Chlorotoxin polypeptides and conjugates and uses thereof
Inventors
Sentissi, Abdellah • Jacoby, Douglas B.
Assignees
Interested in licensing this patent?
MTEC can help explore whether this patent might be available for licensing for your application.
Publication Number
US-9234015-B2
Publication Date
2016-01-12
Expiration Date
Abstract
Reduced lysine chlorotoxin polypeptides that may be used to generate single species conjugates of chlorotoxin. Conjugates comprising such chlorotoxin polypeptides and pharmaceutical compositions thereof. Methods of using such compositions and/or conjugates.
Core Innovation
The invention relates to chlorotoxin-based reduced lysine polypeptides that have at least 90% sequence identity with SEQ ID NO:1 and comprise no more than one lysine residue. The reduction in lysine content is used to prevent formation of mixed conjugate species that can arise from multi-lysine wild-type chlorotoxin. The description further defines reduced lysine chlorotoxin polypeptides, including monolysine chlorotoxin polypeptides and monolysine-like conjugates, intended to provide single species chlorotoxin conjugates.
The invention also concerns chlorotoxin conjugates formed by covalent coupling of the reduced-lysine chlorotoxin polypeptides to a wide range of payloads. The described conjugation basis includes attachment using lysine ε-amino coupling and related conjugation chemistries referenced in the document, including linker attachment and chemistries such as NHS/EDC and thiolation. Linkers are described as cleavable and non-cleavable, supporting covalent conjugates with defined composition.
The payloads described for the chlorotoxin conjugates include therapeutic agents, detectable labels for imaging, and additional specialized functional components. Therapeutic agents include taxanes and calicheamicin enediyne agents, as well as drug-resistance-associated drugs, and nucleic acids such as siRNA/shRNA and other interfering RNA molecules. Detectable labels include radioisotopes, MRI contrast agents such as gadolinium, and fluorescent dyes, and the document also includes photosensitizers, radiosensitizers, superantigens, and prodrug-activating enzyme systems.
Claims Coverage
The independent claim provides a composition-defined polypeptide requirement: at least 90% sequence identity to SEQ ID NO:1 combined with no more than one lysine residue. The dependent claims refine this polypeptide specification by positioning and substitution patterns of the single lysine and by defining covalent chlorotoxin conjugates with selected therapeutic and imaging agent categories.
Polypeptide with at least 90% identity and no more than one lysine residue
A polypeptide comprising an amino acid sequence having at least 90% sequence identity with SEQ ID NO:1 and comprising no more than one lysine residue.
Single lysine residue at position 27
The polypeptide further specifies that the single lysine residue is located at position 27.
Alanine substitutions at Lys15 and Lys23
The polypeptide is modified by substituting Lys15 and Lys23 with alanine.
Chlorotoxin conjugate with covalently coupled therapeutic/diagnostic/imaging/targeting agents
A chlorotoxin conjugate is provided in which the polypeptide is covalently coupled to one or more therapeutic, diagnostic, imaging, or targeting agents.
Therapeutic agent selected from a specified set including nucleic-acid interference agents
In a chlorotoxin conjugate, the therapeutic agent is selected from a specified list of chemotherapeutic drugs and nucleic-acid interference agents, including cDNA, siRNA, shRNA, and an RNAi-mediating interfering RNA molecule.
Gadolinium imaging agent in a chlorotoxin conjugate
A chlorotoxin conjugate in which the imaging agent comprises gadolinium.
Overall claim coverage centers on reduced-lysine chlorotoxin polypeptides (at least 90% identity to SEQ ID NO:1) constrained to one lysine or fewer, with refinements that specify lysine position and lysine-related substitutions, and with further coverage to covalent chlorotoxin conjugates that link the polypeptide to selected therapeutic/nucleic-acid interference agents and to imaging agents including gadolinium.
Stated Advantages
Prevents formation of mixed conjugate species arising from multi-lysine wild-type chlorotoxin.
Provides single species chlorotoxin conjugates.
Documented Applications
Breast cancer tumor model studies are described, including studies with paclitaxel- and gemcitabine-linked conjugates and a breast cancer xenograft model.
Ocular neovascularization and related assays are described, including macular degeneration/ocular neovascularization and neovasculature regress.
In vitro assays involving U251 glioma cells and PC3 prostate cancer cells are described.
VEGF/PDGF invasion assay is described.
Interested in licensing this patent?