miR-145-5p靶向调控c-myc促进食管癌细胞铁死亡的分子机制研究

Ferroptosis is a newly discovered programmed cell death in recent years, and the induction of ferroptosis is likely to be a new method for cancer therapy. Our previous work found that overexpression of miR-145-5p significantly increased the sensitivity of esophageal squamous cell carcinoma cells to erastin or RSL3 induced ferroptosis, and down-regulated the expression of c-myc, and silencing c-myc and miR-145-5p overexpression had the similar effects that silencing c-myc also significantly increased the sensitivity of esophageal squamous cell carcinoma cells to erastin or RSL3 induced ferroptosis. In this project, we will further study the molecular mechanism of miR-145-5p promoting the erastin and RSL3 induced ferroptosis via targeting and regulating c-myc; determining whether overexpression of miR-145-5p or c-myc silencing could sensitize esophageal squamous cell carcinoma cells to erastin or RSL3 induced ferroptosis; clarifying the correlation of the expressions of key members in miR-145-5p pathway in primary ESCC tumors, as well as the relationship of these proteins with clinico-pathological parameters and the prognosis of ESCC patients. This project will help provide theoretical foundation for elucidating the mechanisms of the ferroptosis of ESCC cells, and explore the new therapeutic method targeting ferroptosis for ESCC.

铁死亡是近年新发现的程序性细胞死亡方式，诱导铁死亡有望成为抗肿瘤治疗新策略。我们前期发现过表达miR-145-5p可增加食管癌细胞对erastin和RSL3诱发铁死亡的敏感性，并下调c-myc的表达，同时沉默c-myc可增加食管癌细胞对erastin和RSL3诱发铁死亡的敏感性。本项目将利用细胞系、动物模型和食管癌临床标本深入研究miR-145-5p靶向调控c-myc，进而促进erastin和RSL3诱导的食管癌细胞铁死亡的详细分子机制；利用动物模型研究过表达miR-145-5p和沉默c-myc是否能增敏erastin和RSL3诱导的食管癌细胞铁死亡；明确食管癌临床标本中miR-145-5p通路各分子的异常表达相关性、以及与临床病理参数和预后的关系。本研究将为阐明食管癌细胞铁死亡的调控机制提供理论依据，并探索靶向铁死亡的抗食管癌治疗新方法。

铁死亡是近年新发现的程序性细胞死亡方式，诱导铁死亡有望成为抗肿瘤治疗新策略。在前期研究工作的基础上，本项目研究发现miR-145-5p在食管癌组织中表达降低；过表达miR-145-5p抑制食管癌细胞的克隆形成能力，并增加食管癌细胞对RSL3诱导铁死亡的敏感性；miR-145-5p负调控食管癌细胞中GPX4的蛋白水平，不影响其mRNA水平；过表达miR-145-5p下调食管癌细胞中PKCiota的mRNA和蛋白表达水平；沉默PKCiota抑制食管癌细胞的生长，并诱导食管癌细胞铁死亡；PKCiota在食管癌组织中表达升高，且PKCiota基因拷贝数增加是引起mRNA表达上调的重要原因；PKCiota调控GPX4蛋白的自噬降解过程；PKCiota通过结合并活化去泛素化酶USP14，降低GPX4的泛素化，增加食管癌细胞中GPX4的蛋白水平；沉默PKCiota增加食管癌细胞对RSL3诱导铁死亡的敏感性；过表达miR-145-5p或沉默PKCiota均抑制食管癌细胞KYSE510的成瘤能力。这些发现进一步阐明了miR-145-5p在食管癌细胞铁死亡中的调控机制，并为基于铁死亡的抗食管癌治疗提供新的策略和方法。