触发Ferroptosis增加KRAS突变型肺腺癌化疗敏感性的机制探究

Targeted therapy for KRAS mutation driven Lung adenocarcinoma hasn’t been found yet, platinum-doublet chemotherapy remains the first choice. Apoptosis escape is an important cause of low response of chemotherapy. Ferroptosis is a brand new type of cell death completely different from apoptosis in genetic, biochemical and signaling features, which might overcome tumor resistance to chemo-induced apoptosis and improve the response. Our prophase study confirmed that cisplatin could simultaneously induce apoptosis as well as ferroptosis, and its anti-tumor activity was enhanced in combination with ferroptosis inducer erastin, this phenomenon was obvious in KRAS mutation driven lung adenocarcinoma cells. KRAS was considered involving in iron metabolism through RAF/MEK/ERK signaling. Therefore, we proposed that ferroptosis activation could improve the chemosensitivity of KRAS mutation driven lung adenocarcinoma and KRAS regulated RAF/MEK/ERK signaling was involved in this process. This research aims to verify the chemosensitivity of ferroptosis on KRAS mutation driven lung adenocarcinoma and further investigate the underlying mechanism. The completion of this study is of great theoretical significance in exploring the application of ferroptosis inducers in anti-tumor therapy and provides new model of treatment for KRAS mutation driven Lung adenocarcinoma.

KRAS突变肺腺癌现无有效靶向治疗，含铂双药化疗是标准方案。凋亡逃逸是化疗有效率低的重要原因。Ferroptosis（铁死亡）是全新细胞死亡方式，具有完全不同于凋亡的基因表达、调控和信号转导系统，可能克服部分肿瘤对化疗诱导凋亡的抗拒，实现化疗增敏。前期研究发现顺铂能够同时触发细胞凋亡和铁死亡，联用铁死亡诱导剂Erastin表现出显著增强的抗肿瘤效应，在KRAS突变肺腺癌细胞中较为显著。文献发现KRAS参与细胞铁代谢调节，可能与RAF/MEK/ERK信号通路有关。因此我们提出假设：触发铁死亡能够增强KRAS突变肺腺癌化疗敏感性，KRAS下游RAF/MEK/ERK信号通路参与这一过程的调控。本研究将从体内外验证铁死亡对KRAS突变肺腺癌化疗增敏作用，并从分子水平探求KRAS调控这一过程的内在机制。本项目对探索铁死亡诱导剂在肿瘤治疗中的应用有重要理论意义，有利于拓展KRAS突变肺腺癌治疗模式。

KRAS突变型肺腺癌预后差，目前治疗方案仍以化疗为主。凋亡逃逸是化疗有效率低的重要原因。铁死亡是全新细胞死亡方式，具有完全不同于凋亡的基因表达、调控和信号转导系统，可能克服部分肿瘤对化疗诱导凋亡的抗拒，实现化疗增敏。前期研究发现，在KRAS突变肺腺癌细胞中，顺铂能够同时触发细胞凋亡和铁死亡，联用铁死亡诱导剂erastin能够增强抗肿瘤效应。本研究通过检测细胞活性、GSH水平、GPX酶活性、脂质ROS水平等指标，多方面验证了铁死亡诱导剂对化疗药物的增敏作用；构建H1299 KRAS WT/KRAS G12D细胞，分析细胞间的差异表达基因，推测EPAS1基因在触发KRAS G12D突变肺腺癌细胞铁死亡过程中发挥关键作用；利用公共数据库分析铁死亡相关基因在肺腺癌组织与正常组织中的表达差异，提示相比于正常肺组织，铁死亡在肺癌组织中可能处于受抑制的状态。同时收集了123例初诊KRAS突变型肺腺癌患者的临床信息及NGS检测结果，待完成病理标本的免疫组化检测和生存随访后进行统计分析。本项目验证了铁死亡诱导剂对化疗药物的增敏作用，推测EPAS1基因是触发KRAS G12D突变肺腺癌细胞铁死亡的重要因素，为进一步探索铁死亡诱导剂在KRAS突变型肺腺癌中的临床应用提供了一定理论依据。