Single cell RNA sequencing analysis of freshly resected PC9 cell line-derived tumor xenografts

The non-small cell lung carcinoma (NSCLC) PC9 cell line is an established preclinical model for tyrosine kinase inhibitors. Using PC9 cells, we generated EGFR-mutant lung cancer xenografts to study the differences in response between individual cells and cell populations. We performed treatment of PC9 xenograft tumors with the combination of osimertinib and crizotinib as well as single drugs, followed by Drop-seq. The addition of crizotinib was guided by our previous data in PC9 grown in cell culture that identified an erlotinib-resistant drug population sensitive to crizotinib. The results of the xenograft study show that combination treatment targets specific osimertinib-tolerant cell populations but leaves a subset of the population that is tolerant to the combo. Each cell subpopulation is characterized by specific molecular signatures. The results of our study help to address emerging drug resistance that limits clinical usefulness of targeted strategies, particularly in NSCLC. Overall design: examining drug resistant cell populations using single cell RNA-seq

非小细胞肺癌（non-small cell lung carcinoma, NSCLC）PC9细胞系是酪氨酸激酶抑制剂（tyrosine kinase inhibitors）的经典临床前模型。本研究以PC9细胞构建EGFR突变型肺癌异种移植瘤模型，以探究单细胞与细胞群体间的响应差异。我们分别采用奥希替尼（osimertinib）、克唑替尼（crizotinib）单药及二者联合方案处理PC9异种移植瘤，随后进行Drop-seq测序。联合克唑替尼的给药方案设计参考了我们前期在细胞培养条件下培养的PC9细胞中的实验数据——该数据鉴定出了对厄洛替尼（erlotinib）耐药、但对克唑替尼敏感的药物抗性细胞群体。异种移植瘤实验结果显示，联合治疗可靶向特定的奥希替尼耐受细胞群体，但仍残留有对联合治疗方案耐受的细胞亚群。各细胞亚群均具有特异性分子特征谱。本研究结果有助于解决限制靶向治疗策略临床应用的新兴耐药难题，尤其在非小细胞肺癌领域。整体实验设计：通过单细胞RNA测序（single cell RNA-seq）探究药物抗性细胞群体。