METTL3 promotes an immunosuppressive microenvironment in bladder cancer via m6A-dependent CXCL5/CCL5 regulation
Background Bladder cancer (BLCA) is a challenging malignancy with a poor prognosis, particularly in muscle-invasive cases. Despite recent advancements in immunotherapy, response rates remain suboptimal. This study investigates the role of METTL3, an m6A RNA methylation “writer,” in regulating the im...
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| Format: | Article |
| Language: | English |
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BMJ Publishing Group
2025-04-01
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| Series: | Journal for ImmunoTherapy of Cancer |
| Online Access: | https://jitc.bmj.com/content/13/4/e011108.full |
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| author | Jian Wu Kun Tang Yu He Zhihua Wang Zhiqiang Chen Ding Xia Yonghua Tong Qiu Huang Haojie Shang Ejun Peng Xiaoyu Liang |
| author_facet | Jian Wu Kun Tang Yu He Zhihua Wang Zhiqiang Chen Ding Xia Yonghua Tong Qiu Huang Haojie Shang Ejun Peng Xiaoyu Liang |
| author_sort | Jian Wu |
| collection | DOAJ |
| description | Background Bladder cancer (BLCA) is a challenging malignancy with a poor prognosis, particularly in muscle-invasive cases. Despite recent advancements in immunotherapy, response rates remain suboptimal. This study investigates the role of METTL3, an m6A RNA methylation “writer,” in regulating the immune microenvironment of BLCA.Methods Through bioinformatics analysis, we identified METTL3 as being associated with the formation of an immunosuppressive microenvironment in BLCA and poor response to immunotherapy. Subsequently, we silenced METTL3 expression in BLCA cells using short hairpin RNA (shRNA) or inhibited its function with STM2457. The effectiveness of these interventions in remodeling the BLCA tumor microenvironment (TME) was confirmed through animal experiments and flow cytometry. Mechanistically, RNA sequencing and methylated RNA immunoprecipitation (MeRIP) sequencing revealed the molecular pathways by which METTL3 regulates the TME. This was further validated using in vitro cell co-culture, immunoprecipitation, ELISA, and RNA degradation assays. The synergistic effect of METTL3 with anti-Programmed Cell Death Protein 1 (PD-1) treatment in BLCA was confirmed in both orthotopic and ectopic BLCA animal models.Results METTL3 was found to increase CXCL5 levels and suppress CCL5 expression in an m6A-dependent manner, leading to increased recruitment of myeloid-derived suppressor cells (MDSCs) and reduced infiltration of CD8+T cells. Silencing METTL3 or inhibiting its function restored immune cell balance and significantly enhanced the efficacy of anti-PD-1 therapy. Clinically, METTL3 overexpression correlated with poor complete response rate to immune checkpoint inhibitors (ICIs) therapy, associated with an immunosuppressive microenvironment characterized by elevated MDSC levels and reduced CD8+T cell infiltration.Conclusions These findings highlight METTL3 as a key regulator of the immune microenvironment in BLCA and a promising therapeutic target to improve immunotherapy outcomes. Targeting METTL3 could potentially enhance the efficacy of ICIs in patients with BLCA. |
| format | Article |
| id | doaj-art-db896cdbd32c4331a7d2e62c5de5a505 |
| institution | OA Journals |
| issn | 2051-1426 |
| language | English |
| publishDate | 2025-04-01 |
| publisher | BMJ Publishing Group |
| record_format | Article |
| series | Journal for ImmunoTherapy of Cancer |
