Patent Application
20250222026
This application claims priority to Chinese Patent Application No. 202110640020.5 (filed on Jun. 8, 2021 and titled CD7-BASED CHIMERIC ANTIGEN RECEPTOR AND USE THEREOF) and Chinese Patent Application No. 202210271824.7 (filed on Mar. 18, 2022 and titled CD7-BASED HUMANIZED CHIMERIC ANTIGEN RECEPTOR AND USE THEREOF), the disclosure of which is incorporated herein by reference in their entireties.
The present application relates to the field of cellular immunotherapy of tumors and, in particular, to a CD7-based humanized chimeric antigen receptor and use thereof, specifically a method for constructing chimeric antigen receptor T (CAR-T) cells based on a tumor-specific target CD7 and use thereof in anti-tumor therapy.
With the development of tumor immunology theories and clinical techniques, chimeric antigen receptor T (CAR-T) cell immunotherapy has become one of the most promising tumor immunotherapies. In general, a chimeric antigen receptor (CAR) consists of a tumor-associated antigen binding region, an extracellular hinge region, a transmembrane region, and an intracellular signal transduction region. Generally, the CAR contains a single-chain variable fragment (scFv) region of an antibody or a domain specifically binding to a tumor-associated antigen (TAA), which is coupled to a cytoplasmic domain of a T-cell signaling molecule through hinge and transmembrane regions. The most common lymphocyte activating moiety includes a T-cell costimulatory domain in tandem with a moiety (for example, CD3ζ) triggering the function of a T-cell effector. CAR-mediated adoptive immunotherapy allows CAR-transplanted T cells to directly recognize TAAs on target tumor cells in a non-HLA-restricted manner.
Most patients suffering from T-cell malignant tumors (including T-cell acute lymphocytic leukemia (T-ALL) and T-cell lymphoma) die of their diseases. One method for treating these patients is to perform gene modification on T cells through CAR expression to target antigens expressed on tumor cells. The CAR is an antigen receptor designed to recognize cell surface antigens in a human leukocyte antigen (HLA)-independent manner. An attempt to treat these types of patients with CAR-expressing genetically modified cells has made a promising success.
CD19 molecules are potential targets for the treatment of B lymphocytic tumors and also a hotspot in CAR-related research. The expression of CD19 is limited to normal and malignant B cells, and CD19 is a widely accepted CAR target. Chimeric antigen receptor genetically modified T cells targeting CD19 molecules (CD19 CAR-T) have achieved a great success in treating resistant and refractory B cell acute lymphocytic leukemia. However, related CAR-T treatment techniques for treating refractory and recurrent T lymphocytic leukemia and T lymphocytic lymphoma are relatively slow and lacking in development.
CN104788573A discloses a chimeric antigen receptor hCD19scFv-CD8α-CD28-CD3ζ and a use thereof. The chimeric antigen receptor consists of light chain and heavy chain variable regions of an anti-human CD19 monoclonal antibody HI19a (hCD19scFv), a hinge region of human CD8α, a transmembrane region and an intracellular region of human CD28, and an intracellular region of human CD3ζ, which are connected in tandem. In this patent, the expression of CD19 is reduced after one CAR-T cell infusion but a single target immune mechanism is easy to escape by the tumor cells. However, the application of CAR-T technology for targeting T cell tumors is relatively lacking.
The CD7 molecule is a cell surface glycoprotein having a molecular weight of 40×103, belongs to an immunoglobulin superfamily, and plays an important role in lymphocyte maturation. When CD7 molecules adhere to an antibody or an antibody derivative, endocytosis occurs rapidly. This property makes CD7 very appropriate to be targeted by immunotoxins, where the immunotoxins along with antigens are internalized and then poison cells from the inside of the cells. However, CD7 remains unknown as a cell surface targeting molecule of the CAR. Whether CD7 CAR-T cells can effectively target T-cell tumor still requires to be confirmed through experiments. Studies have shown that CD7 is highly expressed in many types of T-ALL and T-cell lymphoma so that CD7 is likely to become one of the potential therapeutic targets for T lymphoid hematopoietic tumors.
The current CAR-T technology targeting the T-cell tumors is not well established yet, and a tumor microenvironment that affects the therapeutic effect of CAR-T is still a challenge. Therefore, a CD7-based chimeric antigen receptor (CD7 CAR-T) technology has been developed, which has a great potential for the treatment of recurrent/refractory CD7-positive T-cell malignant tumors.
