EGFR突变型NSCLC肿瘤内异质性的模式及相关分子机制研究

Treatment of lung cancer is very challenging for its high incidence rate and mortality, one of the most amazing advancement of which recently is tumor heterogeneity in different subclones. The tumor heterogeneity exists in genetics, epigenetic and phenotype et al., leading to difference in biological behavior, function, also playing a key role in tumor recurrence, metastasis and drug resistance. Therefore, tumor heterogeneity becomes more and more decisive in diagnosis and treatment of non-small cell lung cancer (NSCLC). Our previous study found EGFR (epidermal growth factor receptor) mutations status may occur alteration after chemotherapy, which might derive from intratumor heterogeneity. Based on this phenomenon, we propose to further explore the patterns of tumor heterogeneity in EGFR mutant NSCLC and to investigate their dynamic changes in the process of disease treatment and potential molecular mechanism. This project will also establish dynamic and quantitative molecular platforms to detect EGFR-TKIs related sensitive and resistant genes and explore individual interventions; expect to establish individual treatment system based on tumor heterogeneity. Meanwhile, identifying molecular mechanisms related with intratumor heterogeneity and phenotype alteration will provide theoretical basis for accurate molecular diagnosis, outcome predicting and optimized targeted therapeutic strategy.

肺癌以其高发病率和死亡率成为世界上最具挑战性的肿瘤。近年肺癌研究的重要进展之一是发现肿瘤组织内存在各种亚克隆即肿瘤内异质性，其在表型、遗传学或表观遗传学上均存在一定差异，从而导致其功能和生物学行为的不同并在肿瘤复发、转移和耐药中扮演重要的角色。本课题组前期工作发现EGFR突变在化疗后会发生动态改变，而肿瘤内EGFR突变的异质性则可能是此改变的分子基础。基于此，本项目拟以EGFR突变型非小细胞肺癌为研究对象,进一步探寻EGFR突变型肺癌瘤内异质性的模式、动态变化规律及潜在分子机制，通过建立并验证肿瘤内异质性的模式，探讨EGFR敏感与耐药基因的动态、定量检测体系，探寻个体化干预手段、建立异质性基础上的个体化诊疗体系。在此基础上，研究肿瘤异质性及表型转化的相关分子机制，为NSCLC靶向治疗的精确诊断、预测预后和优化治疗策略提供依据。

本课题组围绕EGFR突变型肺腺癌进行了深入系统研究，成果如下：.1) 利用气管镜活检标本建立移植瘤动物模型，成功率35%（66/188）。通过二代测序比较亲本组织和移植瘤模型免疫表型及分子表型的异同，为后续EGFR突变异质性模型的筛选和研究奠定了基础（Cancer letters 2018).2) 对EGFR突变型肺癌中具有疗效异质性特点的突变型鳞癌的耐药机制和应对策略进行深入研究(PNAS, 2105）.3) 通过体内外研究明确雌激素受体ER-beta剪切变异体1高表达可能与EGFR突变型肺腺癌对TKI的原发耐药有关(Scientific report,2015).4) 回顾性分析了肺腺癌患者外周血EGFR突变含量(异质性程度)与EGFR-TKI疗效与预后的相关性（Oncotarget,2016，J Thoracic Oncol 2017 ）.5) 应用功能性干性标记1B50-1及广谱的干细胞表面标记CD133，通过流式细胞技术等方法在细胞系及移植瘤模型中筛选1B50-1及CD133阳性表达细胞，验证其干细胞特性(Clin Cancer Res 2018).6) 利用二代测序技术对EGFR突变型肺腺癌EGFR-TKIs原发耐药机制与临床意义进行了探索性研究（J Thoracic Oncol 2017）.7) 牵头国际首个基于外周血ctDNA进行EGFR突变检测决定EGFR-TKI（易瑞沙）治疗的大样本、多中心、前瞻性临床研究，为液体活检基因分型指导肺癌个性化治疗提供迄今国内外最高级别循证医学证据(Lancet Res Med 2018).8) 利用TCGA和ICGC数据库，分析了不同DDR通路基因变异与TMB和新生抗原的关系，以及在免疫治疗疗效预测中的意义(Cancer Res 2018)