title: Retrovirally transduced murine T lymphocytes expressing FasL mediate effective killing of prostate cancer cells.
abstract: Adoptively transferred T cells possess anticancer activities partially mediated by T-cell FasL engagement of Fas tumor targets. However, antigen-induced T-cell activation and clonal expansion, which stimulates FasL activity, is often inefficient in tumors. As a gene therapy approach to overcome this obstacle, we have created oncoretroviral vectors to overexpress FasL or non-cleavable FasL (ncFasL) on murine T cells of a diverse T-cell receptor repertoire. Expression of c-FLIP was also engineered to prevent apoptosis of transduced cells. Retroviral transduction of murine T lymphocytes has historically been problematic, and we describe optimized T-cell transduction protocols involving CD3/CD28 co-stimulation of T cells, transduction on ice using concentrated oncoretrovirus, and culture with IL-15. Genetically modified T cells home to established prostate cancer tumors in vivo. Co-stimulated T cells expressing FasL, ncFasL and ncFasL/c-FLIP each mediated cytotoxicity in vitro against RM-1 and LNCaP prostate cancer cells. To evaluate the compatibility of this approach with current prostate cancer therapies, we exposed RM-1, LNCaP, and TRAMP-C1 cells to radiation, mitoxantrone, or docetaxel. Fas and H-2(b) expression were upregulated by these methods. We have developed a novel FasL-based immuno-gene therapy for prostate cancer that warrants further investigation given the apparent constitutive and inducible Fas pathway expression in this malignancy.
authors.affiliation: Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada.
authors.forename: J C
authors.initials: JC
authors.lastname: Symes
authors.forename: C
authors.initials: C
authors.lastname: Siatskas
authors.forename: D H
authors.initials: DH
authors.lastname: Fowler
authors.forename: J A
authors.initials: JA
authors.lastname: Medin
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D002460:Cell Line; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D000077143:Docetaxel; D053222:Fas Ligand Protein / Q000276:immunology / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D007167:Immunotherapy / Q000379:methods*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008942:Mitoxantrone / Q000494:pharmacology; D010641:Phenotype; D011471:Prostatic Neoplasms / Q000235:genetics / Q000276:immunology / Q000628:therapy*; D012190:Retroviridae / Q000235:genetics* / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology; D043823:Taxoids / Q000494:pharmacology; D014161:Transduction, Genetic
chemical_list: D000970:Antineoplastic Agents; D053222:Fas Ligand Protein; D043823:Taxoids; D000077143:Docetaxel; D008942:Mitoxantrone