| Objective To observe the killing effect of Adenovirus vectors encoding herpes simplex virus thymidine kinase gene/ganciclovir(ADV-HSV-Tk/GCV) system on human Adenoid Cystic Carcinoma Cells(ACC-2 and ACC-M) in vitro. Methods Both ACC-2 and ACC-M cell lines were transduced with the ADV-GFP at the proportion of 1:10,1:20,1:30 for 12 to 36 hour. Next, the adenoid cystic carcinoma cell lines which exposed to ADV-HSV-TK at different M.O.I(5 to 60) were treated with ganciclovir (GCV) in different concentration, while the two cell lines were transferred at an M.O.I of 100 and subsequently mixed with non- transferred cells at varying proportion, the cell killing and also the "bystander effect" were detected with MTT assay. Results It was demonstrated that both ACC-2 and ACC-M could be transduced with AD-GFP in vitro. The minimal multiplicity of infection (MOI;for the purpose of this study the number of vector genomes per target cell) was 10 to 20,and the gene transduction efficiency was dependent on multiplicity of infection. The system could present the killing activity to both ACC-2 and ACC-M cells in a dose-dependent manner at lower concentration of MOI(5) and GCV(25ug/ml ).Detection of MTT showed that when they were exposed to ADV-HSV-Tk, the growth of Acc-2 and Acc-M cells were inhibited significantly by GCV when its concentration was equal to or over 25ug/ml, and the rate of inhibition was 38% to 66% respectively, while the same cell lines were not or only slightly inhibited by GCV of any concentration the otherwise. The transferred ADV-HSV-Tk cells mixed with none-transferred cells in different proportion revealed the existence of "bystander effect", the more the transferred cells, the less the living cells existence. Conclusion ACC can be transferred effectively by Ad-GFP in a dose and time dependent manner . The growth of ACC-2 and Acc-M can be inhibited by the ADV-HSV-Tk/GCV system at a low MOI in vitro. However, the system is still to be modified to enhance the cell killing efficiency and the "bystander effect". |
