title: Engineered drug resistant γδ T cells kill glioblastoma cell lines during a chemotherapy challenge: a strategy for combining chemo- and immunotherapy.
abstract: Classical approaches to immunotherapy that show promise in some malignancies have generally been disappointing when applied to high-grade brain tumors such as glioblastoma multiforme (GBM). We recently showed that ex vivo expanded/activated γδ T cells recognize NKG2D ligands expressed on malignant glioma and are cytotoxic to glioma cell lines and primary GBM explants. In addition, γδ T cells extend survival and slow tumor progression when administered to immunodeficient mice with intracranial human glioma xenografts. We now show that temozolomide (TMZ), a principal chemotherapeutic agent used to treat GBM, increases the expression of stress-associated NKG2D ligands on TMZ-resistant glioma cells, potentially rendering them vulnerable to γδ T cell recognition and lysis. TMZ is also highly toxic to γδ T cells, however, and to overcome this cytotoxic effect γδ T cells were genetically modified using a lentiviral vector encoding the DNA repair enzyme O(6)-alkylguanine DNA alkyltransferase (AGT) from the O(6)-methylguanine methyltransferase (MGMT) cDNA, which confers resistance to TMZ. Genetic modification of γδ T cells did not alter their phenotype or their cytotoxicity against GBM target cells. Importantly, gene modified γδ T cells showed greater cytotoxicity to two TMZ resistant GBM cell lines, U373(TMZ-R) and SNB-19(TMZ-R) cells, in the presence of TMZ than unmodified cells, suggesting that TMZ exposed more receptors for γδ T cell-targeted lysis. Therefore, TMZ resistant γδ T cells can be generated without impairing their anti-tumor functions in the presence of high concentrations of TMZ. These results provide a mechanistic basis for combining chemotherapy and γδ T cell-based drug resistant cellular immunotherapy to treat GBM.
authors: Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA. Lawrence.Lamb@ccc.uab.edu
authors: Lawrence S
authors: LS
authors: Lamb
authors: Joscelyn
authors: J
authors: Bowersock
authors: Anindya
authors: A
authors: Dasgupta
authors: G Yancey
authors: GY
authors: Gillespie
authors: Yun
authors: Y
authors: Su
authors: Austin
authors: A
authors: Johnson
authors: H Trent
authors: HT
authors: Spencer
mesh_terms: D018906:Antineoplastic Agents, Alkylating / Q000494:pharmacology; D001932:Brain Neoplasms / Q000276:immunology / Q000473:pathology / Q000628:therapy; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics / Q000276:immunology; D002478:Cells, Cultured; D003602:Cytotoxicity, Immunologic / Q000187:drug effects / Q000235:genetics / Q000276:immunology; D003606:Dacarbazine / Q000031:analogs & derivatives* / Q000494:pharmacology; D004164:Diphosphonates / Q000494:pharmacology; D019008:Drug Resistance, Neoplasm / Q000187:drug effects / Q000235:genetics / Q000276:immunology; D005434:Flow Cytometry; D058851:GPI-Linked Proteins / Q000276:immunology / Q000378:metabolism; D005818:Genetic Engineering; D005822:Genetic Vectors / Q000235:genetics; D005909:Glioblastoma / Q000276:immunology / Q000473:pathology / Q000628:therapy; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D036341:Intercellular Signaling Peptides and Proteins / Q000276:immunology / Q000378:metabolism; D007376:Interleukin-2 / Q000494:pharmacology; D016086:Lentivirus / Q000235:genetics; D019853:O(6)-Methylguanine-DNA Methyltransferase / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000276:immunology* / Q000378:metabolism; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D000077204:Temozolomide; D000077211:Zoledronic Acid
chemical_list: D018906:Antineoplastic Agents, Alkylating; D004164:Diphosphonates; D058851:GPI-Linked Proteins; D007093:Imidazoles; D036341:Intercellular Signaling Peptides and Proteins; D007376:Interleukin-2; D016692:Receptors, Antigen, T-Cell, gamma-delta; C423230:ULBP2 protein, human; D000077211:Zoledronic Acid; D003606:Dacarbazine; D019853:O(6)-Methylguanine-DNA Methyltransferase; D000077204:Temozolomide