polynucleotide into a cell, a wash buffer, a control reagent, a control vector, a control RNA polynucleotide, a reagent for in vitro production of the polypeptide from DNA, adaptors for sequencing and the like. A buffer can be a stabilization buffer, a reconstituting buffer, a diluting buffer, or the like. In some embodiments, a kit also comprises one or more components that can be used to facilitate or enhance the on-target binding or the cleavage of DNA by the endonuclease, or improve the specificity of targeting.
In addition to the above-mentioned components, a kit further comprises instructions for using the components of the kit to practice the methods. The instructions for practicing the methods are generally recorded on a suitable recording medium. For example, the instructions may be printed on a substrate, such as paper or plastic, etc. The instructions nay be present in the kits as a package insert, in the labeling of the container of the kit or components thereof (i.e., associated with the packaging or subpackaging), etc. The instructions can be present as an electronic storage data file present on a suitable computer readable storage medium, e.g. CD-ROM, diskette, flash drive, etc. In some instances, the actual instructions are not present in the kit, but means for obtaining the instructions from a remote source (e.g. via the Internet), can be provided. An example of this case is a kit that comprises a web address where the instructions can be viewed and/or from which the instructions can be downloaded. As with the instructions, this means for obtaining the instructions can be recorded on a suitable substrate.
Guide RNA Formulation
Guide RNAs of the present disclosure are formulated with pharmaceutically acceptable excipients such as carriers, solvents, stabilizers, adjuvants, diluents, etc., depending upon the particular mode of administration and dosage form. Guide RNA compositions are generally formulated to achieve a physiologically compatible pH, and range from a pH of about 3 to a pH of about 11, about pH 3 to about pH 7, depending on the formulation and route of administration. In some embodiments, the pH is adjusted to a range from about pH 5.0 to about pH 8. In some embodiments, the compositions comprise a therapeutically effective amount of at least one compound as described herein, together with one or more pharmaceutically acceptable excipients. Optionally, the compositions comprise a combination of the compounds described herein, or may include a second active ingredient useful in the treatment or prevention of bacterial growth (for example and without limitation, anti-bacterial or anti-microbial agents), or may include a combination of reagents of the present disclosure.
Suitable excipients include, for example, carrier molecules that include large, slowly metabolized macromolecules such as proteins, polysaccharides, polylactic acids, polyglycolic acids, polymeric amino acids, amino acid copolymers, and inactive virus particles. Other exemplary excipients can include antioxidants (for example and without limitation, ascorbic acid), chelating agents (for example and without limitation, EDTA), carbohydrates (for example and without limitation, dextrin, hydroxyalkylcellulose, and hydroxyalkylmethylcellulose), stearic acid, liquids (for example and without limitation, oils, water, saline, glycerol and ethanol), wetting or emulsifying agents, pH buffering substances, and the like.
Other Possible Therapeutic Approaches
Gene editing can be conducted using nucleases engineered to target specific sequences. To date there are four major types of nucleases: meganucleases and their derivatives, zinc finger nucleases (ZFNs), transcription activator like effector nucleases (TALENs), and CRISPR-Cas9 nuclease systems. The nuclease platforms vary in difficulty of design, targeting density and mode of action, particularly as the specificity of ZFNs and TALENs is through protein-DNA interactions, while RNA-DNA interactions primarily guide Cas9. Cas9 cleavage also requires an adjacent motif, the PAM, which differs between different CRISPR systems. Cas9 from Streptococcus pyogenes cleaves using a NRG PAM, CRISPR from Neisseria meningitidis can cleave at sites with PAMs including NNNNGATT, NNNNNGTTT and NNNNGCTT. A number of other Cas9 orthologs target protospacer adjacent to alternative PAMs.
CRISPR endonucleases, such as Cas9, can be used in the methods of the present disclosure. However, the teachings described herein, such as therapeutic target sites, could be applied to other forms of endonucleases, such as ZFNs, TALENs, HEs, or MegaTALs, or using combinations of nucleases. However, in order to apply the teachings of the present disclosure to such endonucleases, one would need to, among other things, engineer proteins directed to the specific target sites.
Additional binding domains may be fused to the Cas9 protein to increase specificity. The target sites of these constructs would map to the identified gRNA specified site, but would require additional binding motifs, such as for a zinc finger domain. In the case of Mega-TAL, a meganuclease can be fused to a TALE DNA-binding domain. The meganuclease domain can increase specificity and provide the cleavage. Similarly, inactivated or dead Cas9 (dCas9) can be fused to a cleavage domain and require the sgRNA/Cas9 target site and adjacent binding site for the fused DNA-binding domain. This likely would require some protein engineering of the dCas9, in addition to the catalytic inactivation, to decrease binding without the additional binding site.
Zinc Finger Nucleases
Zinc finger nucleases (ZFNs) are modular proteins comprised of an engineered zinc finger DNA binding domain linked to the catalytic domain of the type II endonuclease FokI. Because FokI functions only as a dimer, a pair of ZFNs must be engineered to bind to cognate target “half-site” sequences on opposite DNA strands and with precise spacing between them to enable the catalytically active FokI dimer to form. Upon dimerization of the FokI domain, which itself has no sequence specificity per se, a DNA double-strand break is generated between the ZFN half-sites as the initiating step in genome editing.
The DNA binding domain of each ZFN is typically comprised of 3-6 zinc fingers of the abundant Cys2-His2 architecture, with each finger primarily recognizing a triplet of nucleotides on one strand of the target DNA sequence, although cross-strand interaction with a fourth nucleotide also can be important. Alteration of the amino acids of a finger in positions that make key contacts with the DNA alters the sequence specificity of a given finger. Thus, a four-finger zinc finger protein will selectively recognize a 12 bp target sequence, where the target sequence is a composite of the triplet preferences contributed by each finger, although triplet preference can be influenced to varying degrees by neighboring fingers. An important aspect of ZFNs is that they can be readily re-targeted to almost any genomic address simply by modifying individual fingers, although considerable expertise is required to do this well. In most applications of ZFNs, proteins of 4-6 fingers are used, recognizing 12-18 bp respectively. Hence, a pair of ZFNs will typically recognize a combined target sequence of 24-36 bp, not including the 5-7 bp spacer between half-sites. The binding sites can be separated further with larger spacers, including 15-17 bp. A target sequence of this length is likely to be unique in the human genome, assuming repetitive sequences or gene homologs are excluded during the design process. Nevertheless, the ZFN protein-DNA interactions are not absolute in their specificity so off-target binding and cleavage events do occur, either as a heterodimer between the two ZFNs, or as a homodimer of one or the other of the ZFNs. The latter possibility has been effectively eliminated by engineering the dimerization interface of the FokI domain to create “plus” and “minus” variants, also known as obligate heterodimer variants, which can only dimerize with each other, and not with themselves. Forcing the obligate heterodimer prevents formation of the homodimer. This has greatly enhanced specificity of ZFNs, as well as any other nuclease that adopts these FokI variants.
A variety of ZFN-based systems have been described in the art, modifications thereof are regularly reported, and numerous references describe rules and parameters that are used to guide the design of ZFNs; see, e.g., Segal et al., Proc Natl Acad Sci USA 96(6):2758-63 (1999); Dreier B et al., J Mol Biol. 303(4):489-502 (2000); Liu Q et al., J Biol Chem. 277(6):3850-6 (2002); Dreier et al., J Biol Chem 280(42):35588-97 (2005); and Dreier et al., J Biol Chem. 276(31):29466-78 (2001).
Transcription Activator-Like Effector Nucleases (TALENs)
TALENs represent another format of modular nucleases whereby, as with ZFNs, an engineered DNA binding domain is linked to the FokI nuclease domain, and a pair of TALENs operate in tandem to achieve targeted DNA cleavage. The major difference from ZFNs is the nature of the DNA binding domain and the associated target DNA sequence recognition properties. The TALEN DNA binding domain derives from TALE proteins, which were originally described in the plant bacterial pathogen Xanthomonas sp. TALEs are comprised of tandem arrays of 33-35 amino acid repeats, with each repeat recognizing a single basepair in the target DNA sequence that is typically up to 20 bp in length, giving a total target sequence length of up to 40 bp. Nucleotide specificity of each repeat is determined by the repeat variable diresidue (RVD), which includes just two amino acids at positions 12 and 13. The bases guanine, adenine, cytosine and thymine are predominantly recognized by the four RVDs: Asn-Asn, Asn-Ile, His-Asp and Asn-Gly, respectively. This constitutes a much simpler recognition code than for zinc fingers, and thus represents an advantage over the latter for nuclease design. Nevertheless, as with ZFNs, the protein-DNA interactions of TALENs are not absolute in their specificity, and TALENs have also benefited from the use of obligate heterodimer variants of the FokI domain to reduce off-target activity.
Additional variants of the FokI domain have been created that are deactivated in their catalytic function. If one half of either a TALEN or a ZFN pair contains an inactive FokI domain, then only single-strand DNA cleavage (nicking) will occur at the target site, rather than a DSB. The outcome is comparable to the use of CRISPR/Cas9/Cpf1 “nickase” mutants in which one of the Cas9 cleavage domains has been deactivated. DNA nicks can be used to drive genome editing by HDR, but at lower efficiency than with a DSB. The main benefit is that off-target nicks are quickly and accurately repaired, unlike the DSB, which is prone to NHEJ-mediated mis-repair.
A variety of TALEN-based systems have been described in the art, and modifications thereof are regularly reported; see, e.g., Boch, Science 326(5959):1509-12 (2009); Mak et al., Science 335(6069):716-9 (2012); and Moscou et al., Science 326(5959):1501 (2009). The use of TALENs based on the “Golden Gate” platform, or cloning scheme, has been described by multiple groups; see, e.g., Cermak et al., Nucleic Acids Res. 39(12):e82 (2011); Li et al., Nucleic Acids Res. 39(14):6315-25(2011); Weber et al., PLoS One. 6(2):e16765 (2011); Wang et al., J Genet Genomics 41(6):339-47, Epub 2014 May 17 (2014); and Cermak T et al., Methods Mol Biol. 1239:133-59 (2015).
Homing Endonucleases
Homing endonucleases (HEs) are sequence-specific endonucleases that have long recognition sequences (14-44 base pairs) and cleave DNA with high specificity—often at sites unique in the genome. There are at least six known families of HEs as classified by their structure, including LAGLIDADG (SEQ ID NO: 4), GIY-YIG (SEQ ID NO: 5), His-Cis box, H—N—H, PD-(D/E)×K (SEQ ID NO: 6), and Vsr-like that are derived from a broad range of hosts, including eukarya, protists, bacteria, archaea, cyanobacteria and phage. As with ZFNs and TALENs, HEs can be used to create a DSB at a target locus as the initial step in genome editing. In addition, some natural and engineered HEs cut only a single strand of DNA, thereby functioning as site-specific nickases. The large target sequence of HEs and the specificity that they offer have made them attractive candidates to create site-specific DSBs.
A variety of HE-based systems have been described in the art, and modifications thereof are regularly reported; see, e.g., the reviews by Steentoft et al., Glycobiology 24(8):663-80 (2014); Belfort and Bonocora, Methods Mol Biol. 1123:1-26 (2014); Hafez and Hausner, Genome 55(8):553-69 (2012); and references cited therein.
MegaTAL/Tev-mTALEN/MegaTev
As further examples of hybrid nucleases, the MegaTAL platform and Tev-mTALEN platform use a fusion of TALE DNA binding domains and catalytically active HEs, taking advantage of both the tunable DNA binding and specificity of the TALE, as well as the cleavage sequence specificity of the HE; see, e.g., Boissel et al., NAR 42: 2591-2601 (2014); Kleinstiver et al., G3 4:1155-65 (2014); and Boissel and Scharenberg, Methods Mol. Biol. 1239: 171-96 (2015).
In a further variation, the MegaTev architecture is the fusion of a meganuclease (Mega) with the nuclease domain derived from the GIY-YIG homing endonuclease I-TevI (Tev). The two active sites are positioned ˜30 bp apart on a DNA substrate and generate two DSBs with non-compatible cohesive ends; see, e.g., Wolfs et al., NAR 42, 8816-29 (2014). It is anticipated that other combinations of existing nuclease-based approaches will evolve and be useful in achieving the targeted genome modifications described herein.
dCas9-FokI or dCpf1-Fok1 and Other Nucleases
Combining the structural and functional properties of the nuclease platforms described above offers a further approach to genome editing that can potentially overcome some of the inherent deficiencies. As an example, the CRISPR genome editing system typically uses a single Cas9 endonuclease to create a DSB. The specificity of targeting is driven by a 20 or 22 nucleotide sequence in the guide RNA that undergoes Watson-Crick base-pairing with the target DNA (plus an additional 2 bases in the adjacent NAG or NGG PAM sequence in the case of Cas9 from S. pyogenes). Such a sequence is long enough to be unique in the human genome, however, the specificity of the RNA/DNA interaction is not absolute, with significant promiscuity sometimes tolerated, particularly in the 5′ half of the target sequence, effectively reducing the number of bases that drive specificity. One solution to this has been to completely deactivate the Cas9 or Cpf1 catalytic function—retaining only the RNA-guided DNA binding function—and instead fusing a FokI domain to the deactivated Cas9; see, e.g., Tsai et al., Nature Biotech 32: 569-76 (2014); and Guilinger et al., Nature Biotech. 32: 577-82 (2014). Because FokI must dimerize to become catalytically active, two guide RNAs are required to tether two FokI fusions in close proximity to form the dimer and cleave DNA. This essentially doubles the number of bases in the combined target sites, thereby increasing the stringency of targeting by CRISPR-based systems.
As further example, fusion of the TALE DNA binding domain to a catalytically active HE, such as I-TevI, takes advantage of both the tunable DNA binding and specificity of the TALE, as well as the cleavage sequence specificity of I-TevI, with the expectation that off-target cleavage may be further reduced.
Additional Aspects
Provided herein are nucleic acids, vectors, cells, methods, and other materials for use in ex vivo and in vivo methods for creating permanent changes to the genome by deleting, inserting, or modulating the expression of or function of one or more nucleic acids or exons within or near a target gene or other DNA sequences that encode regulatory elements of the target gene or knocking in a cDNA, expression vector, or minigene, which may be used to treat a medical condition such as, by way of non-limiting example, cancer, inflammatory disease and/or autoimmune disease. Also provided herein are components, kits, and compositions for performing such methods. Also provided are cells produced by such methods.
The following paragraphs are also encompassed by the present disclosure:
1) encoded by a nucleic acid sequence comprising SEQ ID NO: 1475 or an amino acid sequence comprising SEQ ID NO: 1499 or
2) encoded by a nucleic acid sequence comprising SEQ ID NO: 1476 or an amino acid sequence comprising SEQ ID NO: 1500.
1) encoded by a nucleic acid sequence comprising SEQ ID NO: 1477-1498 or an amino acid sequence comprising SEQ ID NO: 1501-1522 or
2) encoded by a nucleic acid sequence comprising SEQ ID NO: 1485 or an amino acid sequence comprising SEQ ID NO: 1509.
(a) one or more gRNAs for editing a TRAC gene, the one or more gRNAs comprising a spacer sequence selected from the group consisting of the nucleic acid sequences of SEQ ID NOs: 83-158;
(b) one or more gRNAs for editing a B2M gene, the one or more gRNAs comprising a spacer sequence selected from the group consisting of the nucleic acid sequences of SEQ ID NOs: 458-506;
(c) one or more gRNAs for editing a CIITA gene, the one or more gRNAs comprising a spacer sequence selected from the group consisting of the nucleic acid sequences of SEQ ID NOs: 699-890;
(d) one or more gRNAs for editing a CD3ε gene, the one or more gRNAs comprising a spacer sequence selected from the group consisting of the nucleic acid sequences of SEQ ID NOs: 284-408; or
(e) one or more gRNAs for editing a PD1 gene, the one or more gRNAs comprising a spacer sequence selected from the group consisting of the nucleic acid sequences of SEQ ID NOs: 1083-1274.
