Control of cell growth. IV. Growth properties of a new cell line established from an estrogen-dependent kidney tumor of the Syrian hamster.

A permanent cell line has been established in culture from an estrogen-dependent kidney tumor of the Syrian hamster. The cells were selected from mixed populations by three methods: 1) animal passage enrichment, 2) growth on petri dishes, and 3) serum-type dependence. The inoculation of these cells, designated the H-301 line, into host animals showed tumor formation in estrogen-treated males or estrogen-treated females, but no tumor formation in normal or castrated hamsters of either sex. The estrogen-dependent tumor formation in male hamsters by H-301 cells was inhibited by progesterone, hydrocortisone, and testosterone. When H-301 cell growth was examined in culture, the addition of estrogens or other steroid hormones to the medium over the range of 0.1 to 10 ng/ml showed no growth-stimulating or inhibiting effects. Medium prepared with charcoal-extracted serum (to reduce by 90% the endogenous levels of steroid hormones) supported growth as well as medium prepared with normal serum. Furthermore, the addition of either estrogens, testosterone, or antiestrogens to medium prepared with charcoal-extracted serum showed no significant effects upon growth. We have shown also that culture medium prepared with serum from young calves did not support the growth of the cells, and the addition of estrogens to this medium did not change this growth pattern. However, the addition of fetal calf serum to medium already containing calf serum promoted maximal growth. Evidence is presented that the growth-promoting agent in fetal calf serum was inactivated by a 90 C heat treatment. Furthermore, the ether-soluble fractions from fetal calf serum and horse serum did not significantly improve growth when added to calf serum containing medium. We conclude that estrogens or other steroid hormones alone are not sufficient to promote the growth of the H-301 cells, but that heat-labile serum factors are required.