Patent Application
20230365635
A computer readable form of the Sequence Listing is filed with this application by electronic submission and is incorporated into this application by reference in its entirety. The Sequence Listing is contained in the file created on Mar. 1, 2023 having the file name “22-0288-US.xml” and is 445,171 bytes in size.
Peptides represent an important class of therapeutics due to their diverse functionalities, ease of synthesis, and improved screening/design technologies. Nonetheless, when administered systemically, peptide therapeutics often face the challenges of short circulation half-life and insufficient bioavailability at the target diseased site. Further, membranolytic peptide therapeutics such as antimicrobial peptides (AMPs) and anticancer peptides (ACPs), which disrupt bacteria membrane and cancer cell membrane respectively, tend to elicit off-target toxicity, limiting their utility beyond local administration. To unleash clinical potential of these therapeutics, there is a great need in development of formulations to overcome these barriers to systemic administration of therapeutic peptides.
In one aspect, the disclosure provides fusion proteins, comprising:
In one embodiment, the fusion protein comprises a linear fusion protein. In another embodiment, each X4 domain is linked to at least one X3 domain without an intervening X1 or X2 domain. In another embodiment, an X4 domain is present at one terminus of the fusion protein. In one embodiment, the fusion protein includes only 1 X2 domain. In another embodiment, the fusion protein includes only 1 X4 domain. In another embodiment, the fusion protein comprises 1, 2, or 3 X1 domains. In a further embodiment, the fusion protein comprises 2 or 3 X1 domains, and wherein at least 2 X1 domains are linked without an intervening X2, X3, or X4 domain. In one embodiment, the fusion protein comprises 1, 2, 3, or 4 X3 domains. In another embodiment, the fusion protein comprises 2, 3, or 4 X3 domains, and wherein at least 2 X3 domains are linked without an intervening X1, X2, or X4 domain, and optionally wherein at least one X1 domain is linked to an X2 domain without an intervening X3 or X4 domain. In a further embodiment, the fusion protein further comprises at least one X5 domain comprising a targeting polypeptide.
In another embodiment, the fusion protein comprises a branched fusion protein. In one embodiment, an X4 domain is present at a terminus of the fusion protein. In a further embodiment, a branch of the fusion protein comprises at least one X3 domain. In another embodiment, a branch of the fusion protein comprises at least one X3 domain linked to an X4 domain. In one embodiment, the branched fusion protein further comprises at least one X5 domain comprising a targeting polypeptide. In another embodiment, a branch of the fusion protein is linked to the primary fusion protein backbone at a location between an X2 domain and one of an X1, X2, X3, or X5 domain. In various embodiments, the fusion protein includes only 1 X2 domain; the fusion protein includes only 1 X4 domain; and/or the fusion protein comprises 1 or 2 X1 domains. In one embodiment, the branched fusion protein comprises 2 X1 domains, and wherein the 2 X1 domains are linked without an intervening X2, X3, or X4 domain. In another embodiment, the branched fusion comprises 1, 2, 3, or 4 X3 domains.
In another embodiment of any of the fusion proteins herein, each X1 domain independently comprises a half-life extension compound selected from the group consisting of an albumin-binding polypeptide, an antibody/Fc domain (such as human Fc or mouse Fc), an unstructured XTEN polypeptide, a proline/alanine-rich sequence polypeptide (PAS), and poly(ethylene glycol). In another embodiment, each X1 domain independently comprises an albumin or albumin-binding polypeptide, including but not limited to human serum albumin, mouse serum albumin and albumin-binding domain. In a further embodiment, each X1 domain independently comprises the amino acid sequence each X1 domain independently comprises the amino acid sequence selected from the group consisting of SEQ ID NO:1-5.
In one embodiment, each X2 domain independently comprises an amino acid sequence selected from the group consisting of
In another embodiment, each X2 domain independently comprises the amino acid sequence (EEG)x, wherein “x” is 1-20, 2-16, 3-12, 4-10, 5-8, 1-15, 1-10, 2-10, 3-10, 4-10, 5-10, 2-8, 3-8, 4-8, 5-8, 5-7, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10.
