Jinlin Duan, Tao Chen, Qiwei Li, Yu Zhang, Ting Lu, Junyan Xue, Yang Sun, Ling Gao, Yonglong Zhang
{"title":"蛋白精氨酸甲基转移酶6通过STING途径增强免疫检查点阻断在mmr熟练的结直肠癌中的效果。","authors":"Jinlin Duan, Tao Chen, Qiwei Li, Yu Zhang, Ting Lu, Junyan Xue, Yang Sun, Ling Gao, Yonglong Zhang","doi":"10.1136/jitc-2024-010639","DOIUrl":null,"url":null,"abstract":"<p><strong>Background: </strong>The emergence of immunotherapy has revolutionized the paradigm of cancer treatment with immune checkpoint blockades (ICB) in solid cancers, including colorectal cancer (CRC). However, only a small subset of CRC patients harboring deficient mismatch repair (dMMR) or microsatellite instability-high (MSI-H) benefits from ICB therapy. A very limited response to ICB therapy has been achieved in MMR-proficient CRC, representing a significant challenge limiting the clinical application of immunotherapy. MMR is the critical DNA repair pathway that maintains genomic integrity by correcting DNA mismatches, which is mediated by the MutSα or MutSβ complex consisting of MSH2 with MSH6 and MSH3, respectively. Given that MMR status directs effective immune response, we sought to determine whether targeting MMR capacity boosts ICB efficacy.</p><p><strong>Methods: </strong>Azoxymethane/dextran sodium sulfate (AOM/DSS)-induced CRC and xenograft model were used to evaluate the function of PRMT6 and response to PRMT6 inhibitor EPZ020411 and combination therapy of PD1 and EPZ020411. Biochemical assays were performed to elucidate the underlying mechanism of PRMT6-mediated MSH2 methylation and immune evasion.</p><p><strong>Results: </strong>We have identified PRMT6 as a crucial regulator of MMR capacity via MSH2 dimethylation at R171 and R219. Such a modification abrogates its MMR capacity and prevents the recruitment of MSH3 and MSH6. PRMT6 loss or inhibition triggers cytosolic DNA accumulation and cGAS-STING signaling activation, leading to enhanced immune response in PRMT6-deficient colon tumors or xenografts. Pharmacological inhibition of PRMT6 using EPZ020411 promotes mutagenesis and destabilizes MutSα or MutSβ assembly, and prolonged EPZ020411 exposure maintains an MSI-like phenotype in microsatellite stability (MSS) cells. EPZ020411 treatment sensitizes ICB efficacy of MSS cells, but not MSI cells in vivo. Similar effects have been observed in MSS colon tumors induced by AOM/DSS.</p><p><strong>Conclusions: </strong>Our study provides a preclinical proof of concept to overcome resistance to immunotherapy by targeting PRMT6 in CRC with MSS.</p>","PeriodicalId":14820,"journal":{"name":"Journal for Immunotherapy of Cancer","volume":"13 3","pages":""},"PeriodicalIF":10.3000,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11907083/pdf/","citationCount":"0","resultStr":"{\"title\":\"Protein arginine methyltransferase 6 enhances immune checkpoint blockade efficacy via the STING pathway in MMR-proficient colorectal cancer.\",\"authors\":\"Jinlin Duan, Tao Chen, Qiwei Li, Yu Zhang, Ting Lu, Junyan Xue, Yang Sun, Ling Gao, Yonglong Zhang\",\"doi\":\"10.1136/jitc-2024-010639\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><strong>Background: </strong>The emergence of immunotherapy has revolutionized the paradigm of cancer treatment with immune checkpoint blockades (ICB) in solid cancers, including colorectal cancer (CRC). However, only a small subset of CRC patients harboring deficient mismatch repair (dMMR) or microsatellite instability-high (MSI-H) benefits from ICB therapy. A very limited response to ICB therapy has been achieved in MMR-proficient CRC, representing a significant challenge limiting the clinical application of immunotherapy. MMR is the critical DNA repair pathway that maintains genomic integrity by correcting DNA mismatches, which is mediated by the MutSα or MutSβ complex consisting of MSH2 with MSH6 and MSH3, respectively. Given that MMR status directs effective immune response, we sought to determine whether targeting MMR capacity boosts ICB efficacy.</p><p><strong>Methods: </strong>Azoxymethane/dextran sodium sulfate (AOM/DSS)-induced CRC and xenograft model were used to evaluate the function of PRMT6 and response to PRMT6 inhibitor EPZ020411 and combination therapy of PD1 and EPZ020411. Biochemical assays were performed to elucidate the underlying mechanism of PRMT6-mediated MSH2 methylation and immune evasion.