Phase II rehabilitation/prevention of brain tumor: Effect of the HSV-TK/ACV system mediated by cationic lipsome on the proliferative activity of human glioma cells

Background: Gene therapy is a popular topic in domestic and overseas studies on biological therapy for brain tumor. Objective: By using a newly constructed eukaryotic expression vector of pCR3-TK, the effect of the HSV-TK/ACV system on the proliferative activity of human glioma cells was investigated. Design: Experimental study based on cells. Setting: Department of neurosurgery and department of oncology in a university hospital. Materials: The study was conducted at the National Key Laboratory of Veterinary Biotechnology of Harbin Veterinary Research Institute from January to April in 2004. The eukaryotic expression vector of pCR3-TK was constructed by the author. The TJ905 strain was a gift from professor Pu Pei-yu, who worked in the Neurology Institute of Tianjin city. The nontransfected cells and the cells transfected with pCR3-Uni vector were set as controls. Methods: By using Lipofectamine(a cationic liposome), the pCR3-Uni vector and the recombinant pCR3-TK plasmid(inserted with HSV-TK gene) were transfected into the human glioma cell strain-TJ905. Then the positive clones were picked out and were given ACV(50 mg/L). Totally 72 hours later, the cover slips were collected and silver staining for nucleolus organizer regions(AgNORs) was performed. Main outcome measures: After the ACV treatment and AgNORs staining, the numbers of silver-stained granules in TJ905 cells with or without transfections were counted respectively. Results: In those cells transfected with HSV-TK gene, after ACV treatment, a significant decreasing in proliferative activity could be observed, and the average numbers of the silver-stained granules in cells transfected with pCR3-Uni or pCR3-TK were 14.33 and 6.67 respectively(P < 0.01). Conclusion: As an easy-to-operate method, AgNOR counting is helpful for the studies on the proliferative activity of cells and the investigations into the potential anti-tumor mechanism of the HSV-TK/ACV system.