This project will address the therapy of mesothelin expressing tumors by developing and testing engineered? T cells with potent antitumor cytotoxicity. Mesothelin is a tumor-associated antigen that is frequently over? expressed on mesothelioma, non-small cell lung cancer, pancreatic and ovarian cancers. The strategy to be? used is the """"""""T-body"""""""" approach, which employs genetically reprogrammed, patient-derived lymphocytes? transfected with a novel chimeric receptor that contains combinations of the signal transduction domains of? 4-1BB (CD137), CD28, and CD3zeta as well as anti-mesothelin scFv (anti-meso-CD28-41BB-zeta). The central? hypothesis to be tested is that previous trials of adoptive therapy for cancer have used insufficient numbers? of cytotoxic T lymphocytes (CTL) that have shown inadequate engraftment, persistence and effector? function to self antigens. Presently, we are the only laboratory in the world that is actively testing lentiviral? modified T cells in the clinic, and in that trial we have demonstrated safety and prolonged lentiviral gene? transfer. The following three specific aims will test the hypothesis that engineered human T cells expressing? an 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 will? be optimized to obtain highly efficient lentiviral vectors that retarget T cells to specifically kill tumor cells that? express mesothelin at low effector to target ratios in vitro; (2) carrying out in vitro experiments to optimize? the effector functions of anti-mesothelin scFv CD28-41BB-zeta T bodies. Experiments will determine optimal? conditions for redirected T cell serial killing, cytokine production and proliferation, and compare this to? natural MHC restricted CTLs; and (3) performing in vivo experiments in immunodeficient NOD/SCID/beta2null? mice xenografted with human tumors that express mesothelin. These experiments will test the hypothesis? that vectors with high affinity scFv receptors and 4-1BB and CD28 signaling modules will have the most? potent anti-tumor effects. Finally, the engraftment, persistence and antitumor effects of chimeric T cells? given by intravenous and intraperitoneal routes will be compared using bioluminescence imaging. In? summary, an outstanding team of basic and translational scientists has been assembled that will develop? and 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 the? immune system does not generate sufficient numbers of T cells to eradicate the tumor cells. It is now? possible 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 uncommon? tumors such as mesothelioma and a variety of commonly lethal tumors including pancreatic, ovarian and? non-small cell lung carcinoma.?
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