| spelling | doaj-art-db896cdbd32c4331a7d2e62c5de5a5052025-08-20T02:11:50ZengBMJ Publishing GroupJournal for ImmunoTherapy of Cancer2051-14262025-04-0113410.1136/jitc-2024-011108METTL3 promotes an immunosuppressive microenvironment in bladder cancer via m6A-dependent CXCL5/CCL5 regulationJian Wu0Kun Tang1Yu He2Zhihua Wang3Zhiqiang Chen4Ding Xia5Yonghua Tong6Qiu Huang7Haojie Shang8Ejun Peng9Xiaoyu Liang101 Department of Urology, Huazhong University of Science and Technology, Wuhan, China1 Department of Urology, Huazhong University of Science and Technology, Wuhan, China1 Department of Urology, Huazhong University of Science and Technology, Wuhan, China1 Department of Urology, Huazhong University of Science and Technology, Wuhan, China1 Department of Urology, Huazhong University of Science and Technology, Wuhan, China1 Department of Urology, Huazhong University of Science and Technology, Wuhan, China1 Department of Urology, Huazhong University of Science and Technology, Wuhan, China1 Department of Urology, Huazhong University of Science and Technology, Wuhan, China1 Department of Urology, Huazhong University of Science and Technology, Wuhan, China1 Department of Urology, Huazhong University of Science and Technology, Wuhan, China2 State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangzhou, Guangdong, ChinaBackground Bladder cancer (BLCA) is a challenging malignancy with a poor prognosis, particularly in muscle-invasive cases. Despite recent advancements in immunotherapy, response rates remain suboptimal. This study investigates the role of METTL3, an m6A RNA methylation “writer,” in regulating the immune microenvironment of BLCA.Methods Through bioinformatics analysis, we identified METTL3 as being associated with the formation of an immunosuppressive microenvironment in BLCA and poor response to immunotherapy. Subsequently, we silenced METTL3 expression in BLCA cells using short hairpin RNA (shRNA) or inhibited its function with STM2457. The effectiveness of these interventions in remodeling the BLCA tumor microenvironment (TME) was confirmed through animal experiments and flow cytometry. Mechanistically, RNA sequencing and methylated RNA immunoprecipitation (MeRIP) sequencing revealed the molecular pathways by which METTL3 regulates the TME. This was further validated using in vitro cell co-culture, immunoprecipitation, ELISA, and RNA degradation assays. The synergistic effect of METTL3 with anti-Programmed Cell Death Protein 1 (PD-1) treatment in BLCA was confirmed in both orthotopic and ectopic BLCA animal models.Results METTL3 was found to increase CXCL5 levels and suppress CCL5 expression in an m6A-dependent manner, leading to increased recruitment of myeloid-derived suppressor cells (MDSCs) and reduced infiltration of CD8+T cells. Silencing METTL3 or inhibiting its function restored immune cell balance and significantly enhanced the efficacy of anti-PD-1 therapy. Clinically, METTL3 overexpression correlated with poor complete response rate to immune checkpoint inhibitors (ICIs) therapy, associated with an immunosuppressive microenvironment characterized by elevated MDSC levels and reduced CD8+T cell infiltration.Conclusions These findings highlight METTL3 as a key regulator of the immune microenvironment in BLCA and a promising therapeutic target to improve immunotherapy outcomes. Targeting METTL3 could potentially enhance the efficacy of ICIs in patients with BLCA.https://jitc.bmj.com/content/13/4/e011108.full |
| spellingShingle | Jian Wu Kun Tang Yu He Zhihua Wang Zhiqiang Chen Ding Xia Yonghua Tong Qiu Huang Haojie Shang Ejun Peng Xiaoyu Liang METTL3 promotes an immunosuppressive microenvironment in bladder cancer via m6A-dependent CXCL5/CCL5 regulation Journal for ImmunoTherapy of Cancer |
| title | METTL3 promotes an immunosuppressive microenvironment in bladder cancer via m6A-dependent CXCL5/CCL5 regulation |
| title_full | METTL3 promotes an immunosuppressive microenvironment in bladder cancer via m6A-dependent CXCL5/CCL5 regulation |
| title_fullStr | METTL3 promotes an immunosuppressive microenvironment in bladder cancer via m6A-dependent CXCL5/CCL5 regulation |
| title_full_unstemmed | METTL3 promotes an immunosuppressive microenvironment in bladder cancer via m6A-dependent CXCL5/CCL5 regulation |
| title_short | METTL3 promotes an immunosuppressive microenvironment in bladder cancer via m6A-dependent CXCL5/CCL5 regulation |
| title_sort | mettl3 promotes an immunosuppressive microenvironment in bladder cancer via m6a dependent cxcl5 ccl5 regulation |
| url | https://jitc.bmj.com/content/13/4/e011108.full |
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