[Expression of Fas and induction of apoptosis by anti-Fas monoclonal antibody in human bile duct carcinoma cells, and enhancement of induction of apoptosis by IFN-gamma].

: We investigated the expression of Fas, the induction of apoptosis by anti-Fas monoclonal antibody CH-11, and the effect of IFN-gamma on the induction of apoptosis in human bile duct carcinoma cells HuCCT1 and HuH28. Fas was expressed in 21.7% and 30.9% of HuCCT1 and HuH28 cells, respectively. Pretreatment with IFN-gamma increased the Fas expression by 17.6% in HuCCT1 cells. However, IFN-gamma did not affect the expression of Fas in HuH28 cells. In HuCCT1 and HuH28 cells treated with CH-11, the peak corresponding to that of positive control cells was detected with the TUNEL method by FCM. The condensation and fragmentation of the nucleus, and the apoptotic body were observed as morphological changes specific to apoptosis. CH-11 dose-dependently reduced HuCCT1 and HuH28 cell counts by up to 16.4% and 71.7%, respectively on day 3. Interferon-gamma attenuated the reduction of HuCCT1 cell counts by 12.8% on day 3. However, IFN-gamma had no effect on HuH28 cell counts. These results suggest that Fas was expressed, apoptosis was induced by CH-11 and the induction of apoptosis was enhanced by IFN-gamma in human bile duct carcinoma cells.