Project description:CD8+ cytotoxic T cells play essential roles in anti-tumor immune responses. Here, we performed in vivo screens in CD8+ T cells and identified regulators of tumor infiltration and killing, which are directly relevant to cancer immunotherapy. Unlike in vitro screens, the in vivo screen robustly re-identified canonical immunotherapy targets such as PD-1 and Tim-3, along with genes that have not been characterized in T cells. The infiltration and degranulation screens converged on an RNA helicase Dhx37. Dhx37 knockout enhanced the efficacy of antigen-specific CD8+ T cells against cancer in vivo. Immunological characterization in mouse and human CD8+ T cells revealed that DHX37 suppresses effector function, cytokine production, and T cell activation. Transcriptomic profiling and biochemical interrogation revealed a role for DHX37 in modulating the NF-kB pathway. These data demonstrated the power of high-throughput in vivo genetic screens for immunotherapy target discovery, and uncovered DHX37 as a functional regulator of CD8+ T cells.
Project description:CD8+ cytotoxic T cells play essential roles in anti-tumor immune responses. Here, we performed in vivo screens in CD8+ T cells and identified regulators of tumor infiltration and killing, which are directly relevant to cancer immunotherapy. Unlike in vitro screens, the in vivo screen robustly re-identified canonical immunotherapy targets such as PD-1 and Tim-3, along with genes that have not been characterized in T cells. The infiltration and degranulation screens converged on an RNA helicase Dhx37. Dhx37 knockout enhanced the efficacy of antigen-specific CD8+ T cells against cancer in vivo. Immunological characterization in mouse and human CD8+ T cells revealed that DHX37 suppresses effector function, cytokine production, and T cell activation. Transcriptomic profiling and biochemical interrogation revealed a role for DHX37 in modulating the NF-kB pathway. These data demonstrated the power of high-throughput in vivo genetic screens for immunotherapy target discovery, and uncovered DHX37 as a functional regulator of CD8+ T cells.
Project description:By killing tumor cells, cytotoxic CD8+ T cells are the major effectors in antitumor immunity. A subset of CD4+ T cells also possesses cytotoxic activity by expressing perforin and granzymes and is associated with immunotherapy efficacy. Despite the progress made in characterizing cytotoxic CD4+ T cells in various diseases, the status of cytotoxic CD4+ T cells in non-small cell lung cancer (NSCLC) and the driving mechanisms and forces involved in reviving intratumoral cytotoxic CD4+ T cells remain unclear. Here, we showed that CD4+GzmB+ T cells obtained from patients with NSCLC expressed increased levels of SLC7A5 compared with their counterparts. Upregulation of SLC7A5 was essential for the differentiation of CD4+GzmB+ T cells from naïve CD4+ T cells stimulated with TCR and IL-2. Both T-bet and Eomes are required for the differentiation of CD4+GzmB+ T cells. Interestingly, IL-15 can further increase SLC7A5 expression in differentiated CD4+GzmB+ T cells. Moreover, through activation of the AKT-FOXO1-T-bet axis, IL-15 increased the effector function of intratumoral CD4+GzmB+ T cells. In addition to IL-15, owing to the unique expression profile of PD-1 and CD85j in tumor-infiltrating CD4+GzmB+ T cells, using patient-derived lung cancer explants, we showed that simultaneous blockade of PD-1 and CD85j promoted the effector function of CD4+GzmB+ T cells by activating the AKT pathway. Importantly, using a mouse model of lung cancer, we demonstrated that intrinsic MHC II expression in cancer cells determines the significance of CD4+GzmB+ T-cell-mediated antitumor immunity in response to immunotherapy.
Project description:A number of reports have demonstrated that tumor-intrinsic mechanisms of resistance, such as the loss of genes critical for antigen presentation and inflammatory responses, along with the activation of various cellular signaling cascades, can limit the efficacy of immunotherapy. Strategies to sensitize tumor cells to immunotherapy may overcome some resistance mechanisms, but identifying therapeutic targets has remained challenging. Here, we integrate a two-cell type (2CT) whole-genome CRISPR-Cas9 screen with dynamic transcriptional profiling of the tumor/T cell interaction to comprehensively identify tumor genes that are induced to promote tumor survival. We assessed the therapeutic potential of pharmacological inhibition of these and other top CRISPR identified targets as combinatorial targets to improve the efficacy of tumor destruction by T cells.