HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) An erratum has been published Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Cong, L. Articles by Zhao, A. Z Search for Related Content PubMed PubMed Citation Articles by Cong, L. Articles by Zhao, A. Z

¹ Department of Cell Biology and Physiology, University of Pittsburgh, S-326, BSTWR, 3500 Terrace Street, Pittsburgh, Pennsylvania 15261, USA
² Department of Endocrinology and Metabolism, The Second Affiliated Hospital, Harbin Medical University, Harbin, 150086 China

(Requests for offprints should be addressed to A Z Zhao; Email: azhao{at}pitt.edu)

Obesity is one of the well-established risk factors for endometrial cancer. Recent clinical studies have demonstrated that circulating adiponectin concentrations are inversely correlated with the incidence of endometrial carcinoma. Such epidemiological findings are consistent with the paradoxical observations that adiponectin levels are reduced in obesity. This study investigated the direct effects of adiponectin on two endometrial carcinoma cell lines, HEC-1-A and RL95–2. These cell lines express both variants of adiponectin receptors, adipo-R1 and adipo-R2. Adiponectin treatment leads to suppression of cell proliferation in both cell types, which is primarily due to the significant increase of cell populations at G₁/G₀-phase and to the induction of apoptosis. The inhibition of growth in these two cell lines appears to be mediated by different signaling pathways. Although adiponectin treatment markedly increases the phosphorylation (Thr172) of AMP-activated protein kinase in both HEC-1-A and RL95–2 within 30 min, prolonged exposure (48 h) leads to inactivation of Akt as well as reduction of cyclin D1 protein expression in HEC-1-A cells. In contrast, similar treatment of RL95–2 cells with adiponectin, while having no effects on Akt activity and cyclin D1 expression, causes a decrease in cyclin E2 expression and the activity of mitogen-activated kinase (p42/44). We conclude that adiponectin exerts direct anti-proliferative effects on HEC-1-A and RL95–2 cells by inducing cell cycle arrest and apoptosis. Depending on the genotypes of the endometrial cancer cells, the inhibitory effects of adiponectin are associated with the reduction of different pro-growth regulators of cell cycle and signaling proteins. Our study thus provides a cellular mechanism underlying the linkages between endometrial cancer and obesity.