In Vitro Effect of Liposome-mediated Combined p16 and p53 Gene Transfer to the Human Glioblastoma Cell Lines

ABSTRACT

OBJECTIVE: To overcome the limitations of the single gene transfer, the authors present the results of wild-type p16 and p53 combined genes transfer in vitro to the U251MG and U373MG cell lines using cationic liposome as a vector. METHODS: To compare the therapeutic effect of the combined p16 and p53 genes transfer with the single p16 and p53 gene transfer, full length of wild-type human p16 and p53 gene, and combined p16-p53 genes were transferred in vitro to the U251MG and U373MG cell lines using cationic liposome as a vector. As the U251MG and U373MG cell lines are devoid of p16 and p53 genes, the therapeutic effect of the three groups of gene transfer could be evaluated by the growth suppression or percentage of the viable cells. Reverse transcription polymerase chain reaction(RT-PCR), flow cytometry, and electron microscopy(EM) were used for evaluation of the growth suppression or apoptosis of the tumor cells. RESULTS: p16 gene, p53 gene and the combined p16-p53 genes were effectively transferred to the cell lines using cationic liposome as a vector resulting in dramatic decrease of the viable tumor cells in comparison to the control group(p=0.004). The cytotoxic effect of the gene transfer in the U251MG cell line was the most significant in the combined p16-p53 group. However, in the U373MG cell line p53 single gene transfer group showed more significant effect than the combined gene transfer group. Apoptosis was confirmed by EM in the combined p16-p53 genes group. The G1 phase arrest effect, confirmed by the flow cytometry was more prevalent in the p16 gene transfer group than the other groups. CONCLUSION: Cationic liposome-mediated transfer of combined p16-p53 genes to the human glioblastoma cell lines is proven effective. However, the therapeutic effect of the combined p16-p53 genes transfer was not consistently superior to the single p16 or p53 gene transfer.