This project will address the therapy of mesothelin expressing tumors by developing and testing engineeredT cells with potent antitumor cytotoxicity. Mesothelin is a tumor-associated antigen that is frequently overexpressed on mesothelioma, non-small cell lung cancer, pancreatic and ovarian cancers. The strategy to beused is the 'T-body' approach, which employs genetically reprogrammed, patient-derived lymphocytestransfected with a novel chimeric receptor that contains combinations of the signal transduction domains of4-1BB (CD137), CD28, and CD3zeta as well as anti-mesothelin scFv (anti-meso-CD28-41BB-zeta). The centralhypothesis to be tested is that previous trials of adoptive therapy for cancer have used insufficient numbersof cytotoxic T lymphocytes (CTL) that have shown inadequate engraftment, persistence and effectorfunction to self antigens. Presently, we are the only laboratory in the world that is actively testing lentiviralmodified T cells in the clinic, and in that trial we have demonstrated safety and prolonged lentiviral genetransfer. The following three specific aims will test the hypothesis that engineered human T cells expressingan anti-mesothelin-CD28-41BB-zeta chimeric receptor will have potent antitumor activity in vitro and in vivo by:(1) developing and optimizing the anti-meso scFv vector. The avidity and the cytosolic signaling modules willbe optimized to obtain highly efficient lentiviral vectors that retarget T cells to specifically kill tumor cells thatexpress mesothelin at low effector to target ratios in vitro; (2) carrying out in vitro experiments to optimizethe effector functions of anti-mesothelin scFv CD28-41BB-zeta T bodies. Experiments will determine optimalconditions for redirected T cell serial killing, cytokine production and proliferation, and compare this tonatural MHC restricted CTLs; and (3) performing in vivo experiments in immunodeficient NOD/SCID/beta2nullmice xenografted with human tumors that express mesothelin. These experiments will test the hypothesisthat vectors with high affinity scFv receptors and 4-1BB and CD28 signaling modules will have the mostpotent anti-tumor effects. Finally, the engraftment, persistence and antitumor effects of chimeric T cellsgiven by intravenous and intraperitoneal routes will be compared using bioluminescence imaging. Insummary, an outstanding team of basic and translational scientists has been assembled that will developand test a universal T cell receptor to target some of the most common and drug resistant tumors.Lay Description. A common reason for failure of immunotherapy of epithelial tumors is that theimmune system does not generate sufficient numbers of T cells to eradicate the tumor cells. It is nowpossible to use lentiviral vector technology to engineer T cells with potent and specific antitumor effects.This project will evaluate engineered T cells that target mesothelin that is overexpressed on both uncommontumors such as mesothelioma and a variety of commonly lethal tumors including pancreatic, ovarian andnon-small cell lung carcinoma.
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