Retroviral Vector Introduced in the Construction of HSV1-tk/GCV Antitumor Suicide-gene Therapeutic System

【Objective】 To explore a method for the construction of antitumor suicide-gene therapeutic system. 【Methods】 The thymidine kinase gene of herpes simplex virus type 1 (HSV1-tk) was orientationally cloned into the retroviral vector plasmid (pLXSN) by DNA recombinant technique, and then the recombinant plasmid of pLXSN-tk was identified by restriction endonuclease cutting and DNA sequencing. Introduced by PolyFect Transfection reagent, the recombinant plasmid was transfected into the packaging cell line PT67. Screened by G418, a cell line, which could produce virus stably, was obtained. The virus was transfected into human gastric carcinomatous cell strain SGC-7901 and the transfected SGC-7901 was applied to evaluate an anti-tumor effect. 【Results】 The identification with restriction endonuclease cutting and DNA sequencing showed that HSV1-tk was successfully inserted into the recombined plasmid of pLXSN-tk. The stable cloned PT67/tk was obtained by screening with G418 and then its amount was enlarged by culture, the titer of the PT67/tk solution being 4×10~4 cfu/mL. The anti-G418 cloned cell line SGC-7901/tk was got by infecting SGC-7901 with the virus. Anti-tumor experiment showed that GCV had an obvious toxic effect on SGC-7901/tk but had no effect on SGC-7901, indicating recombinant retroviral HSV1-tk expressed HSV1-tk gene which had biological activity. 【Conclusion】 Cloning HSV1-tk into the retroviral vector is effective in obtaining the recombinant retroviral HSV1-tk which can express HSV1-tk gene, and also effective in establishing an antitumor suicide-gene therapeutic system. This research naturally lays a foundation for further studying of Chinese medicines having synergistic anti-tumor action with suicide gene.