A novel variant of ER-alpha, ER-alpha36 mediates testosterone-stimulated ERK and Akt activation in endometrial cancer Hec1A cells

Lin Sheng-Li, Yan Li-Ying, Liang Xing-Wei, Wang Zhen-Bo, Wang Zhao-Yi, Qiao Jie, Schatten Heide, Sun, Sun Qing-Yuan

Description

Endometrial cancer is one of the most common gynecologic malignancies and its incidence has recently increased. Experimental and epidemiological data support that testosterone plays an important role in the pathogenesis of endometrial cancer, but the underlying mechanism has not been fully understood. Recently, we identified and cloned a variant of estrogen receptor (ER) alpha, ER-alpha36. The aim of the present study was to investigate the role of ER-alpha36 in testosterone carcinogenesis. Methods The cellular localization of ER-alpha36 was determined by immunofluorescence. Hec1A endometrial cancer cells (Hec1A/V) and Hec1A cells with siRNA knockdown of ER-alpha36 (Hec1A/RNAi) were treated with testosterone, ERK and Akt phosphorylation was assessed by Western blot analysis. Furthermore, the kinase inhibitors U0126 and LY294002 and the aromatase inhibitor letrozole were used to elucidate the pathway underlying testosterone-induced activities. Results Immunofluorescence shows that ER-alpha36 was localized on the plasma membrane of the both ER-alpha- and androgen receptor-negative endometrial cancer Hec1A cells. Testosterone induced ERK and Akt phosphorylation, which could be abrogated by ER-alpha 36 shRNA knockdown or the kinase inhibitors, U0126 and LY294002, and the aromatase inhibitor letrozole. Conclusion Testosterone induces ERK and Akt phosphorylation via the membrane-initiated signaling pathways mediated by ER-alpha36, suggesting a possible involvement of ER-alpha 36 in testosterone carcinogenesis.

Informations

• Publié par: biomed
• Publié le: 01 janvier 2009
• Nombre de lectures: 35
• Langue: English

Extrait

Reproductive Biology and Endocrinology

BioMedCentral

Open Access Research A novel variant of ERalpha, ERalpha36 mediates testosteronestimulated ERK and Akt activation in endometrial cancer Hec1A cells 1,2 3 1 1,2 ShengLi Lin , LiYing Yan , XingWei Liang , ZhenBo Wang , 4 3 5 1 ZhaoYi Wang , Jie Qiao , Heide Schatten and QingYuan Sun*

1 2 Address: State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China, Graduate School, 3 Chinese Academy of Sciences, Beijing, China, Center of Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University 4 Third Hospital, Beijing, China, Department of Medical Microbiology and Immunology, Creighton University Medical School, Omaha, USA and 5 Department of Veterinary Pathobiology, University of Missouri, Columbia, MO 65211, USA

Email: ShengLi Lin  [e-mail]; LiYing Yan  [e-mail]; XingWei Liang  [e-mail]; Zhen Bo Wang  [e-mail]; ZhaoYi Wang  [e-mail]; Jie Qiao  [e-mail]; Heide Schatten  [e-mail]; QingYuan Sun*  [e-mail] * Corresponding author

Published: 24 September 2009 Received: 27 June 2009 Accepted: 24 September 2009 Reproductive Biology and Endocrinology2009,7:102 doi:10.1186/147778277102 This article is available from: http://www.rbej.com/content/7/1/102 © 2009 Lin et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract Background:Endometrial cancer is one of the most common gynecologic malignancies and its incidence has recently increased. Experimental and epidemiological data support that testosterone plays an important role in the pathogenesis of endometrial cancer, but the underlying mechanism has not been fully understood. Recently, we identified and cloned a variant of estrogen receptor (ER) alpha, ERalpha36. The aim of the present study was to investigate the role of ERalpha36 in testosterone carcinogenesis. Methods:The cellular localization of ERalpha36 was determined by immunofluorescence. Hec1A endometrial cancer cells (Hec1A/V) and Hec1A cells with siRNA knockdown of ERalpha36 (Hec1A/RNAi) were treated with testosterone, ERK and Akt phosphorylation was assessed by Western blot analysis. Furthermore, the kinase inhibitors U0126 and LY294002 and the aromatase inhibitor letrozole were used to elucidate the pathway underlying testosteroneinduced activities. Results:Immunofluorescence shows that ERalpha36 was localized on the plasma membrane of the both ERalpha and androgen receptornegative endometrial cancer Hec1A cells. Testosterone induced ERK and Akt phosphorylation, which could be abrogated by ERalpha 36 shRNA knockdown or the kinase inhibitors, U0126 and LY294002, and the aromatase inhibitor letrozole.

Conclusion:Testosterone induces ERK and Akt phosphorylation via the membraneinitiated signaling pathways mediated by ERalpha36, suggesting a possible involvement of ERalpha 36 in testosterone carcinogenesis.

Page 1 of 8 (page number not for citation purposes)