Project description:The histone variant macroH2A has been implicated as a tumor suppressor in melanoma and other cancers, yet its role in the tumor microenvironment remains unappreciated. Here we show that mice constitutively lacking macroH2A variants exhibit increased melanoma tumor burden compared to their wild-type counterparts, which is associated with an altered intratumoral immune cell compartment. MacroH2A-deficient tumors display an accumulation of immunosuppressive monocytes and decreased functional cytotoxic T cells. Consistent with this compromised anti-tumor response, macroH2A-deficient tumors displayed upregulation of chemokines such as Ccl2, Cxcl1 and Il6. Through single cell transcriptomics of the entire melanoma microenvironment, we identified the source of these pro-tumor myeloid chemoattractants as cancer-associated fibroblasts, whose frequency and activation were increased in the absence of macroH2A. Chemokine gene expression was hyper-inducible in the absence of macroH2A and accompanied by an altered epigenetic landscape. In sum, we uncovered a tumor suppressive role for macroH2A through repression of chemokine induction in the tumor stroma.
Project description:The histone variant macroH2A has been implicated as a tumor suppressor in melanoma and other cancers, yet its role in the tumor microenvironment remains unappreciated. Here we show that mice constitutively lacking macroH2A variants exhibit increased melanoma tumor burden compared to their wild-type counterparts, which is associated with an altered intratumoral immune cell compartment. MacroH2A-deficient tumors display an accumulation of immunosuppressive monocytes and decreased functional cytotoxic T cells. Consistent with this compromised anti-tumor response, macroH2A-deficient tumors displayed upregulation of chemokines such as Ccl2, Cxcl1 and Il6. Through single cell transcriptomics of the entire melanoma microenvironment, we identified the source of these pro-tumor myeloid chemoattractants as cancer-associated fibroblasts, whose frequency and activation were increased in the absence of macroH2A. Chemokine gene expression was hyper-inducible in the absence of macroH2A and accompanied by an altered epigenetic landscape. In sum, we uncovered a tumor suppressive role for macroH2A through repression of chemokine induction in the tumor stroma.
Project description:The histone variant macroH2A has been implicated as a tumor suppressor in melanoma and other cancers, yet its role in the tumor microenvironment remains unappreciated. Here we show that mice constitutively lacking macroH2A variants exhibit increased melanoma tumor burden compared to their wild-type counterparts, which is associated with an altered intratumoral immune cell compartment. MacroH2A-deficient tumors display an accumulation of immunosuppressive monocytes and decreased functional cytotoxic T cells. Consistent with this compromised anti-tumor response, macroH2A-deficient tumors displayed upregulation of chemokines such as Ccl2, Cxcl1 and Il6. Through single cell transcriptomics of the entire melanoma microenvironment, we identified the source of these pro-tumor myeloid chemoattractants as cancer-associated fibroblasts, whose frequency and activation were increased in the absence of macroH2A. Chemokine gene expression was hyper-inducible in the absence of macroH2A and accompanied by an altered epigenetic landscape. In sum, we uncovered a tumor suppressive role for macroH2A through repression of chemokine induction in the tumor stroma.
Project description:MacroH2A has tumor suppressive functions in melanoma and other cancers, yet its role in the tumor microenvironment remains unappreciated. Using an autochthonous, immunocompetent mouse model of melanoma, we demonstrate that mice devoid of macroH2A variants exhibit increased tumor burden compared to wild type counterparts. MacroH2A-deficient tumors accumulate immunosuppressive monocytes and decreased functional cytotoxic T cells, and consistent with this compromised anti-tumor response, exhibit upregulation of pro-inflammatory cytokines. Single cell transcriptomics not only identifies cancer-associated fibroblasts (CAFs), whose frequency and activation increase in the absence of macroH2A, as the source of myeloid chemoattractants but also demonstrates dedifferentiation along the neural crest lineage of the tumor compartment. CAFs lacking macroH2A display hyper-inducible inflammatory gene expression and promoters of these genes present increased chromatin looping to enhancers that gain H3K27ac. In sum, we reveal a tumor suppressive role for macroH2A variants through regulation of chromatin architecture of inflammatory genes in the tumor stroma with potential implications for human melanoma.
Project description:MacroH2A has tumor suppressive functions in melanoma and other cancers, yet its role in the tumor microenvironment remains unappreciated. Using an autochthonous, immunocompetent mouse model of melanoma, we demonstrate that mice devoid of macroH2A variants exhibit increased tumor burden compared to wild type counterparts. MacroH2A-deficient tumors accumulate immunosuppressive monocytes and decreased functional cytotoxic T cells, and consistent with this compromised anti-tumor response, exhibit upregulation of pro-inflammatory cytokines. Single cell transcriptomics not only identifies cancer-associated fibroblasts (CAFs), whose frequency and activation increase in the absence of macroH2A, as the source of myeloid chemoattractants but also demonstrates dedifferentiation along the neural crest lineage of the tumor compartment. CAFs lacking macroH2A display hyper-inducible inflammatory gene expression and promoters of these genes present increased chromatin looping to enhancers that gain H3K27ac. In sum, we reveal a tumor suppressive role for macroH2A variants through regulation of chromatin architecture of inflammatory genes in the tumor stroma with potential implications for human melanoma.