The present application provides a CD7-based humanized chimeric antigen receptor and use thereof. The chimeric antigen receptor prepared in the present application improves the immune effect of a target and enhances the therapeutic effect of CAR-T cells through CD7-targeted gene modification of T cells so that CD7 CAR-T cells are expected to become a new direction for the treatment of T-cell tumor.
In a first aspect, the present application provides a CD7-based humanized chimeric antigen receptor. The humanized chimeric antigen receptor includes an antigen binding domain, a transmembrane domain, a costimulatory signaling region, and a CD3ζ signaling domain, which are connected in tandem; wherein the antigen binding domain binds to a tumor surface antigen, and the tumor surface antigen is CD7.
In the present application, the antigen binding domain binds to the tumor surface antigen CD7, and then particular humanized gene modification is performed on the CD7 chimeric antigen receptor so that the tumor surface antigen CD7 can specifically bind to the chimeric antigen receptor of the present application. Compared with other chimeric antigen receptors and other tumor antigens, the chimeric antigen receptor has an improved effect and can be expressed at high levels to the targets that the immune effect of CAR-T cells is enhanced.
Preferably, the antigen binding domain includes a humanized CD7 single-chain antibody.
Preferably, a nucleotide sequence of the humanized CD7 single-chain antibody includes a sequence having more than 80% homology to a sequence shown in SEQ ID NO. 1.
Preferably, an amino acid sequence of the humanized CD7 single-chain antibody includes a sequence having more than 80% homology to a sequence shown in SEQ ID NO. 2.
Preferably, a nucleotide sequence of the humanized chimeric antigen receptor includes a sequence having more than 80% homology to a sequence shown in SEQ ID NO. 3, SEQ ID NO. 4, or SEQ ID NO. 5.
Preferably, an amino acid sequence of the humanized chimeric antigen receptor includes a sequence having more than 80% homology to a sequence shown in SEQ ID NO. 6, SEQ ID NO. 7, or SEQ ID NO. 8.
In the present application, the humanized CD7 single-chain antibody (CD7 scFv) is obtained through humanized engineering and specific modification so that an antibody expressed by the modified sequence has a stronger antigen-antibody binding ability and can be expressed in vivo more stably for a long term.
Preferably, the amino acid sequence of the humanized CD7 single-chain antibody includes a sequence having more than 90% homology to the sequence shown in SEQ ID NO. 2.
Preferably, the nucleotide sequence of the humanized chimeric antigen receptor includes a sequence having more than 80% homology to the sequence shown in SEQ ID NO. 3, SEQ ID NO. 4, or SEQ ID NO. 5.
Preferably, the amino acid sequence of the humanized chimeric antigen receptor includes a sequence having more than 80% homology to the sequence shown in SEQ ID NO. 6, SEQ ID NO. 7, or SEQ ID NO. 8.
Preferably, the transmembrane domain is a CD28 transmembrane domain and/or a CD8α transmembrane domain. In some embodiments, the transmembrane domain may be selected or modified through an amino acid substitution.
Preferably, the costimulatory signaling region is a combination of a CD28 signaling domain and a 4-1BB, CD27, or IL-15R signaling domain. The arrangement of the CD28 signaling domain and the 4-1BB, CD27, or IL-15R signaling domain may be adjusted by those skilled in the art as required, and different arrangements of the CD28 signaling domain and the 4-1BB, CD27, or IL-15R signaling domain have no effect on the humanized chimeric antigen receptor.
Preferably, the humanized chimeric antigen receptor further includes a self-destructing domain, and the self-destructing domain includes a caspase 9 domain.
Preferably, the self-destructing domain is connected in tandem with the CD3ζ signaling domain through a 2A sequence. The 2A sequence makes a protein expressed by the self-destructing domain be broken from a protein of the humanized chimeric antigen receptor so that the humanized chimeric antigen receptor can exert its effect. An activator is injected to activate the self-destructing domain so that the humanized chimeric antigen receptor loses its effect.
Preferably, the humanized chimeric antigen receptor further includes a signal peptide. The signal peptide may be any signal peptide capable of directing the transmembrane transfer of the chimeric antigen receptor, and those skilled in the art may select a conventional signal peptide in the art as required.