(a) one or more gRNAs for editing a TRAC gene, the one or more gRNAs comprising a spacer sequence selected from the group consisting of the nucleic acid sequences of SEQ ID NOs: 83-158;
(b) one or more gRNAs for editing a B2M gene, the one or more gRNAs comprising a spacer sequence selected from the group consisting of the nucleic acid sequences of SEQ ID NOs: 458-506;
(c) one or more gRNAs for editing a CIITA gene, the one or more gRNAs comprising a spacer sequence selected from the group consisting of the nucleic acid sequences of SEQ ID NOs: 699-890 for editing the CIITA gene;
(d) one or more gRNAs for editing a CD3ε gene, the one or more gRNAs comprising a spacer sequence selected from the group consisting of the nucleic acid sequences of SEQ ID NOs: 284-408;
(e) one or more gRNAs for editing a PD1 gene, the one or more gRNAs comprising a spacer sequence selected from the group consisting of the nucleic acid sequences of SEQ ID NOs: 1083-1274;
(f) one or more gRNAs for editing a TRAC gene, the one or more gRNAs comprising a spacer sequence comprising the nucleic acid sequence of SEQ ID NO: 1299;
(g) one or more gRNAs for editing a CTLA-4 gene, the one or more gRNAs comprising a spacer sequence comprising the nucleic acid sequence of SEQ ID NO: 1277;
(h) one or more gRNAs for editing a AAVS1 (PPP1R12C) gene the one or more gRNAs comprising a spacer sequence selected from the group consisting of the nucleic acid sequences of SEQ ID NOs: 1301-1302;
(i) one or more gRNAs for editing a CD52 gene, the one or more gRNAs comprising a spacer sequence selected from the group consisting of the nucleic acid sequences of SEQ ID NOs: 1303-1304; and
(j) one or more gRNAs for editing a RFX5 gene, the one or more gRNAs comprising a spacer sequence selected from the group consisting of the nucleic acid sequences of SEQ ID NOs: 1305-1307.
a) one or more ribonucleoprotein particles effect one or more single-strand breaks or double-strand breaks in the TRAC target gene resulting a permanent deletion in the TRAC gene, wherein the ribonucleoprotein particles comprise one or more sgRNAs comprising a sequence SEQ ID NO: 1342 or 1343 and one or more deoxyribonucleic acid (DNA) endonucleases; and
b) one or more ribonucleoprotein particles effect one or more single-strand breaks or double-strand breaks in the B2M target gene resulting a permanent deletion in the B2M gene, wherein the ribonucleoprotein particles comprise one or more sgRNAs comprising a sequence of SEQ ID NO: 1344 or 1345 and one or more deoxyribonucleic acid (DNA) endonucleases
a) the isolated nucleic acid comprises a nucleotide sequence of SEQ ID Nos: 1348, 1354, 1358, 1359, 1362 and 1364;
b) one or more gRNAs comprise a spacer sequence selected from SEQ ID Nos: 83-158 and one or more deoxyribonucleic acid (DNA) endonucleases, effect one or more single-strand breaks or double-strand breaks in the TRAC gene resulting a permanent deletion in the TRAC gene; and
c) one or more gRNAs comprising a spacer sequence selected from SEQ ID Nos: 458-506 and one or more deoxyribonucleic acid (DNA) endonucleases, effect one or more single-strand breaks or double-strand breaks in the B2M gene resulting a permanent deletion in the B2M gene.
a) the isolated nucleic acid comprises a nucleotide sequence is selected from the group consisting of SEQ ID NO: 1348-1357;
b) one or more ribonucleoprotein particles effect one or more single-strand breaks or double-strand breaks in the TRAC target gene resulting a permanent deletion in the TRAC target gene, wherein the ribonucleoprotein particles comprise one or more sgRNAs comprising a sequence SEQ ID NO: 1342 or 1343 and one or more deoxyribonucleic acid (DNA) endonucleases; and
c) one or more ribonucleoprotein particles effect one or more single-strand breaks or double-strand breaks in the B2M target gene resulting a permanent deletion in the B2M target gene, wherein the ribonucleoprotein particles comprise one or more sgRNAs comprising a sequence of SEQ ID NO: 1344 or 1345 and one or more deoxyribonucleic acid (DNA) endonucleases.
a) the isolated nucleic acid comprises a nucleotide sequence is selected from the group consisting of SEQ ID NO: 1358 and 1359;
b) one or more ribonucleoprotein particles effect one or more single-strand breaks or double-strand breaks in the TRAC target gene resulting a permanent deletion in the TRAC target gene, wherein the ribonucleoprotein particles comprise one or more sgRNAs comprising a sequence SEQ ID NO: 1342 or 1343 and one or more deoxyribonucleic acid (DNA) endonucleases; and
c) one or more ribonucleoprotein particles effect one or more single-strand breaks or double-strand breaks in the B2M target gene resulting a permanent deletion in the B2M target gene, wherein the ribonucleoprotein particles comprise one or more sgRNAs comprising a sequence of SEQ ID NO: 1344 or 1345 and one or more deoxyribonucleic acid (DNA) endonucleases.
a) the isolated nucleic acid comprises a nucleotide sequence is selected from the group consisting of SEQ ID NO: 1362 and 1364;
b) one or more ribonucleoprotein particles effect one or more single-strand breaks or double-strand breaks in the TRAC target gene resulting a permanent deletion in the TRAC target gene, wherein the ribonucleoprotein particles comprise one or more sgRNAs comprising a sequence SEQ ID NO: 1342 or 1343 and one or more deoxyribonucleic acid (DNA) endonucleases; and
c) one or more ribonucleoprotein particles effect one or more single-strand breaks or double-strand breaks in the B2M target gene resulting a permanent deletion in the B2M target gene, wherein the ribonucleoprotein particles comprise one or more sgRNAs comprising a sequence of SEQ ID NO: 1344 or 1345 and one or more deoxyribonucleic acid (DNA) endonucleases.
i) isolating a T cell from the patient;
ii) editing within or near a target gene of the T cell or other DNA sequences that encode regulatory elements of the target gene of the T cell; and
iii) implanting the genome-edited T cell into the patient.
i) isolating a T cell from a donor;
ii) editing within or near a target gene of the T cell or other DNA sequences that encode regulatory elements of the target gene of the T cell; and
iii) implanting the genome-edited T cell into the patient.
i) editing within or near one or more target genes of the T cell, or one or more other DNA sequences that encode regulatory elements of the target gene of the T cell; and
ii) implanting the genome-edited T cell into the patient.
The term “comprising” or “comprises” is used in reference to compositions, methods, and respective component(s) thereof, that are essential to the invention, yet open to the inclusion of unspecified elements, whether essential or not.
The term “consisting essentially of” refers to those elements required for a given aspect. The term permits the presence of additional elements that do not materially affect the basic and novel or functional characteristic(s) of that aspect of the invention.
The term “consisting of” refers to compositions, methods, and respective components thereof as described herein, which are exclusive of any element not recited in that description of the aspect.
The singular forms “a,” “an,” and “the” include plural references, unless the context clearly dictates otherwise.
Certain numerical values presented herein are preceded by the term “about.” The term “about” is used to provide literal support for the numerical value the term “about” precedes, as well as a numerical value that is approximately the numerical value, that is the approximating unrecited numerical value may be a number which, in the context it is presented, is the substantial equivalent of the specifically recited numerical value. The term “about” means numerical values within +10% of the recited numerical value.
When a range of numerical values is presented herein, it is contemplated that each intervening value between the lower and upper limit of the range, the values that are the upper and lower limits of the range, and all stated values with the range are encompassed within the disclosure. All the possible sub-ranges within the lower and upper limits of the range are also contemplated by the disclosure.
The invention will be more fully understood by reference to the following embodiments, which provide illustrative non-limiting aspects of the invention.
The examples describe the use of the CRISPR system as an illustrative genome editing technique to create defined therapeutic genomic deletions, insertions, or replacements, termed “genomic modifications” herein, in or near a target gene that lead to permanent correction of mutations in the genomic locus, or expression at a heterologous locus, that restore target protein activity. Introduction of the defined therapeutic modifications represents a novel therapeutic strategy for the potential amelioration of various medical conditions, as described and illustrated herein.
To identify a large spectrum of gRNAs able to edit the cognate DNA target region, an in vitro transcribed (IVT) gRNA screen was conducted. Spacer sequences were incorporated into a backbone sequence to generate full length sgRNAs. Examples of backbone sequences are shown in Table 1. To generate a list of spacer sequences to be used for gene disruption, protein coding exons were selected for each target gene, particularly those containing the initiating ATG start codon and/or coding for critical protein domains (e.g., DNA binding domains, extracellular domains, etc.). The relevant genomic sequence was submitted for analysis using gRNA design software. The resulting list of gRNAs was narrowed to a list of about ˜200 gRNAs based on uniqueness of sequence (only gRNAs without a perfect match somewhere else in the genome were screened) and minimal predicted off target effects. This set of gRNAs was in vitro transcribed, and transfected using messenger Max into HEK293T cells that constitutively express Cas9. Cells were harvested 48 hours post transfection, the genomic DNA was isolated, and editing efficiency was evaluated using Tracking of Indels by DEcomposition (TIDE) analysis. The results are shown in
It is conventional in the art to describe a gRNA spacer sequence in the context of a DNA target (e.g., genomic) sequence, which is abject to the PAM sequence. It is understood, however, that the actual gRNA spacer sequence used in the methods and compositions herein is the equivalent of the DNA target sequence. For example, the TRAC gRNA spacer sequence described as including AGAGCAACAGTGCTGTGGCC (SEQ ID NO: 76),actual includes the RNA spacer sequence AGAGCAACAGUGCUGUGGCC (SEQ ID NO: 152).
TRAC gRNA Screen
For TRAC, genomic segments containing the first three (3) protein coding exons were used as input in the gRNA design software. The genomic segments also included flanking splice site acceptor/donor sequences. Desired gRNAs were those that would lead to insertions or deletions in the coding sequence disrupting the amino acid sequence of TRAC leading to out of frame/loss of function allele(s). All 76 in silico-identified gRNA spacers targeting TRAC were used in an IVT screen. Seventy three (73) yielded measurable data by TIDE analysis. Nine (9) gRNA sequences yielded InDel percentages above 50% that could be suitable for secondary screens.
A homology-dependent assessment of the TRAC gRNA comprising SEQ ID NO: 152 showed that this guide had an indel frequency of less than 0.5% at an off-target site. This data guided selection of this particular TRAC gRNA for further analysis.
In some embodiments, a gRNA comprises the sequence of any one of SEQ ID NOs: 83-158 or targets the sequence of any one of SEQ ID NOs: 7-82.
CD3ε gRNA Screen
For CD3ε (CD3E), genomic segments containing the five (5) protein coding exons were used as input in the gRNA design software. The genomic segments also included flanking splice site acceptor/donor sequences. Desired gRNAs were those that would lead to insertions or deletions in the coding sequence disrupting the amino acid sequence of CD3E leading to out of frame/loss of function allele(s). One hundred twenty five (125) in silico identified gRNA spacers targeting CD3E were used in an IVT screen. One hundred twenty (120) yielded measurable data by TIDE analysis. Nine (9) gRNA sequences yielded InDel percentages above 50% that could be suitable for secondary screens.
In some embodiments, a gRNA comprises the sequence of any one of SEQ ID NOs: 284-408 or targets the sequence of any one of SEQ ID NOs: 159-283.
B2M gRNA Screen
For B2M, genomic segments containing the first three (3) protein coding exons were used as input in the gRNA design software. The genomic segments also included flanking splice site acceptor/donor sequences. Desired gRNAs were those that would lead to insertions or deletions in the coding sequence disrupting the amino acid sequence of B2M leading to out of frame/loss of function allele(s). All forty nine (49) in silico-identified gRNA spacers targeting B2M were used in an IVT screen. All gRNAs yielded measurable data by TIDE analysis. Eight (8) gRNA sequences yielded InDel percentages above 50% that could be suitable for secondary screens.
A homology-dependent assessment of the B2M gRNA comprising SEQ ID NO: 466 showed that this guide had an indel frequency of less than 0.5% at an off-target site. This data guided selection of this particular B2M gRNA for further analysis.
In some embodiments, a gRNA comprises the sequence of any one of SEQ ID NOs: 458-506 or targets the sequence of any one of SEQ ID NOs: 409-457.
CIITA gRNA Screen
For CIITA, genomic segments containing the ATG exon downstream of the Type 3 promoter, the Type IV promoter/alternative exon 1, and the next three (3) downstream exons (here termed exon3-exon5) were used as input into the gRNA design software (see Muhlethaler-Mottet et al., 1997. EMBO J. 10, 2851-2860 for CIITA gene annotation). The genomic segments included protein coding regions and flanked splicing acceptor/donor sites as well as potential gene expression regulatory elements. Desired gRNAs were those that would lead to insertions or deletions in the coding sequence disrupting the amino acid sequence of CIITA leading to out of frame/loss of function allele(s). Only gRNAs without a perfect match elsewhere in the genome were screened. From a total of ˜274 gRNA spacers targeting CIITA (identified in silico), one hundred ninety six (196) gRNA spacers were chosen for IVT screening. One hundred eighty (180) sgRNAs yielded measurable data by TIDE analysis. Eighty one (81) gRNA sequences yielded InDel percentages above 50% that could be suitable for secondary screens.
In some embodiments, a gRNA comprises the sequence of any one of SEQ ID NOs: 699-890 or targets the sequence of any one of SEQ ID NOs: 507-698.
PD1 gRNA Screen
For PDCD1 (PD1), genomic segments containing the first three (3) protein coding exons were used as input in the gRNA design software. The genomic segments also included flanking splice site acceptor/donor sequences. Desired gRNAs were those that would lead to insertions or deletions in the coding sequence disrupting the amino acid sequence of PDCD1 leading to out of frame/loss of function allele(s). One hundred ninety two (192) in silico identified gRNA spacers targeting PDCD1 were used in an IVT screen. One hundred ninety (190) yielded measurable data by TIDE analysis. Forty (40) gRNA sequences yielded InDel percentages above 50% that could be suitable for secondary screens.
In some embodiments, a gRNA comprises the sequence of any one of SEQ ID NOs: 1083-1275 or comprises a sequence that targets the sequence of any one of SEQ ID NOs: 891-1082.
PD1 Screen in SpCas9/HEK293T Cells and T Cells
Five (5) PD1 gRNAs were selected for further analysis in HEK293T cells and T cells. Three out of the five guides performed better (higher indel percentage) than the positive control (PD1 control). Surprisingly, the guide producing the highest indel percentage (editing frequency) (Guide 2) did not produce the greatest level of PD1 protein expression knockdown (compared to Guides 3-5—see Table 9).
A homology-dependent assessment of the PD1 gRNAs of Table 9 showed that PD1 Guide 5 (comprising SEQ ID NO: 1276) had an indel frequency of 20% at an off-target site, while PD1 Guide 4 (SEQ ID NO: 1086) had an indel frequency of less than 2.0% at an off-target site. This data guided selection of PD1 Guide 4 for further analysis.
CTLA-4 Screen in T Cells
One (1) million T cells were electroporated with 1000 pmol gRNA and 200 pmol Cas9 protein. 48-72 hours post-EP, cells were stimulated with a PMA/ionomycin cocktail solution and simultaneously stained with CTLA4 antibody (1:100 dilution, Biolegend #349907). Four (4) hours post-stimulation, cells were collected for FACS analysis. Two different donors were used (Donor 46 and Donor 13). Protein expression was measured by flow cytometry. The results are shown in Table 10. Use of Guide 5 (with spacer SEQ ID NO: 1292) consistently resulted in the lowest protein expression (e.g., 8.6%). Use of Guide 2 (with spacer SEQ ID NO: 1290) and Guide 9 (with spacer SEQ ID NO: 1297) also resulted in low protein expression (11.9% and 12.2%, respectively).
This example demonstrates efficient knockout by CRISPR/Cas9 of Graft vs. Host (GVH) or Host vs. Graft (HVG) or Immune checkpoint genes at the genotypic and phenotypic levels in primary human T cells.
