[Membrane-initiated nongenomic effect on mitogen-activated protein kinase signal transduction of estrogen in endometrial carcinoma cell].

OBJECTIVE:To study the nongenomic effect on mitogen-activated kinase (MAPK) signal transduction of 17beta-estradiol at plasma membrane in endometrial cancer cell Ishikawa. METHODS:Estradiol-bovine serum albumin conjugates (E(2)-BSA) was added to Ishikawa cells at different time points. Western blot was used to detect the protein expression of phosphorylated extracellular signal-regulated kinase (ERK) 1/2. Confocal was used to verify if the phosphorylation of ERK1/2 was initiated at the membrane. RESULTS:Phosphorylation of ERK1/2 was elicited after 5 minute exposure to 1 x 10(-7) mol/L E(2)-BSA. It was induced to a maximum following 60 minute exposure and descended after 2 hours. The expression levels of phosphorylated ERK1/2 were 0.52, 0.98, and 0.09, respectively. Confocal proved that E(2)-BSA combined with membrane receptors after 5 minutes and elevated the phosphorylation of ERK1/2. CONCLUSION:Membrane actions of estrogen can activate the rapid signaling cascades of MAPK in endometrial carcinoma cells.