EGFR-AS1调控VEGF-A可变剪接促进肾癌TKI靶向药物耐药的作用及机制研究

Targeted therapy resistance in advanced renal cancer severely limits the efficacy of targeted drugs, and there is currently no breakthrough in the study of this mechanism. In the previous study of our team, the expression of lncRNA EGFR-AS1 associated with renal cancer metastasis was significantly increased in target resistant renal cell carcinoma tissues. Knockdown of EGFR-AS1 promoted the sensitivity of drug-resistant cell lines to targeted drugs. At the same time, EGFR-AS1 regulates the formation of VEGF-A alternative splicing by directly interacting with HNRNPH1, while the up-regulated expression of VEGF165 splicing induces the survival and drug resistance phenotype of renal cancer cells, which ultimately leads to the formation of drug resistance in renal cancer. Previous studies suggest that EGFR-AS1 may promote the development of targeted therapy resistance in renal cancer by regulating VEGF-A alternative splicing. Our study is intended to clarify the correlation between EGFR-AS1 and targeted therapy resistance from a large number of drug-resistant samples, and to analyze the molecular mechanism of EGFR-AS1 mediated by VEGF-A alternative splicing to target EGFR-AS1 – VEGF-A pathway molecule-based strategy for predicting and reversing resistance.

晚期肾癌的靶向耐药严重限制了靶向药物的疗效，目前对这一机制研究尚缺乏突破性的进展。项目组前期研究发现，与肾癌转移相关的lncRNA EGFR-AS1在靶向药物耐药的肾癌组织标本中表达显著升高，敲减EGFR-AS1能促进耐药细胞株对靶向药物的敏感性，同时EGFR-AS1通过直接与HNRNPH1相互作用调控VEGF-A可变剪接体形成，而上调表达的VEGF165剪接体诱导肾癌细胞存活和耐药表型，最终导致肾癌靶向药物耐药形成。研究发现EGFR-AS1可能通过调控VEGF-A可变剪接促进肾癌靶向药物耐药发生。本项目拟从大量耐药组织标本明确EGFR-AS1与靶向药物耐药的相关性，解析EGFR-AS1通过VEGF-A可变剪接调控靶向耐药的分子机制，建立以靶向EGFR-AS1 – VEGF-A通路分子为基础的预测和逆转耐药的策略。

近年来，在世界范围内肾细胞癌(RCC)的发生率逐年上升。靶向药物治疗成为晚期肾癌的重要治疗方式。但靶向药物耐药严重限制了药物的疗效，目前对这一机制研究尚缺乏突破性的进展和逆转耐药的靶点。鉴于EGFR-AS1在肾癌中的重要作用，我们推测EGFR-AS1可能参与了靶向药物耐药的发生。研究发现lncRNA EGFR-AS1在靶向药物耐药的肾癌组织标本中表达显著升高，并且与肾癌的不良预后密切相关。EGFR-AS1的下调能减弱耐药细胞株对靶向药物的耐药性。相反，EGFR-AS1的过表达增强了耐药细胞株的耐药性。从机理上讲，EGFR-AS1与RNA剪接蛋白HNRNPH1存在直接相互作用，并能调控VEGF-A可变剪接体的形成倾向。上调表达的VEGF165剪接体能够促进肾癌细胞存活和耐药表型，最终导致肾癌靶向药物耐药形成。EGFR-AS1/ HNRNPH1通过调节VEGF-A可变剪接产生VEGF165，并通过自分泌形式，促进细胞的存活和耐药表型，诱导肾癌靶向药物耐药的形成。此外，本研究也探索了RNA甲基化酶在肾癌转移中的重要作用。METTL14在肾癌组织中明显下调表达，是肾癌患者的独立预后因素。研究发现METTL14通过YTHDF2依赖的RNA降解途径抑制lncRNA NEAT1表达，进而抑制肿瘤的增殖和转移。同时课题组构建了多个基于肾癌大数据分子特征为基础的肾癌预后模型，为肾癌预后判断提供了工具。以上研究结果对于进一步明确肾癌发展、转移和耐药机制提供了新的思路，同时为进一步早期诊断、逆转耐药、预后预测提供了新的理论指导，具有重要的科学意义。本项目资助下，以第一/通讯作者发表SCI论文4篇；协助培养硕士研究生3名，完成肾癌相关毕业论文3项。