Primary human T cells were isolated from peripheral blood (AllCells, Alameda, Calif.) using EasySep Direct Human T Cell Isolation Kit (Stemcell Technologies, Vancouver, Canada). The cells were plated at 0.5×106 cells/mL in large flasks. Human T-Activator CD3/CD28 Dynabeads (Thermo Fisher Scientific, Waltham, Mass.) were resuspended and washed with PBS prior to adding to the cells. The cells were incubated with Human T-Activator CD3/CD28 Dynabeads (Thermo Fisher Scientific, Waltham, Mass.) at a bead-to-cell ratio of 1:1 in X-vivo 15 hematopoietic serum-free medium (Thermo Fisher Scientific, Waltham, Mass.) supplemented with 5% human serum (Sigma-Aldrich, St. Louis, Mo.), 50 ng/mL human recombinant IL-2 (Peprotech, Rocky Hill, N.J.), and 10 ng/mL human recombinant IL-7 (Thermo Fisher Scientific, Waltham, Mass.). After 3 days, the cells were transferred to a 15 mL tube and the beads were removed by placing the tube on a magnet for 5 mins. Cells were then transferred, pelleted and plated at 0.5×106 cells/mL.
Three (3) days after beads were removed, T cells were electroporated using the 4D-Nucleofector (program E0115) (Lonza, Walkersville, Md.) and Human T Cells Nucleofector Kit (Lonza, Walkersville, Md.). The nucleofection mix contained the Nucleofector Solution, 106 cells, 1 μM Cas9 (Feldan, Québec, Canada), and 5 μM 2′-O-methyl 3′ phosphorothioate (MS) modified sgRNA (TriLink BioTechonologies, San Diego, Calif.) (As described in Hendel et al., 2015: PMID: 26121415). The MS modification was incorporated at three nucleotides at both the 5′ and 3′ ends. To allow for stable Cas9:sgRNA ribonucleoproteins (RNPs) formation, Cas9 was pre-incubated with sgRNAs in a Cas9:sgRNA molar ratio of 1:5 at 37° C. for 10 min prior to adding the nucleofection mix. For multiplex editing experiments, 1 μM (final concentration) each of Cas9 pre-complexed individually with sgRNAs was added to the electroporation buffer mix. Typical controls for each experiment included: non-electroporated cells, one mock treatment without the RNPs, one treatment with Cas9 alone and one treatment with MS modified AAVS1 sgRNA to monitor transfection efficiency. Following nucleofection, the cells were incubated at 37° C. for 4-7 days and analyzed by flow cytometry for surface protein expression and Tracking of InDels by Decomposition (TIDE) for insertions or deletions (InDels) on genomic DNA.
TIDE is a web tool to rapidly assess genome editing by CRISPR/Cas9 of target locus determined by a guide RNA (gRNA or sgRNA). Based on quantitative sequence trace data from two standard capillary sequencing reactions, the TIDE software quantifies the editing efficacy and identifies the predominant types of insertions and deletions (InDels) in the DNA of a targeted cell pool.
This example and the following example tested sgRNAs delivered by RNP. The sgRNA sequence comprise a 20 nucleotide spacer sequence (indicated in each example) followed by a backbone sequence. Table 11 lists target sequences specific to the indicated gene that were used as sgRNAs in synthetic and modified form that when complexed with Cas9 protein produced the indicated InDel % in primary human T cells. Table 11 lists InDel frequencies for synthetic and/modified sgRNA sequences (delivered as RNPs) targeting the indicated genes and target sequences in primary human T cells.
Examples of backbone sequences are shown in Table 1.
This example demonstrates the in vitro functional consequences in primary human T cells of editing TCR components (TCRa and CD3ε). The results of which are shown in
For flow cytometry experiments, approximately 0.5×106 to 1×106 RNP transfected cells were removed from culture 4-6 days post electroporation and transferred to a clean Eppendorf tube. Cells were pelleted by centrifugation at 1,200 rpm for 5 min and resuspended in 100 μL FACS buffer (0.5% BSA/PBS). To stain the cells, appropriate antibody cocktail was added to the sample, followed by incubation for 10-15 min at room temperature. UltraComp eBeads (Ebioscience, San Diego, Calif.) were used for preparing compensation controls along with the specific conjugated antibody when necessary. The compensation beads were stained at 1:100 with individual specific primary antibody used in the experiment for about 5 min. Stained samples (including compensation controls) were washed with 1 mL FACS buffer, centrifuged at 1,200 rpm, and aspirated to remove the buffer. Compensation beads were resuspended in 200 μL FACS buffer and passed through a 5 mL FACS tube with a cell strainer cap (Corning Inc., Corning, N.Y.). Cell samples were resuspended in 200 μL FACS buffer containing 1:1000 7AAD (Thermo Fisher Scientific, Waltham, Mass.), and passed through a 5 mL FACS tube with a cell strainer cap. Samples were then examined on NovoCyte ACEA 3000 flow cytometer (ACEA Biosciences, San Diego, Calif.) using the automatic compensation software and data was analyzed on Flowjo10.1r5. Antibodies used include BV510 anti-human CD3 (UCHT1, BioLegend, San Diego, Calif.), PE anti-human TCRαβ (BW242/412, Miltenyi Biotec, Auburn, Calif.), PE/Cy7 anti-human CD8 (SK1, BioLegend, San Diego, Calif.), and APC/Cy7 anti-human CD4 (RPA-T4, BioLegend, San Diego, Calif.).
Without being bound by theory, the reason for disrupting TCR in therapeutic T cells was that these T cells would not signal through upstream stimuli to the TCR, and thus not react with recipient peptides/antigens, but would maintain their ability to respond to downstream TCR signaling even after TCR knock-out. Phytohemagglutanin (PHA) and phorbol myristate acetate (PMA)/Ionomycin are two commonly used stimulation regimens for in vitro T cell activation, but they act through distinct mechanisms. PHA is a mitogenic lectin that activates the cells by crosslinking the TCR/CD3 complex as well as other glycosylated membrane proteins. On the contrary, PMA/Ionomycin stimulates T cells by directly activating TCR downstream pathways, bypassing the need for surface receptor stimulation. Therefore, TCR/CD3 deficient T cells were expected to react to PMA/Ionomycin but not to PHA.
To assess the function of TCR ablated T cells, primary human T cells were edited with CRISPR/Cas9 to disrupt TCR components TCRa or CD3c, treated with the two stimulation regimens, and tested for activation, proliferation, degranulation, and cytokine production using a series of assays described below. Primary human T cells were first electroporated with Cas9 or Cas9:sgRNA RNP complexes targeting AAVS1 (GGGGCCACTAGGGACAGGAT (SEQ ID NO: 1301)), TRAC (AGAGCAACAGTGCTGTGGCC (SEQ ID NO: 76)), or CD3c (GGGCACTCACTGGAGAGTTC (SEQ ID NO: 226)). Six (6) days post transfection, cells were stained for CD3ε and the percentage of cells with low or absent levels of CD3ε were assessed by flow cytometry. The results showed that transfection with Cas9:TRAC sgRNA or Cas9:CD3ε sgRNA largely reduced surface presentation of CD3. The CD3− population in Cas9:TRAC sgRNA and Cas9:CD3ε sgRNA transfected cells was 89% and 81%, respectively, whereas the percentage were 10% and 5% in Cas9 only or Cas9:AAVS1 sgRNA transfected cells. This confirmed that the CRISPR/Cas9 edited cells had deficient TCR/CD3 complexes. These cells served as inputs for the assessment in the subsequent assay experiments. The gRNAs used in this Example comprise the following spacer sequences:
CD69 Activation Assay
CD69 is a surrogate marker of T-cell responsiveness to mitogen and antigen stimulus and is used as a measure of T-cell activation. 7 days post transfection, cells were stimulated with either PHA-L (Ebioscience, San Diego, Calif.) or PMA/Ionomycin and grown for additional 2 days. Cells were then stained with APC mouse anti-human CD69 antibody (L78, BD Biosciences, San Jose, Calif.) and the levels of CD69 were assayed by flow cytometry (
CFSE Proliferation Assay
To further examine cell proliferation in TCR/CD3 deficient cells, the response to PHA and PMA/Ionomycin in the TCR/CD3 deficient cells was assessed. Carboxyfluorescein succinimidyl ester (CFSE) is a cell-permeant fluorescein-based dye used for monitoring lymphocyte proliferation. After transfection, the cells were labeled with 500 nM CFSE for 15 min at 37° C. After washing, cells were plated in serum and cytokine free media for 4 days. CFSE levels were measured by flow cytometry in the FITC channel (
Flow Cytometry Evaluation of CD107a and Intracellular Cytokines
Two other T cell activation events, degranulation and cytokine production, were also examined using flow cytometry. The transfected cells were either untreated, PHA or PMA treated in serum and cytokine free media. Concurrently, cells were incubated with Golgi Plug (BD Biosciences, San Jose, Calif.), Golgi Stop (BD Biosciences, San Jose, Calif.) and PE-Cy7 anti-human CD107a antibody (H4A3, Biolegend, San Diego, Calif.). Four (4) hours post treatment, cells were surface stained with the following antibodies anti-human CD3 (UCHT1, BioLegend, San Diego, Calif.), PE/Cy7 anti-human CD8 (SK1, BioLegend, San Diego, Calif.), and APC/Cy7 anti-human CD4 (RPA-T4, BioLegend, San Diego, Calif.) and fixed and permeabilized using BD Cytofix/Cytoperm Plus kit (BD Biosciences, San Jose, Calif.). Finally, cells were stained for intracellular cytokines with FITC anti-human TNFα antibody (Mab11, Biolegend, San Diego, Calif.), APC mouse anti-human IFNγ antibody (25723.11, BD Biosciences, San Jose, Calif.), and PE rat anti-human IL-2 antibody (MQ1-17H12, BD Biosciences, San Jose, Calif.), washed, and analyzed by flow cytometry.
Surface expressed CD107a is a marker for CD8+ T cell degranulation following stimulation. Control cells that had received neither PHA nor PMA/Ionomycin treatment showed minimal surface expression of CD107. Both PHA and PMA/Ionomycin treatments induced CD107a expression in mock transfected, Cas9 alone, and Cas9:AAVS1 sgRNA transfected groups. Again, TCRα or CD3ε deficient cells showed base levels of CD107a expression after PHA treatment but largely increased levels of CD107a expression after PMA/Ionomycin treatment (
Similarly, enhanced levels of intracellular cytokine TNF, IFNγ, and IL-2 were observed after either PHA or PMA/Ionomycin treatment in the mock transfected, Cas9 alone, and Cas9:AAVS1 sgRNA transfected cells (
Taken together, these experiments demonstrated that the TCR/CD3 complex is disrupted in the gene edited cells with signaling downstream of the TCR remaining intact in TCR/CD3 deficient cells, as indicated by cell proliferation, degranulation and effector cytokine production.
This example demonstrates the in vitro functional consequences in primary human T cells of editing MHC II components (CIITA or RFX5). The results are shown in
Primary human T cells were transfected with RNP containing synthetic sgRNAs targeting AAVS1 (GGGGCCACTAGGGACAGGAT (SEQ ID NO: 1301)), B2M (GCTACTCTCTCTTTCTGGCC (SEQ ID NO: 417)), CIITA (GGTCCATCTGGTCATAGAAG (SEQ ID NO: 546)), RFX5-1 (TACCTCGGAGCCTCTGAAGA (SEQ ID NO: 1305)), RFX5-5 (TGTGCTCTTCCAGGTGGTTG (SEQ ID NO: 1306)), and RFX5-10 (ATCAAAGCTCGAAGGCTTGG (SEQ ID NO: 1307)). 4-6 days post transfection cells were treated with PMA/ionomycin overnight and surface levels of MHC-II were assessed by flow cytometry (Tu39, PE-Cy7 conjugate, Biolegend). The amount of MHC-II induction (assessed by median fluorescent intensity [MFI]) per test sample was normalized to the amount of MHC-II present on control (AAVS1) transfected cells (
In addition, RNPs containing Cas9 and sgRNAs targeting CIITA or RFX5 diminish surface levels of MHC-II in induced primary human T cells.
The gRNAs used in this Example comprise the following spacer sequences: AAVS1 gRNA spacer (GGGGCCACUAGGGACAGGAU (SEQ ID NO: 1308)); B2M gRNA spacer (GCUACUCUCUCUUUCUGGCC (SEQ ID NO: 466)); CIITA gRNA spacer (GGUCCAUCUGGUCAUAGAAG (SEQ ID NO: 738)), RFX5-1 gRNA spacer (UACCUCGGAGCCUCUGAAGA (SEQ ID NO: 1309)), RFX5-5 gRNA spacer (UGUGCUCUUCCAGGUGGUUG (SEQ ID NO: 1310)), and RFX5-10 gRNA spacer (AUCAAAGCUCGAAGGCUUGG (SEQ ID NO: 1311)).
Primary human T cells were transfected with RNP containing synthetic sgRNAs targeting PD-1 (CGCCCACGACACCAACCACC (SEQ ID NO: 916) and comprising the spacer sequence of SEQ ID NO: 1108) or control. 4-6 days post transfection cells were treated with PMA/ionomycin, and surface levels of PD-1 were assessed by flow cytometry (EH12.2H7, BV421 conjugate, Biolegend). The amount of PD1 induction (assessed by median fluorescent intensity [MFI]) per test sample was normalized to the amount of PD1 present in untreated control transfected cells. Data are from 3 biological donors for single or dual sgRNA(s) transfected cells, respectively. Statistical significance was assessed using Student's t test.
In addition, RNPs containing Cas9 and sgRNAs targeting PD1 diminish surface levels of PD1 in induced primary human T cells.
This example demonstrates efficient multiplex editing and target protein knock out in primary human T cells. The results are shown in
Primary human T cells were transfected with RNP containing synthetic sgRNAs targeting the indicated genes. For the knockout of 2 or more genes and their protein products in the same cell (multiplex editing), 1 μM (final concentration) each of Cas9 pre-complexed individually with sgRNAs was added to the nucleofection mix. Surface levels of the indicated proteins were measured by flow cytometry 4-6 days after transfection. Antibodies used include BV510 anti-human CD3 (UCHT1, BioLegend, San Diego, Calif.), PE anti-human TCRαβ (BW242/412, Miltenyi Biotec, Auburn, Calif.), APC anti-human B2M (2M2, Biolegend), FITC anti-human CD52 (097, Biolegend). Each symbol is data from an individual biological donor where test RNP treated cells are compared to control RNP treated cells. Statistical significance was assessed by Student's t test.
Guides used in this example are listed below with the respective target and spacer sequences:
In order to assess the feasibility of triple knockout using CRISPR/Cas9, primary T cells (5×106) were transfected with pre-formed RNPs targeting three separate genes: TRAC, B2M, and CIITA. RNP containing sgRNAs targeting AAVS1 served as a negative control. After 4 days, cells were split into two halves: one half was treated with anti-CD3/anti-B2M biotin antibodies and subsequently purified using Streptavidin Microbeads (Miltenyi Biotec, Cambridge, Mass.), and the other half remained untreated. Purified (pur) and unpurified (un) cells were both analyzed by TIDE. TIDE analysis showed that this approach produced a triple knockout InDel frequency of ˜36% compared to the control group, proving, at the DNA level, that it is possible to knockout three genes simultaneously using Cas9:sgRNA RNPs in a single experiment (
In addition, the data in
This example demonstrates efficient transgene insertion in primary human T cells via homology directed repair (HDR) by Cas9:sgRNA RNP-mediated double-stranded genomic DNA breaks with an AAV6 donor DNA template.
Primary human T cells were isolated and activated with anti-CD3/CD28 beads as described in Example 2. Beads were removed after 3 days. On day 4, T cells (5×106) were electroporated with Cas9 alone or Cas9:AAVS1 sgRNA (targeting GGGGCCACTAGGGACAGGAT (SEQ ID NO: 1301)) RNP. 45 min. post transfection, 1×106 of the Cas9 treated or the RNP treated cells were either mock transduced (control), transduced with an AAV6-MND-GFP viral vector with AAVS1 homology arms with lengths of either 400 (HA 400) or 700 (HA700) bp flanking the MND-GFP cassette (
To assess the efficiency of AAV6/RNP-mediated HDR, a PCR analysis (
This example demonstrates efficient transgene insertion and concurrent gene knockout by Cas9:sgRNA RNP (for double stranded break induction) and AAV6 delivered donor template to facilitate HDR in primary human T cells.
