Innovation Center China, AstraZeneca Global R&D, Zhangjiang Hi-Tech Park, Shanghai, People's Republic of China.
Department of Pathology, Zhongshan Hospital, Fudan University, Shanghai, People's Republic of China.
Lab Invest. 2014 Aug;94(8):917-26. doi: 10.1038/labinvest.2014.77. Epub 2014 Jul 7.
The purpose of this study was to establish and characterize patient-derived esophageal squamous cell carcinoma xenograft (PDECX) mice for utilization in antitumor drug discovery. A total of 96 esophageal squamous cell carcinoma (ESCC) tissues from Chinese patients were transplanted subcutaneously into immunodeficient mice. Histology, EGFR, K-ras, B-raf, and PIK3CA mutations, and HER2 gene amplifications were analyzed in both patient tumors and mouse xenograft tissues using immunohistochemistry, mutant-enriched liquid chip sequencing and fluorescence in situ hybridization assays, respectively. Furthermore, in vivo efficacy studies using five PDECX mice harboring a variety of genetic aberrations were performed using the chemotherapy agents 5-fluorouracil (5-FU) and cisplatin. Thirty-seven PDECX mouse models were successfully established in immunodeficient mice. Pathological analysis revealed similar histological architecture and degrees of differentiation between patient ESCC and xenografted tumors. No mutations were identified in EGFR, K-ras, and B-raf genes in either xenograft models or patient ESCC tissues. In contrast, PIK3CA gene mutations were detected in 12.5% (12/96) ESCC patients and 18.9% (7/37) PDECX models. Interestingly, patient ESCC tissues exhibiting HER2 overexpression or gene amplification were unable to survive in immunodeficient mice. Further analysis showed that PDECX models carrying HER2 2+ expression had no response to 5-FU/cisplatin, compared with HER2-negative models. In conclusion, a panel of PDECX mouse models, which include PIK3CA mutant and HER2-positive models, was established and characterized thus mimicking the current clinical genetic setting of esophageal carcinoma. The sensitivity of HER2-negative ESCC models to chemotherapy supports stratification approaches in the treatment of esophageal carcinoma patients and warrants further investigation of the impact of PI3KCA on treatment response.
本研究旨在建立并鉴定人源性食管鳞癌异种移植瘤（PDECX）小鼠，用于抗肿瘤药物的发现。将 96 例中国患者的食管鳞癌（ESCC）组织进行皮下移植，建立免疫缺陷小鼠模型。采用免疫组织化学、突变富集液芯片测序和荧光原位杂交技术，分别分析患者肿瘤和小鼠异种移植瘤组织中的组织学、EGFR、K-ras、B-raf 和 PIK3CA 突变以及 HER2 基因扩增情况。此外，对携带多种遗传异常的 5 只 PDECX 小鼠进行体内药效学研究，使用化疗药物 5-氟尿嘧啶（5-FU）和顺铂进行治疗。成功建立了 37 例免疫缺陷小鼠 PDECX 模型。病理分析显示患者 ESCC 和异种移植瘤具有相似的组织学结构和分化程度。在异种移植瘤模型或患者 ESCC 组织中均未检测到 EGFR、K-ras 和 B-raf 基因突变。相反，在 12.5%（12/96）的 ESCC 患者和 18.9%（7/37）的 PDECX 模型中检测到 PIK3CA 基因突变。有趣的是，HER2 过表达或基因扩增的患者 ESCC 组织无法在免疫缺陷小鼠中存活。进一步分析显示，HER2 表达为 2+的 PDECX 模型对 5-FU/顺铂无反应，而 HER2 阴性模型则有反应。总之，建立了一组 PDECX 小鼠模型，包括 PIK3CA 突变和 HER2 阳性模型，并对其进行了鉴定和特征描述，从而模拟了当前食管癌的临床遗传背景。HER2 阴性 ESCC 模型对化疗的敏感性支持食管癌患者分层治疗的方法，并需要进一步研究 PI3KCA 对治疗反应的影响。
