Cytosine deaminase and herpes simplex virus thymidine kinase gene expression via adenoviral infection of human cholangiocarcincoma cells occurs in the presence of human bile

We previously demonstrated cytotoxicity to cholangiocarcinoma cells via ade noviral delivery of cytosine deaminase gene (AdCMVCD), The biliary milieu m ay present obstacles to gene transfer in situ, This study determined whethe r toxin gene (CD or herpes simplex virus thymidine kinase (HSV-tk)) transfe r to cholangiocarcinoma cells occurs in human bile, Human cholangiocarcinom a (SK-ChA-1 and Oz) and HeLa cells were infected in Optimem or 10% human bi le (filter sterilized and diluted) with an adenoviral vector, AdCMVLacZ enc oding the LacZ gene, then FAGS analysis performed. Cholangiocarcinoma cells were infected with AdCMVCD, or AdCMVHSV-tk, in Optimem or 10% bile, and tr eated with 5-FC or ganciclovir (GCV), then proliferation assays performed. SK-ChA-1 and Oz cells were efficiently transduced by AdCMVLacZ in the prese nce of human bile (98% and 78%), compared to Optimem (98% and 85%), For SK- ChA-1 cells infected with AdCMVCD and exposed to 5-FC, 84% cytotoxicity occ urred in bile compared to 62% in Optimem (P < 0.0001). For Oz cells infecte d with AdCMVHSV-tk and exposed to GCV, 40% cytotoxicity occurred in bile co mpared to 64% in Optimem (P < 0.0001) but was not synergistic. These result s demonstrate effective toxin gene function in a biliary physiologic contex t.