Project description:Elucidating the mechanisms by which immune cells become dysfunctional in tumors is critical to developing next-generation immunotherapies. We profiled proteomes of cancer cells, monocyte/macrophages, CD4+ and CD8+ T cells, and NK cells isolated from tumors, liver, and blood of 48 patients with hepatocellular carcinoma. We found that tumor macrophages induce the sphingosine-1-phospate-degrading enzyme SGPL1, which dampened their inflammatory phenotype and anti-tumor function in vivo. We further discovered that the signaling scaffold protein AFAP1L2, typically only found in activated NK cells, is also upregulated in chronically stimulated CD8+ T cells in tumors. Ablation of AFAP1L2 in CD8+ T cells increased their viability upon repeated stimulation and enhanced their antitumor activity synergistically with PD-L1 blockade in mouse models. Our data revealed new targets for immunotherapy and provide a resource on immune cell proteomes in liver cancer (www.immunomics.ch/liver).
Project description:Recent work has shown that cytotoxic T cells play a central role in immune-mediated control of cancers1-3, and monoclonal antibodies that target inhibitory receptors on T cells can induce significant clinical benefit in patients despite advanced disease4-6. However, many of the regulatory pathways that result in loss of T cell function within immunosuppressive tumors remain unknown. Here we show that such regulatory mechanisms can be systematically discovered in vivo in the tumor microenvironment. We devised a pool shRNA screening approach aimed at identifying genes that block the function of tumor-infiltrating CD8 T cells. We postulated that shRNAs targeting key inhibitors would enable robust T cell infiltration and proliferation in tumors, despite multiple inhibitory signals. Candidate shRNAs were discovered by transfer of shRNA-transduced T cells into tumor-bearing mice, followed by deep sequencing to quantify the representation of all hairpins in tumors and lymphoid organs. A subset of shRNAs induced T cell accumulation in tumors but not the spleen, demonstrating feasibility of discovering shRNAs with differential action across tissues. One of the targets was Ppp2r2d, a regulatory subunit of the family of PP2A phosphatases7. Control shRNA-transduced T cells underwent apoptosis upon recognition of melanoma cells, while Ppp2r2d shRNA-transduced T cells accumulated in tumors due to enhanced proliferation and reduced apoptosis. Ppp2r2d shRNAexpressing T cells also significantly delayed tumor growth. This in vivo approach has wide applications to dissect complex immune functions in relevant tissue microenvironments. OT-I derived T cells were transduced with shRNA's and adoptively transferred to B16 tumor bearing mice. Following incubation the T cells were purified from either tumors or spleens. The shRNA's targeted either a control gene (LacZ) or one of 5 selected genes found to regulate the presence of T cells in tumors vs in spleen
Project description:Elucidating the mechanisms by which immune cells become dysfunctional in tumors is critical to developing next-generation immunotherapies. We profiled proteomes of cancer cells, as well as monocyte/macrophages, and CD4+ and CD8+ T cells isolated from tumors, livers, and blood of 48 patients with hepatocellular carcinoma. We found that tumor macrophages induce the sphingosine-1-phospate-degrading enzyme SGPL1, which dampened their inflammatory phenotype and anti-tumor function in vivo. We further discovered that the signaling scaffold protein AFAP1L2 is upregulated in chronically activated CD8+ T cells in tumors but is not present during the canonical T cell activation program. Ablation of AFAP1L2 in CD8+ T cells increased their viability upon repeated stimulation and enhanced their antitumor activity synergistically with PD-L1 blockade in mouse models. Our data revealed new targets for immunotherapy and provide a resource on immune cell proteomes in liver cancer (www.immunomics.ch/liver).
Project description:Recent work has shown that cytotoxic T cells play a central role in immune-mediated control of cancers1-3, and monoclonal antibodies that target inhibitory receptors on T cells can induce significant clinical benefit in patients despite advanced disease4-6. However, many of the regulatory pathways that result in loss of T cell function within immunosuppressive tumors remain unknown. Here we show that such regulatory mechanisms can be systematically discovered in vivo in the tumor microenvironment. We devised a pool shRNA screening approach aimed at identifying genes that block the function of tumor-infiltrating CD8 T cells. We postulated that shRNAs targeting key inhibitors would enable robust T cell infiltration and proliferation in tumors, despite multiple inhibitory signals. Candidate shRNAs were discovered by transfer of shRNA-transduced T cells into tumor-bearing mice, followed by deep sequencing to quantify the representation of all hairpins in tumors and lymphoid organs. A subset of shRNAs induced T cell accumulation in tumors but not the spleen, demonstrating feasibility of discovering shRNAs with differential action across tissues. One of the targets was Ppp2r2d, a regulatory subunit of the family of PP2A phosphatases7. Control shRNA-transduced T cells underwent apoptosis upon recognition of melanoma cells, while Ppp2r2d shRNA-transduced T cells accumulated in tumors due to enhanced proliferation and reduced apoptosis. Ppp2r2d shRNAexpressing T cells also significantly delayed tumor growth. This in vivo approach has wide applications to dissect complex immune functions in relevant tissue microenvironments.
Project description:Elucidating the mechanisms by which immune cells become dysfunctional in tumors is critical to developing next-generation immunotherapies. We profiled proteomes of cancer cells, as well as monocyte/macrophages, and CD4+ and CD8+ T cells isolated from tumors, livers, and blood of 48 patients with hepatocellular carcinoma. We found that tumor macrophages induce the sphingosine-1-phospate-degrading enzyme SGPL1, which dampened their inflammatory phenotype and anti-tumor function in vivo. We further discovered that the signaling scaffold protein AFAP1L2 is upregulated in chronically activated CD8+ T cells in tumors but is not present during the canonical T cell activation program. Ablation of AFAP1L2 in CD8+ T cells increased their viability upon repeated stimulation and enhanced their antitumor activity synergistically with PD-L1 blockade in mouse models. Our data revealed new targets for immunotherapy and provide a resource on immune cell proteomes in liver cancer (www.immunomics.ch/liver).
Project description:Immunotherapy with chimeric antigen receptor T cells for pediatric solid and brain tumors is constrained by available targetable antigens. Cancer-specific exons present a promising reservoir of targets; however, these have not been explored and validated systematically in a pan-cancer fashion. To identify cancer specific exon targets, we analyze 1,532 RNA-seq datasets from 16 types of pediatric solid and brain tumors for comparison with normal tissues using a newly developed workflow. We find 2,933 exons in 157 genes encoding proteins of the surfaceome or matrisome with high cancer specificity either at the gene (n=148) or the alternatively spliced isoform (n=9) level. Expression of selected alternatively spliced targets, including the EDB domain of fibronectin 1, and gene targets, such as COL11A1, are validated in pediatric patient derived xenograft tumors. We generate T cells expressing chimeric antigen receptors specific for the EDB domain or COL11A1 and demonstrate that these have antitumor activity. The full target list, explorable via an interactive web portal (https://cseminer.stjude.org/), provides a rich resource for developing immunotherapy of pediatric solid and brain tumors using gene or AS targets with high expression specificity in cancer.