Fu Siyuan, Sun Dapeng, Wang Zongyan, Zhu Peng, Ding Wenbin, Huang Jian, Guo Xinggang, Yang Yun, Gu Fangming
The Third Department of Hepatic Surgery, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University (Naval Medical University), Shanghai, China.
Cancer Biother Radiopharm. 2024 Dec;39(10):745-754. doi: 10.1089/cbr.2023.0186. Epub 2024 Sep 12.
Accumulating studies reveal that mA RNA methylation plays a critical role in cancer pathogenesis and progression. METTL3 as a mA methyltransferase acts as an oncogene in multiple malignancies including hepatocellular carcinoma (HCC). However, the role and underlying mechanism by which METTL3 contributes to HCC remains unclear. The association of METTL3 expression with clinicopathological characteristics and prognosis in patients with HCC was assessed by reverse transcription polymerase chain reaction, Western blot, and public TCGA dataset. MTT, colony formation, Transwell assays, and xenograft tumor models were executed to reveal the role of METTL3 in HCC. mA dot blot, RNA immunoprecipitation (RIP), mA methylated RIP, and Western blot assays were used to uncover the regulatory mechanism of METTL3 in HCC cells. We found that METTL3 was dramatically upregulated in HCC tissue samples and acted as an independent prognostic factor for poor survival and tumor recurrence in patients with HCC. Silencing of METTL3 repressed cell growth and invasion and , but restored expression of METTL3 boosted these effects. Mechanistical investigations revealed that METTL3 could directly interact with FMRP and harbor a positive correlation with FMRP expression. Knockdown of METTL3 reduced FMRP mA levels as well as its mRNA and protein expression. FMRP overexpression drove cell colony formation and cell invasion and abolished METTL3 knockdown-induced antitumor effects and AKT/mTORC1 signaling inactivation. Elevated expression of FMRP could act as an independent prognostic factor for poor survival and tumor recurrence in patients with HCC. Our findings demonstrate that METTL3-mediated mA modification of FMRP promotes growth and invasion of HCC cells and may provide a promising therapeutic target for HCC.
越来越多的研究表明，m⁶A RNA甲基化在癌症的发生和发展中起关键作用。METTL3作为一种m⁶A甲基转移酶，在包括肝细胞癌（HCC）在内的多种恶性肿瘤中发挥癌基因的作用。然而，METTL3促进HCC发生发展的作用及潜在机制仍不清楚。通过逆转录聚合酶链反应、蛋白质免疫印迹法以及公共的TCGA数据集评估METTL3表达与HCC患者临床病理特征及预后的相关性。采用MTT法、集落形成实验、Transwell实验以及异种移植瘤模型来揭示METTL3在HCC中的作用。利用m⁶A斑点杂交、RNA免疫沉淀（RIP）、m⁶A甲基化RIP以及蛋白质免疫印迹实验来揭示METTL3在HCC细胞中的调控机制。我们发现，METTL3在HCC组织样本中显著上调，并且是HCC患者生存不良和肿瘤复发的独立预后因素。敲低METTL3可抑制细胞生长和侵袭，而恢复METTL3的表达则增强这些效应。机制研究表明，METTL3可直接与FMRP相互作用，且与FMRP表达呈正相关。敲低METTL3可降低FMRP的m⁶A水平及其mRNA和蛋白质表达。FMRP过表达促进细胞集落形成和细胞侵袭，并消除了METTL3敲低诱导的抗肿瘤作用以及AKT/mTORC1信号失活。FMRP表达升高可作为HCC患者生存不良和肿瘤复发的独立预后因素。我们的研究结果表明，METTL3介导的FMRP的m⁶A修饰促进了HCC细胞的生长和侵袭，可能为HCC提供一个有前景的治疗靶点。
