NR5A2促进NSCLC抵抗EGFR-TKI治疗的作用与机制

EGFR-TKI has become the standard treatment for advanced lung adenocarcinoma habouring EGFR mutations, whereas patients who are effective are eventually resistant. The mechanism of TKI resistance is very complicated, and the molecules and signaling pathways involved in drug resistance regulation have not yet been fully elucidated. Therefore, to further explore the key regulatory factors in the process of drug resistance is of great significance. The preliminary experiment of this project selected NR5A2 from EGFR-TKI resistant cells and discovered that NR5A2 up-regulated PKM2 levels and activated glucose metabolism signaling pathway and thus induced cell resistance. Meanwhile , we found upstream CDK16 play a regulatory role on NR5A2. Therefore, this research intends to investigate the effect of CDK16 / NR5A2 / PKM2 signal chain on the resistance of EGFR-TKI at the molecular, cellular and animal levels. Besidies, clarify the effect of CDK16 on the stability and transcriptional activity of NR5A2 and elucidate the regulatory mechanism of NR5A2 on the promoter of PKM2 gene. Finally, take NR5A2 as a target and to verify the treatment efficacy of NR5A2 inhibitors combined with EGFR-TKI. This project will eventually provide a new theory for the mechanism of TKI resistance in lung cancer and provide a new feasible target for the future development of new therapies.

EGFR-TKI已成为治疗晚期EGFR突变肺腺癌患者的标准治疗药物，然而治疗有效的患者最终都产生耐药。TKI耐药机制十分复杂，参与耐药调控的分子及信号通路仍未被完全阐明。本项目预实验在肺癌EGFR-TKI耐药细胞中筛选出NR5A2；发现NR5A2上调PKM2水平、激活葡萄糖代谢信号通路诱导细胞耐药，上游CDK16对NR5A2具有调控作用。这些结果提示新的通路介导了TKI耐药。因此，本课题拟从分子、细胞以及动物水平多层次探讨CDK16/NR5A2/PKM2信号链对EGFR-TKI抵抗的调控作用；明确CDK16对NR5A2的稳定性及转录活性的影响，阐明NR5A2对PKM2基因启动子的调控机制；最后以NR5A2为靶点，验证NR5A2抑制剂联合EGFR-TKI的治疗效果。本项目将最终为肺癌TKI耐药机制提供新的理论，为将来开发新药物提供新的可行性靶点。

TKI耐药是肺癌临床治疗失败的重要原因，耐药癌细胞糖代谢增强是导致耐药的重要机制之一。然而目前促进癌细胞糖代谢的基因报道的较少。挖掘相关癌基因，并针对这些靶点开发靶向抑制剂药物对降低肺癌耐药的发生有着十分重要的意义。本项目中发现NR5A2促进了肺癌TKI耐药，并且证明了CDK16/NR5A2/PKM2信号链通过增强糖代谢水平介导耐药。具体研究发现如下：1.通过细胞实验证实了NR5A2通过对靶基因PKM2的调控促进肺癌TKI耐药；2.发现了NR5A2结合在PKM2启动子区的DNA序列。3.定位了影响NR5A2转录活性的氨基酸位点S243和S238。4.发现CDK16可与NR5A2相互作用调节NR5A2入核并促进其转录活性。5.验证了PKM2是介导CDK16增强NSCLC对吉非替尼耐药的关键分子。6.发现NR5A2反向激动剂联合TKI具有显著的协同杀伤TKI耐药肺癌细胞的作用。总之本课题的完成为肺癌TKI耐药机制提供新的理论，为肺癌提供潜在的诊断标志物及药物治疗靶点。