Li Nan, Jing Ying, Xu Long, Wang Maonan
Department of Gastroenterology, Jilin Province People's Hospital, Changchun, China.
Department of Abdominal Tumor Surgery, Jilin Cancer Hospital, Changchun, China.
Mol Carcinog. 2025 May;64(5):858-869. doi: 10.1002/mc.23892. Epub 2025 Feb 17.
METTL1, a well-established RNA methyltransferase for the N(7)-methylguanosine (m7G) methylation modification, is responsible for human tumorigenesis. Here, we aimed to examine the activity and molecular determinants of METTL1 in colorectal cancer (CRC) development. METTL1 and ribosomal RNA processing 9 (RRP9) mRNA analysis was performed by quantitative PCR. Protein expression was detected by immunoblotting and immunohistochemistry (IHC). Cell sphere formation, invasion, and proliferation were assessed by sphere formation, transwell, and MTT assays, respectively. Cell migration was tested by transwell and wound healing assays. Subcutaneous xenografts were produced to analyze the role in vivo. The influence of METTL1 in m7G methylation and stability of RRP9 mRNA was evaluated by methylated immunoprecipitation (MeRIP) assay and Actinomycin D (Act D) treatment, respectively. METTL1 was highly expressed in CRC tumors and cell lines. METTL1 depletion suppressed CRC cell proliferation, invasiveness, migratory ability, and sphere formation potential in vitro, while increased METTL1 expression had opposite effects. METTL1 positively correlated with RRP9 expression in CRC. Mechanistically, METTL1 promoted RRP9 mRNA stability by mediating its m7G methylation, and METTL1 regulated the PI3K/AKT signaling by RRP9. Increased RRP9 expression partially reversed the suppressive effects of METTL1 depletion on CRC cell phenotypes in vitro. METTL1 depletion impeded the growth of HCT-116 subcutaneous xenografts in vivo by RRP9. Our observations identified METTL1 as a crucial protumorigenic factor to drive growth, metastasis, and stemness of CRC cells through RRP9, offering new targets for combating CRC.
METTL1是一种公认的负责N(7)-甲基鸟苷（m7G）甲基化修饰的RNA甲基转移酶，与人类肿瘤发生有关。在此，我们旨在研究METTL1在结直肠癌（CRC）发生发展中的活性及分子决定因素。通过定量PCR进行METTL1和核糖体RNA加工9（RRP9）mRNA分析。通过免疫印迹和免疫组织化学（IHC）检测蛋白表达。分别通过成球实验、Transwell实验和MTT实验评估细胞成球、侵袭和增殖能力。通过Transwell实验和伤口愈合实验检测细胞迁移能力。制作皮下异种移植模型以分析其在体内的作用。分别通过甲基化免疫沉淀（MeRIP）实验和放线菌素D（Act D）处理评估METTL1对m7G甲基化和RRP9 mRNA稳定性的影响。METTL1在CRC肿瘤组织和细胞系中高表达。敲低METTL1可抑制CRC细胞在体外的增殖、侵袭能力、迁移能力和成球潜力，而增加METTL1表达则有相反作用。在CRC中，METTL1与RRP9表达呈正相关。机制上，METTL1通过介导RRP9的m7G甲基化促进其mRNA稳定性，且METTL1通过RRP9调节PI3K/AKT信号通路。增加RRP9表达可部分逆转敲低METTL1对CRC细胞体外表型的抑制作用。敲低METTL1可通过RRP9抑制HCT-116皮下异种移植瘤在体内的生长。我们的研究结果表明，METTL1是驱动CRC细胞生长、转移和干性的关键促肿瘤因子，通过RRP9发挥作用，为对抗CRC提供了新的靶点。
