Epidermal growth factor receptor (EGFR) and methods of use in adenoviral-associated virus type 6 (AAV6) transduction
Inventors
Chiorini, John • Weller, Melodie L. • Schmidt, Michael
Assignees
US Department of Health and Human Services
Publication Number
US-9439979-B2
Publication Date
2016-09-13
Expiration Date
2030-09-10
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Abstract
Comparative gene analysis (CGA) was combined with pathway visualization software to identify a positive correlation between AAV6 transduction and epidermal growth factor receptor (EGFR) expression. It was found that EGFR is necessary for vector internalization and functions as a co-receptor for AAV6. The identification and characterization of AAV6's requirement of EGFR expression for high transduction activity has allowed construction of recombinant AAV6 vectors which are capable of targeting and killing specific types of head and neck tumors that because of this high EGFR activity, were until now, refractory to current therapies.
Core Innovation
The invention identifies epidermal growth factor receptor (EGFR) as a co-receptor necessary for adeno-associated virus type 6 (AAV6) internalization and efficient vector transduction in mammalian cells. This discovery was made through comparative gene analysis combined with pathway visualization, revealing a positive correlation between AAV6 transduction efficiency and EGFR expression.
The problem addressed by the invention relates to the limited understanding of receptor usage by different AAV serotypes for tissue-specific transduction, which hampers targeted gene therapy applications. Specifically, there was a need to improve gene therapy for diseases such as cancer by enabling more efficient and selective transduction of cells expressing relevant receptors such as EGFR, which prior vector systems had not effectively targeted.
By establishing EGFR as necessary for AAV6 infection and vector internalization, the invention enables the construction of recombinant AAV6 vectors capable of targeted delivery of heterologous nucleic acids to EGFR-expressing cells, particularly cancer cells derived from head and neck tumors exhibiting high levels of EGFR and refractory to current therapies. This targeted approach facilitates the use of gene-directed enzyme prodrug therapy by encoding genes that increase susceptibility to prodrugs or cytotoxic agents, thereby allowing selective killing of tumor cells.
Claims Coverage
The claims include one independent claim focusing on a therapeutic method employing AAV6 vectors targeting EGFR-expressing tumors. The inventive features relate to using recombinant AAV6 vectors carrying heterologous nucleic acids encoding prodrug-converting proteins administered directly to tumors and subsequent prodrug administration to treat the tumor.
Method of treating EGFR-expressing tumors with AAV6 vectors and prodrugs
A method comprising direct administration to a tumor of a pharmaceutical composition including a recombinant AAV vector with the AAV6 viral genome or a functional portion, containing a heterologous nucleic acid sequence encoding a polypeptide or protein that converts a prodrug into a cytotoxin that kills EGFR-expressing cells, followed by administering a therapeutically effective amount of the prodrug to treat the tumor.
Specific use of head or neck tumors as treatment targets
The method wherein the tumor treated is specifically a head or neck tumor expressing EGFR.
Use of specific genes encoding prodrug-converting enzymes
The heterologous nucleic acid encodes a gene selected from E. coli nitroreductase, cytosine deaminase, Varicella Zoster-tk, Cytochrome P450 B1 (CYP2B1), carboxypeptidase G2 (CPG2), E. coli purine nucleoside phosphorylase (ePNP), and Herpes Simplex Virus thymidine kinase (HSV-tk).
Encoding Herpes Simplex Virus thymidine kinase (HSV-tk) and use of ganciclovir
The gene encodes HSV-tk, and the corresponding prodrug administered is ganciclovir.
Temporal administration between vector and prodrug
The method includes a delay of a period of time between administering the recombinant AAV6 vector and administering the prodrug.
Selective transduction of EGFR-expressing cells
The method specifically transduces EGFR-expressing cells with recombinant AAV6 vectors, while non-EGFR-expressing cells are not transduced, with transduced cells containing approximately 4.6×10^4 copies of vector genome per mg of tissue.
The claims collectively cover a targeted therapeutic approach using AAV6 vectors that rely on EGFR expression for efficient transduction of tumor cells, encoding prodrug-converting genes, and employing prodrug administration to selectively kill EGFR-expressing tumor cells, particularly in head or neck cancers, including specific vector constructs, timing of administration, and selective transduction features.
Stated Advantages
EGFR is identified as a necessary co-receptor for efficient AAV6 internalization and transduction, improving targeting specificity.
Recombinant AAV6 vectors enable selective transduction and killing of EGFR-expressing tumor cells, including those resistant to current therapies.
Use of AAV6 vectors induces lower serum-neutralizing antibody responses compared to other serotypes, potentially enhancing therapeutic efficacy.
The method allows targeted gene delivery to a broad range of mammalian cells, including specific head and neck cancer cells.
Provides flexibility in treatment by encoding genes that increase susceptibility to various prodrugs or cytotoxic agents, enabling combined therapies.
Documented Applications
Treatment of tumors expressing EGFR, especially head and neck squamous cell carcinoma (HNSCC), by delivering recombinant AAV6 vectors encoding cytotoxic genes followed by prodrug administration.
Gene-directed enzyme prodrug therapy (GDEPT) to ablate EGFR-expressing cancer cells using AAV6-mediated delivery of suicide genes such as HSV-tk.
In vivo delivery of transgenes to EGFR-expressing tumors in xenograft mouse models via direct intratumoral injection of recombinant AAV6 vectors.
Potential intravascular or convection-enhanced infusion of AAV6 vectors to treat EGFR-expressing tumors in mammals.
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