Cancer therapy using genetically altered autologous T cells offers the potential benefit of tumor-specific killing and decreased toxicity relative to conventional chemoradiotherapy or adoptive therapy with allogeneic T cells. Even so, a number of obstacles can limit the effectiveness of such treatment, including the immune evasion tactics of tumor cells, such as secretion of the inhibitory molecule TGF-beta. Thus, after extending therapeutic advances in highly immunogenic tumors to Hodgkin disease and other less immunogenic tumors (Years 1-4), this program project will shift its focus to the design, evaluation and clinical implementation of strategies to counteract negative immunoregulatory influences and to improve the trafficking of activated cytotoxic T lymphocytes (CTLs) to tumor deposits. This long-term goal will be pursued in a series of iterative preclinical and clinical studies conducted within four research projects supported by three core services (Cell Processing, Vector Manufacturing, Administrative/Regulatory/Biostatistics). This plan of research was devised to address three central questions. Can one circumvent the active and passive immune evasion tactics that allow tumors to escape T-cell responses? Is it possible to modulate the tumor microenvironment to secure optimal T-cell function? Can homing of infused CTLs to tumor sites be optimized? Investigators in Project 1 will test whether the introduction of a dominant negative TGF-beta type II receptor on tumor specific CTLs will render the cells resistant to the adverse effects of TGF-beta. In Project 2 the emphasis will be on CD4+ CD25+ regulatory T cells (Tregs) in the microenvironment and whether their negative influence on cancer vaccines and CTL therapy can be reversed by treatment with ligands for Toll-like receptors. The thrust of Project 3 will be to determine if the introduction of heterologous chemokine receptors into neuroblastoma-specific effector T cells) can enhance their trafficking to tumor sites. Finally, in Project 4, the investigators will attempt to improve on their promising results with CTL therapy targeting EBV antigens in NPC by infusing T cells that harbor multiple antitumor specificities to reduce the risk of tumor escape by antigenic modulation. All investigators selected for this research program have demonstrated expertise in cancer immunology, clinical trials of cellular therapy, EBV virology and investigations with animal models. This background, together with long-standing collaborations among the project leaders, predicts extensive, possibly synergistic, interactions over the next funding cycle. Lay summary - Immunotherapy holds much promise as an effective cancer treatment. But for this promise to be realized, certain obstacles must be overcome. Investigators in this research program will attempt to combat several of the most common immune evasion strategies used by tumor cells.
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