目的： 研究5/35嵌合型溶瘤腺病毒SG635在体外对肝癌HepG2和SMMC-7721细胞的特异性杀伤作用。 方法： 将SG600载体中5型腺病毒（Ad5）纤毛蛋白的knob和shaft结构域替换为35型腺病毒(Ad35)纤毛蛋白的相应结构域，构建成5/35嵌合型溶瘤腺病毒SG635。流式细胞术检测5/35嵌合型腺病毒Ad5/35-EGFP对HepG2和SMMC-7721细胞的感染效率，体外病毒增殖实验观察溶瘤腺病毒SG635的增殖能力，Western blotting检测SG635感染后肝癌细胞中E1A蛋白的表达，CCK-8实验检测SG635对肝癌HepG2和SMMC-7721细胞的杀伤作用。 结果： 在肝癌HepG2和SMMC-7721细胞中，Ad5/35-EGFP的感染效率明显强于5型腺病毒Ad5-EGFP；5/35嵌合型溶瘤腺病毒SG635在HepG2和SMMC-7721细胞中72 h的增殖倍数高于5型溶瘤腺病毒SG600（15 848.93 vs 6 309.57, 6 309.57 vs 5 011.87，均P<0.01），而在人正常成纤维细胞BJ中几乎不增殖。SG635感染后，HepG2和SMMC-7721细胞中E1A蛋白表达高于SG600感染，在BJ中则无E1A表达。在一定MOI范围内，SG635对于HepG2细胞和SMMC-7721细胞的杀伤作用逐渐增强，且杀伤率明显强于SG600（MOI为1时，90% vs 60%; MOI为10时，90% vs 50%)，对BJ无杀伤作用。 结论： 5/35嵌合型溶瘤腺病毒SG635能够高效感染并特异性杀伤肝癌细胞，具有较好的靶向性和安全性。

Objective : To investigate the specific cytotoxicity effect of 5/35 chimeric oncolytic adenovirus SG635 on hepatocellular carcinoma HepG2 and SMMC-7721 cells. Methods: The knob and shaft domains of type 5 adenovirus (Ad5) in SG600 plasmid were replaced by the domains of type 35 adenovirus (Ad35), and chimeric oncolytic adenovirus Ad5/35 was established. Flow cytometry was used to examine the infection efficiency of chimeric adenovirus Ad5/35 (Ad5/35-EGFP) in HepG2 and SMMC-7721 cells; replication assay was used to evaluate the replication of oncolytic adenovirus SG635; Western blotting analysis was used to examine the expression of E1A in cells after SG635 infection; and Kit-8 assay was used to assess the cytotoxicity of SG635 and SG600 on HepG2 and SMMC-7721 cells. Results: The infection efficiency of Ad5/35-EGFP in HepG2 and SMMC-7721 cells was obviously enhanced compared with Ad5-EGFP. The replication activity of SG635 in HepG2 and SMMC-7721 cells was higher than that of SG600 72 h after infection (15 848.93, 6 309.57 vs 6 309.57, 5 011.87, P<0.01), but SG635 did not replicate in normal BJ cells. Moreover, SG635 induced a higher expression of E1A protein in HepG2 and SMMC-7721 cells than SG600, but did not induce E1A expression in normal BJ cells. At a certain MOI, SG635 showed increasing cytotoxicity on HepG2 (MOI=1, 90% vs 60%) and SMMC-7721 (MOI=10, 90% vs 50%) cells, and the cytotoxicity was stronger than SG600, without causing significant cytotoxicity on normal BJ cells. Conclusion: The 5/35 chimeric oncolytic adenovirus SG635 can effectively infect and specifically kill hepatocarcinoma cells with satisfactory safety and specificity.

十一五国家科技重大专项课题资助项目（No. 2008ZX10002-025，No. 2008ZX10002-026）；国家重点基础研究发展计划（973计划）资助项目（No. 2009CB522404）；教育部新世纪优秀人才基金资助项目（No. NCET-08-0583）；全国优秀博士论文专项基金资助项目（No. FANEDD 200774）