Ack1介导新型EGFR三代抑制剂120067耐药机制研究

The first-generation EGFR inhibitors, such as gefitinib and erlotinib, have been proved for the treatment of non-small cell lung cancer (NSCLC) containing EGFR sensitizing mutations. However, acquired resistance limits the clinical use of the first-generation EGFR inhibitors, of which EGFR T790M point mutation is the most leading cause of resistance (>50%). Therefore, the development of the third-generation EGFR inhibitors that selectively inhibit the EGFR T790M mutation while sparing EGFR WT has become a hot spot for NSCLC treatment. Compound 120067 is a novel third-generation EGFR inhibitor developed by our research group. It effectively inhibits the EGFR T790M resistant mutation and EGFR sensitizing mutations while exhibits less potency on EGFR WT, which shows activity and selectivity comparable to that of AZD9291, the only third-generation EGFR inhibitor approved by the US Food and Drug Administration (FDA) for the treatment of EGFR T790M+ NSCLC patients. 120067 with good pharmacokinetic properties has been developed into Phase I /II clinical trial in China, and exhibits great clinical safety and effects..In our previous work, we had successfully constructed 120067 resistant H1975 cells lines and subcutaneous xenografts. By analyzing the difference between the resistant cells and the parental cells, a totally new resistance biomarker Ack1 was discovered and the preliminary mechanism studies had been performed. In this research, we are going to study on the function of Ack1 as well as its upstream and downstream molecules, explore its mechanisms mediating resistance to 120067, identify effective strategies to overcome drug resistance and carry out clinical verification. The study will not only lay the foundation for clinical strategies to overcome 120067 resistance and provide new ideas for the clinical rational drug use of other third generation EGFR inbitors, but also highlight the potential value of Ack1 in drug resistance and provide the basis for Ack1 as a novel target for antitumor therapy in NSCLC.

EGFR T790M突变是EGFR一代抑制剂耐药最主要的原因（>50%），有效抑制该突变的三代抑制剂是新的研究热点。120067是本课题组合作开发的具有我国自主知识产权的EGFR三代抑制剂，其活性与选择性与上市药物AZD9291相当，并在I/II期临床研究显示出了良好的安全耐受性和治疗效果。. 本课题围绕120067展开新耐药生物标志物的发现和机制研究。通过耐药与亲本细胞差异分析，发现了全新的耐药标志分子Ack1。本项目将深入研究Ack1及其上下游分子在耐药中的作用，探讨Ack1介导耐药的具体机制，确定克服耐药的有效联用策略并进行临床验证。旨在确证120067关键的新耐药生物标志物，以更好地指导其临床合理用药，推进其临床研发进程，并为同类抑制剂耐药机制研究提供参考，也为Ack1作为NSCLC治疗潜在新靶点提供思路。

表皮生长因子受体（EGFR）是非小细胞肺癌（NSCLC）治疗的经典靶标，有效抑制EGFR T790M突变和EGFR激活突变而对野生型EGFR（EGFR WT）抑制活性较弱的EGFR三代抑制剂成为了NSCLC治疗的重要策略，但其获得性耐药问题仍然不可避免，其新耐药机制及克服耐药策略研究也受到广泛关注。.ASK120067（120067）是本团队合作研发的新型EGFR三代抑制剂，目前已经获得新药上市申请（NDA）受理，有望开发成具有我国自主知识产权的抗肿瘤新药。在开展新药研发和临床评价的同时，本课题前瞻性地开展了EGFR三代抑制剂新耐药机制及克服耐药策略的研究。在前期构建了ASK120067耐药肺癌细胞株，发现耐药肿瘤中Ack1异常活化支持肿瘤生长和耐药的基础上，深入开展机制研究，发现活化的Cdc42相关激酶1 （Ack1） 通过激活下游AKT信号通路下调促凋亡蛋白Bim表达，介导耐药细胞凋亡抵抗；ASK120067联用Ack1抑制剂可协同抑制p-AKT，诱导BIM表达，体内外逆转耐药。该研究表明Ack1是介导EGFR三代抑制剂耐药的重要分子，为EGFR抑制剂耐药NSCLC的治疗具提供了潜在靶标。鉴于目前的Ack1抑制剂存在活性弱或选择性差等缺陷，本项目也开展了Ack1选择性抑制剂的开展，目前已经筛选优化获得多个新结构高活性Ack1抑制剂，正在开展体内抗肿瘤作用评价。. 同时针对临床确证的EGFR三代抑制剂主要耐药突变EGFR C797S（10-26%），本研究也开展了有效克服该突变的新一代抑制剂（EGFR四代抑制剂）的研发，利用构建的EGFR四代抑制剂筛选平台，与化学家合作、设计、筛选获得了多个新结构高活性化合物。. 综上，本项目以自主研发的候选新药ASK120067为分子探针，一方面揭示了Ack1旁路激活介导EGFR三代抑制剂耐药的具体分子机制，找到了克服耐药的潜在联用策略，为ASK120067临床合理用药、延缓和克服耐药提供依据。另一方面针对临床确证的ASK120067及其他三代抑制剂新的耐药突变EGFR C797S，开发了多个新结构高活性四代抑制剂，为开发克服该耐药突变的候选药物奠定基础。