DNMT1介导的MEI启动子甲基化在卵巢癌紫杉醇耐药中的作用及机制研究

卵巢癌是妇科肿瘤中死亡率最高的肿瘤，导致其高死亡率的主要原因是化疗药物紫杉醇耐药的发生。耐药的发生机制十分复杂，涉及多个基因、多种通路，目前尚未完全阐明。我们实验室长期致力于紫杉醇耐药机制的相关研究，2020年发表文章显示代谢关键酶G6PD介导细胞代谢重组可诱导紫杉醇耐药的发生。而我们在随后实验中发现另一关键代谢酶苹果酸酶1（ME1）在耐药细胞中高表达；高表达ME1催化NADPH大量生成，抑制活性氧杀伤作用，促进紫杉醇耐药的发生。同期研究结果提示低表达DNA甲基化转移酶（DNMT1）激活ME1转录表达。为此我们提出假设：在卵巢癌耐药细胞中，DNMT1通过调节ME1启动子区域DNA甲基化水平，促进ME1表达，从而抵御紫杉醇引起的活性氧杀伤作用。本项目拟采用免疫印迹、Co-IP、ChIP-qPCR等方法从细胞、动物模型及临床水平深入探索ME1促进卵巢癌耐药的分子机制，为耐药治疗提供新策略。

Ovarian cancer has the highest mortality in gynecological tumors. The main cause of its high mortality is the occurrence of paclitaxel resistance. The mechanism of drug resistance is complex, involving multiple genes and different pathways, which has not been fully elucidated. Our laboratory has been focus on the mechanism of paclitaxel resistance for long time, and published articles in 2020 show that G6PD, a key metabolic enzyme, can induce the occurrence of paclitaxel resistance. In our subsequent experiments, we found that another key metabolic enzyme, malic acid enzyme 1 (ME1), was highly expressed in drug-resistant cells; ME1 could catalyze NADP+ to NADPH, protect ovarian cancer cells from the killing effect of reactive oxygen species, and promote the paclitaxel resistance. At the same time, our results also suggest that low expression of DNMT1 can activate ME1 transcription. Therefore, we hypothesized that DNMT1 could promote the expression of ME1 by regulating the DNA methylation level of ME1 promoter region in ovarian cancer drug-resistant cells, so as to defense the reactive oxygen species induced by paclitaxel. In this project, Western blotting, CO-IP, ChIP-qPCR and other methods are used to explore the molecular mechanism of ME1 promoting drug resistance in ovarian cancer from the cellular, animal model and clinical level, so that we can provide new strategies for drug resistance treatment.