Morphological study of the TK cholangiocarcinoma cell line with three-dimensional cell culture.

Cholangiocarcinoma is an intractable carcinoma originating from the bile duct epithelium. To gain an understanding of the cell biology of cholangiocarcinoma, in vitro cell culture is valuable. However, well­characterized cell lines are limited. In the present study, the morphology of the TK cholangiocarcinoma cell line was analyzed by three­dimensional culture. Dispersed TK cells were injected into a gelatin mesh scaffold and cultivated for 3­20 days. The morphology of the TK cells was investigated by phase­contrast microscopy, optical microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). TK cells were observed to proliferate three-dimensionally in the scaffold. The cells exhibited a globoid structure and attached to the scaffold. The SEM observation demonstrated typical microvilli and plicae on the surface of the structure. Light microscopy and TEM confirmed intercellular and cell­to­scaffold attachment in the three­dimensional mesh. The culture also exhibited the formation of a duct-like structure covered by structured microvilli. In conclusion, three­dimensional culture of TK cells demonstrated the morphological characteristics of cholangiocarcinoma in vitro. Production of high levels of carbohydrate antigen (CA)19­9, CA50 and carcinoembryonic antigen was previously confirmed in the TK cell line. As a characteristic morphology was demonstrated in the present study, the TK cholangiocarcinoma cell line may be useful as an experimental model for further study of cholangiocarcinoma.