基于TAMseq NGS和PDX技术的胃癌曲妥珠单抗选择性进化耐药规律及靶向干预研究

It is key important to monitor "variability" of a drug resistance pathway and "mobility" of the target of intervention of drug resistance to overcome the resistance of gastric cancer treated with trastuzumab. However, there are no effective monitoring methods and intervention strategies to overcome the resistance of gastric cancer treated with trastuzumab. In our previous work, we found a group of trastuzumab resistance related genes in gastric cancer using tagged-amplicon deep next-generation sequencing (TAMseq NGS). In this study, we are to simulate the dynamic process of selective evolution of drug resistance of trastuzumab using HER2-amplified patient-derived tumor xenografts models; to identify the mutations and the target of intervention of drug resistance in the treatment of gastric cancer with trastuzumab using TAMseq NGS; to provide the target genes of drug resistance in the treatment of gastric cancer with trastuzumab using circulating tumor DNA (ctDNA) based TAMseq NGS; to find out the drug resistance pathway and the target of intervention of drug resistance in the treatment of gastric cancer with trastuzumab; to provide the potential drugs to interfere drug resistance of trastuzumab. The aim of this study are to monitor "variability" of a drug resistance pathway and "mobility" of the target of intervention of drug resistance to realized the targeted interfere of the resistance of trastuzumab in gastric cancer patients; to establish a real-time dynamic monitoring and intervention strategy for the treatment of gastric cancer with trastuzumab based on PDX model and TAMseq NGS tto improve the clinical efficacy and prognosis of gastric cancer.

实现对胃癌曲妥珠单抗耐药的有效监控是克服其耐药的关键。目前临床缺乏有效的监控方法和干预策略。前期工作中我们利用标记扩增深度二代测序（TAMseq NGS）技术找到一组胃癌曲妥珠单抗耐药相关基因。本研究拟利用HER2扩增型胃癌患者来源肿瘤移植瘤（PDX）模型来实时模拟曲妥珠单抗治疗的耐药过程；利用TAMseq NGS技术进一步确定胃癌PDX模型经曲妥珠单抗治疗过程中出现的耐药基因和干预耐药靶点；为临床胃癌患者曲妥珠单抗耐药提供基于循环肿瘤DNA（ctDNA）的TAMseq NGS检测的目标基因，进而实时发现曲妥珠单抗治疗中出现的相关耐药途径和干预耐药靶点，为临床干预胃癌曲妥珠单抗耐药提示可选择的治疗药物。研究旨在实现胃癌曲妥珠单抗耐药途径和耐药靶点的实时监控和靶向干预耐药，为临床建立一种基于PDX模型和TAMseq NGS技术的胃癌曲妥珠单抗耐药的监控和干预策略，提高胃癌临床疗效和改善预后。

实现对胃癌曲妥珠单抗耐药的有效监控是克服其耐药的关键。目前临床缺乏有效的监控方法和干预策略。本研究利用HER2扩增型胃癌患者来源肿瘤移植瘤（PDX）模型来实时模拟曲妥珠单抗治疗的耐药过程；利用NGS技术确定胃癌PDX模型经曲妥珠单抗治疗过程中出现的耐药基因和干预耐药靶点，为临床干预胃癌曲妥珠单抗耐药提示可选择的治疗药物。本研究成功建立了HER2 扩增型胃癌PDX 移植瘤模型、并实现了曲妥珠单抗诱导耐药，同时对曲妥珠单抗耐药过程基于NGS技术和PDX模型的实时性动态化监测。采用NGS技术发现发现曲妥珠单抗耐药后肿瘤突变负荷（TMB）增加，出现高度微卫星不稳定（MSI-H、新发NF1基因突变。我们同期构建了免疫重建的胃癌曲妥珠单抗耐药PDX移植瘤模型，评价了免疫检查点抑制剂（Pembrolizumab）对该例PDX移植瘤模型的干预治疗作用。研究发现，采用Pembrolizumab对TMB高、MSI-H的曲妥珠单抗耐药的胃癌PDX移植瘤有效。研究结果为临床提示实时性干预曲妥珠单抗耐药的可选择药物。研究结果有望为临床建立一种基于胃癌PDX 模型和NGS 技术的胃癌曲妥珠单抗耐药的实时性动态化监控和干预策略，实现胃癌的精准化干预耐药，从而提高胃癌治疗的临床疗效和改善预后。