Rationally designed capsid and transgene cassette of AAV6 vectors for dendritic cell-based cancer immunotherapy.
Dendritic cell (DC)-based immunotherapy has recently demonstrated a great potential for clinical applications; however, additional progress in the methods of tumor-specific antigen delivery to DCs is necessary for the further development of anti-tumor vaccines. To this end, a capsid-optimized adeno-associated virus serotype 6 (AAV6-T492V+S663V) vector was developed by site-directed mutagenesis of surface-exposed serine (S) and threonine (T) residues, which have a critical role in intracellular trafficking of AAV vectors. This double-mutant AAV6 vector had ∼ 5-fold greater transduction efficiency in monocyte-derived DCs (moDCs) compared with wild-type (WT)-AAV6 vectors. The increase in the transduction efficiency correlated with the improved nuclear translocation of AAV6-T492V+S663V over that of the WT-AAV6 vector. Additional studies of the CD11c promoter identified critical regulatory elements that fit into the AAV expression cassette and drive EGFP expression in moDCs. Development of a chimeric promoter (chmCD11c) that contains functional modules of CD11c and a Simian virus (SV40) enhancer element dramatically increased the EGFP expression in moDCs. MoDCs transduced by the capsid-optimized AAV6 vector carrying human prostate-specific antigen (hPSA) driven by CBA (AAV6-T492V+S663V-CBA-hPSA) or chmCd11c (AAV6-T492V+S663V-chmCD11c-hPSA) generated specific T-cell clone proliferation and superior cytotoxic T lymphocytes (CTLs) with higher killing capability against human prostate adenocarcinoma cells, LNCaP, compared with WT-AAV6 induced CTLs. Taken together, these studies suggest that optimization of capsid and promoter components of AAV vectors can be a useful approach for efficient targeting of moDCs and may prove to be a promising tool for cancer immunotherapy.
Department of Microbiology and Cell Science, University of Florida, College of Medicine, Gainesville, FL, USA.
Jheel
J
Pandya
Division of Cellular and Molecular Therapy, Department of Pediatrics; University of Florida, College of Medicine, Gainesville, FL, USA.
Luis
L
Ortiz
Division of Cellular and Molecular Therapy, Department of Pediatrics; University of Florida, College of Medicine, Gainesville, FL, USA.
Chen
C
Ling
Division of Hematology/Oncology, Department of Pediatrics, University of Illinois at Chicago, Chicago, IL, USA.
Angela E
AE
Rivers
Division of Cellular and Molecular Therapy, Department of Pediatrics; University of Florida, College of Medicine, Gainesville, FL, USA.
George
G
Aslanidi
D000230:Adenocarcinoma / Q000235:genetics / Q000276:immunology / Q000628:therapy*; D002213:Capsid / Q000276:immunology*; D045744:Cell Line, Tumor; D003713:Dendritic Cells / Q000276:immunology*; D000229:Dependovirus; D005822:Genetic Vectors; D006801:Humans; D007167:Immunotherapy / Q000379:methods*; D008297:Male; D011471:Prostatic Neoplasms / Q000235:genetics / Q000276:immunology / Q000628:therapy*; D019076:Transgenes