Primary human T cells were activated with CD3/CD28 magnetic beads (as above). Three days later activation beads were removed. The next day 5×106 cells were electroporated with RNP complexes with sgRNAs targeting either AAVS1 (1 RNP), TRAC+B2M (2 separately complexed RNPs), or TRAC+B2M+AAVS1 (3 separately complexed RNPs). 1 hr post electroporation, cells were infected with −/+AAV6-MND-GFP viral vector with AAVS1 homology arms with lengths of 700 bp flanking the MND-GFP cassette (AAV6 (HA700-GFP) (
Guides used in this example target the following sequences:
sgRNA sequences used herein: TRAC SEQ ID NO: 686, B2M SEQ ID NO: 688 and AAVS1 SEQ ID NO: 690, and can be modified as follows: TRAC SEQ ID NO: 685, B2M SEQ ID NO: 687 and AAVS1 SEQ ID NO: 689. The gRNAs used in this Example comprise the following spacer sequences: AAVS1 gRNA spacer (GGGGCCACUAGGGACAGGAU (SEQ ID NO: 1308)); TRAC gRNA spacer (AGAGCAACAGUGCUGUGGCC (SEQ ID NO: 152)); and B2M gRNA spacer (GCUACUCUCUCUUUCUGGCC (SEQ ID NO: 466)).
This example describes the production by CRISPR/Cas9 and AAV6 of allogeneic human T cells that lack expression of the TCR and MHC I and express a chimeric antigen receptor targeting CD19+ cancers.
Schematic depiction of CRISPR/Cas9 generated allogeneic CAR−T cells is shown in
CRISPR/Cas9 was used to disrupt (knockout [KO]) the coding sequence of the TCRα constant region gene (TRAC). This disruption leads to loss of function of the TCR and renders the gene edited T cell non-alloreactive and suitable for allogeneic transplantation, minimizing the risk of graft versus host disease. The DNA double stranded break at the TRAC locus was repaired by homology directed repair with an AAV6-delivered DNA template containing right and left homology arms to the TRAC locus flanking a chimeric antigen receptor cassette (−/+ regulatory elements for gene expression). To reduce host versus graft (host vs CAR−T) and allow for persistence of the allogeneic CAR−T product, the B2M gene was disrupted by CRISPR/Cas9 components. Together, these genome edits result in a T cell with surface expression of a CAR (expressed from the TRAC locus) targeting CD19+ cancers along with loss of the TCR and MHC I, to reduce GVH and HVG disease, respectively.
Schematics of the AAV vetor genome carrying donor templates to facilitate targeted genomic insertion of CAR expression cassettes by HDR of Cas9-evoked site specific DNA double stranded breaks are shown in
GCTGCTGCCTTTGTCCCGGTATTTCTCCCAGCCAAACCG
APRPPTPAPTIASQPLSLRPEACRPAAGGAVHTRGLDFACDI
YIWAPLAGTCGVLLLSLVITLYCNHRNRSKRSRLLHSDYM
CTX-131 (SEQ ID NO: 1348) contains a CAR (FMC63-CD8[tm]-CD28[co-stimulatory domain]-CD3z) construct (SEQ ID NO: 1316) with a synthetic 3′ poly adenylation sequence (pA) whose expression is driven by the MND promoter and is translationally linked by a picornavirus 2A sequence to any potential downstream transcript (GFP is shown in this example). CTX-131 contains homology arms flanking a genomic Cas9/sgRNA target site in the AAVS1 locus. CTX-132 (SEQ ID NO: 1349) is the same version of this construct, but lacking homology arms to AAVS1.
CTX-133 (SEQ ID NO: 1350) contains a CAR (FMC63-CD8[tm]-CD28[co-stimulatory domain]-CD3z) construct (SEQ ID NO: 1316) with a synthetic 3′ poly adenylation sequence (pA) whose expression is driven by the EF1a promoter and is translationally linked by a picornavirus 2A sequence to any potential downstream transcript (GFP is shown in this example). CTX-133 contains homology arms flanking a genomic Cas9/sgRNA target site in the TRAC locus. CTX-134 (SEQ ID NO: 1351) is the same version of this construct, but lacking homology arms to TRAC. CTX-138 (SEQ ID NO: 1354) is a version of CTX-133 lacking the 2A-GFP sequence, and the 500 bp flanking homology arms are replaced with 800 bp flanking homology arms. CTX-139 (SEQ ID NO: 1355) is a version of CTX-138 where the TRAC left homology arm was replaced with a 678 bp homology arm (TRAC-LHA (680 bp)).
CTX-140 (SEQ ID NO: 1356) contains a CAR (FMC63-CD8[tm]-CD28[co-stimulatory domain]-CD3z) construct (SEQ ID NO: 1316) with a synthetic 3′ poly adenylation sequence (pA) whose expression is driven by endogenous TCR regulatory elements and is translationally linked by a picornavirus 2A sequence to any potential upstream TCRa transcript. CTX-140 contains homology arms flanking a genomic Cas9/sgRNA target site in the TRAC locus (distinct from CTX-133, CTX-138, and CTX-139). CTX-141 (SEQ ID NO: 1357) is the same version of the CTX-140 construct and is also translationally linked to any potential downstream sequence by an additional 2A sequence (GFP is shown in this example).
CTX-139.1 construct (SEQ ID NO: 1583) is a similar version of the CTX-139 construct however the left homology arm (LHA) sequence is replaced with an alternate 800 bp TRAC-LHA, creating a larger deletion upon homologous recombination. CTX-139.2 is similar to CTX139.1 but with an extended 20 bp LHA and 105 bp RHA that brings homologous sequence closer to the Exon1_T7 guide cut site but is missing the Exon1_T7 guide target sequence. CTX-139.3 is similar to CTX-139.2 with an additional 21 bp added to the LHA and 20 bp added to the RHA. CTX-139.2 contains all the Exon1_T7 guide target sequence but has a mutation in the corresponding PAM sequence.
CTX-135 (SEQ ID NO: 1352) contains a CAR (FMC63-CD8[tm]-CD28[co-stimulatory domain]-CD3z) construct (SEQ ID NO: 1316) with a synthetic 3′ poly adenylation sequence (pA) whose expression is driven by endogenous CD3E regulator elements and is translationally linked by a picornavirus 2A sequence to any potential downstream transcript (GFP is shown in this example). CTX-135 contains 700 bp homology arms flanking a genomic Cas9/sgRNA target site in the CD3E locus. CTX-136 (SEQ ID NO: 1353) is a version of CTX-135 but lacking homology arms to CD3E.
CRISPR/Cas9 Mediated Knockout of TCR and MHC I Components, Expression of Chimeric Antigen Receptor (CAR) Constructs, and Retained Effector Function
This example describes the production by CRISPR/Cas9 and AAV6 of allogeneic human T cells that lack expression of TCR and MHC I, that express a chimeric antigen receptor targeting CD19+ cancers, and that retain T cell effector function.
Transgene insertion in primary human T cells via homology directed repair (HDR) and concurrent gene knockout by Cas9:sgRNA RNA was performed as described above in Examples 8 and 9. Primary human T cells were first electroporated with Cas9 or Cas9:sgRNA RNP complexes targeting TRAC (AGAGCAACAGTGCTGTGGCC (SEQ ID NO: 76)), B2M1 (GCTACTCTCTCTTTCTGGCC (SEQ ID NO: 417)), or AAVS1 (GGGGCCACTAGGGACAGGAT (SEQ ID NO: 1301)). The gRNAs used in this Example comprise the following spacer sequences: AAVS1 gRNA spacer (GGGGCCACUAGGGACAGGAU (SEQ ID NO: 1308)); TRAC gRNA spacer (AGAGCAACAGUGCUGUGGCC (SEQ ID NO: 152)); and B2M gRNA spacer (GCUACUCUCUCUUUCUGGCC (SEQ ID NO: 466)).
T cell staining was performed as described above in Example 3 with a modification in which the cells were stained with anti-mouse Fab2 antibody labeled with biotin (115-065-006, Jackson ImmunoRes) at a dilution of 1:5 for 30 minutes at 4° C. The cells were then washed and stained with a streptavidin conjugate. The flow cytometry results are shown in
The ability of the engineered cells to lyse Raji lymphoma cells and to produce interferon gamma (IFNg or IFNγ) was then analyzed using a cell kill assay and ELISA. Briefly, the cell kill assay and ELISA were performed using black walled 96 well plates, 100 ug Staurosporine (Fisher 1285100U), Cell Stimulation Cocktail (PMA) (Fisher 501129036), Trypan Blue (Fisher 15250061), PBS, and Raji media (10% Heat-Inactivated Fetal Bovine Serum (Sigma F4135-500ML, 15L115)) and RPMI 1640 (Life Technologies 61870036)) or K562 Media (10% Heat-Inactivated Fetal Bovine Serum (Sigma F4135-500ML, 15L115) and IMDM (Life Technologies 12440061).
T-cells and CAR−T samples were re-suspended in the appropriate RPMI/10% FBS to a dilution of 4.0×105/100 μL, and Luciferase expressing cells were re-suspended at 1.0×105/100 μL. After re-suspension, all samples were plated at a final volume of 200 uL per well as shown. Plates were incubated overnight, and after 24 hours, plates were spun down for 10 minutes. Thirty (30) μL of the top supernatant media was collected for use in the IFNγ ELISA (RD Systems SIF50) on a new plate. The remaining plate volume was then used in the Luciferase Assay (Perkin Elmer 6RT0665).
T cells expressing an anti-CD19 CAR construct either from the AAVS1 locus (AAVS1 RNP+CTX-131) or from the TRAC locus (TRAC RNP+CTX-138) were able to lyse the Raji lymphoma cells in a coculture assay (
CAR Expression Using rAAV Constructs with Different TRAC sgRNAs
This example describes the effect of donor design and guide selection on CAR expression in allogeneic human T cells that lack expression of TCR and MHC I, and express a chimeric antigen receptor. Cells were prepared using the following sgRNAs: TRAC gRNA spacer “EXON1_T32”: AGAGCAACAGUGCUGUGGCC (SEQ ID NO: 152); sgRNA (SEQ ID NO: 1345); TRAC gRNA spacer “Exon1_T7” (GAGAAUCAAAAUCGGUGAAU (SEQ ID NO: 88); sgRNA (SEQ ID NO: 1588), and rAAV constructs show in the table below.
The homology arms used in AAV constructs can be designed to more efficiently pair with gRNAs and/or induce a deletion or mutation in the targeted gene locus (e.g.: TRAC locus) following transgene insertion. For example, the homology arms can be designed to flank one or more spacer sequences that results in the deletion of the spacer sequence(s) following transgene insertion by HDR (e.g.: CTX-138). Alternatively, homology arms can be designed with alterations in the TRAC sequence that result in base pair changes, generating mutations in the PAM or spacer sequences. Specific guide design, paired with a particular guide RNA can improve CAR expression.
On-target amplicon analysis was conducted the TRAC and B2M locus following gene editing using the following guides:
Following gene editing, on-target amplicon analysis was conducted around the TRAC and B2M locus in TRAC-/B2M-/anti-CD19 CAR+ cells.
An initial PCR was performed using the 2×Kapa HiFi Hotstart Mastermix (Kapa Biosystems, Wilmington, Mass.). 50 ng of input gDNA was combined with 300 nM of each primer. The TRAC_F and TRAC_R primers were paired for the TRAC locus, and the B2M _F and B2M _R primers were paired to amplify the B2M locus (Table ##).
Analysis of the B2M locus in a population of T cells following gene editing to produce TRAC−/B2M−/CAR+ T cells results in the following indel frequencies and edited gene sequences at the B2M locus (deletions as dashes and insertions in bold).
Analysis of the TRAC locus in a population of T cells following gene editing to produce TRAC−/B2M−/CAR+ T cells results in the following indel frequencies and edited gene sequences at the TRAC locus in T cells without a CAR insertion (deletions as dashes and insertions in bold).
CRISPR/Cas9 technologies have been applied to develop anti CD19 allogeneic chimeric antigen receptor T cells (CAR−T) with reduced potential for graft vs. host disease (GVHD), and reduced rejection potential for the treatment of CD19 positive malignancies. The efficiency of the CRISPR/Cas9 system enables rapid production of homogeneous CAR−T product from prescreened healthy donors and thus can potentially be developed as an “off-the-shelf” therapy for efficient delivery to patients. Autologous CAR−T therapeutics targeting CD19 have shown impressive responses in B-cell malignancies but currently require significant individualized manufacturing efforts and can suffer from manufacturing failures. In addition, these autologous CAR−Ts are produced using retrovirus or lentivirus, for which the variable nature of integration can lead to a heterogeneous product. Allogeneic or “off-the-shelf” CAR−T products with site-specific CAR integration generated with gene editing technologies may address some of these significant challenges seen for autologous products.
CRISPR-Cas9 technology was utilized in primary human T cells to produce allogeneic CAR−T cells by multiplexed genome editing. A robust system for site-specific integration of CAR and concurrent multiplexed gene editing in single T cells has been developed by utilizing homology-directed repair (HDR) with Cas9 ribonucleoprotein (RNP) and an AAV6-delivered donor template.
With CRISPR/Cas9 editing technology, high frequency knockout of the constant region of the TCRα gene (TRAC) with ˜98% reduction of TCR surface expression in human primary T-cells from healthy donors, which aims to significantly impair graft-versus-host disease (GVHD), was achieved. High frequency knockout of the β-2-microglobulin (B2M) gene could also be obtained, which aims to increase persistence in patients, potentially leading to increased potency overall. TRAC/B2M double knockout frequencies have been obtained in ˜80% of T cells without any subsequent antibody-based purification or enrichment. Human T cells expressing a CD19-specific CAR from within a disrupted TRAC locus, produced by homology-directed repair using an AAV6-delivered donor template, along with knockout of the B2M gene have been consistently produced at a high efficiency. This site-specific integration of the CAR protects against the potential outgrowth of CD3+CAR+ cells, further reducing the risk of GVHD, while also reducing the risk of insertional mutagenesis associated with retroviral or lentiviral delivery mechanisms. These engineered allogeneic CAR−T cells show CD19-dependent T-cell cytokine secretion and potent CD19-specific cancer cell lysis.
We are able to use genome editing with the CRISPR-Cas9 system to efficiently create an allogeneic or “off-the-shelf” CAR−T cell product (e.g.: TC1) that demonstrates potent and specific anticancer effects for patients with CD19-expressing human cancers. More specifically, and as demonstrated herein the production of allogeneic anti-CD19 CAR−T product (
In this example, the efficacy of CAR−T cells against the subcutaneous Raji Human Burkett's Lymphoma tumor xenograft model in NOG mice was evaluated. Transgene insertion in primary human T cells via homology directed repair (HDR) and concurrent gene knockout by Cas9:sgRNA RNA was performed as described above in Examples 8-10 to produce cells lacking TCR and B2M surface expression and to concurrently express an anti-CD19 CAR construct (TRAC−B2M−CD19CAR+ cells). Primary human T cells were first electroporated with Cas9 or Cas9:sgRNA RNP complexes targeting TRAC (AGAGCAACAGTGCTGTGGCC (SEQ ID NO: 76) and B2M1 (GCTACTCTCTCTTTCTGGCC (SEQ ID NO: 417)). The DNA double stranded break at the TRAC locus was repaired by homology directed repair with an AAV6-delivered DNA template (CTX-138; SEQ ID NO: 675) containing right and left homology arms to the TRAC locus flanking a chimeric antigen receptor cassette (−/+ regulatory elements for gene expression). The resulting modified T cells (TC1) are TRAC−/B2M−CD19CAR+. The ability of the modified TRAC−/B2M−CD19CAR+ T cells to ameleriote disease caused by a CD19+ lymphoma cell line (Raji) was evaluated in NOG mice using methods employed by Translational Drug Development, LLC (Scottsdale, Ariz.). In brief, 12, 5-8 week old female, CIEA NOG (NOD.Cg-PrkdcscidIl2rgtm1Sug/JicTac) mice were individually housed in ventilated microisolator cages, maintained under pathogen-free conditions, 5-7 days prior to the start of the study. On Day 1 mice received a subcutaneous inoculation of 5×106 Raji cells/mouse. The mice were further divided into 3 treatment groups as shown in Table 13. On Day 8 (7 days post inoculation with the Raji cells), treatment group 2 and group 3 received a single 200 μl intravenous dose of TRAC−/B2M−CD19CAR+ cells (TC1) according to Table 13. The gRNAs used in this Example comprise the following spacer sequences:
Tumor volume and body weight was measured and individual mice were euthanized when tumor volume was ≥500 mm3.
