Identification and characterization of novel mediators of tumor-induced T-cell dysfunction

Abstract

Abstract Immunotherapies targeting T-cell functionality, such as anti-PD-1, have been shown to have efficacy in numerous cancers, including non-small cell lung cancer (NSCLC). However, treatment with anti-PD-1 induces responses in only a subset of patients. This raises the possibility that other effectors of T-cell dysfunction remain to be elucidated. To evaluate possible novel mediators of T-cell dysfunction, we isolated CD8+ T-cells from orthotopic KrasG12D/p53−/− murine lung adenocarcinomas (HKP-1) that exhibited either stable or progressive disease as a function of tumor growth, both in the presence and absence of anti-PD-1 therapy. RNAseq analysis revealed increased expression of numerous genes including Tim3, PD-1, Lag3, 2B4, and CISH, and decreased expression of GzmB and Eomes in CD8+ T-cells isolated from progressive tumors indicative of a dysfunctional state, as well as multiple novel genes not previously associated with T-cell dysfunction. To explore the functional role of the novel candidate genes, we have developed in vitro and in vivo assays evaluating cytotoxicity, cytokine production, proliferation, and tumor growth, leveraging Ova expression in our HKP-1 cell line (KP1-Ova). We have begun to target this unique set of candidate genes associated with dysfunction in tumor-specific T-cells through RNAi/shRNA and adoptive transfer approaches to facilitate therapeutic reprogramming and enhanced T-cell-mediated immunity in lung cancer. We expect to provide novel strategies for designing rational immunotherapies targeting dysfunctional tumor-specific CD8+ T-cells to generate durable anti-tumor immune responses for the treatment of lung adenocarcinoma.