In a further embodiment, each X3 domain independently comprises an amino acid sequence selected from the linker amino acid sequences selected from SEQ ID NO: 6-70, 171, and 173-187 and/or the non-peptide linkers shown in Table 4 (S86-S96).
In one embodiment, at least one, or each, X4 domain comprises a cationic therapeutic peptide, an anti-microbial peptide, an anti-cancer peptide, and/or a hydrophobic therapeutic peptide. In a further embodiment, at least one, or each, X4 domain comprises an amino acid sequence selected from the group consisting of SEQ ID NO:74-140.
In another embodiment,
In a further embodiment, the X5 domain, when present, comprises the amino acid sequence selected from the group consisting of SEQ ID NO:141-155 and 188-192. In a further embodiment, the fusion protein comprises a structure selected from SEQ ID NO:156-170 and 193-204, wherein any detectable labels are optional.
In another embodiment, the disclosure provides compositions, comprising a plurality of fusion proteins according to any embodiment herein. In some embodiments, the composition further comprises a pharmaceutically acceptable carrier.
In one embodiment, the fusion protein is genetically encodable. In other embodiments, the disclosure provides nucleic acids encoding a genetically encodable fusion protein herein, expression vectors comprising the nucleic acid operatively linked to a suitable regulatory sequence, and host cells comprising the nucleic acid and/or the expression vector.
The disclosure also provides methods for treating a microbial infection or cancer in a subject, comprising administering to the subject an amount effective to treat the microbial infection or cancer of the fusion protein, composition, nucleic acid, expression vector, or host cell of any embodiment herein.
As used herein, the amino acid residues are abbreviated as follows: alanine (Ala; A), asparagine (Asn; N), aspartic acid (Asp; D), arginine (Arg; R), cysteine (Cys; C), glutamic acid (Glu; E), glutamine (Gln; Q), glycine (Gly; G), histidine (His; H), isoleucine (Ile; I), leucine (Leu; L), lysine (Lys; K), methionine (Met; M), phenylalanine (Phe; F), proline (Pro; P), serine (Ser; S), threonine (Thr; T), tryptophan (Trp; W), tyrosine (Tyr; Y), and valine (Val; V).
In all embodiments of polypeptides disclosed herein, any N-terminal methionine residues are optional (i.e.: the N-terminal methionine residue may be present or may be absent).
As used herein and unless otherwise indicated, the terms “a” and “an” are taken to mean “one”, “at least one” or “one or more”. Unless otherwise required by context, singular terms used herein shall include pluralities and plural terms shall include the singular.
Unless the context clearly requires otherwise, throughout the description and the claims, the words ‘comprise’, ‘comprising’, and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to”. Words using the singular or plural number also include the plural or singular number, respectively. Additionally, the words “herein,” “above” and “below” and words of similar import, when used in this application, shall refer to this application as a whole and not to any particular portions of this application.
All embodiments of any aspect of the invention can be used in combination, unless the context clearly dictates otherwise.
In one embodiment, the disclosure provides fusion protein, comprising:
The fusion proteins disclosed herein comprise pro-therapeutic peptides based on a half-life extension compound-therapeutic peptide conjugate which is long-circulating and has a masked biological activity that can be activated upon cleavage of the linker.
As used herein, “fusion protein” requires at least some polypeptide components, but may include non-polypeptide components as well, as disclosed herein. The fusion protein may comprise one each of X1, X2, X3, and X4 domains, or may independently comprise 2, 3, 4, or more such domains.
In one embodiment, the fusion protein comprises a linear fusion protein (i.e., non-branched). In one embodiment, each X4 domain (therapeutic peptide) is linked to at least one X3 domain (cleavage-susceptible linker) without an intervening X1 or X2 domain. This embodiment enables activation of therapeutic peptide X4 from the fusion protein. In this embodiment, the X3-X4 linkage may be direct (with no linker), or may include a linker, such as an amino acid linker, between the X3 and X4 domains, but cannot include an X1 or X2 domain between the X3 and X4 domains. Other embodiments disclosed herein regarding such linkage between two domains without any intervening other domains can similarly be direct (with no linker), or may include a linker, such as an amino acid linker.