By Day 18, the data show a statistically significant decrease in the tumor volume in response to TC1cells as compared to untreated mice (
In addition to CT1 described above, additional modified T cells expressing a chimeric antigen receptor (CAR) comprising an extracellular domain comprising an anti-CD19 scFv and further comprising a double knock-out of the TRAC and B2M genes are contemplated for use this and other examples described herein. In certain embodiments the TRAC−/B2M− CD19CAR+ cells, the TRAC deletion may be accomplished using any one of the TRAC spacer sequences described herein. In certain embodiments of the TRAC−B2M−CD19CAR+ cells, the β2M deletion may be accomplished using any one of the B2M spacer sequences described herein.
Intravenous Disseminated Raji Human Burkett's Lymphoma Tumor Xenograft Model
The Intravenous Disseminated Model (Disseminated Model) using the Raji Human Burkett's Lymphoma tumor cell line in NOG mice was used in this example to further demonstrate the efficacy of TRAC−/B2M−CD19CAR+ cells. Generation of the TRAC−/B2M−CD19CAR+ cells (TC1) used in this model was described in the Examples above and evaluated in the Disseminated Model using methods employed by Translations Drug Development, LLC (Scottsdale, Ariz.) and described herein. In brief, 24, 5-8 week old female CIEA NOG (NOD.Cg-PrkdcscidIl2rgtm1Sug/JicTac) mice were individually housed in ventilated microisolator cages, maintained under pathogen-free conditions, 5-7 days prior to the start of the study. At the start of the study, the mice were divided into 5 treatment groups as shown in Table 15. On Day 1 mice in Groups 2-5 received an intravenous injection of 0.5×106 Raji cells/mouse. The mice were inoculated intravenously to model disseminated disease. On Day 8 (7 days post injection with the Raji cells), treatment Groups 3-5 received a single 200 μl intravenous dose of TC1 cells per Table 15.
During the course of the study mice were monitored daily and body weight was measured two times weekly. A significant endpoint was the time to peri-morbidity and the effect of T-cell engraftment was also assessed. The percentage of animal mortality and time to death were recorded for every group in the study. Mice were euthanized prior to reaching a moribund state. Mice may be defined as moribund and sacrificed if one or more of the following criteria were met:
Loss of body weight of 20% or greater sustained for a period of greater than 1 week;
Tumors that inhibit normal physiological function such as eating, drinking, mobility and ability to urinate and or defecate;
Prolonged, excessive diarrhea leading to excessive weight loss (>20%); or
Persistent wheezing and respiratory distress.
Animals were also considered moribund if there was prolonged or excessive pain or distress as defined by clinical observations such as: prostration, hunched posture, paralysis/paresis, distended abdomen, ulcerations, abscesses, seizures and/or hemorrhages.
Similar to the subcutaneous xenograph model (Example 12), the Disseminated Model revealed a statistically significant survival advantage in mice treated with TRAC−/B2M− CD19CAR+ cells (TC1) as shown in
A second experiment was run using the Intravenous Disseminated model described above.
On Day 1 mice in Groups 2-4 received an intravenous injection of 0.5×106 Raji cells/mouse. The mice were inoculated intravenously to model disseminated disease. On Day 4 (3 days post injection with the Raji cells), treatment Groups 2-4 received a single 200 μl intravenous dose of TC1 cells per Table 17.
Again, the Disseminated Model revealed a statistically significant survival advantage in mice treated with TRAC−/B2M−CD19CAR+ cells (TC1) as shown in
Evaluation of Splenic Response to TC1 Treatment
The spleen was collected from mice 2-3 weeks following Raji injection and the tissue was evaluated by flow cytometry for the persistence of TC1 cells and eradication of Raji cells in the spleen.
Flow cytometry Analysis Procedure
The Spleen was transferred to 3 mL of 1×DPBS CMF in a C tube and dissociated using the MACS Octo Dissociator. The sample was transferred through a 100 micron screen into a 15 mL conical tube, centrifuged (1700 rpm, 5 minutes, ART with brake) and resuspended in 1 mL of 1×DPBS CMF for counting using the Guava PCA. Bone marrow was centrifuged and resuspended in 1 mL of 1×DPBS CMF for counting using the Guava PCA. Cells were resuspended at a concentration of 10×106 cells/mL in 1×DPBS CMF for flow cytometry staining.
Specimens (50 μL) were added to 1 mL 1× Pharm Lyse and incubated for 10-12 minutes at room temperature (RT). Samples were centrifuged and then washed once with 1×DPBS CMF. Samples were resuspended in 50 μL of 1×DPBS and incubated with Human and Mouse TruStain for 10-15 minutes at RT. The samples were washed once with 1 mL 1×DPBS CMF and resuspend in 50 μL of 1×DPBS CMF for staining. Surface antibodies were added and the cells incubated for 15-20 minutes in the dark at RT and then washed with 1 mL 1×DPBS CMF. Then samples were resuspended in 125 μL of 1×DPBS CMF for acquisition on the flow cytometer.
Cells were stained with the following surface antibody panel:
Cell populations were determined by electronic gating (Pl=total leukocytes) on the basis of forward versus side scatter. Compensation to address spill over from one channel to another was performed upon initial instrument set up using Ultra Comp Beads from Thermo Fisher. The flow cytometer was set to collect 10,000 CD45+ events in each tube. Flow cytometric data acquisition was performed using the FACSCantoll™ flow cytometer. Data was acquired using BO FACSDiva™ software (version 6.1.3 or 8.0.1). Flow cytometry data analysis was in the form of Flow Cytograms, which are graphical representations generated to measure relative percentages for each cell type.
This example demonstrates that following TC1 cell treatment, the therapeutically beneficial TRAC−/B2M−CD19CAR+ cells persist in the spleen and selectively eradicate Raji cells from the tissue (
Intravenous Disseminated Nalm-6 Human Acute Lymphoblastic Leukemia Tumor Xenograft Model
The Intravenous Disseminated Model (Disseminated Model) using the Nalm-6 Human Acute Lymphoblastic Leukemia tumor cell line in NOG mice was used in this example to further demonstrate the efficacy of TRAC−/B2M−CD19CAR+ cells. Generation of the TRAC−/B2M−CD19CAR+ cells (TC1) used in this model was described in the Examples above and evaluated in the Disseminated Model using methods employed by Translations Drug Development, LLC (Scottsdale, Ariz.) and described herein. In brief, 24, 5-8 week old female CIEA NOG (NOD.Cg-PrkdcscidIl2rgtm1Sug/JicTac) mice were individually housed in ventilated microisolator cages, maintained under pathogen-free conditions, 5-7 days prior to the start of the study. At the start of the study, the mice were divided into 5 treatment groups as shown in Table 20. On Day 1 mice in Groups 2-4 received an intravenous injection of 0.5×106 Nalm6 cells/mouse. The mice were inoculated intravenously to model disseminated disease. On Day 4 (3 days post injection with the Nalm6 cells), treatment Groups 2-4 received a single 200 μl intravenous dose of TC1 cells per Table 20.
During the course of the study mice were monitored daily and body weight was measured two times weekly as described above.
Similar to the Raji intravenous disseminated model (above), the Nalm6 Model also showed a statistically significant survival advantage in mice treated with TRAC−/B2M− CD19CAR+ cells (TC1) as shown in
The production of the TRAC−/B2M−CD19CAR+ cells, TC1, may result in unwanted off-target editing that could generate cells with adverse properties. One of these adverse properties could be uncontrolled cell growth. In this experiment, we assessed the ability of TC1 cells to grow in the absence of cytokines and/or serum.
1×106 TC1 cells were plated ˜2 weeks post production (Day 0). The number of viable cells were enumerated 7 and 14 days post plating in either full media, 5% human serum without cytokines (IL-2 and IL-7), or base media lacking serum and cytokines. No cells were detected at 14 days plated in the cultures that lacked cytokines suggesting that any potential off-target effects due to genome editing did not bestow growth factor independent growth/proliferation to TC1 cells. The TC1 cells only proliferated in the presence of cytokines (e.g. full media that contains cytokines) and did not proliferate in the presence of serum alone as shown in
This example describes the production by CRISPR/Cas9 and AAV6 of allogeneic human T cells that lack expression of TCR, or TCR and MHC I, and express a chimeric antigen receptor targeting CD70+ cancers.
A schematic depiction of CRISPR/Cas9 generated allogeneic CAR−T cells is shown in
Similar to Example 9 above, CRISPR/Cas9 was used to disrupt (knockout [KO]) the coding sequence of the TCRa constant region gene (TRAC). This disruption leads to loss of function of TCR and renders the gene edited T cell non-alloreactive and suitable for allogeneic transplantation, minimizing the risk of graft versus host disease (GVHD). The DNA double stranded break at the TRAC locus was repaired by homology directed repair with an AAV6-delivered DNA template containing right and left homology arms to the TRAC locus flanking a chimeric antigen receptor cassette (−/+ regulatory elements for gene expression). To reduce host versus graft (HVG) (e.g.: host vs CAR−T) and allow for persistence of the allogeneic CAR−T product, the B2M gene was also disrupted using CRISPR/Cas9 components. Together, these genome edits result in a T cell with surface expression of a CAR (expressed from the TRAC locus) targeting CD70+ cancers along with loss of the TCR and MHC I, to reduce GVHD and HVG, respectively. The T cell can be referred to as a TRAC−/B2M−CD70CAR+ cell.
For certain experiments, described in the following examples, single knock-out TRAC-CD70 CAR+ cells were also produced and tested.
A schematic of DNA plasmid constructs for production of recombinant AAV virus carrying donor templates to facilitate targeted genomic insertion of CAR expression cassettes by HDR of Cas9-evoked site specific DNA double stranded breaks is shown in
CTX-142 and CTX-145 are derived from CTX-138 but the CAR has been modified to comprise anti-human CD70 scFV coding regions (
Anti CD70 CAR T cells were produced with CRISPR/Cas9 and AAV components as described (herein). Transgene insertion in primary human T cells via homology directed repair (HDR) and concurrent gene knockout by Cas9:sgRNA RNA was performed as described above in Examples 8 and 9. Primary human T cells were first electroporated with Cas9 or Cas9:sgRNA RNP complexes targeting TRAC (AGAGCAACAGTGCTGTGGCC (SEQ ID NO: 76); comprising sgRNA (SEQ ID NO: 1343) and B2M1 (GCTACTCTCTCTTTCTGGCC (SEQ ID NO: 417); comprising sgRNA (SEQ ID NO: 1345). The gRNAs used in this Example comprise the following spacer sequences: TRAC gRNA spacer (AGAGCAACAGUGCUGUGGCC (SEQ ID NO: 152)); and B2M gRNA spacer (GCUACUCUCUCUUUCUGGCC (SEQ ID NO: 466)).
sgRNA sequences can be modified as follows: TRAC SEQ ID NO: 1342, B2M SEQ ID NO: 1345.
The DNA double stranded break at the TRAC locus was repaired by homology directed repair with an AAV6-delivered DNA template (CTX-142 or CTX-145).
This example demonstrates efficient transgene insertion and concurrent gene knockout by Cas9:sgRNA RNP (for double stranded break induction) and AAV6 delivered donor template (CTX-142 or CTX-145) containing a CD70 CAR construct in primary human T cells.
Primary human T cells were activated with CD3/CD28 magnetic beads (as described previously in Example 2). Three days later activation beads were removed. The next day cells were electroporated with RNP complexes including sgRNAs targeting either TRAC alone, or TRAC+B2M (2 separately complexed RNPs). 7 days post manipulation, cells were analyzed by flow cytometry, as previously described herein and in Example 2.
Guides used in this example target:
The gRNAs used in this Example comprise the following spacer sequences: TRAC gRNA spacer (AGAGCAACAGUGCUGUGGCC (SEQ ID NO: 152)); and B2M gRNA spacer (GCUACUCUCUCUUUCUGGCC (SEQ ID NO: 466)).
sgRNA sequences can be modified as follows: TRAC SEQ ID NO: 1342, B2M SEQ ID NO: 1344.
In addition, cells infected with AAV6 encoding CTX-145 alone do not express high levels of anti CD70 CAR. A double stranded break induced by a TRAC sgRNA containing RNP and subsequent repair by HDR using CTX-145 donor template is required for surface expression of anti CD70 CAR (
The percentage of cells expressing CD70 was tracked during the production of CD70 CAR−T cells. At day 0 a small percentage of T cells express CD70 and are mostly CD4+ (
K562 cells were infected with lentiviral particles encoding a human CD70 cDNA under the control of the EF1a promoter as a well as a puromycin expression cassette (Genecopoeia). Cells were selected in 2 mg/mL puromycin for 4-7 days and assayed for CD70 surface expression using an Alexa fluor 647 conjugated anti-CD70 antibody (Biolegend, 355115).
A panel of other cell lines was also tested for CD70 surface expression using flow cytometry: Nalm6 (lymphoid), 293 (embryonic kidney), ACHN (renal), Caki-2 (renal), Raji (lymphoid), Caki-1 (renal), A498 (renal), and 786-0 (renal). The results are shown in
Interferon Gamma Stimulation by Genetically Engineered T Cells Expressing a CD70 CAR
The ability of the engineered cells to produce interferon gamma (IFNγ) in a target cell was analyzed using an ELISA assay, as described above and in Example 10.
The specificity of genetically modified T cells expressing a CD70 CAR integrated into the TRAC gene, was evaluated in an in vitro ELISA assay. IFNγ from supernatants of cell co-cultures was measured. Only TRAC−/anti-CD70 CAR+ cells secrete high levels of IFNγ when cultured with CD70+K562. IFNγ secretion was not detected when TRAC−/anti-CD70 CAR+ cells were cultured with K562 cells that were not engineered to overexpress surface CD70 (
Similarly, the TRAC/anti-CD70CAR+ cells only stimulated IFNγ CD70+ Raji cells, but not the CD70− Nalm6 cells (
GranzymeB Assay
To further assess the effector functions of TRAC-/anti-CD70CAR+ cells, intracellular GranzymeB levels in target cells were measured in a surrogate cell lysis assay. Target cells that are GranzymeB+ had perforin containing membrane pores formed and subsequent injection of GranzymeB through the pores to initiate apoptosis by the TRAC-/anti-CD70CAR+ cells. The GranToxiLux assay was performed with either Raji cells (CD70 positive cells) or Nalm6 cells (CD70 negative cells) according to the manufacturer's instructions (Oncoimmunin Inc.). Fluorescently labeled target cells were co-cultured at a 2:1 ratio with test T cells (e.g.: TRAC/anti-CD70CAR+:Target cells) in GranzymbeB substrate for 2 hrs at 37° C. Cells were then washed and % of target cells positive for GranzymbeB activity was quantitated by flow cytometry. Other control test cells were also evaluated at similar ratios (unedited T cells (TRC+) and TRAC− T cells).
Cell Kill Assay in Adherent Renal Cell Carcinoma—in the Context of CD28 Co-Stim
To assess the ability of CRISPR/Cas9 modified T cells expressing a CD70 CAR to kill CD70 expressing adherent renal cell carcinoma (RRC) derived cell lines, a cell killing assay was devised. Adherent cells were seeded in 96-well plates at 50,000 cells per well and left overnight at 37° C. The next day T cells were added to the wells containing target cells at a 2:1 ratio. After the indicated incubation period, T cells were removed from the culture by aspiration and 100 μL Cell titer-Glo (Promega) was added to each well of the plate to assess the number of remaining viable cells. The amount of light emitted per well was then quantified using a plate reader. TRAC−CD70CAR+ cells induced potent cell killing of renal cell carcinoma derived cell lines after a 72 hr co-incubation (
Evaluation of Costimulatory Domains 41Bb and CD28 in Anti-CD70 CAR T Cells
CTX145b (SEQ ID NO: 1360) is derived from CTX145 where CD28[co-stimulatory domain] has been replaced by 41BB[co-stimulatory domain] (
Efficient Creation of TRAC, B2M Double Knockout Anti-41BB-CD70 CAR−T Cells
This example demonstrates efficient transgene insertion and concurrent gene knockout by Cas9:sgRNA RNP (for double-stranded break induction) and AAV6 delivered donor template (CTX-145b (SEQ ID NO: 1360)) containing a CD70 CAR construct in primary human T cells. The production of allogenic human T cells is as described in Example 16. The high efficiency is similar when using AAV6 delivered donor template CTX-145 (SEQ ID NO: 1359) and CTX145b (89.7% CAR+ cells using CTX-145 v. 88.6% CAR+ cells using CTX-145b, compared to 2.38% CAR+ cells with control (no donor template)).