</p><p><strong>Results: </strong>We have identified PRMT6 as a crucial regulator of MMR capacity via MSH2 dimethylation at R171 and R219. Such a modification abrogates its MMR capacity and prevents the recruitment of MSH3 and MSH6. PRMT6 loss or inhibition triggers cytosolic DNA accumulation and cGAS-STING signaling activation, leading to enhanced immune response in PRMT6-deficient colon tumors or xenografts. Pharmacological inhibition of PRMT6 using EPZ020411 promotes mutagenesis and destabilizes MutSα or MutSβ assembly, and prolonged EPZ020411 exposure maintains an MSI-like phenotype in microsatellite stability (MSS) cells. EPZ020411 treatment sensitizes ICB efficacy of MSS cells, but not MSI cells in vivo. Similar effects have been observed in MSS colon tumors induced by AOM/DSS.</p><p><strong>Conclusions: </strong>Our study provides a preclinical proof of concept to overcome resistance to immunotherapy by targeting PRMT6 in CRC with MSS.</p>\",\"PeriodicalId\":14820,\"journal\":{\"name\":\"Journal for Immunotherapy of Cancer\",\"volume\":\"13 3\",\"pages\":\"\"},\"PeriodicalIF\":10.3000,\"publicationDate\":\"2025-03-13\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11907083/pdf/\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal for Immunotherapy of Cancer\",\"FirstCategoryId\":\"3\",\"ListUrlMain\":\"https://doi.org/10.1136/jitc-2024-010639\",\"RegionNum\":1,\"RegionCategory\":\"医学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"IMMUNOLOGY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal for Immunotherapy of Cancer","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.1136/jitc-2024-010639","RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"IMMUNOLOGY","Score":null,"Total":0}
Protein arginine methyltransferase 6 enhances immune checkpoint blockade efficacy via the STING pathway in MMR-proficient colorectal cancer.
Background: The emergence of immunotherapy has revolutionized the paradigm of cancer treatment with immune checkpoint blockades (ICB) in solid cancers, including colorectal cancer (CRC). However, only a small subset of CRC patients harboring deficient mismatch repair (dMMR) or microsatellite instability-high (MSI-H) benefits from ICB therapy. A very limited response to ICB therapy has been achieved in MMR-proficient CRC, representing a significant challenge limiting the clinical application of immunotherapy. MMR is the critical DNA repair pathway that maintains genomic integrity by correcting DNA mismatches, which is mediated by the MutSα or MutSβ complex consisting of MSH2 with MSH6 and MSH3, respectively. Given that MMR status directs effective immune response, we sought to determine whether targeting MMR capacity boosts ICB efficacy.
Methods: Azoxymethane/dextran sodium sulfate (AOM/DSS)-induced CRC and xenograft model were used to evaluate the function of PRMT6 and response to PRMT6 inhibitor EPZ020411 and combination therapy of PD1 and EPZ020411. Biochemical assays were performed to elucidate the underlying mechanism of PRMT6-mediated MSH2 methylation and immune evasion.
Results: We have identified PRMT6 as a crucial regulator of MMR capacity via MSH2 dimethylation at R171 and R219. Such a modification abrogates its MMR capacity and prevents the recruitment of MSH3 and MSH6. PRMT6 loss or inhibition triggers cytosolic DNA accumulation and cGAS-STING signaling activation, leading to enhanced immune response in PRMT6-deficient colon tumors or xenografts. Pharmacological inhibition of PRMT6 using EPZ020411 promotes mutagenesis and destabilizes MutSα or MutSβ assembly, and prolonged EPZ020411 exposure maintains an MSI-like phenotype in microsatellite stability (MSS) cells. EPZ020411 treatment sensitizes ICB efficacy of MSS cells, but not MSI cells in vivo. Similar effects have been observed in MSS colon tumors induced by AOM/DSS.
Conclusions: Our study provides a preclinical proof of concept to overcome resistance to immunotherapy by targeting PRMT6 in CRC with MSS.
期刊介绍：
The Journal for ImmunoTherapy of Cancer (JITC) is a peer-reviewed publication that promotes scientific exchange and deepens knowledge in the constantly evolving fields of tumor immunology and cancer immunotherapy. With an open access format, JITC encourages widespread access to its findings. The journal covers a wide range of topics, spanning from basic science to translational and clinical research. Key areas of interest include tumor-host interactions, the intricate tumor microenvironment, animal models, the identification of predictive and prognostic immune biomarkers, groundbreaking pharmaceutical and cellular therapies, innovative vaccines, combination immune-based treatments, and the study of immune-related toxicity.
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