METTL14-mediated N6-methyladenosine modification of SOX4 mRNA inhibits tumor metastasis in colorectal cancer
METTL14-mediated N6-methyladenosine modification of SOX4 mRNA inhibits tumor metastasis in colorectal cancer
复制标题
N6-甲基腺苷修饰SOX 4基因抑制大肠癌转移
DOI：
10.1186/s12943-020-01220-7
复制
发表时间：
2020-06-17
期刊：
影响因子：
37.3
通讯作者：
Wang, Shukui
中科院分区：
文献类型：
--
作者：
Chen, Xiaoxiang;Xu, Mu;Wang, Shukui
背景：结直肠癌（Colorectal cancer，CRC）是世界范围内肿瘤相关死亡的主要原因之一，其主要死亡原因是远处转移。甲基转移酶样14（Methyltransferase-like 14，缩写为L14）是一种主要的RNA N6-腺苷甲基转移酶，通过调节RNA的功能参与肿瘤的进展。方法：采用实时荧光定量PCR（qRT-PCR）、免疫印迹（western blot）和免疫组化（IHC）方法检测结直肠癌细胞系和组织中的胃L14和SOX 4。通过体外和体内实验证实了胃L14的生物学功能。采用染色质免疫沉淀（ChIP）、跨膜RNA测序（RNA-Seq）、m6 A-RNA免疫沉淀测序（MeRIP-Seq）、RNA免疫沉淀和荧光素酶报告基因分析等方法探讨胃癌L14的作用机制。单因素和多因素考克斯回归分析均显示胃L14是影响结直肠癌预后的独立因素。此外，赖氨酸特异性组蛋白去甲基化酶5C（KDM 5C）介导的组蛋白H3赖氨酸4三甲基化（H3 K4 me 3）在胃L14的启动子中的去甲基化抑制胃L14的转录。在功能上，我们分别通过体外和体内试验验证了胃L14抑制CRC细胞的迁移、侵袭和转移。此外，我们确定SRY相关的高迁移率族蛋白盒4（SOX 4）是MHL 14介导的m6 A修饰的靶点。敲低胃L14可显著消除SOX 4 mRNA m6 A修饰和升高的SOX 4 mRNA表达。我们还发现，胃L14介导的SOX 4 mRNA降解依赖于YTHDF 2依赖性途径。结论：胃癌L14的表达降低促进了大肠癌的转移，提示胃癌L14可能是一个潜在的预后生物标志物和有效的治疗靶点。
Background: Colorectal cancer (CRC) is one of the leading causes of tumor-related death worldwide, and its main cause of death is distant metastasis. Methyltransferase-like 14(METTL14), a major RNA N6-adenosine methyltransferase, is involved in tumor progression via regulating RNA function. The goal of the study is to uncover the biological function and molecular mechanism of METTL14 in CRC.Methods: Quantitative real-time PCR (qRT-PCR), western blot and immunohistochemical (IHC) assays were employed to detect METTL14 and SOX4 in CRC cell lines and tissues. The biological functions of METTL14 were demonstrated using in vitro and in vivo experiments. Chromatin immunoprecipitation (ChIP), Transcrptomic RNA sequencing (RNA-Seq), m6A-RNA immunoprecipitation sequencing (MeRIP-Seq), RNA immunoprecipitation and luciferase reporter assays were used to explore the mechanism of METTL14 action.Results: METTL14 expression was significantly downregulated in CRC and decreased METTL14 was associated with poor overall survival (OS). Both the univariate and multivariate Cox regression analysis indicated that METTL14 was an independent prognostic factor in CRC. Moreover, lysine-specific histone demethylase 5C(KDM5C)-mediated demethylation of histone H3 lysine 4 tri-methylation(H3K4me3) in the promoter of METTL14 inhibited METTL14 transcription. Functionally, we verified that METTL14 inhibited CRC cells migration, invasion and metastasis through in vitro and in vivo assays, respectively. Furthermore, we identified SRY-related high-mobility-group box 4(SOX4) as a target of METTL14-mediated m6A modification. Knockdown of METTL14 markedly abolished SOX4 mRNA m6A modification and elevated SOX4 mRNA expression. We also revealed that METTL14-mediated SOX4 mRNA degradation relied on the YTHDF2-dependent pathway. Lastly, we demonstrated that METTL14 might inhibit CRC malignant process partly through SOX4-mediated EMT process and PI3K/Akt signals.Conclusions: Decreased METTL14 facilitates tumor metastasis in CRC, suggesting that METTL14 might be a potential prognostic biomarker and effective therapeutic target for CRC.