Efficient Production of PD1, TRAC, B2M Triple Knockout Anti-CD70 CAR−T Cells, with a 4-1BB or a CD28 Costimulatory Domain
This example demonstrates efficient transgene insertion and concurrent gene knockout by Cas9:sgRNA RNP (for double stranded break induction) and AAV6 delivered donor template (CTX-145 or CTX-145b) containing an anti-CD70 CAR construct in primary human T cells. The production of allogenic human T cells is as described in Example 24, where CTX-138 was replaced by CTX-145 (CD28 co-stim) or CTX-145b (4-1BB co-stim).
The high efficiency was similar when using AAV6-delivered donor template (compare CTX-145 and CTX145b) (
Cell Kill Assay in Adherent Renal Cell Carcinoma
To assess the ability of CRISPR/Cas9 modified T cells expressing an anti-CD70 CAR to kill CD70 expressing adherent renal cell carcinoma (RRC) derived cell lines, a cell killing assay was devised as described above. TRAC-/B2M-/anti-CD70 CAR+ cells demonstrated potent cell killing of renal cell carcinoma derived cell lines (A498 cells) after 24 hours co-incubation (
CD70 expressing adherent renal cell carcinoma (RRC) derived cell line, ACHN at a 3:1 ratio T cell: target cell.
CRISPR/Cas9 Mediated Knockout of TCR and MHC I Components and Expression of BCMA Chimeric Antigen Receptor Constructs
This example describes the production by CRISPR/Cas9 and AAV6 of allogeneic human T cells that lack expression of TCR, or TCR and MHC I, and express a chimeric antigen receptor targeting BCMA+ cancers.
A schematic depiction of CRISPR/Cas9 generated allogeneic CAR−T cells is shown in
Similar to Example 9 and 15 above, CRISPR/Cas9 was used to disrupt (knockout [KO]) the coding sequence of the TCRα constant region gene (TRAC). This disruption leads to loss of function of TCR and renders the gene edited T cell non-alloreactive and suitable for allogeneic transplantation, minimizing the risk of graft versus host disease (GVHD). The DNA double stranded break at the TRAC locus was repaired by homology directed repair with an AAV6-delivered DNA template containing right and left homology arms to the TRAC locus flanking a chimeric antigen receptor cassette (−/+ regulatory elements for gene expression). To reduce host versus graft (HVG) (e.g.: host vs CAR−T) and allow for persistence of the allogeneic CAR−T product, the B2M gene was also disrupted using CRISPR/Cas9 components. Together, these genome edits result in a T cell with surface expression of a CAR (expressed from the TRAC locus) targeting BCMA+ cancers along with loss of the TCR and MHC I, to reduce GVHD and HVG, respectively. The T cell can be referred to as a TRAC−/B2M−/anti-BCMA CAR+ cell.
For certain experiments, described in the following examples, single knock-out TRAC-BCMA CAR+ cells were also produced and tested.
A schematic of DNA plasmid constructs for production of recombinant AAV virus carrying donor templates to facilitate targeted genomic insertion of CAR expression cassettes by HDR of Cas9-evoked site specific DNA double stranded breaks is shown in
CTX-153 (SEQ ID NO: 1362) and CTX-155 (SEQ ID NO: 1364) are derived from CTX-145 but with the anti-CD70 scFv coding region of CTX-145 is replaced with anti-human BCMA scFv coding region (
The VH and VL chains that were used to construct the anti-BCMA scFvs are BCMA_VH1 (SEQ ID NO: 1523) and BCMA_VL1 (SEQ ID NO: 1525), respectively. These chains were derived from mouse antibodies. A humanized version of the VH sequence have been constructed (SEQ ID NO: 1524) and two humanized versions of the VL sequence have been constructed (SEQ ID NOs: 1526 and 1527). These were used to construct humanized anti-BCMA constructs scFv BCMA-3, scFv BCMA-4, scFv BCMA-5 and scFv BCMA-6 (SEQ ID NOs: 1503-1506) using the method described above. Any one of these scFvs can be used to construct CAR constructs as described previously. The humanized scFv CAR constructs have the linker sequence of GGGGSGGGGSGGGGS (SEQ ID NO: 1341).
Additional anti-BCMA scFvs were constructed using the method described above. For example, VH and VL chains BCMA_VH2 (SEQ ID NO: 1528) and BCMA_VL2 (SEQ ID NO: 1529) can be used to construct anti-BCMA scFvs. These variable chains were used to construct the anti-BCMA constructs scFv BCMA-7 (VH-VL; SEQ ID NO: 1507) and scFv BCMA-8 (VL-VH; SEQ ID NO: 1508). Any one of these scFvs can be used to construct CAR constructs as described previously.
In another example, the VH and VL chains BCMA_VH3 (SEQ ID NO: 1530) and BCMA_VL3 (SEQ ID NO: 1531) were used to construct anti-BCMA scFvs. Specifically, these variable chains were used to construct the anti-BCMA constructs scFv BCMA-9 (VH-VL; SEQ ID NO: 1513) and scFv BCMA-10 (VL-VH; SEQ ID NO: 1514). Any one of these scFvs can be used to construct CAR constructs as described previously. Anti BCMA CAR T cells were produced with CRISPR/Cas9 and AAV components as described (herein). Transgene insertion in primary human T cells via homology directed repair (HDR) and concurrent gene knockout by Cas9:sgRNA RNA was performed as described above in Examples 8 and 9. Primary human T cells were first electroporated with Cas9 or Cas9:sgRNA RNP complexes targeting TRAC (AGAGCAACAGTGCTGTGGCC (SEQ ID NO: 76); sgRNA (SEQ ID NO: 1343) and B2M1 (GCTACTCTCTCTTTCTGGCC (SEQ ID NO: 417); sgRNA (SEQ ID NO: 1345).
sgRNA sequences can be modified as follows: TRAC SEQ ID NO: 1342, B2M SEQ ID NO: 1344.
The DNA double stranded break at the TRAC locus was repaired by homology directed repair with an AAV6-delivered DNA template (CTX-152, or CTX-154).
High Efficiency Multi-Editing by CRISPR/Cas9 to Produce Anti-BCMA CAR−T Cells
Multi-editing resulted in decreased surface expression of TCR and MHC-I, as well as high CAR expression. More than 60% T-cells possessed all three (TCR-/β2M-/anti-BCMA CAR+) or four (TCR-/β2M-/PD1-/anti-BCMA CAR+) desired modifications (
Similar editing efficiencies were observed with double or triple knockouts. The CD4/CD8 ratios remained similar in multi-edited anti-BCMA CAR−T cells (
The following gRNA spacer sequences were used in this example:
The donor template used in this example was SEQ ID NO: 1408 (LHA to RHA of CTX-166), which includes the anti-BCMA CAR comprising SEQ ID NO: 1434.
Multi-edited Anti-BCMA CAR−T Cells Show Improved Anti-Cancer Properties
Anti-BCMA CAR−T cells efficiently and selectively killed the BCMA-expressing MM cell line MM.1S in a 4-hour cell kill assay, while sparing the BCMA-negative leukemic line K562 (
PD1 KO Reduces Expression of Lag3 Exhaustion Marker in Long-term In Vitro Culture
No change in Lag3 exhaustion marker was observed between double (TCR-/β2M-/anti-BCMA CAR+) or triple (TCR-/β2M-/PD1-/anti-BCMA CAR+) KO anti-BCMA CAR−T cells after 1 week in culture. However, following four (4) weeks in culture, Lag3 expression was reduced in the triple KO anti-BCMA CAR−T cells indicating that the cells with the PD1 KO were less exhausted.
It should be understood that for any one of the constructs provided in Table 24, the scFv fragment of the CAR may be substituted with any other scFv fragment listed in Table 24.
This example demonstrates efficient transgene insertion and concurrent gene knockout by Cas9:sgRNA RNP (for double stranded break induction) and AAV6 delivered donor template (CTX-152 or CTX-154) containing a BCMA CAR construct in primary human T cells.
Primary human T cells were activated with CD3/CD28 magnetic beads (as described previously in Example 2). Three days later activation beads were removed. The next day cells were electroporated with RNP complexes including sgRNAs targeting TRAC or B2M (2 separately complexed RNPs). 7 days post manipulation, cells were analyzed by flow cytometry, as previously described herein and in Example 2.
Guides used in this example target:
The gRNAs used in this Example comprise the following spacer sequences: TRAC gRNA spacer (AGAGCAACAGUGCUGUGGCC (SEQ ID NO: 152)); and B2M gRNA spacer (GCUACUCUCUCUUUCUGGCC (SEQ ID NO: 466)).
sgRNA sequences can be modified as follows: TRAC SEQ ID NO: 1342, B2M SEQ ID NO: 1345.
FACS analysis demonstrated that 77% of T cells were TRAC-, B2M- following treatment with TRAC sgRNA contain RNP and B2M sgRNA containing RNP (
Cell Kill Assay in BCMA Expressing Cells
To assess the ability of TRAC−B2M−/anti-BCMA CAR+ T cells to kill suspension cell lines a flow cytometry based cell killing assay was designed. The TRAC−B2M−/anti-BCMA CAR+ T cells (see Example 19 for Table of CARs used) were co-cultured with cells of the BCMA-expressing RPMI8226 (ATCC Cat# ATCC-155) human plasmacytoma target cell line, cells of the BCMA-expressing U-266 cell line, or cells of the K562 cell line, which do not express BCMA (collectively referred to as the “target cells”. The target cells were labeled with 5 μM efluor670 (eBiosciences), washed and incubated in co-cultures with the TRAC−/B2M−/anti-BCMA CAR+ T cells at varying ratios (from 0.1:1 to 8:1 T cells to target cells) at 50,000 target cells per well of a U-bottom 96-well plate overnight. The next day wells were washed, media was replaced with 200 μL of media containing a 1:500 dilution of 5 mg/mL DAPI (Molecular Probes) (to enumerate dead/dying cells). Finally, 25 μL of CountBright beads (Life Technologies) was added to each well. Cells were then processed by flow cytometry.
Target cells per μL were then calculated from analyzed flow cytometry data:
Cells/μL=((number of live target cell events)/(number of bead events))×((Assigned bead count of lot (beads/50 μL))/(volume of sample))
Total target cells were calculated by multiplying cells/μL×the total volume of cells.
The percent cell lysis was then calculated with the following equation:
% Cell lysis=(1-((Total Number of Target Cells in Test Sample)/(Total Number of Target Cells in Control Sample))×100
Interferon Gamma Stimulation by Genetically Engineered T Cells Expressing a BCMA CAR
The ability of the engineered cells to produce interferon gamma (IFNγ) in a target cell was analyzed using an ELISA assay, as described above and in Example 10 and 18.
The specificity of genetically modified T cells expressing an anti-BCMA CAR integrated into the TRAC gene, was evaluated in an in vitro ELISA assay. IFNγ from supernatants of cell co-cultures was measured. RPMI8226 cells were cultured with genetically engineered T cells expressing the anti-BCMA CAR, or controls.
A droplet digital PCR (ddPCR) assay was designed to measure the efficiency of integration of the CAR construct (CTX-138) into the TRAC locus. The primers and probes used in the ddPCR assay are shown in Table 25. SEQ ID NO: 1554-1556 were used to detect integration of the CAR construct, and SEQ ID NOs: 1557-1559 were used to amplify a control reference genomic region.
Forty (40) ng of genomic DNA was used in ddPCR reactions, droplets generated and then run in a thermocycler under the conditions shown in Table 26 and Table 27.
The percentage of cells that stained CD19 CAR+ by flow cytometry was plotted against the percentage of cells that were positive for an integrated CAR construct from 4 healthy donor TRAC-B2M-CAR−T cells (
In this example the effector functions of TRAC-/B2M-/anti-CD19 CAR+ T cells when co-cultured with the Nalm6 human B-ALL cell line were assessed.
GranzymeB Assay
To further assess the effector functions of TRAC-/B2M-/anti-CD19 CAR+ T cells, intracellular GranzymeB levels in target cells were measured in a surrogate cell lysis assay. GranzymeB secretion was assessed as described in Example 18. TRAC-/B2M-/anti-CD19 CAR+ T cells or control cells were cocultured with the Nalm6 cell line. As shown in
Interferon Gamma Stimulation by Genetically Engineered T Cells Expressing a CD19 CAR
The ability of the engineered cells to produce interferon gamma (IFNγ) in a target cell was analyzed using an ELISA assay, as herein and in Example 10.
IFNγ from supernatants of cell co-cultures was measured. TRAC−/B2M−/anti-CD19 CAR+ T cells secrete high levels of IFNγ when cultured with CD19 positive Nalm6 cells, as shown in
Cell Kill Assay for Suspension Cell Lines
To assess the ability of TRAC−/B2M−/anti-CD19 CAR+ T cells to kill suspension cell lines a flow cytometry based cell killing assay was designed. Cells were co-cultured with the Nalm6 human B-cell acute lymphoblastic leukemia (B-ALL) target cell line. The Nalm6 target cells were labeled with 5 μM efluor670 (eBiosciences), washed and incubated in co-cultures with T cells at varying ratios (from 0.1:1 to 8:1 T cells to target cells) at 50,000 target cells per well of a U-bottom 96-well plate overnight. The next day wells were washed, media was replaced with 200 μL of media containing a 1:500 dilution of 5 mg/mL DAPI (Molecular Probes) (to enumerate dead/dying cells). Finally, 25 μL of CountBright beads (Life Technologies) was added to each well. Cells were then processed by flow cytometry.
Cells per μL were then calculated from analyzed flow cytometry data:
Cells/μL=((number of live target cell events)/(number of bead events))×((Assigned bead count of lot (beads/50 μL))/(volume of sample))
Total cells were calculated by multiplying cells/μL×the total volume of cells.
The percent cell lysis was then calculated with the following equation:
% Cell lysis=(1-((Total Number of target Cells in Test Sample)/(Total Number of Target Cells in Control Sample))×100.
This example describes the production by CRISPR/Cas9 and AAV6 of allogeneic human T cells that lack expression of the TCR, MHC I, and PD1 and express a chimeric antigen receptor targeting CD19+ cancers.
CRISPR/Cas9 and AAV6 were used as above (see for example, Examples 8-10 and 12) to create human T cells that lack expression of the TCR, B2M and PD1 with concomitant expression from the TRAC locus using a CAR construct targeting CD19 (CTX-138; SEQ ID NO: 675). In this example activated T cells were electroporated with 3 distinct RNP complexes containing sgRNAs targeting TRAC (e.g.: SEQ ID NO: 76), B2M (e.g.: SEQ ID NO: 417 and PD1 (CTGCAGCTTCTCCAACACAT (SEQ ID NO: 916)). The gRNAs used in this Example comprise the following spacer sequences: TRAC gRNA spacer (AGAGCAACAGUGCUGUGGCC (SEQ ID NO: 152)); B2M gRNA spacer (GCUACUCUCUCUUUCUGGCC (SEQ ID NO: 466)); and PD1 gRNA spacer (CUGCAGCUUCUCCAACACAU (SEQ ID NO: 1086)). About 1 week post electroporation cells were either left untreated or treated with PMA/ionomycin overnight. The next day cells were processed for flow cytometry.
