Caveolin-1/β3-integrin通路在生物电微环境影响EGFR-TKI耐药中的作用和机制

Tumor microenvironment(TME) plays an important role in regulation of EGFR-TKI resistance in lung cancer. Endogenous bio-electric fields (EFs) is an important component of TME, while little is known about its influence on TKI resistance. Supported by the previous NSFC, we have conducted research on electrical control of lung cancer invasion and directional migration. We have found: ① Endogenous EFs existed on the surface of lung cancer xenografts, and the EF magnitude on xenografts of TKI-resistant cells is larger than that of the TKI-sensitive cells; ② EF stimulation upregulated the anti-apoptotic ability of TKI-sensitive lung cancer cells, induced EMT, and decreased TKI-induced apoptosis; ③ EF stimulation increased expression of Caveolin-1 and phosphoralyted Caveolin-1 in TKI-sensitive lung cancer cells. Previously, it was reported that integrin played a role in sensing EFs, while β3-integrin/NF-kB pathway was involved in TKI resistance. Caveolin-1 was able to modulate integrin expression, distribution and trafficing. Thus, we speculate that bio-EFs may control EGFR-TKI resistance through activation of β3-integrin/NF-kB pathway and EMT. The current project aims to find out the key mechanism of electrical control of TKI resistance, thus providing new approaches to solve the problem of EGFR-TKI resistance in lung cancer.

肿瘤微环境是影响肺癌EGFR-TKI耐药的重要因素。内源性生物电场是肿瘤微环境重要组成部分，但其是否影响TKI耐药尚不明确。我们在前一个国家自然科学基金研究生物电调控肺癌侵袭的过程中发现：①肺癌细胞移植瘤表面存在内源性生物电场，且TKI耐药细胞移植瘤表面电场强度显著大于敏感细胞移植瘤；②生物电上调TKI敏感肺癌细胞抗凋亡能力，诱导EMT，减弱TKI杀伤作用；③电刺激上调微囊蛋白Caveolin-1（Cav-1）表达，增强其活化。有研究表明，整合素（integrin）与细胞应答生物电信号有关，且β3-integrin/NF-kB通路参与调控TKI耐药。整合素的表达、分布及转运均接受Cav-1调控。据此推测，生物电可能通过活化Cav-1/β3-integrin通路，引起肺癌EMT及TKI耐药。本项目旨在明确肺癌应答生物电发生TKI耐药的关键分子机制，为解决肺癌TKI耐药难题提供理论基础与思路。

肿瘤微环境是影响肺癌EGFR-TKI耐药的重要因素。内源性生物电场是肿瘤微环境重要组成部分，但其是否影响TKI耐药，机制如何，尚无报道。本研究系统性研究了生物电信号对肺癌EGFR-TKI敏感性的调控作用及其分子机制，取得了以下系列发现：（1）生物电刺激(100mV/mm)显著减弱第三代EGFR-TKI奥希替尼对肺癌细胞的杀伤作用，增强了肺癌细胞的增殖能力和抗凋亡能力；（2）生物电刺激诱导肺癌细胞发生上皮间叶转化，且依赖于AKT活化；（3）全转录组分析提示，生物电显著改变奥希替尼对肺癌基因表达的调控作用，KEGG分析提示PI3K-AKT为生物电刺激后变化最明显的信号通路；（4）生物电场显著减弱奥希替尼对AKT活化的抑制作用；而抑制AKT活化可显著减弱生物电信号的促增殖和抗凋亡效应，并削弱其减弱奥希替尼杀伤的效应；（5）生物电刺激显著活化AKT/FOXO3a/Bim信号通路，上调磷酸化FOXO3a的水平，减弱非磷酸化FOXO3a入核，进而下调Bim表达，增强肺癌细胞的抗凋亡能力，减弱奥希替尼杀伤。本研究通过系列细胞生物学和分子生物学实验，首次证实肿瘤微环境中的生物电信号是影响肺癌EGFR-TKI疗效的重要因素，其通过活化AKT，促FOXO3a磷酸化，减弱非磷酸化FOXO3a入核，降低Bim表达，最终影响奥希替尼的杀伤。本研究为深入理解肿瘤微环境调控肺癌靶向治疗耐药的机制，研发增强肺癌靶向治疗耐药的新策略提供了实验证据。