In another embodiment, an X4 domain (therapeutic peptide) is present at one terminus of the fusion protein. As used herein, “at one terminus” means that there are no X1, X2, X3, or X5 (discussed below) domains between the terminus and the X4 domain at the terminus. In this embodiment, there may be other moieties present between the X4 domain and the terminus, but none of the defined X1, X2, X3, or X5 domains. In one embodiment, the X4 domain may be present at an amino terminus of the linear fusion protein. In another embodiment, the X4 domain may be present at the carboxy terminus of the linear fusion protein. In a further embodiment, the fusion protein includes only 1 X4 domain.
In one embodiment, the linear fusion proteins comprise comprising 1, 2, or 3 X1 domains (half-life extension compounds). In another embodiment, the fusion protein comprises 2 or 3 X1 domains, wherein at least 2 X1 domains are linked without an intervening X2, X3, or X4 domain. This embodiment may be helpful in tuning biological activity masking and half-life of therapeutics.
In a further embodiment, the linear fusion proteins comprise 1, 2, 3, or 4 X3 domains (linkers susceptible to cleavage at a site of disease). In one embodiment, the linear fusion protein comprises 2, 3, or 4 X3 domains, wherein at least 2 X3 domains are linked without an intervening X1, X2, or X4 domain. Multiple X3 domains enable tuning of therapeutic peptide activation.
In another embodiment of the linear fusion proteins, at least one X1 domain is linked to an X2 domain without an intervening X3 or X4 domain.
The fusion proteins may further comprise at least one X5 domain comprising a targeting polypeptide. As used herein, a “targeting polypeptide” is any polypeptide that can serve to direct the fusion protein to a desired cell or tissue location.
In various non-limiting embodiments, the linear fusion proteins comprise a general formula selected from the group consisting of:
In another embodiment, the fusion protein comprises a branched fusion protein (i.e., at least one domain is covalently linked to a side chain of an amino acid along a protein backbone using a chemical crosslinker). The branched covalent linkage may be accomplished using any conjugation technique suitable for a specific branched fusion protein. In one non-limiting embodiment, the branched covalent linkage may be accomplished via chemical linkages between Cys-Maleimide and DBCO-azide, as exemplified herein.
All disclosure relative to linear fusion protein domains and linkages above are equally relevant to branched fusion proteins unless the context clearly indicates otherwise.
In one embodiment, an X4 domain is present at a terminus of the branched fusion protein. In another embodiment, a branch of the fusion protein comprises at least one X3 domain. In another embodiment, a branch of the fusion protein comprises at least one X3 domain linked to an X4 domain. Flexible positioning of X3 domains ensure optimal activation at the disease site. In another embodiment, the branched fusion protein further comprises at least one X5 domain comprising a targeting polypeptide.
In a further embodiment, a branch of the fusion protein is linked to the primary fusion protein backbone at a location between an X2 domain and one of an X1, X2, X3, or X5 domain. The embodiment ensures proximity of X2 to X4 for activity masking via electrostatic interaction.
In one embodiment, the branched fusion protein includes only 1 X2 domain. In another embodiment, the branched fusion protein includes only 1 X4 domain.
In a further embodiment, the branched fusion protein comprises 1 or 2 X1 domains. In another embodiment, the branched fusion protein comprises 2 X1 domains, wherein the 2 X1 domains are linked without an intervening X2, X3, or X4 domain. In one embodiment, the branched fusion protein comprises 1, 2, 3, or 4 X3 domains.
In various non-limiting embodiments, the branched fusion proteins comprise a general formula selected from the group consisting of formula 1-34 s shown in Table 1.