NOG mice were injected subcutaneously with 5×106 A498 renal cell carcinoma cells. At day 10 post inoculation mice were either left untreated or injected intravenously (I.V.) with a therapeutic dose of 1×107 or 2×107 anti-CD70 CAR−T cells. Tumor volumes were measured every 2 days for the duration of the study (31 days). Injection of anti-CD70 CART cells lead to decreased tumor volumes at both doses (
Transgene insertion in primary human T cells via homology directed repair (HDR) and concurrent gene knockout by Cas9:sgRNA RNA was performed as described above in Example 16 to produce cells lacking TCR surface expression and to concurrently express an anti-CD70 CAR construct (TRAC/anti-CD70CAR+ cells). Primary human T cells were first electroporated with Cas9 or Cas9:sgRNA RNP complexes targeting TRAC (AGAGCAACAGTGCTGTGGCC (SEQ ID NO: 76); TRAC gRNA spacer (AGAGCAACAGUGCUGUGGCC (SEQ ID NO: 152)). The DNA double stranded break at the TRAC locus was repaired by homology directed repair with an AAV6-delivered DNA template (CTX-145; SEQ ID NO: 1359) containing right and left homology arms to the TRAC locus flanking a chimeric antigen receptor cassette (−/+ regulatory elements for gene expression). The resulting modified T cells are TRAC/anti-CD70CAR+. The ability of the modified TRAC−/anti-CD70CAR+ T cells to ameliorate disease caused by a CD70+ renal carcinoma cell line was evaluated in NOG mice using methods employed by Translational Drug Development, LLC (Scottsdale, Ariz.). In brief, twelve (12), 5-8 week old female, CIEA NOG (NOD.Cg-PrkdcscidIl2rgtm1Sug/JicTac) mice were individually housed in ventilated microisolator cages, maintained under pathogen-free conditions, 5-7 days prior to the start of the study. On Day 1 mice received a subcutaneous inoculation of 5×106 A498 renal carcinoma cells/mouse. The mice were further divided into 3 treatment groups as shown in Table 26. On Day 10 (9 days post inoculation with the A498 cells), treatment group 2 and group 3 received a single 200 μl intravenous dose of TRAC−/anti-CD70CAR+ cells according to Table 26.
Tumor volumes were measured every 2 days. By Day 18 treatment with the anti-CD70 CART cells at both doses began to show a decrease in tumor volume (
Allogeneic anti-BCMA CAR T cells were generated as described above. Anti-BCMA CAR expression was measured by determining the percent of cells that bound biotinylated BCMA subsequently detected by FACS using streptavidin-APC (
Anti-BCMA CAR constructs were then evaluated for their ability to kill RPMI-8226 cells. All Anti-BCMA CAR T cells with ≥10% expression were potently cytotoxic towards effector cells, while allogeneic T cells lacking a CAR showed little cytotoxicity (
Allogenic anti-CD19 CAR T cells were generated as described above. At 21 days post gene editing, the following protocol was used to stain cells for expression of the indicated marker:
Stain cells with the following antibody for 30 min at 4° C.
Anti-mouse Fab2 biotin 115-065-006 (Jackson ImmunoRes) 1:5
Wash cells 1× with FACS buffer.
Add 1 μg of normal mouse IGG (Peprotech 500-M00) to 100 μL of cells for 10 min at RT.
Wash cells 1× with FACS buffer and resuspend in 100 μL of FACS buffer.
Stain cells with the following cocktail for 15 min at RT.
The antibodies used in this Example are as follows:
This data shows that health of TRAC-/B2M-/anti-CD19+CAR T cells is maintained at day 21 post gene editing (the cells behave as normal (unedited) cells).
TRAC-/B2M-/anti-CD19+CAR T cells (TC1) cells were produced and were depleted using TCRab antibodies and the Prodigy System (Miltenyi Biotech). Purities of >99.5% TCRab− cells in the total population were achieved from starting inputs of 95.5% TCRab-cells.
This example demonstrates the generation of an allogeneic anti-BCMA CAR−T cells using CRISPR/Cas9 genome editing. High efficiency editing was attained with over 60% of the cells harboring the three desired edits. The CAR-−T cells maintain a normal CD4/CD8 ratio, as well as characteristic cytokine dependency, suggesting neither abnormal tonic signaling from CAR insertion nor transformation due to the editing process have occurred. The CAR−T cells selectively killed BCMA+ cells and secreted T cell activation cytokines following encounter with BCMA-expressing cells. The CAR−T cells eradicated MM cells in a subcutaneous RPMI-8226 tumor xenograft model, confirming potent activity in vivo.
High Efficiency Genome Editing by CRISPR/Cas9
TRAC−/B2M−/anti-BCMA CAR+ cells were generated using the methods described in Example 19.
T Cell CD4+/CD8+ Ratio Following Editing
At two weeks post gene editing, the following protocol was used to stain TCR-/β2M-/anti-BCMA CAR+ cells for expression of the indicated marker:
Stain cells with the following antibody for 30 min at 4° C.
Recombinant biotinylated human BCMA (Acro Biosystems Cat:# BC7-H82F0 at a concentration of 100 nM
Wash cells 1× with FACS buffer and resuspend in 100 μL of FACS buffer.
Stain cells with the following cocktail for 15 min at RT.
The antibodies used in this Example were CD4 and CD8 (See Table 27). This data showed that the edited T cells had the same CD4+/CD8+ ratio as unedited T cells. (data not shown).
Two weeks following editing and anti-BCMA CAR knock-in, serum and/or cytokines were removed from the growth media. As expected, in the absence of cytokines no further proliferation of T-cells was observed (
Allogeneic Anti-BCMA CAR T Cells Show Potent and Specific Activity In Vitro
To assess the ability of TRAC−/B2M−/anti-BCMA CAR+ T cells to selectively kill a BCMA expressing multiple myeloma cell line (MM.1S), a flow cytometry based cell killing assay was designed, similar to the assay described in Example 21. The TRAC−/B2M−/anti-BCMA CAR+ T cells (see Example 19 for Table of CARs used) were co-cultured with cells of the BCMA-expressing MM.1S multiple myeloma cell line or cells of the K562 cell line, which do not express BCMA (collectively referred to as the “target cells”).
Target cells per μL were then calculated from analyzed flow cytometry data:
Cells/μL=((number of live target cell events)/(number of bead events))×((Assigned bead count of lot (beads/50 μL))/(volume of sample))
Total target cells were calculated by multiplying cells/μL×the total volume of cells.
The percent cell lysis was then calculated with the following equation:
% Cell lysis=(1-((Total Number of Target Cells in Test Sample)/(Total Number of Target Cells in Control Sample))×100.
The ability of the engineered TRAC-/B2M-/anti-BCMA CAR+ T cells to produce interferon gamma (IFNγ) and IL-2 in response to target cells was analyzed using an ELISA assay, as described above and in Examples, 10, 18, and 21.
The specificity of genetically modified T cells expressing an anti-BCMA CAR integrated into the TRAC gene, was evaluated in an in vitro ELISA assay. IFNγ and IL-2 from supernatants of cell co-cultures was measured. MM.1S cells were cultured with genetically engineered T cells expressing the anti-BCMA CAR, or controls.
The cell kill assay was repeated with the addition of the multiple myeloma cell line H929, which expresses higher levels of BCMA compared to MM.1S (
Thus, not only do the anti-BCMA CAR T cells of the present disclosure produce IFNγ and IL-2, they do so specifically in the presence of BCMA-expressing cells.
Allogeneic Anti-BCMA CAR T Cells Show Potent Activity In Vivo
In this example, the efficacy of CAR−T cells against the subcutaneous RPMI-8226 tumor xenograft model in NOG mice was evaluated. In brief, 12, 5-8 week old female, CIEA NOG (NOD.Cg-PrkdcscidIl2rgtm1Sug/JicTac) mice were individually housed in ventilated microisolator cages, maintained under pathogen-free conditions, 5-7 days prior to the start of the study. On Day 1 mice received a subcutaneous inoculation of 10×106 RPMI-8226 cells/mouse. The mice were further divided into two treatment group. Ten (10) days post inoculation with RPMI-8226 cells, the first treatment group (N=5) received a single 200 μl intravenous dose of 10×106 edited TRAC−/B2M−/anti-BCMA CAR+ T cells, and the second treatment group (N=5) received a single 200 μl intravenous dose of 20×106 edited TRAC−/B2M−/anti-BCMA CAR+ T cells.
Tumor volume and body weight was measured and individual mice were euthanized when tumor volume was ≥500 mm3. By Day 18, the data show a statistically significant decrease in the tumor volume in response to TRAC−/B2M−/anti-BCMA CAR+ T cells as compared to untreated mice (
PD1, B2M, TRAC Triple Knockout Anti-BCMA CAR−T Cells
This example describes the production by CRISPR/Cas9 and AAV6 of allogeneic human T cells that lack expression of the TCR, MHC I, and PD1 and express a chimeric antigen receptor targeting BCMA+ cancers.
CRISPR/Cas9 and AAV6 were used as above (see for example, Examples 8-10 and 12) to create human T cells that lack expression of the TCR, B2M and PD1 with concomitant expression from the TRAC locus using a CAR construct targeting BCMA (SEQ ID NO: 1434). In this example activated T cells were electroporated with 3 distinct RNP complexes containing sgRNAs targeting TRAC (e.g., TRAC gRNA spacer SEQ ID NO: 152), B2M (e.g., B2M gRNA spacer SEQ ID NO: 466) and PD1 (e.g., PD1 gRNA spacer SEQ ID NO: 1086). About 1 week post electroporation cells were either left untreated or treated with PMA/ionomycin overnight. The next day cells were processed for flow cytometry.
High Efficiency CRISPR/Cas9 Gene Editing to Produce Allogeneic Anti-CD70 CAR−T Cells
This example demonstrates efficient transgene insertion and concurrent gene knockout by Cas9:sgRNA RNP (for double stranded break induction) and AAV6 delivered donor template containing a CD70 CAR construct (SEQ ID NO: 1424) in primary human T cells. The experiments described here are similar to those described in Example 16.
Primary human T cells were activated with CD3/CD28 magnetic beads (as described previously in Example 2). Three days later activation beads were removed. The next day cells were electroporated with RNP complexes including sgRNAs targeting either TRAC alone, or TRAC+B2M (two separately complexed RNPs). Seven days post manipulation, cells were analyzed by flow cytometry, as previously described herein and in Example 2.
Guides used in this example target:
The gRNAs used in this Example comprise the following spacer sequences: TRAC gRNA spacer (AGAGCAACAGUGCUGUGGCC (SEQ ID NO: 152)); and B2M gRNA spacer (GCUACUCUCUCUUUCUGGCC (SEQ ID NO: 466)).
Anti-CD70 CAR−T Cells Kill Multiple Myeloma Cells
To assess the ability of TRAC−B2M−/anti-CD70 CAR+ T cells to kill a CD70-expressing multiple myeloma cell line (MM.1S), a flow cytometry-based cell killing assay was designed, similar to the assay described in Examples 21 and 29. The TRAC−/B2M−/anti-CD70 CAR+ T cells were co-cultured with cells of the BCMA-expressing MM.1s multiple myeloma cell line.
CAR Expression
Allogeneic TRAC-/B2M-/anti-BCMA CAR T+ cells were generated, as described above, having either a CD28 co-stimulatory domain (encoded by CTX-160 or CTX-166) or a 4-1BB co-stimulatory domain (encoded by CTX160b or CTX166b). Anti-BCMA CAR expression was measured by determining the percent of cells that bound biotinylated BCMA subsequently detected by FACS using streptavidin-APC (
Cytotoxicity
To assess the ability of the same TRAC−/B2M−/anti-BCMA (CD28 v. 4-1BB) CAR+ T cells to selectively kill a BCMA expressing multiple myeloma cell line (MM.1S), a flow cytometry based cell killing assay was designed, similar to the assay described in Example 21. The TRAC−/B2M−/anti-BCMA CAR+ T cells were co-cultured with cells of the BCMA-expressing MM.1S multiple myeloma cell line.
Target cells per μL were then calculated from analyzed flow cytometry data:
Cells/μL=((number of live target cell events)/(number of bead events))×((Assigned bead count of lot (beads/50 μL))/(volume of sample))
Total target cells were calculated by multiplying cells/μL×the total volume of cells.
The percent cell lysis was then calculated with the following equation:
% Cell lysis=(1−((Total Number of Target Cells in Test Sample)/(Total Number of Target Cells in Control Sample))×100.
Interferon Gamma Secretion
The ability of the engineered TRAC-/B2M-/anti-BCMA (CD28 v. 4-1BB) CAR+ T cells to produce interferon gamma (IFNγ) in response to target cells was analyzed using an ELISA assay, as described above and in Examples, 10, 18, and 21.
The specificity of genetically modified T cells was evaluated in an in vitro ELISA assay. IFNγ from supernatants of cell co-cultures was measured. MM.1S cells were cultured with genetically engineered T cells expressing the anti-BCMA CAR, or controls.
Thus, not only do the anti-BCMA CAR T cells of the present disclosure produce IFNγ, they do so specifically in the presence of BCMA-expressing cells.
Cell Kill Assay
To assess the ability of TRAC−/B2M−/anti-BCMA (4-1BB) CAR+ T cells to kill suspension cell lines, a flow cytometry-based cell killing assay was designed. The TRAC− /B2M−/anti-BCMA CAR+ T cells were co-cultured with cells of the BCMA-expressing RPMI-8226 (ATCC Cat# ATCC-155) human plasmacytoma target cell line, cells of the BCMA-expressing U-266 cell line, cells of the multiple myeloma cell line H929, or cells of the K562 cell line, which do not express BCMA (collectively referred to as the “target cells”. The target cells were labeled with 5 μM efluor670 (eBiosciences), washed and incubated in co-cultures with the TRAC−/B2M−/anti-BCMA CAR+ T cells at varying ratios (from 0.1:1 to 8:1 T cells to target cells) at 50,000 target cells per well of a U-bottom 96-well plate overnight. The next day wells were washed, media was replaced with 200 μL of media containing a 1:500 dilution of 5 mg/mL DAPI (Molecular Probes) (to enumerate dead/dying cells). Finally, 25 μL of CountBright beads (Life Technologies) was added to each well. Cells were then processed by flow cytometry.
Target cells per μL were then calculated from analyzed flow cytometry data:
Cells/μL=((number of live target cell events)/(number of bead events))×((Assigned bead count of lot (beads/50 μL))/(volume of sample))
Total target cells were calculated by multiplying cells/μL×the total volume of cells.
The percent cell lysis was then calculated with the following equation:
% Cell lysis=(1-((Total Number of Target Cells in Test Sample)/(Total Number of Target Cells in Control Sample))×100
Interferon Gamma and IL-2 Stimulation
The ability of the TRAC-/B2M-/anti-BCMA (4-1BB) CAR+ T cells to produce interferon gamma (IFNγ) in a target cell was analyzed using an ELISA assay, as described above and in Example 10 and 18.
The specificity of genetically modified T cells expressing an anti-BCMA CAR integrated into the TRAC gene, was evaluated in an in vitro ELISA assay. IFNγ and IL-2 from supernatants of cell co-cultures was measured. Target RPMI-8226, U2261, H929, or K562 cells were cultured with genetically engineered T cells expressing the anti-BCMA CAR, or controls.
Similar studies as above were repeated using TRAC-/B2M-/anti-BCMA (4-1BB) CAR+ T cells compared to TRAC-/B2M-/PD-1-/anti-BCMA (4-1BB) CAR+ T cells. The edited cells were assayed with MM.1S cells or K562 cells for cytotoxicity, IFN-γ stimulation, and IL-2 stimulation. The results are depicted in
The efficacy of TRAC-/B2M-/anti-BCMA (CD28 co-stim) CAR+ T cells and TRAC-/B2M-/PD-1-/anti-BCMA (CD28 co-stim) CAR+ T cells against the subcutaneous RPMI-8226 tumor xenograft model in NOG mice was evaluated. In brief, thirty five (35), 5-8 week old female, CIEA NOG (NOD.Cg-PrkdcscidIl2rgtm1Sug/JicTac) mice were individually housed in ventilated microisolator cages, maintained under pathogen-free conditions, 5-7 days prior to the start of the study. On Day 1 mice received a subcutaneous inoculation of 10×106 RPMI-8226 cells/mouse. Ten (10) days post inoculation with RPMI-8226 cells, the mice were divided into 6 treatment groups (N=5) and dosed as indicated in Table 30.
