Estrogen receptor-related receptor alpha (
ERRalpha) was reported to compete with
estrogen receptor alpha (
ERalpha) in a constitutive manner as an orphan nuclear closely related to (
ERalpha). To discuss the role of
ERRalpha in the
endometrial carcinoma cells, this study was performed. ER-responsive
endometrial carcinoma cells Ishikawa and ER-nonresponse HEC-1A cells were treated with different concentration of 17beta-E2 or E2 plus
ICI 182780. Semiquantitative reverse transcription-polymerase chain reaction and western blot were performed to analysis the expression of human
estrogen receptor-related receptor alpha (hERRalpha). Plasmid PLXSN-hERRalpha was constructed and transfected into cells. Selected in the medium containing high-dose
G418, the Ishikawa and HEC-1A cells with stable overexpression of hERRalpha were constructed and renamed as Ishikawa/hERRalpha and HEC-1A/hERRalpha, respectively. To discuss the effect of overexpression of hERRalpha in the cell
biological behavior (3-[4,5-dimethylth-lazol-2yl]-2,5-diphenyltetrazolium bromid) (MTT) cell assay was performed.
Estrogen downregulates
ERRalpha expression in ER-positive Ishikawa cells, while upregulates the expression of
ERRalpha in ER-negative HEC-1A cells. In Ishikawa cells, the downregulation of 17beta-E2 in
ERRalpha expression cells could be blocked by
ICI 182780. A decreasing expression of hERalpha was observed in the ER-responsive cells with overexpression of
ERRalpha (Ishikawa/hERRalpha). Overexpression of hERRalpha inhibits the cell proliferation in the
ERalpha-responsive Ishikawa cells and stimulated the cell proliferation in the
ERalpha-nonresponsive HEC-1A cells. Function of hERRalpha depends on the expression and function of hERalpha. ER-mediated signaling might be the important factor resulting in the
hormone-dependent
endometrial carcinoma, whereas
ERRalpha-mediated pathway might act as the vital role in
hormone-independent
endometrial carcinoma.