The X1 domains may comprise any compound that can serve to increase the half-life of the fusion protein upon administration to a subject. In one embodiment, each X1 domain independently comprises a half-life extension compound selected from the group consisting of an albumin-binding polypeptide, an antibody/Fc domain (such as human Fc or mouse Fc), an unstructured XTEN polypeptide (see, for example, Nature Biotechnology volume 27, pages 1186-1190 (2009), incorporated herein by reference), a proline/alanine-rich sequence polypeptide (PAS), and/or poly(ethylene glycol). In one embodiment, the half-life extension compound is a half-life extension polypeptide. In embodiments where the fusion protein comprises more than one X1 domain, each X1 domain may independently be the same or different. In another embodiment, each X1 domain independently comprises an albumin or albumin-binding polypeptide, including but not limited to human serum albumin, mouse serum albumin and/or albumin-binding domain. In another embodiment, each X1 domain independently comprises the amino acid sequence selected from
wherein the residues in parentheses are optional and may be present or absent. In one embodiment, each X1 domain independently comprises the amino acid sequence LKEAKEKA IEELKKAGIT SDYYFDLINK AKTVEGVNAL KDEILKA (SEQ ID NO: 5).
Any X2 domain can be used that provides an anionic block as suitable for an intended use. In one embodiment, the anionic block is may be combined with cationic therapeutic peptides (X4), including but not limited to antimicrobial peptides or anticancer peptides. In other embodiments, the anionic block may serve as a solubility enhancer for hydrophobic therapeutic peptides. In one embodiment, each X2 domain independently comprises an amino acid sequence selected from those in Table 2, wherein residues within parentheses are optional amino acids at that position.
In one embodiment, each X2 domain independently comprises the amino acid sequence (EEG)x, wherein “x” is 1-20, 2-16, 3-12, 4-10, 5-8, 1-15, 1-10, 2-10, 3-10, 4-10, 5-10, 2-8, 3-8, 4-8, 5-8, 5-7, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10.
Any linker susceptible to cleavage at a site of disease can be used as the X3 domain(s), as appropriate for an intended use. In one embodiment, each X3 domain independently comprises an amino acid sequence selected from the linker amino acid sequences listed in Table 3 (SEQ ID NO:6-70, 171, and 173-187), and/or the non-peptide linkers shown in Table 4 (S86-S96) In embodiments with more than one X3 domain, each X3 domain may be the same or different.
In one embodiment, a spacing sequence may independently be inserted between different domains. In one embodiment, a spacing sequence is provided between each domain. In other embodiments, a spacing sequence is provided between some, but not all of the domains. Any spacing sequence may be used as appropriate for an intended use. In various embodiments, the spacing sequences independently comprise the amino acid sequence selected from Gx, (GS)x, (GGS)x, (GSA)x, (GGGS)x (SEQ ID NO: 71), (GGGGS)x (SEQ ID NO: 72), where x=1-4, or SPSTPPTPSPSTPP (SEQ ID NO: 73)
Any therapeutic peptide may be used as an X4 domain as appropriate for an intended use. In one embodiment, the therapeutic peptide is a cationic therapeutic peptide. In another embodiment, the therapeutic peptide is an anti-microbial peptide. In additional embodiment, the therapeutic peptide is an anti-cancer peptide. In another embodiment, the therapeutic peptide is a cell-penetrating peptide fused to therapeutic peptide for intracellular targeting. In other embodiments, the therapeutic peptide may be a hydrophobic therapeutic peptide.
In various embodiments, each X4 domain comprises an amino acid sequence selected from the therapeutic peptide sequences listed in Table 5 SEQ ID NO:74-103).
In some embodiments, each X4 domains may comprise a detectable marker, including but not limited to Cy7, Cy5, AF647, AF680, or small molecule therapeutics (ciprofloxacin, LpxC inhibitors, aminoglycosides, rifampicin, linezolid, chemotherapeutics (doxorubicin, monomethyl auristatin E, monomethyl auristatin F, trabectedin, SN-38)). In one embodiment, the detectable marker may be located at the carboxy-terminus of a peptide X4 domain. In other embodiments, 1, 2, 3, or all X4 domains may comprise an azide linkage or other functional groups for conjugation, including but not limited to an Azidoacetyl linkage. In one embodiment, the azide linkage may be at the N-terminus of a peptide X4 domain. Non-limiting examples of such “functionalized” X4 domains are provided in Table 6 (SEQ ID NO:104-136).
