Project description:Current anti-cancer therapies cannot eliminate all the cancer cells, which hijack normal arginine methylation as a means to promote their own maintenance via unknown mechanisms. Herein, we show that targeting protein arginine methyltransferase 9 (PRMT9), whose activities are elevated in leukemia stem cells (LSCs) from patients with acute myeloid leukemia (AML), eliminates disease via cancer-intrinsic mechanisms and cancer-extrinsic Type-I Interferon (IFN-I)-associated immunity. PRMT9 ablation in AML cells decreased arginine methylation of regulators of RNA translation and the DNA damage response, suppressing cell survival. Notably, PRMT9 inhibition promoted DNA damage and activated cGAS, which underlies the IFN-I response. Genetically activating cGAS in AML cells blocked leukemogenesis. We also report synergy of a PRMT9 inhibitor with anti-PD1 in eradicating PRMT9-proficient cancers, including AML and lymphoma. We conclude that PRMT9 governs LSCs survival and immune evasion, and that combining a PRMT9 inhibitor with an immune checkpoint inhibitor represents a novel anti-cancer strategy.
Project description:Current anti-cancer therapies cannot eliminate all the cancer cells, which hijack normal arginine methylation as a means to promote their own maintenance via unknown mechanisms. Herein, we show that targeting protein arginine methyltransferase 9 (PRMT9), whose activities are elevated in leukemia stem cells (LSCs) from patients with acute myeloid leukemia (AML), eliminates disease via cancer-intrinsic mechanisms and cancer-extrinsic Type-I Interferon (IFN-I)-associated immunity. PRMT9 ablation in AML cells decreased arginine methylation of regulators of RNA translation and the DNA damage response, suppressing cell survival. Notably, PRMT9 inhibition promoted DNA damage and activated cGAS, which underlies the IFN-I response. Genetically activating cGAS in AML cells blocked leukemogenesis. We also report synergy of a PRMT9 inhibitor with anti-PD1 in eradicating PRMT9-proficient cancers, including AML and lymphoma. We conclude that PRMT9 governs LSCs survival and immune evasion, and that combining a PRMT9 inhibitor with an immune checkpoint inhibitor represents a novel anti-cancer strategy.
Project description:Current anti-cancer therapies cannot eliminate all the cancer cells, which hijack normal arginine methylation as a means to promote their own maintenance via unknown mechanisms. Herein, we show that targeting protein arginine methyltransferase 9 (PRMT9), whose activities are elevated in leukemia stem cells (LSCs) from patients with acute myeloid leukemia (AML), eliminates disease via cancer-intrinsic mechanisms and cancer-extrinsic Type-I Interferon (IFN-I)-associated immunity. PRMT9 ablation in AML cells decreased arginine methylation of regulators of RNA translation and the DNA damage response, suppressing cell survival. Notably, PRMT9 inhibition promoted DNA damage and activated cGAS, which underlies the IFN-I response. Genetically activating cGAS in AML cells blocked leukemogenesis. We also report synergy of a PRMT9 inhibitor with anti-PD1 in eradicating PRMT9-proficient cancers, including AML and lymphoma. We conclude that PRMT9 governs LSCs survival and immune evasion, and that combining a PRMT9 inhibitor with an immune checkpoint inhibitor represents a novel anti-cancer strategy.
Project description:One of the most common metabolic defects of cancer cells is the deficiency in arginine synthesis due to suppressed expression of argininosuccinate synthetase 1 (ASS1) which renders cancer cells auxotrophic to external arginine supply. Arginine deprivation has been effectively used as a treatment for leukemias, with several clinical trials on solid tumors underway. We previously showed that in prostate cancer arginine depletion induced mitochondrial dysfunction and excessive ROS production resulting in chromatin autophagy, nuclear DNA leakage, and cellular death, but the detailed mechanism of arginine starvation-induced cell death remains unclear. In this study, we demonstrated that arginine deprivation coordinately suppressed metabolic genes, including those responsible for mitochondrial oxidative phosphorylation (OXPHOS), nucleotide metabolism, and DNA repair. The consequent ROS production and impaired DNA damage response resulted in nuclear DNA leakage and cGAS-STING activation which is accompanied by upregulation of type I interferon response. We also showed that coordinated silencing of OXPHOS and DNA repair genes is caused in part by the depletion of α-ketoglutarate (αKG) and inactivation of histone demethylases. Supplementing cell-permeable dimethyl α-ketoglutarate (DMKG) both reduced repressive histone methylations and partially restored OXPHOS gene expressions, mitochondrial functions, and mitigated nuclear DNA leakage. Using our dietary arginine-restriction model, we demonstrate that arginine starvation slows prostate cancer growth with evidence of enhanced interferon responses and recruitment of immune cells. Our data suggests arginine starvation induces cell killing of ASS1-low cancer cells by metabolic depletion and epigenetic silencing of metabolic genes, leading to DNA damage and leakage. Resulting cGAS-STING activation may further enhance these killing effects. We used microarray to analyze the expression difference between control and arginine-depleted cells to find out what genes involved in the regulation of mitochondrial function and arginine deprivation-induced cell death.
Project description:One of the most common metabolic defects of cancer cells is the deficiency in arginine synthesis due to suppressed expression of argininosuccinate synthetase 1 (ASS1) which renders cancer cells auxotrophic to external arginine supply. Arginine deprivation has been effectively used as a treatment for leukemias, with several clinical trials on solid tumors underway. We previously showed that in prostate cancer arginine depletion induced mitochondrial dysfunction and excessive ROS production resulting in chromatin autophagy, nuclear DNA leakage, and cellular death, but the detailed mechanism of arginine starvation-induced cell death remains unclear. In this study, we demonstrated that arginine deprivation coordinately suppressed metabolic genes, including those responsible for mitochondrial oxidative phosphorylation (OXPHOS), nucleotide metabolism, and DNA repair. The consequent ROS production and impaired DNA damage response resulted in nuclear DNA leakage and cGAS-STING activation which is accompanied by upregulation of type I interferon response. We also showed that coordinated silencing of OXPHOS and DNA repair genes is caused in part by the depletion of α-ketoglutarate (αKG) and inactivation of histone demethylases. Supplementing cell-permeable dimethyl α-ketoglutarate (DMKG) both reduced repressive histone methylations and partially restored OXPHOS gene expressions, mitochondrial functions, and mitigated nuclear DNA leakage. Using our dietary arginine-restriction model, we demonstrate that arginine starvation slows prostate cancer growth with evidence of enhanced interferon responses and recruitment of immune cells. Our data suggests arginine starvation induces cell killing of ASS1-low cancer cells by metabolic depletion and epigenetic silencing of metabolic genes, leading to DNA damage and leakage. Resulting cGAS-STING activation may further enhance these killing effects.
Project description:Arginine starvation elicits chromatin leakage and cGAS-STING activation via epigenetic silencing of metabolic and DNA-repair genes.
Project description:Arginine starvation elicits chromatin leakage and cGAS-STING activation via epigenetic silencing of metabolic and DNA-repair genes [microarray]