中文摘要：

目的：构建可诱导表达人巨细胞病毒（HCMV）UL138蛋白的稳定遗传胃癌细胞系,并评价UL138对胃癌细胞的生物学效应。方法：将p CMV-tet3G质粒转染BGC-823胃癌细胞,通过G418及荧光素酶活性检测筛选BGCTet-on细胞株。再将含有UL138外源基因的p TRE3G-UL138质粒转染稳定BGCTet-on细胞株,通过G418及潮霉素双抗筛选,获得诱导性表达UL138基因的胃癌细胞（BGC-UL138_（Tet-on））。强力霉素（DOX）诱导后,采用Western blot验证UL138蛋白表达,采用流式细胞术及CCK8试剂盒检测UL138蛋白表达对胃癌细胞的生长周期及增殖的影响。构建荷瘤裸鼠模型,体内验证UL138蛋白表达对胃癌细胞增殖的影响。结果：成功构建了DOX诱导性表达的、携带UL138基因的BGC-UL138_（Tet-on）稳转细胞株。UL138蛋白表达可显著抑制胃癌细胞增殖;流式细胞术检测显示UL138蛋白表达阻滞BGC-823细胞周期在G_1期。荷瘤裸鼠模型体内实验发现,DOX腹腔注射诱导UL138蛋白表达后,BGC-UL138_（Tet-on）移植瘤体积缩小甚至消失。结论：成功构建可诱导表达UL138蛋白的胃癌细胞株,进一步证实HCMV基因UL138的表达可在体内和体外抑制胃癌细胞的增殖,细胞实验提示细胞周期阻断在G_1期。

英文摘要：

Objective： To establish a stably inherited gastric cell line with inducible expression of human cytomegalovirus UL 138 protein and then to evaluate the biological effect of UL 138 protein on gastric cancers （GCs）, which will offer a convincing tool for researching the specific function of UL138 protein impact on GCs. Methods： Transfect pCMV-tet3G plasmids into BGC-823 and then screen for stablely transfected clones BGCTet.on by G418 and luciferase assay. Then transfect the recombinant plasmid pTRE3G-UL 138 into the selected clone and screen for stably transfected clones BGC-UL 138T~t.on by G418 and hygromycin. Validate the expression of UL 138 induced by doxycycline （DOX） by western blot. Besides, detect the growth impact of UL138 protein on GCs by flow cytometry and CCK8 test. Establish GC xenografl nude mice models and verify the GC inhibition function of UL138 protein in vivo. Results： Gastric cancer cell line BGC-UL138T0t.on with DOX inducible expression of human cytomegalo- virus UL 138 protein was successfully established. Expression of UL 138 protein inhibited proliferation of GC cells distinctly. Flow cytometry test indicated UL138 protein could block GC cell cycle at G1 phase. The data of GC xenograft nude mice models further demonstrated that the BGC-UL138Tot.on xenografls were decreased, and even disappeared, when UL138 expression was induced by DOX intraperitoneal injection. Conclusion： We successfully established a specific GC cell line with inducible expression of human cytomegalovirus UL138 protein and then we found HCMV UL138 gene could inhibit proliferation of GC cells in vitro and in vivo and block its cell cycle.