X3 denotes cleavable linker connected to one or
X3 denotes cleavable linker
X3 denotes cleavable linker connected to one or
X3 denotes cleavable linker
X3 denotes cleavable linker connected to one or
X3 denotes cleavable linker
X3 denotes cleavable linker connected to one or
In specific embodiments, each X4 domain may independently comprise the amino acid sequence selected from SEQ ID NO:136-139.
wherein residues in lower case are D amino acids and residues in upper case are L amino acids or glycine (which is achiral) and Dab and Orn denote L-diaminobutyric acid and L-ornithine respectively.
In other specific embodiments, of the fusion proteins:
In one such embodiment, the fusion protein comprises 1 X1 domain, 1 X2 domain, 1 X3 domain, and 1 X4 domain.
Any targeting domain may be used as the X5 domain(s), as deemed appropriate for an intended purpose. In various embodiments, the X5 domain comprises the amino acid sequence selected from the group consisting of those shown in Table 7 (SEQ ID NO:141-155 and 188-192).
The fusion proteins may be made via any suitable technique, including chemical synthesis. In some embodiments of the linear fusion proteins, the fusion protein may be genetically encodable and can be expressed using standard recombinant techniques.
The disclosure further comprises nucleic acids encoding a genetically encodable fusion protein, expression vectors comprising a nucleic acid encoding the fusion protein operatively linked to a suitable regulatory sequence, and host cells comprising the nucleic acids and/or the expression vector. The nucleic acid may comprise RNA or DNA, and may comprise additional sequences useful for promoting expression and/or purification of the encoded protein, including but not limited to polyA sequences, modified Kozak sequences. “Expression vectors” includes vectors that operatively link a nucleic acid coding region or gene to any control sequences capable of effecting expression of the gene product. “Control sequences” operably linked to the nucleic acid sequences of the invention are nucleic acid sequences capable of effecting the expression of the nucleic acid molecules. The control sequences need not be contiguous with the nucleic acid sequences, so long as they function to direct the expression thereof. Thus, for example, intervening untranslated yet transcribed sequences can be present between a promoter sequence and the nucleic acid sequences and the promoter sequence can still be considered “operably linked” to the coding sequence. Other such control sequences include, but are not limited to, polyadenylation signals, termination signals, and ribosome binding sites. Such expression vectors include but are not limited to, plasmid and viral-based expression vectors. The control sequence used to drive expression of the disclosed nucleic acid sequences in a mammalian system may be constitutive (driven by any of a variety of promoters, including but not limited to, CMV, SV40, RSV, actin, EF) or inducible (driven by any of a number of inducible promoters including, but not limited to, tetracycline, ecdysone, steroid-responsive). The expression vector must be replicable in the host organisms either as an episome or by integration into host chromosomal DNA. In various embodiments, the expression vector may comprise a plasmid, viral-based vector (including but not limited to a retroviral vector or oncolytic virus), or any other suitable expression vector. The host cells can be transiently or stably engineered to incorporate the expression vector, using techniques including but not limited to bacterial transformations, calcium phosphate co-precipitation, electroporation, or liposome mediated-, DEAE dextran mediated-, polycationic mediated-, or viral mediated transfection. (See, for example, Molecular Cloning: A Laboratory Manual (Sambrook, et al., 1989, Cold Spring Harbor Laboratory Press); Culture of Animal Cells: A Manual of Basic Technique, 2nd Ed. (R. I. Freshney. 1987. Liss, Inc. New York, NY)). A method of producing a polypeptide according to the invention is an additional part of the invention. The method comprises the steps of (a) culturing a host according to this aspect of the invention under conditions conducive to the expression of the fusion protein, and (b) optionally, recovering the expressed fusion protein.
In various non-limiting embodiments, the fusion protein comprises the structure selected from the fusion proteins listed in Table 8 (SEQ ID No: 156-170 and 193-204, wherein any detectable labels are optional.
In one embodiment, the fusion protein comprises the structure of (ABD)2-(EEG)6-S12-(D)Pex (SEQ ID NO:157), (ABD)2-(EEG)6-S12-(D)Pex-Cy7 (SEQ ID NO:158), (ABD)2-(EEG)6-S12-S12-POL7080 (SEQ ID NO:159), or (ABD)2-(EEG)6-S12-S12-Colistin (SEQ ID NO:161).
