靶向间充质干细胞miR-26a和miR-146a克服非小细胞肺癌发生EGFR-TKI获得性耐药的机制

Drug resistance is the bottleneck of anti-cancer treatments. Our previous publications show that mesenchymal stem cells (MSC), as the progenitor of most stromal cells, play a vital role in the tumor growth, anti-apoptosis and acquired drug resistance (《Stem cells》 etc）. Currently, the drug resistance of EGFR-TKI is the most difficult challenge in the treatment of in non-small cell lung cancer (NSCLC). However, nearly all the studies of drug resistance focus on tumor cells but ignore the effect of tumor microenvironment. Our previous studies have demonstrated that NSCLC derived MSCs expressed a down-regulated miR-26a and an abnormally up-regulated miR-146a, which could induce NSCLC cells against EGFR-TKI gefitinib treatment. Therefore, we propose that tumor derived MSC, as the important component of tumor microenvironment, influences NSCLC cells resistance against EGFR-TKI via miR-26a and miR-146a mechanism. We plan to investigate the following isssues: 1) further exploring the molecular mechanisms for the abnormal expression of miR-26a and miR-146a from lung cancer derived MSCs and their protection effects; 2) exploring the liquid and tissue biomarkers for EGFR-TKI drug resistance; 3) Screening effective monoclonal antibodies, gene antagonists and small molecular TKIs to overcome EGFI-TKI drug resistance in NSCLC cell lines and xenograft mice. The anticipated results will contribute to explore the novel strategies for NSCLC EGFR-TKI drug resistance by targeting the tumor microenvironment, with a potentially translational value in clinical decision-making and treatment.

耐药问题是限制肿瘤治疗的瓶颈。申请人既往研究显示：间充质干细胞（MSC）在介导肿瘤的生长、抵抗凋亡和获得性耐药等发挥了重要作用（《Stem cells》等）。当前，通过靶向肿瘤微环境探讨非小细胞肺癌（NSCLC）发生EGFR-TKI的获得性耐药的研究报道较少。申请人前期研究发现，肺癌来源的MSC通过异常表达miR-26a和miR-146a调控促肿瘤细胞因子增强NSCLC细胞对EGFR-TKI的抗药性。因此提出“肿瘤来源MSC通过miR-26a和miR-146a促进NSCLC发生EGFR-TKI获得性耐药”。本研究拟进一步探讨MSC异常表达miR-26a和miR-146a和其促进耐药的分子机制；探索EGFR-TKI获得性耐药的生物学标志物；利用细胞系和裸鼠原位移植瘤模型筛选最佳拮抗剂逆转EGFR-TKI耐药。此转化研究有助于建立靶向肿瘤微环境逆转肺癌EGFR-TKI 获得性耐药的治疗新策略。

肿瘤微环境在介导肿瘤获得性耐药和抵抗细胞死亡的生理性调节中发挥了重要作用。间充质干细胞（mesenchymal stem cell，MSC）是来源于中胚层的成体干细胞，是肿瘤微环境中大多数间质细胞的前体细胞。有文献报道MSC具有靶向迁移至肿瘤部位的特性。通过向肿瘤组织的归巢和向间质成分分化，改变肿瘤微环境，影响肿瘤的生长、转移和耐药。通过探讨MSC与NSCLC细胞的相互作用，作为研究肿瘤微环境介导NSCLC的耐药模型，具有重要意义。. 我们阐述肿瘤来源MSC发生异常表观遗传学特征，iR-26a和miR-146a表达显著改变，高表达分泌HGF,IL-6,IL-8和IGF-1等促癌因；通过旁分泌机制，MSC促进肺癌细胞转运蛋白和药物代谢基因ABCG2和CYP2C9的表达升高，从而促进EGFR外显子突变的肺腺癌细胞抵抗EGFR-TKI的药物作用。此外，提出GGO肺癌人群临床特征重新定义肺癌早筛高危人群；亚肺叶切除可作为早期肺类癌以及老年NSCLC患者的可选手术方式；TP53基因突变和PD-L1表达是早期可切除NSCLC预后不良的生物学标志物，以及铁死亡相关基因signature可以作为肺腺癌预后的生物学标；提出一种基于PDL1,TMB,吸烟史,治疗线数,治疗方式和FAT1突变状态结合起来建立多元回归模型，可以用来筛选免疫治疗合适的患者和指导临床治疗。我们还应用数据库筛选肺腺癌的关键致病基因并挖掘靶向药物，并通过二代测序方法揭示我国人群少见胸部肿瘤的致病驱动基因突变和靶向治疗靶点。. 总之，我们围绕MSC在肺癌疾病发生和发展中的作用，以及胸部肿瘤基因突变和靶向治疗开展了一系列临床与基础研究。阐述了肿瘤微环境在介导肿瘤侵袭性生长，转移和获得性耐药等生理性调节中发挥的重要作用和机制，并为胸部肿瘤的精准治疗提供新的理论基础和治疗策略。