Tumor volume and body weight was measured and individual mice were euthanized when tumor volume was ≥500 mm3. By Day 18, the data show a statistically significant decrease in the tumor volume in response to TRAC-/B2M-/anti-BCMA (CD28 co-stim) CAR+ T cells and TRAC-/B2M-/PD-1-/anti-BCMA (CD28 co-stim) CAR+ T cells as compared to untreated mice (
NOG mice were injected subcutaneously with 5×106 A498 renal cell carcinoma cells. When tumors reached ˜150 mm3, mice were either left untreated or injected intravenously (I.V.) with a therapeutic dose of 1×107 anti-CD70 CAR−T cells. Tumor volumes were measured every 2 days for the duration of the study. Injection of anti-CD70 CART cells lead to decreased tumor volumes (
The anti-CD70 CAR+ T cells were generated as described above in Example 18. Furthermore the in vivo study was conducted similarly to the one described in Example 25. The ability of the modified TRAC−/B2M- or TRAC-/B2M-/PD1-anti-CD70CAR+ T cells, with CD28 or 41BB co-stimulatory domains, to ameliorate disease caused by a CD70+ renal carcinoma cell line was evaluated in NOG mice using methods employed by Translational Drug Development, LLC (Scottsdale, Ariz.). In brief, 5-8 week old females, CIEA NOG (NOD.Cg-PrkdcscidIl2rgtm1Sug/JicTac) mice were individually housed in ventilated microisolator cages, maintained under pathogen-free conditions, 5-7 days prior to the start of the study. On Day 1 mice received a subcutaneous inoculation of 5×106 A498 renal carcinoma cells/mouse. The mice were further divided into 5 treatment groups as shown in Table 31. When tumors reach ˜150 mm3, treatment groups 2, 3, 4 and 5 received a single 200 μl intravenous dose of TRAC/anti-CD70CAR+ cells according to Table 31.
Tumor volumes were measured every 2 days. These data demonstrate that TRAC-/B2M- or TRAC-/B2M-/PD1-anti-CD70 CAR+ T cells, with CD28 or 41BB costimulatory domains, have similar anti-tumor activity against CD70+ kidney cancer tumors in vivo.
While the present disclosure provides descriptions of various specific aspects for the purpose of illustrating various aspects of the present invention and/or its potential applications, it is understood that variations and modifications will occur to those skilled in the art. Accordingly, the invention or inventions described herein should be understood to be at least as broad as they are claimed, and not as more narrowly defined by particular illustrative aspects provided herein.
Any patent, publication, or other disclosure material identified herein is incorporated by reference into this specification in its entirety unless otherwise indicated, but only to the extent that the incorporated material does not conflict with existing descriptions, definitions, statements, or other disclosure material expressly set forth in this specification. As such, and to the extent necessary, the express disclosure as set forth in this specification supersedes any conflicting material incorporated by reference. Any material, or portion thereof, that is said to be incorporated by reference into this specification, but which conflicts with existing definitions, statements, or other disclosure material set forth herein, is only incorporated to the extent that no conflict arises between that incorporated material and the existing disclosure material. Applicants reserve the right to amend this specification to expressly recite any subject matter, or portion thereof, incorporated by reference herein.
This application is a continuation of application Ser. No. 15/977,798, filed May 11, 2018 and which claims the benefit under 35 U.S.C. § 119(e) of U.S. provisional application No. 62/505,649, filed May 12, 2017, U.S. provisional application No. 62/508,862, filed May 19, 2017, U.S. provisional application No. 62/538,138, filed Jul. 28, 2017, U.S. provisional application No. 62/567,012, filed Oct. 2, 2017, U.S. provisional application No. 62/567,008, filed Oct. 2, 2017, U.S. provisional application No. 62/583,793, filed Nov. 9, 2017, U.S. provisional application No. 62/639,332, filed Mar. 6, 2018, U.S. provisional application No. 62/648,138, filed Mar. 26, 2018, and U.S. provisional application No. 62/655,510, filed on Apr. 10, 2018, each of which is incorporated by reference herein in its entirety.
| Number | Name | Date | Kind |
|---|---|---|---|
| 7083785 | Browning et al. | Aug 2006 | B2 |
| 7435596 | Campana et al. | Oct 2008 | B2 |
| 7446179 | Jensen et al. | Nov 2008 | B2 |
| 7446190 | Sadelain et al. | Nov 2008 | B2 |
| 7452981 | Wijdenes et al. | Nov 2008 | B2 |
| 7491390 | Law et al. | Feb 2009 | B2 |
| 7641903 | Law et al. | Jan 2010 | B2 |
| 7662387 | Law et al. | Feb 2010 | B2 |
| 7700739 | Lacy et al. | Apr 2010 | B2 |
| 7741465 | Eshhar et al. | Jun 2010 | B1 |
| 7771720 | Staunton et al. | Aug 2010 | B2 |
| 7888121 | Urnov et al. | Feb 2011 | B2 |
| 8067546 | McDonagh et al. | Nov 2011 | B2 |
| 8124738 | Terret et al. | Feb 2012 | B2 |
| 8337838 | Law et al. | Dec 2012 | B2 |
| 8440806 | Wijdenes et al. | May 2013 | B2 |
| 8535678 | Law et al. | Sep 2013 | B2 |
| 8562987 | McDonagh et al. | Oct 2013 | B2 |
| 8609104 | Law et al. | Dec 2013 | B2 |
| 8629257 | Lacy et al. | Jan 2014 | B2 |
| 8647624 | Law et al. | Feb 2014 | B2 |
| 8663642 | Law et al. | Mar 2014 | B2 |
| 8673304 | Wijdenes et al. | Mar 2014 | B2 |
| 8834882 | Silence et al. | Sep 2014 | B2 |
| 8871908 | Liu et al. | Oct 2014 | B2 |
| 8956828 | Bonini et al. | Feb 2015 | B2 |
| 9023999 | Mori et al. | May 2015 | B2 |
| 9051372 | Law et al. | Jun 2015 | B2 |
| 9102737 | Chen et al. | Aug 2015 | B2 |
| 9120854 | Ryan et al. | Sep 2015 | B2 |
| 9169325 | Keler et al. | Oct 2015 | B2 |
| 9382319 | Tso et al. | Jul 2016 | B2 |
| 9399074 | Liu et al. | Jul 2016 | B2 |
| 9403914 | Kubota | Aug 2016 | B2 |
| 9428585 | McDonagh et al. | Aug 2016 | B2 |
| 9701752 | McDonagh et al. | Jul 2017 | B2 |
| 9758581 | Wijdenes et al. | Sep 2017 | B2 |
| 9765148 | Silence et al. | Sep 2017 | B2 |
| 9765149 | Silence et al. | Sep 2017 | B2 |
| 9889160 | Jantz et al. | Feb 2018 | B2 |
| 9937207 | Gregory et al. | Apr 2018 | B2 |
| 20060051346 | Wijdenes | Mar 2006 | A1 |
| 20080138343 | Law et al. | Jun 2008 | A1 |
| 20090081239 | Staunton et al. | Mar 2009 | A1 |
| 20090148942 | McDonagh et al. | Jun 2009 | A1 |
| 20090208496 | Wijdenes et al. | Aug 2009 | A1 |
| 20100129362 | Law et al. | May 2010 | A1 |
| 20120034159 | Kindsvogel | Feb 2012 | A1 |
| 20120045436 | McDonagh et al. | Feb 2012 | A1 |
| 20120213771 | Keler et al. | Aug 2012 | A1 |
| 20120294863 | Law et al. | Nov 2012 | A1 |
| 20130039911 | Bedi et al. | Feb 2013 | A1 |
| 20130122020 | Liu et al. | May 2013 | A1 |
| 20130138586 | Jung et al. | May 2013 | A1 |
| 20130287748 | June et al. | Oct 2013 | A1 |
| 20140105915 | Algate et al. | Apr 2014 | A1 |
| 20140112942 | Van Eenennaam et al. | Apr 2014 | A1 |
| 20140178936 | McDonagh et al. | Jun 2014 | A1 |
| 20140220008 | Wijdenes et al. | Aug 2014 | A1 |
| 20140349402 | Cooper et al. | Nov 2014 | A1 |
| 20140357844 | Liu et al. | Dec 2014 | A1 |
| 20150176013 | Musunuru et al. | Jun 2015 | A1 |
| 20150266963 | Silence et al. | Sep 2015 | A1 |
| 20150284467 | Lipp et al. | Oct 2015 | A1 |
| 20150337047 | Keler et al. | Nov 2015 | A1 |
| 20150368351 | Vu et al. | Dec 2015 | A1 |
| 20160046724 | Brogdon et al. | Feb 2016 | A1 |
| 20160289675 | Ryan et al. | Oct 2016 | A1 |
| 20170022282 | McDonagh et al. | Jan 2017 | A1 |
| 20170157176 | Wang et al. | Jun 2017 | A1 |
| 20170173080 | Lee et al. | Jun 2017 | A1 |
| 20170183418 | Galletto | Jun 2017 | A1 |
| 20170226216 | Morgan et al. | Aug 2017 | A1 |
| 20170233484 | Sussman et al. | Aug 2017 | A1 |
| 20170267771 | Van Eenennaam et al. | Sep 2017 | A1 |
| 20170281766 | Wiltzius | Oct 2017 | A1 |
| 20170313759 | Batuwangala | Nov 2017 | A1 |
| 20170320957 | Chen et al. | Nov 2017 | A1 |
| 20170335281 | Loew et al. | Nov 2017 | A1 |
| 20170342157 | McDonagh et al. | Nov 2017 | A1 |
| 20170355776 | Xiao et al. | Dec 2017 | A1 |
| 20170362297 | Marasco | Dec 2017 | A1 |
| 20170369581 | Silence et al. | Dec 2017 | A9 |
| 20180002435 | Sasu et al. | Jan 2018 | A1 |
| 20180186878 | Rosenthal | Jul 2018 | A1 |
| 20180325955 | Terrell et al. | Nov 2018 | A1 |
| Number | Date | Country |
|---|---|---|
| 2004073656 | Sep 2004 | WO |
| 2006060878 | Jun 2006 | WO |
| 2006113909 | Oct 2006 | WO |
| 2008121420 | Oct 2008 | WO |
| 2011059836 | May 2011 | WO |
| 2011130434 | Oct 2011 | WO |
| 2012004367 | Jan 2012 | WO |
| 2012058460 | May 2012 | WO |
| 2012079000 | Jun 2012 | WO |
| 2013074916 | May 2013 | WO |
| 2013138586 | Sep 2013 | WO |
| 2013154760 | Oct 2013 | WO |
| 2013176915 | Nov 2013 | WO |
| 2014068079 | May 2014 | WO |
| 2014122143 | Aug 2014 | WO |
| 2014140374 | Sep 2014 | WO |
| 2014158821 | Oct 2014 | WO |
| 2014165119 | Oct 2014 | WO |
| 2014165825 | Oct 2014 | WO |
| 2014191128 | Dec 2014 | WO |
| 2015120096 | Aug 2015 | WO |
| 2015121454 | Aug 2015 | WO |
| 2015136001 | Sep 2015 | WO |
| 2015161276 | Oct 2015 | WO |
| 2015164594 | Oct 2015 | WO |
| 2015187528 | Dec 2015 | WO |
| 2015188056 | Dec 2015 | WO |
| WO-2015187528 | Dec 2015 | WO |
| 2016014789 | Jan 2016 | WO |
| 2016025454 | Feb 2016 | WO |
| 2016063264 | Apr 2016 | WO |
| 2016069282 | May 2016 | WO |
| 2016069283 | May 2016 | WO |
| 2016073955 | May 2016 | WO |
| WO-2016069282 | May 2016 | WO |
| 2016090320 | Jun 2016 | WO |
| 2016094304 | Jun 2016 | WO |
| 2016100985 | Jun 2016 | WO |
| 2016120216 | Aug 2016 | WO |
| 2016151315 | Sep 2016 | WO |
| 2016160721 | Oct 2016 | WO |
| 2016164356 | Oct 2016 | WO |
| 2016174652 | Nov 2016 | WO |
| 2016183041 | Nov 2016 | WO |
| 2017058850 | Apr 2017 | WO |
| 2017062451 | Apr 2017 | WO |
| 2017070429 | Apr 2017 | WO |
| 2017075537 | May 2017 | WO |
| 2017083511 | May 2017 | WO |
| 2017093969 | Jun 2017 | WO |
| 2017100176 | Jun 2017 | WO |
| 2017106528 | Jun 2017 | WO |
| 2017112859 | Jun 2017 | WO |
| 2017130223 | Aug 2017 | WO |
| 2017143069 | Aug 2017 | WO |
| 2017149515 | Sep 2017 | WO |
| 2017156484 | Sep 2017 | WO |
| 2017177137 | Oct 2017 | WO |
| 2017180993 | Oct 2017 | WO |
| 2017186928 | Nov 2017 | WO |
| 2017189959 | Nov 2017 | WO |
| 2017210617 | Dec 2017 | WO |
| 2017211900 | Dec 2017 | WO |
| 2017222593 | Dec 2017 | WO |
| 2018068257 | Apr 2018 | WO |
| 2018073391 | Apr 2018 | WO |
| 2018073393 | Apr 2018 | WO |
| 2018132479 | Jul 2018 | WO |
| Entry |
|---|
| U.S. Appl. No. 15/977,798, filed May 11, 2018, Jonathan Alexander Terrett. |
| U.S. Appl. No. 16/434,079, filed Jun. 6, 2019, Jonathan Alexander Terrett. |
| U.S. Appl. No. 16/435,146, filed Jun. 7, 2019, Jonathan Alexander Terrett. |
| U.S. Appl. No. 16/435,173, filed Jun. 7, 2019, Jonathan Alexander Terrett. |
| U.S. Appl. No. 16/409,737, filed May 10, 2019, Jonathan Alexander Terrett. |
| U.S. Appl. No. 15/977,798, Nov. 8, 2018. |
| Eyquem, J. et al.,“Targeting a CAR to the TRAC locus with CRISPR/Cas9 enhances tumour rejection”, Nature, vol. 543 (7643):113-117(2017). |
| Fraietta, J. et al., “Determinants of response and resistance to CD19 chimeric antigen receptor (CAR) T cell therapy of chronic lymphocytic leukemia”, Nature Medicine, vol. 24(5):563-571 (2018). |
| International Search Report and Written Opinion, PCT/IB2018/001619, dated Jul. 3, 2019, 18 pages. |
| Invitation to Pay Additional Fees and, Where Applicable, Protest Fee, PCT/IB2018/001619, dated May 10, 2019, 16 pages. |
| Jaspers J., et al., “Development of CAR T cells designed to improve antitumor efficacy and safety,” Pharmacology and Therapeutics, vol. 178:83-91 (2017). |
| Liu, X. et al., “CRISPR-Cas9-mediated multiplex gene editing in CAR-T cells”, Cell Research, vol. 27(1):154-157 (2016). |
| MacLeod, D. et al. “Integration of a CD19 CAR into the TCR alpha chain locus streamlines production of allogeneic gene-edited CAR T cells”, Molecular Therapy, vol. 25(4):949-961 (2017). |
| Maude, S. et al., “Chimeric antigen receptor T cells for sustained remissions in leukemia”, The New England Journal of Medicine, vol. 371:1507-1517 (2014). |
| Osborn, M. et al., “Evaluation of TCR gene editing achieved by TALENs, CRISPR/Cas9, and megaTAL nucleases”, Molecular Therapy, vol. 24(3):570-581 (2016). |
| Poirot, L. et al., “Multiplex genome-edited T-cell manufacturing platform for “off-the-shelf” adoptive T-cell immunotherapies”, Cancer Research, vol. 75(18):3853-3864 (2015). |
| Ren J. et al., “Advancing chimeric antigen receptor T cell therapy with CRISPR/Cas9”, Protein & Cell, vol. 8 (9):634-643 (2017). |
| Ren, J. et al. “A versatile system for rapid multiplex genome-edited CAR T cell generation”, ONCOTARGET, vol. 8 (10):17002-17011 (2017). |
| Sen, J. et al., “Multiplex Genome Editing to Generate Universal CAR T Cells Resistant to PD1 Inhibition,” Clinical Cancer Research, vol. 23 (9):2255-2266 (2016). |
| Torikai, H. et al., “A foundation for universal T-cell based immunotherapy: T cells engineered to express a CD19-specific chimeric-antigen-receptor and eliminate expression of endogenous TCR”, Blood, vol. 119(24):5697-5705 (2012). |
| Number | Date | Country | |
|---|---|---|---|
| 20190365808 A1 | Dec 2019 | US |
| Number | Date | Country | |
|---|---|---|---|
| 62567008 | Oct 2017 | US | |
| 62508862 | May 2017 | US | |
| 62567012 | Oct 2017 | US | |
| 62648138 | Mar 2016 | US | |
| 62655510 | Apr 2018 | US | |
| 62538138 | Jul 2017 | US | |
| 62583793 | Nov 2017 | US | |
| 62639332 | Mar 2018 | US | |
| 62505649 | May 2017 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 15977798 | May 2018 | US |
| Child | 16431475 | US |
