Objective: We study the regulation of human progesterone receptor isoforms A and B in uterine endometrial carcinoma cell line by different concentration of human insulin-like growth factor-I (IGF-I) for different time, to investigate the roles of IGF-I and progesterone receptor isoforms in uterine endometrial carcinoma.
Methods: The uterine endometrial adenocarcinoma cell line HEC-IB was cultured in vitro and the breast cancer cell line MCF-7 was used as control. Western blot was applied to examine the changes of the two isoforms by different concentration IGF-I for different time.
Results: (1) In HEC-IB cell line, 10 ng/ml IGF-I made hPRB up-regulated in the first 24 h. But according to lager concentration and longer time, human progesterone receptor (hPR) B became down-regulated, which were significant at 20 ng/ml IGF-I for 72 h and 40 ng/ml IGF-I for 48 - 72 h. The change of hPRA was like hPRB. (2) In MCF-7 cell line, 10 ng/ml and 40 ng/ml IGF-I made hPRA and hPRB significantly up-regulated in 24, 48, 72 h. Twenty ng/ml IGF-I made hPRB up-regulated also in the first 24 h. But in 48 h and 72 h, down-regulation of hPRB was detected. Twenty ng/ml IGF-I made hPRA down-regulated in 24, 48, 72 h.
Conclusions: (1) The regulation of IGF-I to hPR isoforms has cell-type specific and dose-dependent and time-dependent. (2) In HEC-IB cell line, 10 ng/ml IGF-I made hPRB significantly up-regulated in 24 h. But following exposure to IGF-I at larger concentration and longer time, hPRB became down-regulated. The change of hPRA is like hPRB.