ABSTRACT
Purpose To explore the effects of estrogen receptor antagonist on the expression of estrogen receptor subtype (ERα, ERβ), and p57kip2 protein in human endometrioid carcinoma cells named JEC. Methods The JEC cells (moderately differentiated EC cells) cultured in vitro were treated with β-Estradiol (E2) (10～6 mol/L) and two types of estrogen receptor antagonists, tamoxifen (TAM) and fulvestrant (ICI182780) (10-6 mol/L). After 24, 48, 72 h, MTT was used to detect the growth condition of JEC cells, and the light microscopy and electron microscopy were used to observe the growth condition and morphological changes of cells, Western blot was used to detect the expression of ERα, ERβ, PR-A, PR-B and P57kip2 protein in JEC cells. Results MTT results: Compared with the control group, E2 could promote the proliferation of JEC cells significantly (P＜0.05), and ICI182780 could inhibit the proliferation of JEC cells obviously (P＜0.05). Compared with the E2 group, the proliferation ability of JEC cells in E2 + ICI182780 group were lower(P＜0.05). Morphological change: Compared with the control group, the cells density of E2 group increased obviously, and the pathologic mitosis was easy to seen in some cells. The cells density decreased obviously in ICI182780 group. Compared with E2 group, the cells density of E2 + TAM group and E2 + ICI182780 group were decreased, and pathological mitotic figures were difficult to seen. Western blot results: Compared with the control group, the expression of ERβ protein increased, and the expression of p57kip2 protein decreased in E2 group (P＜0.05). The expression of ERβ protein decreased, and the expression of p57kip2 protein increased in ICI182780 group and TAM group, and the difference was statistically significant between ICI182780 group and control group (P＜0.05). Compared with the E2 group, the expression of ERβ protein decreased, and the expression of p57kip2 protein increased in E2 + ICI182780 group and E2 + TAM group, and the difference was statistically significant between E2 + ICI182780 group and E2 group (P＜0.05). ERa protein of JEC cells did not expressed in experimental group or control group. Conclusion ERa protein are not expressed in JEC cells. ICI182780 have a stronger role in antagonizing estrogen, and may induce the expression of p57kip2 protein by down-regulating the expression of ERβ protein in JEC cells, block the cell cycle progression and inhibit the growth of tumor cells. TAM has a weaker estrogen like effect on the growth of JEC cells. It is possible that combined detection of the expression of ERa and p57kip2 protein in EC has an important reference value for individualized selection of endocrine therapy for EC patients.
ABSTRACT
Objective To explore the effects of estrogen on apolipoprotein M ( apoM ).Methods ApoM mRNA was assayed in HepG2 cells by RT-PCR after incubation of estrogen with or without estrogen receptor antagonist at different concentrations and durations.SD female rats were divided into five groups:OVX group,Sham group,OVX+ EB group,normal group and normal + EB group.From a week of being operated,the rats were injected subcutaneously estradiol beuzoate or vehicle.After 12-hrs fasting,serum levels of triglycerides (TG),LDL-cholesterol,HDL-cholesterol,total cholesterol ( TC ) at months 1,2 and 3 after operation were measured.The expression of apoM in rats was detected by using real time RT-PCR and Western blot.Results Estrogen increased mRNA levels of apoM and apoAI in the HepG2 cells with a dose- and time-dependent manner,which could be abolished by addition of estrogen receptor antagonist.Serum apoM,TG,TC,HDL and LDL levels were significantly increased in the ovariectomized or normal rats which received estrogen treatment than those in OVX or normal group rats at month 1 after treatments.Conclusions Estrogen upregulates apoM expression via its receptor.