In another embodiment, the disclosure provides compositions, comprising a plurality of fusion proteins according to any embodiment or embodiments herein. Such compositions may comprise fusion proteins having the same therapeutic peptide or different therapeutic peptides, or the same fusion protein or different fusion proteins (with the same or different therapeutic peptides). In various embodiments, the plurality of fusion proteins comprise 2, 3, 4, 5, 6, 7, 8, 9, 10, or more different therapeutic peptides in total. This embodiment is useful for therapeutic peptide combination that is synergistic in activity.
In another embodiment, the compositions further comprises a pharmaceutically acceptable carrier. Such pharmaceutical compositions of the disclosure can be used, for example, in the methods of the disclosure described herein. The pharmaceutical compositions may further comprise (a) a lyoprotectant; (b) a surfactant; (c) a bulking agent; (d) a tonicity adjusting agent; (e) a stabilizer; (f) a preservative and/or (g) a buffer. In some embodiments, the buffer in the pharmaceutical composition is a Tris buffer, a histidine buffer, a phosphate buffer, a citrate buffer or an acetate buffer. The pharmaceutical composition may also include a lyoprotectant, e.g. sucrose, sorbitol or trehalose. In certain embodiments, the pharmaceutical composition includes a preservative e.g. benzalkonium chloride, benzethonium, chlorohexidine, phenol, m-cresol, benzyl alcohol, methylparaben, propylparaben, chlorobutanol, o-cresol, p-cresol, chlorocresol, phenylmercuric nitrate, thimerosal, benzoic acid, and various mixtures thereof. In other embodiments, the pharmaceutical composition includes a bulking agent, like glycine. In yet other embodiments, the pharmaceutical composition includes a surfactant e.g., polysorbate-20, polysorbate-40, polysorbate-60, polysorbate-65, polysorbate-80 polysorbate-85, poloxamer-188, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan trilaurate, sorbitan tristearate, sorbitan trioleaste, or a combination thereof. The pharmaceutical composition may also include a tonicity adjusting agent, e.g., a compound that renders the formulation substantially isotonic or isoosmotic with human blood. Exemplary tonicity adjusting agents include sucrose, sorbitol, glycine, methionine, mannitol, dextrose, inositol, sodium chloride, arginine and arginine hydrochloride. In other embodiments, the pharmaceutical composition additionally includes a stabilizer, e.g., a molecule which, when combined with a protein of interest substantially prevents or reduces chemical and/or physical instability of the protein of interest in lyophilized or liquid form. Exemplary stabilizers include sucrose, sorbitol, glycine, inositol, sodium chloride, methionine, arginine, and arginine hydrochloride.
The fusion protein(s) may be the sole active agent in the pharmaceutical compositions, or the compositions may further comprise one or more other active agents suitable for an intended use.
In another embodiment, the disclosure provides methods for treating a microbial infection in a subject, comprising administering to the subject an amount effective to treat the microbial infection of the fusion protein, composition, nucleic acid, expression vector, or host cell of any embodiment or combination of embodiments herein, particularly when the therapeutic peptide comprises an anti-microbial peptide.
As used herein, “treat” or “treating” means accomplishing one or more of the following: (a) reducing the severity of the disorder; (b) limiting or preventing development of symptoms characteristic of the disorder(s) being treated; (c) inhibiting worsening of symptoms characteristic of the disorder(s) being treated; (d) limiting or preventing recurrence of the disorder(s) in patients that have previously had the disorder(s); and (e) limiting or preventing recurrence of symptoms in patients that were previously symptomatic for the disorder(s).
The subject may be any subject that has a relevant disorder. In one embodiment, the subject is a mammal, including but not limited to humans, dogs, cats, horses, cattle, etc.
The methods may be used to treat any microbial infection that an AMP in the fusion protein has activity against, and at the site of which the linker will be susceptible to cleavage. In one embodiment, the microbial infection comprises a bacterial infection. In one such embodiment, the linker is susceptible to cleavage by a protease produced by the bacterial that is the cause/a cause of the infection or a protease produced by host cells in response to infection. In various non-limiting embodiments, the bacterial infection comprises one or more of pneumonia, a soft tissue infection, and endocarditis.
