YTHDC2通过对YAP mRNA的m6A修饰调控NSCLC铁死亡机制研究

The expression level of YAP in cancers are up-regulated and closely related to tumorigenesis. The downstream mechanism of YAP dependent transcription factors to promote tumour development have been clearly studied. However, the self-regulation mechanism of YAP, such as the regulation of m6A modification, is still unclear. We have found that the expression level of m6A binding protein YTHDC2 was down-regulated in non-small cell lung cancer (NSCLC). Knockdown of YTHDC2 can inhibit m6A modification of YAP mRNA while prevent YAP mRNA from degradation. Such effects attenuated ferroptosis induced by ferroptosis activator Erastin. Furthermore, knockdown of YAP also can promote ferroptosis in NSCLC cells. Therefore, we hypothesis that YTHDC2 can mediate YAP mRNA degradation by regulating YAP mRNA m6A modification to finally promote NSCLC ferroptosis. In this project, we will perform cell-based, mouse-based experiments and test clinical NSCLC tissue samples to reveal whether and how YTHDC2 promote NSCLC ferroptosis through regulating YAP mRNA m6A modification. Thereby, this project will also provide a reliable theoretical basis for the development of new anticancer drugs targeting against ferroptosis.

肿瘤内癌蛋白YAP表达上调，且与肿瘤发生发展密切相关，尽管YAP依赖转录因子的下游促瘤机制研究较为明确，但YAP自身调控机制，如转录后m6A修饰调控等尚不明确。申请人前期研究发现非小细胞肺癌（NSCLC）中m6A结合蛋白YTHDC2表达下调。敲减YTHDC2能抑制YAP mRNA发生m6A修饰，阻止YAP mRNA降解，且可削弱铁死亡激活剂Erastin诱导的铁死亡；进一步研究发现敲减YAP也可促进NSCLC细胞铁死亡。因此，我们提出如下假说：YTHDC2可通过调控YAP mRNA的m6A修饰介导YAP mRNA降解，最终促进NSCLC铁死亡。本课题拟利用体外细胞实验、体内小鼠实验和临床组织标本检测三个层面探索YTHDC2调控YAP mRNA的m6A修饰介导NSCLC铁死亡的分子机制，为临床以铁死亡为靶点开发抗肿瘤新药提供可靠的理论依据。

RNA甲基化在肺腺癌发生发展中的作用机制尚不清楚。本项目从体外细胞实验、体内小鼠实验和临床组织标本检测三个层面探索了YTHDC2 以m6A依赖的方式促进肺腺癌铁死亡的分子机制，并初步揭示了相关信号通路在肺腺癌发生发展中的重要性。项目主要研究结果为：1）发现YTHDC2通过靶向SLC7A11依赖的抗氧化作用抑制肺腺癌发生发展；2）发现YTHDC2通过靶向SLC3A2诱导肺腺癌中内源性铁死亡的机制；3）发现敲减YAP促进肺腺癌铁死亡，而YTHDC2以m6A依赖的方式降低YAP的稳定性，靶向YAP mRNA m6A修饰可能有助于肺腺癌治疗；4）发现YAP m5C修饰增加了YAP mRNA稳定性，并促进肺腺癌外泌体分泌相关基因Mycn和SOX10依赖性转录；5）开发了二维蛭石纳米片用于肺腺癌的铁死亡治疗的分子机制。本项目借助于对YTHDC2促进肺腺癌铁死亡的分子机制的研究，一定程度上阐明了转录水平RNA甲基化修饰对于肺腺癌发生发展的重要意义，明确了YTHDC2以m6A依赖的方式抑制SCL7A11、SLC3A2、HOXA13和YAP mRNAs，从而促进肺腺癌铁死亡的潜在机制，这一调控机制与肺腺癌发生发展和临床预后密切相关。总之，本项目的研究成果能够为肺腺癌诊断标志物的开发以及靶向治疗策略的设计提供新的思路，具有从基础研究向临床转化的现实意义。