Preferably, the signal peptide is a Secretory signal peptide, and the Secretory signal peptide may be a signal peptide of a CD8a gene, which has a sequence of 21 amino acids: MALPVTALLLPLALLLHAARP (SEQ ID NO. 11), or a signal peptide of a GM-CSFR gene, which has a sequence of 22 amino acids: MLLLVTSLLLCELPHPAFLLIP (SEQ ID NO. 12), or a signal peptide of any secretory protein gene.
The humanized chimeric antigen receptor of the present application may further include a hinge region, such as GGGGS (SEQ ID NO. 13) or GGGGSGGGGS (SEQ ID NO. 14). The hinge region may be selected by those skilled in the art according to actual situations and is not specially limited herein. The presence of the hinge region does not affect the performance of the humanized chimeric antigen receptor of the present application.
Preferably, the humanized chimeric antigen receptor includes a signal peptide, an antigen binding domain, a transmembrane domain, a costimulatory signaling region, a CD3ζ signaling domain, a 2A sequence, and a self-destructing domain, which are connected in tandem.
As a preferred technical solution, the humanized chimeric antigen receptor includes a Secretory signal peptide, a humanized CD7 single-chain antibody (CD7 scFv), a CD8α transmembrane domain and/or a CD28 transmembrane domain, a combination of a CD28 signaling domain and a 4-1BB, CD27, or IL-15R signaling domain, a CD3ζ signaling domain, a 2A sequence, and a caspase 9 domain, which are connected in tandem. Specifically, they may be arranged as the following combinations:
Preferably, the open reading frame (ORF) of the gene of Secretory signal peptide-humanized CD7 single-chain antibody-CD28-4-1BB-CD3ζ-2A-iCasp9 has a nucleotide sequence as shown in SEQ ID NO. 3.
Preferably, the ORF of the gene of the humanized chimeric antigen receptor: Secretory signal peptide-humanized CD7 single-chain antibody-CD28-CD27-CD3ζ-2A-iCasp9 has a nucleotide sequence as shown in SEQ ID NO. 4.
Preferably, the ORF of the gene of Secretory signal peptide-humanized CD7 single-chain antibody-CD28-IL-15R-CD3ζ has a nucleotide sequence as shown in SEQ ID NO. 5.
Preferably, the gene of Secretory signal peptide-humanized CD7 single-chain antibody-CD28-4-1BB-CD3ζ-2A-iCasp9 has an amino acid sequence as shown in SEQ ID NO. 6.
Preferably, the gene of Secretory signal peptide-humanized CD7 single-chain antibody-CD28-CD27-CD3ζ-2A-iCasp9 has an amino acid sequence as shown in SEQ ID NO. 7.
Preferably, the gene of Secretory signal peptide-humanized CD7 single-chain antibody-CD28-IL-15Ra-CD3ζ has an amino acid sequence as shown in SEQ ID NO. 8.
Preferably, a method for preparing the humanized chimeric antigen receptor includes: transducing a nucleotide sequence encoding the humanized chimeric antigen receptor into a T cell for expression.
Preferably, the nucleotide sequence is transduced into the T cell through any one or a combination of at least two of a viral vector, an eukaryotic expression plasmid, or an mRNA sequence; preferably, the nucleotide sequence is transduced into the T cell through the viral vector.
Preferably, the viral vector is any one or a combination of at least two of a lentiviral vector or a retroviral vector, preferably a lentiviral vector.
Preferably, the vector expressing the humanized chimeric antigen receptor further includes a promoter which is any one or a combination of at least two of EF1a, CMV-TAR, or CMV.
In a second aspect, the present application provides a recombinant lentivirus. The recombinant lentivirus includes a vector expressing the CD7-based humanized chimeric antigen receptor described in the first aspect.
Preferably, a method for preparing the recombinant lentivirus includes co-transfecting a viral vector expressing the CD7-based humanized chimeric antigen receptor described in the first aspect and packaging helper plasmids pNHP and pHEF-VSVG into a mammalian cell obtain the recombinant lentivirus.
Preferably, the mammalian cell is any one or a combination of at least two of 293 cells, 293T cells, or TE671 cells.
In a third aspect, the present application provides a composition. The composition includes the CD7-based humanized chimeric antigen receptor described in the first aspect and/or the recombinant lentivirus described in the second aspect.
