Making a model of digestive tract infection and carcinogenisis of Epstein-Barr virus produced by epithelial cell line (GTC) derived from human gastric adenocarcinoma.

EB病毒(Epstein-Barr Virus，EBV)与某些胃腺癌的发病机制有关。我们建立了人胃癌组织上皮细胞系(GTC-4)。该细胞系具有产生EB病毒的能力。我们进一步从GTC-4细胞中克隆了EBV产生细胞系GTC-5，发现GTC-5产生的EBV(GTC-5-EBV)可以感染Balb/c小鼠的消化道，最终感染的小鼠发生消化道腺癌。组织免疫染色显示，EBV灌胃后24小时，胃粘膜中EB病毒核抗原NA-2呈阳性反应，21天后消失。NA-1和LMP-1(潜伏膜蛋白1)在灌胃后5天也出现在胃粘膜中，6个月后消失。灌胃24小时后，用原位杂交方法在胃粘膜中检测到EB病毒编码的小RNA(EBER)，并持续9个月。在接下来的实验中，用6~7周和10个月龄的Balb/c裸鼠来评价GTC-5-EBV的致癌性。每周注射GTC-5-EBV共8次。4个月后，老年小鼠直肠腺癌的发生率为100%。在6个月的观察期内，幼鼠未发现肿瘤。本研究建立的EBV相关性消化道癌变模型可用于EBV相关性疾病的病因学研究和治疗。

Epstein-Barr virus (EBV) has been implicated in the pathogenesis of some type of gastric adenocarcinoma. We established an epithelial cell line (GTC-4) derived form human gastric cancer tissue. The cell line have a capacity of producing EBV. We further cloned EBV producing cell line GTC-5 from GTC-4 cells and found that digestive tract of Balb/c mice can be infected by EBV produced by GTC-5 (GTC-5-EBV) and finally infected mice developed adenocarcinoma of the digestive tract.Balb/c mice were gavaged with 0.2ml of 50% ethanol to produce gastric mucosal injury and than GTC-5-EBV were gavaged. Histoimmunostaining showed that EBV nuclear antigen NA-2 were positive in the gastric mucosa 24 hours after the gavage of EBV and disappeared in 21 days. NA-1 and LMP-1 (latent membrane protein 1) were also present in gastric mucosa 5 days after the gavage and disappeared 6 months later. EBER (EBV-encoded small RNA) were identified in the gastric mucosa by in situ hybridization 24 hours after the gavage and it lasted for 9 months. EBER positive adenocarcinoma were developed in the stomach 9 months after the gavage of EBV.In the next experiment, Balb/c nude mice (6-7W and 10 month, n=10 each) were used to evaluate the carcinogenesis of GTC-5-EBV. GTC-5-EBV was injected weekly for 8 times. After 4 months, adenocarcinoma were found in the rectum of 100 % of elderly mice. In contrast, no cancer was found in the young mice during the observation period of 6 months.Our model of EBV associated carcinogenisis of digestive tract seems useful in studying the etiology and treatment of EBV associated disorders.