Transformation of cultured human fetal gastric fibroblasts with physico-chemical agents.

Treatment of early passage human fetal gastric fibroblasts with ultraviolet (UV) light and the chemical carcinogen ethyl nitrosourea (ENU) in succession resulted in an immortally growing cell line, named GTS 8502. The cells of this line display typical transformation characteristics, such as irregularly shaped nuclei, heteroploidization of karyotype and frequent appearance of heteromorphic chromosomes, the enhanced volume ratio of nucleus to cytoplasm, multinucleoli, appearance of microvilli on the surface of the cells and agglutination reaction to lectin concanavalin A. The transformants have high growing and mitotic indices and the ability of focus-formation on monolayers and anchorage independent growth in soft agar medium. Moreover, these cells induced tumours in nude mice or in immunosuppressed new-born rats through heterotransplantation. The results of various methods including electromicroscopy and histochemical analyses indicate that GTS 8502 cells are of fibroblast origin. Our results thus indicate that synergism of two carcinogens may raise the transformation ratio of normal human cells, which is otherwise extremely low. The transformation of human cells may be utilized to detect environmental carcinogens.