Autocrine Regulation of Cell Proliferation by Estradiol and Hydroxytamoxifen of Transformed Mouse Leydig Cells in Serum-Free Culture*
1988; Oxford University Press; Volume: 122; Issue: 1 Linguagem: Inglês
10.1210/endo-122-1-227
ISSN1945-7170
AutoresYASUKO NISHIZAWA, BUNZO SATO, Yoshihiro Miyashita, Satoshi Tsukada, Takahisa Hirose, Susumu Kishimoto, Keishi Matsumoto,
Tópico(s)Pancreatic function and diabetes
ResumoWe have previously reported that the cloned cell line (B-l-A-2) derived from an estrogen-responsive mouse Leydig cell tumor shows an estrogen-dependent enhancement of cell proliferation in medium supplemented with charcoal-dextranstripped fetal bovine serum. To avoid the involvement of unknown factors present in the serum in the pathway for estrogen - dependent cell growth, the present study was designed to establish a serum-free culture system to which growth factors could be added. To this end, we subcloned B-l cells from the parental tumor cell line. The proliferation of B-l cells was markedly stimulated by the addition of 10-11-10-8 M estradiol into the serum-free medium [Eagle’s Minimum Essential Medium- Ham’s F-12 (1:1, vol/vol) containing 0.2% (wt/vol) BSA]. Epidermal growth factor (0.1–50 ng/ml) or insulin (0.1–50 μg/ml) alone or in combination with 10-8 M estradiol did not affect the proliferation rate of B-l cells. In contrast, a greater than 10-fold molar excess of 4-hydroxytamoxifen blocked estradiol-induced cell proliferation, while 4-hydroxytamoxifen alone failed to show a stimulatory effect on cell multiplication. Additionally, the conditioned medium collected from estradiol-stimulated cells was found to contain a growth-promoting factor(s) whose activity was not antagonized by 4-hydroxytamoxifen. Nonstimulated cells secreted a significant but low level of the growth-promoting factor. Finally, B-l cells were found to be estrogen dependent for cell proliferation in BALB/c mice. Their growth was markedly inhibited by the administration of tamoxifen to the host mice. These results indicate that the serum-free culture system presented here is suitable for studying the autocrine mechanisms of cell growth regulated by estrogens as well as triphenylethylene compounds. (Endocrinology122: 227–235, 1988)
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