Catecholestradiol Activation of Adrenergic Receptors Induces Endometrial Cell Survival via p38 MAPK Signaling.

CONTEXT Enhanced levels of catecholestradiols, 2-OHE2 or 4-OHE2, are reported in endometriosis. During gestation, catecholestradiol activation of adrenergic receptors (AR) elevates estrogen receptor (ER)-independent proliferation of uterine arterial endothelial cells. OBJECTIVE To investigate β-AR-mediated catecholestradiol effects on human endometrial stromal cell (HESC) and epithelial cell survival in endometriosis. DESIGN β-AR immunostaining of eutopic and ectopic endometria (n=9). Assays for cell viability, BrdU proliferation, apoptosis, q-PCR, and estrogenicity (alkaline phosphatase activity), as well as siRNA β-AR silencing and immunoblot analyses of cultured HESCs or Ishikawa cells treated with control or 2-OHE2 or 4-OHE2 ±β-AR antagonist or ±p38 MAPK inhibitor. SETTING University research institution. PATIENTS Women ±endometriosis. INTERVENTIONS None. MAIN OUTCOME MEASURES β-AR expression in eutopic vs. ectopic endometria and regulation of HESC survival by 2-OHE2 and 4-OHE2. RESULTS Eutopic and ectopic endometrial stromal and epithelial cells displayed β2-AR immunoreactivity with increased staining in the functionalis vs. basalis layer (P<0.05). Both 2-OHE2 and 4-OHE2 enhanced HESC and Ishikawa cell survival (P<0.05), an effect abrogated by β-AR antagonist propranolol, but not ER antagonist ICI182,780. 2-OHE2 or 4-OHE2 failed to induce cell survival and estrogenic activity in ADRB2-silenced HESCs and in Ishikawa cells, respectively. While 2-OHE2 inhibited apoptosis and BAX mRNA expression, 4-OHE2 induced proliferation and decreased apoptosis (P<0.05). Both catecholestradiols elevated phospho-p38 MAPK levels (P<0.05), which was blocked by propranolol, and p38 MAPK inhibitor reversed catecholestradiol-enhanced HESC survival. CONCLUSIONS Catecholestradiols increase endometrial cell survival by an ER-independent β-AR-mediated p38 MAPK activation, suggesting that agents blocking β-AR, e.g., propranolol, or inhibiting 2-OHE2- or 4-OHE2-generating enzymes (i.e., CYP1A1/B1) could treat endometriosis.