In another embodiment, the disclosure provides method for treating a cancer in a subject, comprising administering to the subject an amount effective to treat cancer of the fusion protein, composition, nucleic acid, expression vector, or host cell of any embodiment or combination of embodiments herein, particularly when the therapeutic peptide comprises an anti-cancer therapeutic. In one such embodiment, the methods may be used to treat cancer that a therapeutic peptide in the fusion protein has activity against, and at the site of which the linker will be susceptible to cleavage. In one such embodiment, the linker is susceptible to cleavage by a protease produced by cancer and stromal cells in tumor microenvironment.
We report design and development of activatable therapeutic peptide using antimicrobial peptide (AMP) as a model therapeutic peptide. As a specific example, we demonstrate development of a pro-AMP therapeutic based on albumin-binding domain (ABD)-AMP conjugate which is long-circulating with a masked biological activity that can be activated upon cleavage of the cleavable linker (
The novel activatable AMP therapeutics exemplified herein comprise 4 components in tandem; (1) half-life extension domain (including but not limited to albumin-binding domain (ABD) and Fc), (2) anionic block, (3) cleavable linker (e.g. protease substrate), and (4) therapeutic payload (e.g. AMPs ((D)Pexiganan, (D)CAMEL0, Tachyplesin I, POL7080, and colistin)) (
To verify activity masking of our therapeutics, we evaluated antibacterial activity of our model ABD-AMP conjugate candidate ((ABD)2-(EEG)6-S12-(D)Pex) (
Next, we comprehensively characterized our model ABD-AMP conjugate ((ABD)2-(EEG)6-S12-(D)Pex-Cy7) (
Given a favorable biodistribution profile of ABD-AMP conjugate, we next evaluated if our conjugate could improve safety profile of AMP. We performed toxicity evaluation in mice following intravenous treatments with free AMP (D)Pex or conjugate (ABD)2-(EEG)6-S12-(D)Pex at 5 and 10 mg/kg AMP equivalent doses (
To ensure broad application across different therapeutic peptides, we formulated additional AMPS (POL7080 and colistin) into ABD-AMP conjugates and evaluated the extent of activity masking. A 64-fold activity masking was similarly observed for both peptides in term of antibacterial activity on PAO1 (
Finally, we provided an example of a targeted ABD-AMP conjugate where a targeting domain is fused to the N-terminus of the construct to promote engagement in the infected microenvironment (
We designed and developed a platform for formulating activatable therapeutic peptides. Our model construct (ABD-AMP conjugate) exhibits robust activity masking that can be liberated upon cleavage of the cleavable linker. Following systemic administration, the conjugate selectively delivers active AMP to target infected organ while minimizing exposure in other off-target organs leading to improved safety profile of the conjugate. The formulation will increase utility of AMPs for systemic application by increasing circulation time, improving target organ bioavailability and preventing off-target organ toxicity.
Long circulation. AMPS are typically small in size (<5 kDa) and cationic. Hence, they are rapidly cleared off the body either via kidney filtration and/or liver sequestration. Our formulation provides a charge stealth on AMP which reduces liver sequestration while simultaneously increasing its effective size via albumin association to reduce renal filtration. No existing formulation has capitalized on both cationic charge neutralization and steric albumin association in a single conjugate to formulate a pro-AMP therapeutic.
On-target delivery to diseased (infection) organ. Conditional release of AMP upon cleavage of cleavable linker provides an opportunity to tune release profile via optimization of the linker.
Reduction in off-target organ exposure. Our therapeutic conjugate is inherently inactive until activated. Optimization of cleavable linker ensures minimal activation in other off-target organs which leads to improved safety profile of systemically administered AMP.
This application claims priority to U.S. Provisional Patent Application Ser. No. 63/341,061 filed May 12, 2022, incorporated by reference herein in its entirety.
This invention was made with government support under AI142780 and AI132413 awarded by the National Institutes of Health. The government has certain rights in the invention.
| Number | Date | Country | |
|---|---|---|---|
| 63341061 | May 2022 | US |
