RESUMEN
OBJECTIVE: The study was undertaken to explore the antiproliferative mechanism of action of 2-[piperidinoethoxyphenyl]-3-[4-hydroxyphenyl]-2H-benzo(b)pyran (K-1) in estradiol-induced rat uterine hyperplasia. STUDY DESIGN: Adult ovariectomized rats received vehicle or estradiol alone (20 µg/kg) or estradiol along with K-1 (100 or 200 µg/kg) for 14 days. Uterine histomorphometric analysis and immunoblotting were performed. Caspase-3 activity and terminal deoxynucleotidyl transferase-mediated nick end-labeling staining were performed to analyze the apoptotic potential of compound. RESULTS: Compound inhibited estradiol-induced uterine weight and histomorphometric changes pertaining to endometrial growth and down-regulated the expression of estrogen response element and activator protein-1 regulated genes and transcription factors. The compound significantly induced apoptosis, interfered with Akt activation, decreased X-linked inhibitor of apoptosis protein expression leading to an increased cleavage of caspase-9, caspase-3, poly(adenosine diphosphate-ribose) polymerase, increased Bax/Bcl2 ratio, and caspase-3 activity. CONCLUSION: K-1 inhibits endometrial proliferation via nonclassical estrogen receptor signaling mechanisms. It interfered with Akt activation and induced apoptosis via the intrinsic pathway and inhibited estradiol-induced hyperplasia formation in rat uterus.