Abstract 4769: Growth hormone-releasing hormone (GHRH) antagonist attenuates cell motility of human endometrial cancer by down-regulating Twist and N-Cadherin expression.

Abstract

Abstract Introduction : More than 25% of patients diagnosed with endometrial carcinoma have an invasive primary cancer accompanied by metastases. GHRH is secreted by the hypothalamus and stimulates the synthesis and secretion of GH from the pituitary. The expression of GHRH and its receptors has been demonstrated in peripheral tissues. In recent years, many antagonistic analogs of GHRH were developed. GHRH antagonists have effects on tumor cells, but the underlying molecular mechanism is not well known. Although Twist and N-Cadherin play important roles in cancer cell motility, it is not established whether Twist and N-Cadherin are required for GHRH antagonists-attenuated cell motility on endometrial cancer cells. In the present study, we examined the action of GHRH antagonist-attenuated cell motility and the mechanisms of the action in endometrial cancer. Methods and Materials : Endometrial cancer cell line Ishikawa and ECC-1 were derived from an endometrial adenocarcinoma. GHRH antagonist MIA-602 was synthesized by solid phase methods. Cell motility was estimated by invasion and migration assay. Immunoblot analysis and RT-PCR were performed to investigate the expression of GHRH receptor, GHRH, and the effects of GHRH antagonist in Twist and N-Cadherin. Human GHRH receptor siRNA was used to knock down the expression of GHRH receptor for elucidating the mechanisms of GHRH antagonist action. Results : The GHRH receptor was expressed in human endometrial cancer cells. The GHRH antagonist attenuated cell motility in a dose-dependent manner. GHRH antagonist-attenuated cell motility was restored in cells pretreated with GHRH receptor siRNA. GHRH antagonist suppressed Twist and N-Cadherin signaling. Knockdown of GHRH receptor with siRNA recovered the expression of Twist and N-Cadherin signaling. Conclusions These results demonstrate that the GHRH antagonist suppressed the cell motility of human endometrial cancer through the GHRH receptor and the down-regulation of Twist and N-Cadherin. Our findings represent a new concept regarding the mechanisms of GHRH antagonist-suppressed cell motility in human endometrial cancer, suggesting the possibility of GHRH antagonist as a potential therapeutic intervention for the treatment of human endometrial cancer. Citation Format: Hsien-Ming Wu, Andrew V. Schally, Peter C.K. Leung. Growth hormone-releasing hormone (GHRH) antagonist attenuates cell motility of human endometrial cancer by down-regulating Twist and N-Cadherin expression. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4769. doi:10.1158/1538-7445.AM2013-4769 Note: This abstract was not presented at the AACR Annual Meeting 2013 because the presenter was unable to attend.