Chatterjee Biswanath, Majumder Pritha, Chen Chun-Chang, Wang Jing-Ping, Su Po-Hsuan, Lai Hung-Cheng, Liu Ching-Chen, Lin Hsin-Nan, Yu Chen-Hsin A, Yuan Hanna S, Shen Che-Kun James
The PhD Program in Medical Neuroscience, Taipei Medical University, 12F, Education & Research Building, Shuang-Ho Campus, No. 301, Yuantong Road, Zhonghe District, New Taipei City, 235, Taiwan.
Institute of Molecular Biology, Academia Sinica, No. 128, Section 2, Academia Rd, Nangang District, Taipei City, 115, Taiwan.
Cell Mol Biol Lett. 2025 Aug 5;30(1):95. doi: 10.1186/s11658-025-00775-x.
Despite the comprehensive advancement in the field of cancer therapeutics, there remains an urgent need to identify new pathophysiological mechanisms that can be targeted in isolation or in combination with existing therapeutic regimens. The epithelial-to-mesenchymal transitions (EMT) induced by hypoxia, cytokines, and growth factors involves acquisition of invasive and migratory properties by cancer cells. Epigenetic alterations of DNA methylations and/or histone modifications cause substantial transcriptomic reprogramming in cancer cells during EMT and metastasis, which can be therapeutically targeted by a thorough understanding of the mutual interactions among the epigenetic processes. Previously, the mammalian DNA methyltransferases (DNMTs) have been shown to possess redox- and Ca- dependent active DNA 5mC demethylation activities in addition to the cytosine methylation activity.
In this study, we have carried out experiments using a range of molecular, cellular, and genome editing approaches including cell culturing, CRISPR/Cas9-editing, si- or sh-RNA-mediated knockdown, quantitative RT-PCR, western blotting, ChIP-qPCR, Na-bisulfite sequencing, EMT and lung colonization assays in conjunction with DNA methylome and DNMT3A ChIP-Seq analyses, RESULTS: We found that active DNA demethylation activity of DNMT3A is essential for hypoxia-induced EMT of the SW480 colon cancer cells, its global genomic DNA demethylation, and promoter DNA demethylation/transcriptional activation of EMT-associated genes including TWIST1 and SNAIL1. DNMT3A also regulates hypoxia-induced HIF-1α binding to and transcriptional activation of the TWIST1 promoter as well as genome-wide DNA demethylation and EMT of breast cancer and liver cancer cells. Mechanistic analysis supports a regulatory model where hypoxia-induced H3K36me3 mark recruits DNMT3A to demethylate CpG in the hypoxia-responsive element (HRE), thereby facilitating HIF-1α binding and activation of the promoters of EMT genes.
Altogether, this study has provided the first demonstration of a physiological function of the active DNA demethylation activity of the DNMTs. Equally important, our findings have revealed a missing link between the HIF-1α pathway and the O-sensing KDM pathway both of which are known to be essential for a wide set of normal and disease-associated cellular processes. Finally, the active DNA demethylation activity of DNMT3A has now emerged as a new potential target for therapeutic development to prevent EMT and metastasis of cancer cells.
Not applicable.
尽管癌症治疗领域取得了全面进展，但仍迫切需要确定新的病理生理机制，这些机制可单独或与现有治疗方案联合作为靶点。由缺氧、细胞因子和生长因子诱导的上皮-间质转化（EMT）涉及癌细胞获得侵袭和迁移特性。DNA甲基化和/或组蛋白修饰的表观遗传改变在EMT和转移过程中导致癌细胞大量转录组重编程，通过深入了解表观遗传过程之间的相互作用，可将其作为治疗靶点。此前，已证明哺乳动物DNA甲基转移酶（DNMTs）除了具有胞嘧啶甲基化活性外，还具有氧化还原和钙依赖性的活性DNA 5mC去甲基化活性。
在本研究中，我们使用了一系列分子、细胞和基因组编辑方法进行实验，包括细胞培养、CRISPR/Cas9编辑、si-或sh-RNA介导的敲低、定量RT-PCR、蛋白质印迹、ChIP-qPCR、亚硫酸氢钠测序、EMT和肺定植试验，以及DNA甲基化组和DNMT3A ChIP-Seq分析。
我们发现DNMT3A的活性DNA去甲基化活性对于SW480结肠癌细胞的缺氧诱导EMT、其全基因组DNA去甲基化以及包括TWIST1和SNAIL1在内的EMT相关基因的启动子DNA去甲基化/转录激活至关重要。DNMT3A还调节缺氧诱导的HIF-1α与TWIST1启动子的结合及其转录激活，以及乳腺癌和肝癌细胞的全基因组DNA去甲基化和EMT。机制分析支持一种调节模型，即缺氧诱导的H3K36me3标记招募DNMT3A去甲基化缺氧反应元件（HRE）中的CpG，从而促进HIF-1α与EMT基因启动子的结合和激活。
总之，本研究首次证明了DNMTs活性DNA去甲基化活性的生理功能。同样重要的是，我们的研究结果揭示了HIF-1α途径和氧感应KDM途径之间缺失的联系，这两条途径已知对广泛的正常和疾病相关细胞过程至关重要。最后，DNMT3A的活性DNA去甲基化活性现已成为预防癌细胞EMT和转移的治疗开发新的潜在靶点。
不适用。
