Bonde Pramod, Sui Guoping, Dhara Surajit, Wang Jiaai, Broor Apoorv, Kim Irene F, Wiley John E, Marti Guy, Duncan Mark, Jaffee Elizabeth, Montgomery Elizabeth, Maitra Anirban, Harmon John W
Department of Cardiothoracic Surgery, Johns Hopkins University School of Medicine, Baltimore, Md, USA.
J Thorac Cardiovasc Surg. 2007 Mar;133(3):763-9. doi: 10.1016/j.jtcvs.2006.07.044.
The reasons for the increasing incidence of esophageal adenocarcinoma are not clear. A causal relation between gastroesophageal reflux disease and esophageal adenocarcinoma has been suggested. Support for this comes from the development of esophageal adenocarcinoma in the rat reflux model. However, to date, no systematic characterization of the tumors derived from this model has been reported.
We induced biliary reflux by creating esophagojejunal anastomoses in 12 Sprague-Dawley rats. The experiment was terminated at 9 months, and rat esophagi were harvested for histopathologic documentation of reflux-associated changes and evidence of tumor formation. Three cell lines were established from 2 of the reflux-associated tumors. We tested the ability of these cells to grow in vitro in tissue culture and in vivo as xenografts in an orthotopic location at the gastroesophageal junction. Furthermore, we performed a cytogenetic analysis and determined the array-based gene expression profiles of these 3 rodent carcinoma lines compared with normal esophageal mucosa.
At 9 months, 12 of 12 rodents had histologic features of metaplastic columnar epithelium in the esophagus, with 7 having invasive carcinomas with glandular differentiation (either adenocarcinomas or adenosquamous carcinomas). The 3 cell lines established from 2 reflux-associated tumors were capable of sustained in vitro propagation and grew successfully as xenografts in both subcutaneous and orthotopic locations, confirming the tumorigenic nature of these lines. Despite their establishment from primary tumors with glandular features, the histology of the xenografts was that of well-differentiated squamous carcinomas. Karyotype analyses demonstrated cytogenetic heterogeneity and aneuploidy; furthermore, translocation (7:11) was present in all 3 lines. Array-based gene expression profiling confirmed upregulation of several cancer-related genes important in human esophageal cancer. Quantitative reverse transcription-polymerase chain reaction was used to confirm the differential expression of selected transcripts (vascular endothelial growth factor [VEGF], polo-like kinases [PLK], cyclin dependent kinase 4 [CDK4], hypoxia-inducible factor 1alpha [HIF1alpha], and insulin-like growth factor 1 [IGF-1]) in comparison with nonneoplastic esophageal mucosal scrapings.
The rodent reflux model is capable of inducing metaplastic epithelial changes simulating Barrett esophagus, as well as subsequent neoplastic transformation, at a high frequency. Cell lines have been established from these tumors that are capable of in vitro and in vivo passaging. The rodent reflux model should be a valuable model for studying therapy and chemoprevention efforts for Barrett esophagus, whereas the established cell lines provide a useful resource for drug discovery and other high-throughput studies.
食管腺癌发病率上升的原因尚不清楚。胃食管反流病与食管腺癌之间的因果关系已被提出。大鼠反流模型中食管腺癌的发生为此提供了支持。然而，迄今为止，尚未有关于该模型所衍生肿瘤的系统特征描述。
我们通过在12只Sprague-Dawley大鼠中创建食管空肠吻合术来诱导胆汁反流。实验在9个月时终止，收集大鼠食管进行反流相关变化的组织病理学记录及肿瘤形成证据的检测。从2个反流相关肿瘤中建立了3个细胞系。我们测试了这些细胞在体外组织培养中的生长能力以及在体内作为异种移植物在胃食管交界处原位生长的能力。此外，我们进行了细胞遗传学分析，并确定了这3个啮齿类癌系与正常食管黏膜相比基于芯片的基因表达谱。
9个月时，12只啮齿动物中有12只食管出现化生柱状上皮的组织学特征，其中7只患有具有腺分化的浸润性癌（腺癌或腺鳞癌）。从2个反流相关肿瘤中建立的3个细胞系能够在体外持续增殖，并在皮下和原位成功作为异种移植物生长，证实了这些细胞系的致瘤性。尽管它们是从具有腺特征的原发性肿瘤中建立的，但异种移植物的组织学表现为高分化鳞状癌。核型分析显示细胞遗传学异质性和非整倍体；此外，所有3个细胞系中均存在易位（7:11）。基于芯片的基因表达谱分析证实了几种在人类食管癌中重要的癌症相关基因的上调。使用定量逆转录 - 聚合酶链反应来确认与非肿瘤性食管黏膜刮片相比，选定转录本（血管内皮生长因子 [VEGF]、polo样激酶 [PLK]、细胞周期蛋白依赖性激酶4 [CDK4]、缺氧诱导因子1α [HIF1α] 和胰岛素样生长因子1 [IGF-1]）的差异表达。
啮齿动物反流模型能够高频诱导模拟巴雷特食管的化生上皮变化以及随后的肿瘤转化。已从这些肿瘤中建立了能够在体外和体内传代的细胞系。啮齿动物反流模型应是研究巴雷特食管治疗和化学预防的有价值模型，而建立的细胞系为药物发现和其他高通量研究提供了有用资源。
