[Reversal of malignant cell phenotype of human pancreatic adenocarcinoma cell line by recombinant retroviral vector expressing antisense Ki-ras].

A recombinant retroviral vector expressing antisense Ki-ras was constructed. The recombinant virus DNA was packaged with packaging cell line PA317 cells by the calcium phosphate coprecipitation method. The virus supernatant was used to infect human pancreatic carcinoma cell line PC-2. After selection with Puromycin, resistant colonies were obtained. Stable expressions of retrovirus in both PA317 and PC-2 cells were exhibited by Northern blot hybridization. A down regulation of endogenous Ki-ras was found in PC-2 cells infected with antisense Ki-ras construct. It was demonstrated that the antisense Ki-ras did inhibit the cell growth rate and 3H-TdR incorporation rate of PC-2 cells. The ability of colony formation in soft agar and tumorogenicity in nude mice of PC-2 cells were significantly suppressed by the antisense Ki-ras. The results implicate that recombinant retroviral vector containing antisense Ki-ras could inhibit target gene expression and partly reverse malignant phenotype of pancreatic adenocarcinoma cells.