In a fourth aspect, the present application provides use of the CD7-based humanized chimeric antigen receptor described in the first aspect, the recombinant lentivirus described in the second aspect, or the composition described in the third aspect to preparation of a chimeric antigen receptor T cell or a medicament for treating a tumor.
Preferably, the tumor is a blood-related tumor disease, and the blood-related tumor disease is T-cell-associated leukemia or lymphoma.
Compared with the existing art, the present application has the beneficial effects described below.
To further elaborate on the technical means adopted and the effects achieved by the present application, solutions of the present application are further described below through specific examples in conjunction with drawings, but the present application is not limited to the scope of the examples.
Experiments without specific techniques or conditions noted in the examples are conducted according to techniques or conditions described in the literature in the art or a product specification. The reagents or instruments used herein without manufacturers specified are conventional products commercially available from proper channels.
Nucleotide sequences encoding chimeric antigen receptors were obtained through gene synthesis, where the chimeric antigen receptors included a Secretory signal peptide, an antigen binding domain CD7 scFv, CD8a and/or CD28 transmembrane domains, a combination of a CD28 signaling domain and a 4-1BB, CD27, or IL-15R signaling domain, a CD3ζ signaling domain, a 2A sequence, and a caspase 9 domain. The nucleotide sequences of chimeric antigen receptors are shown in SEQ ID NO. 3, SEQ ID NO. 4, and SEQ ID NO. 5, respectively. The nucleotide sequences of the three chimeric antigen receptors were inserted into pTYF lentiviral vectors, separately.
Cell debris was removed through centrifugation to obtain the virus supernatant, the virus supernatant was filtered by a low protein binding filter, and the viruses were divided into small portions and stored at −80° C.
Generally, the transduced cells may produce lentiviral vectors with a titer of greater than 107 transduction units per milliliter of the culture medium.
(2) Concentration of Lentiviral Vectors with Centricon or a Similar Filter
The activated T cells were inoculated and suspended in a culture medium and added with 10 μg/mL of polybrene. The culture medium was AIM-V containing cell culture factors IL-2, IL-7, and IL-15. Three CAR gene lentiviruses concentrated and prepared in Example 3 were added, centrifuged for 100 min at 25° C. at a speed of a 100×g centrifugal force, and cultured for 24 h at 37° C. A culture medium was added and cultured for 4 days, the cells were harvested and counted, and the supernatant was tested for endotoxin and mycoplasma. The cells were amplified in vitro for two days and then infused to patients.
Green fluorescent protein genes were transferred into a CD7-positive human T lymphoma cell strain (Molt-3) via lentiviral vectors and stably expressed as target cells.
Unmodified T cells and non-specific GD2 CAR-T cells were used as negative control groups, and five types of CD7 CAR-T were used as experimental groups, where:
The above CAR-T and Molt-3 tumor were incubated at a ratio of 2:1 in a 37° C. and 5% CO2 incubator for 24 h.
After been killed for 24 h, target cells with green fluorescence were analyzed through flow cytometry and the apoptosis situation of the target cells was quantified through PI/AnnexinV staining. The killing effects of different versions of CD7 CAR-T on Molt-3 were observed as shown in
In this example, three types of CD7 CAR-T designed and prepared in the present application were applied to clinical treatment, which includes the steps below.
In conclusion, the tumor surface antigen CD7 on the tumor cells targeted by the chimeric antigen receptor of the present application is not prone to mutation and has an improved effect as compared with other chimeric antigen receptors and other tumor antigens in targeting T cell cancer. The target-specific CAR is expressed at a high level so that the immune effect and the therapeutic effect of CAR-T cells are enhanced.
The applicant has stated that although the detailed method of the present application is described through the examples described above, the present application is not limited to the detailed method described above, which means that implementation of the present application does not necessarily depend on the detailed method described above. It should be apparent to those skilled in the art that any improvements made to the present application, equivalent replacements of raw materials of the product of the present application, additions of adjuvant ingredients, selections of specific manners, etc., all fall within the protection scope and the disclosure scope of the present application.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202110640020.5 | Jun 2021 | CN | national |
| 202210271824.7 | Mar 2022 | CN | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CN2022/096639 | 6/8/2021 | WO |
