Hormonal regulation of G i2 and mPR in immortalized human oviductal cell line OE-E6/E7

Heterotrimeric G proteins play a key role in membrane-mediated cell-signalling and hormonal regulation. Our earlier studies gave evidence of G protein subunit Galpha(i2) being under hormonal regulation in human in vivo. In this study, we used immortalized human oviduct epithelial cell line OE-E6/E7 as a model to study the hormonal regulation of Galpha(i2). We aimed at clarifying whether estradiol or progesterone could individually regulate the expression of Galpha(i2) and its potential signalling partners. Furthermore, we aimed to investigate which sex hormone receptors could potentially mediate the gene regulation in OE-E6/E7 cell line. OE-E6/E7 cells were cultured for 5 days with different concentrations of estradiol or progesterone. Quantitative real-time polymerase chain reaction (Q-PCR) was performed using cDNA of the hormone-treated cells to reveal any changes in gene expression. The presence of potential receptor targets in these cells was studied using PCR. Our data clearly showed that low concentrations of estradiol up-regulated the expression of Galpha(i2) gene and down-regulated the expression of membrane progesterone receptor mPRalpha gene in OE-E6/E7 cell line. Progesterone had no significant effect on Galpha(i2) gene expression, but it caused up-regulation of mPRalpha gene expression. In conclusion, it appears that sex hormones regulate the expression of Galpha(i2) and mPRalpha genes in a reverse manner in OE-E6/E7 cells. Our results suggest that estrogen receptor ERbeta mediates the regulatory effects of estradiol in these cells.