Establishment and characterization of a new human functional cell line from a choriocarcinoma.

A new human functional tumor cell line, designated as T3M-3, has been established from a xenotransplanted choriocarcinoma grown in nude mice. One of the biggest problems of the in vitro culture of these tumor cells using the xenotransplanted tumors had been the dense contamination of fibroblasts of host nude mouse origin. In the present study, these fibroblasts were completely removed by incubating the cells with antiserum raised against nude mouse spleen cells. The cell line established from the remaining tumor cells has been successfully propagated in vitro for as long as 4 years. These cells show the morphology of epithelioid cells containing a prominent nucleus with one or two large nucleoli. The cells grow in a monolayered sheet with the population-doubling time of 19 hr. The cells show perfect tumor takes when they are reinoculated into nude mice. Chromosomal analysis revealed that the cell is a human aneuploid one with a hypotriploid mode. These cultured cells maintained well the function of secreting large amounts of human chorionic gonadotropin, progesterone, and estrogen. The secretion of human chorionic gonadotropin and progesterone by these cells is enhanced by stimulation with tumor promoters, such as 12-O-tetradecanoylphorbol-13-acetate and teleocidin B, or with epidermal growth factor in a dose-and time-dependent manner. Interestingly, however, the tumor promoters did not exert a marked effect on the cellular binding of epidermal growth factor, indicating that the receptors for these reagents in T3M-3 cells are not shared by epidermal growth factor.