分泌型Cripto1在含有EGFR敏感突变肺腺癌患者对EGFR-TKI原发耐药中的作用研究

Despite impressive clinical response to EGFR-TKI (TKI), approximately 30% of lung adenocarcinoma patients harboring EGFR-sensitizing mutations exhibit primary resistance. Until now there is no effective predictor marker for TKI primary resistance. Recently, one study reported that Cripto1 (CR1) expression in EGFR-mutant NSCLC elicits TKI primary resistance through Src activation. CR1 can be present in membrane-bound and secreted form, however, the role of secreted CR1 in TKI primary resistance was still unknown. Our preliminary work showed that secreted CR1 could also induce TKI primary resistance. The aim of this study was to further investigate the mechanism of TKI primary resistance induced by secreted CR1 and explore whether the level of secreted CR1 in peripheral blood could be a predictive marker for TKI primary resistance. Moreover, we will further uncover the mechanism of TKI primary resistance, and it was also possible to provide noninvasive detection for TKI primary resistance to guide the treatment for EGFR-mutant lung adenocarcinoma patients, which may have important clinical value.

尽管EGFR-TKI（TKI）对具有EGFR突变的肺腺癌患者疗效显著，但是仍然还有约30%的EGFR敏感突变的肺腺癌患者对TKI的首次治疗无效，并且缺乏预测分子标志物。最近研究报道，Cripto1(CR1)通过激活Src诱导EGFR突变的肺癌细胞对TKI原发耐药。CR1既能锚定到细胞膜上也能分泌到细胞外，但分泌型CR1在TKI原发耐药中的作用并不清楚。我们前期研究证实分泌型CR1也能诱导TKI原发耐药。本课题中，拟进一步研究分泌型CR1蛋白导致EGFR突变肺癌细胞对TKI原发耐药的机制，探讨外周血中CR1蛋白水平是否可作为预测EGFR突变患者对TKI敏感性的预测因子，我们的研究不仅会进一步阐明TKI首次治疗EGFR突变肺腺癌患者无效的分子机制，也可能为TKI耐药提供无创检测分子标志物指导EGFR突变肺腺癌患者的治疗，具有重要的临床应用价值。

EGFR突变常见于亚洲肺腺癌患者，具有这些突变的大部分肺癌患者对EGFR-TKI药物敏感，但是仍然还有约30%的EGFR突变的肺癌患者对EGFR-TKI的首次治疗无效，此外，获得性耐药的出现使得EGFR-TKI药物疗效时间仅仅维持一年左右，本项目旨在进一步为 EGFR-TKI 耐药患者的治疗提供潜在的治疗方案，为精确 EGFR-TKI 的获益人群提供更好的标尺。我们建立了EGFR-TKI耐药的肺腺癌细胞系，收集了EGFR-TKI耐药前后的肺腺癌组织样本，筛选鉴定出耐药相关的lncRNA H19，并通过体内外模型研究了H19在EGFR-TKI耐药中发挥的作用和潜在调控机制。结果发现H19是一种发生获得性EGFR-TKI耐药时显著下调的lncRNA，H19调低或过表达分别在体外和体内模型中影响其耐药性或敏感性。H19下调通过与PKM2相互作用和上调PKM2的表达促进AKT磷酸化，从而导致EGFR-TKI耐药，AKT抑制剂可以恢复EGFR-TKI耐药细胞对EGFR-TKI的敏感性。在接受EGFR-TKI治疗的EGFR突变患者中，低H19水平与较短的无进展生存期(PFS)相关(P=0.021)。这些发现揭示了低水平的H19在EGFR突变肺癌中调节EGFR-TKI耐药性的新机制，AKT抑制剂联合EGFR-TKIs治疗EGFR突变肺癌可能是一种合理的治疗方法。我们的研究不仅揭示了lncRNA在调控肺腺癌EGFR-TKI耐药中的重要作用，也为克服EGFR-TKI耐药提供了潜在的治疗方案。