Abstract：
Multiple epigenetic regulatory mechanisms exert critical roles in tumor development, and understanding the interactions and impact of diverse epigenetic modifications on gene expression in cancer is crucial for the development of precision medicine. We found that methyltransferase-like 14 (METTL14) was significantly downregulated in non-small-cell lung cancer (NSCLC) tissues. Functional experiments demonstrated that overexpression of METTL14 inhibited the proliferation and migration of NSCLC cells both in vivo and in vitro, and the colorimetric m6A quantification assay also showed that knockdown of METTL14 notably reduced global m6A modification levels in NSCLC cells. By using the methylated-RNA immunoprecipitation-qPCR and dual-luciferase reporter assays, we verified that long noncoding RNA LINC02747 was a target of METTL14 and was regulated by METTL14-mediated m6A modification, and silencing LINC02747 inhibited the malignant progression of NSCLC by modulating the PI3K/Akt and CDK4/Cyclin D1 signaling pathway. Further studies revealed that overexpression of METTL14 promoted m6A methylation and accelerated the decay of LINC02747 mRNA via increased recognition of the \"GAACU\" binding site by YTHDC2. Additionally, histone demethylase lysine-specific histone demethylase 5B (KDM5B) mediated the demethylation of histone H3 lysine 4 tri-methylation (H3K4me3) in the METTL14 promoter region and repressed its transcription. In summary, KDM5B downregulated METTL14 expression at the transcriptional level in a H3K4me3-dependent manner, while METTL14 modulated LINC02747 expression via m6A modification. Our results demonstrate a synergy of multiple mechanisms in regulating the malignant phenotype of NSCLC, revealing the complex regulation involved in the occurrence and development of cancer.
摘要：
多种表观遗传调控机制在肿瘤发生发展中发挥关键作用，了解不同表观遗传修饰对癌症基因表达的相互作用和影响对精准医学的发展至关重要。我们发现，在非小细胞肺癌（NSCLC）组织中，甲基转移酶样14（METTL14）显着下调。功能实验表明，METTL14的过表达在体内和体外都能抑制NSCLC细胞的增殖和迁移。和比色m6A定量测定也显示METTL14敲低显著降低NSCLC细胞中整体m6A修饰水平。通过使用甲基化RNA免疫沉淀qPCR和双荧光素酶报告基因测定，我们验证了长链非编码RNALINC02747是METTL14的靶标，并且受到METTL14介导的m6A修饰的调节，沉默LINC02747通过调节PI3K/Akt和CDK4/CyclinD1信号通路抑制NSCLC的恶性进展。进一步的研究表明，METTL14的过表达促进了m6A甲基化，并通过增加YTHDC2对“GAACU”结合位点的识别来加速LINC02747mRNA的衰减。此外,组蛋白去甲基酶赖氨酸特异性组蛋白去甲基酶5B（KDM5B）在METTL14启动子区域介导组蛋白H3赖氨酸4三甲基化（H3K4me3）的去甲基化，并抑制其转录。总之,KDM5B以H3K4me3依赖性方式在转录水平下调METTL14表达，而METTL14通过m6A修饰调节LINC02747的表达。我们的结果证明了多种机制在调节NSCLC恶性表型方面的协同作用。揭示了癌症发生发展过程中的复杂调控。
