A key to the success of chimeric antigen receptor (CAR) T-cell based therapies greatly rely on the capacity to identify and target antigens with expression restrained to tumor cells. Here we present a strategy to generate CAR T-cells that are only effective locally (tumor tissue), potentially also increasing the choice of targetable antigens. By fusing an oxygen sensitive subdomain of HIF1α to a CAR scaffold, we generated CAR T-cells that are responsive to a hypoxic environment, a hallmark of certain tumors. Along with the development of oxygen-sensitive CAR T-cells, this work also provides a basic framework to use a multi-chain CAR as a platform to create the next generation of smarter self-decision making CAR T-cells.

expression of FGFR4 CAR on transduced T cells was measured using flow cytometry. The M410 and M412 FGFR4 CARs, both short and long constructs, were tested for cell-mediated cytotoxicity against RMS cell lines. M410-L showed higher cytotoxic activity compared to M412-L. M412-S showed greater cytotoxic activity compared to M412-L CAR. Thus, overall CAR structure format may be important for its functional activity. The remaining scFv will be further analyzed in various CAR formats for its functional activity including cytotoxicity and interferon-gamma production. In summary, the overexpression of FGFR4 protein in RMS versus normal cell lines demonstrates that FGFR4 may be a suitable target for immune-based therapy. FGFR4 CAR-T cell therapy offers the potential of a novel therapeutic intervention for high-risk, refractory and relapsed RMS.