Expression Of Mas1 In Triple-Negative Breast Cancer

Proceedings: AACR 106th Annual Meeting 2015; April 18-22, 2015; Philadelphia, PAMAS1 is a receptor for angiotensin 1-7 (A1-7), which is derived from angiotensin II (A-II) by the action of angiotensin converting enzyme (ACE) 2. We examined the role of MAS1 in 132 cases of invasive ductal carcinoma (IDC) of the breast by using immunohistochemistry. While normal mammary tissues expressed MAS1 at high levels, MAS1 expression was attenuated in all IDCs, especially in scirrhous IDCs. The decrease in MAS1 expression was associated with tumor growth, lymph node metastasis, and grade. MAS1 expression was inversely associated with the proliferation index and epidermal growth factor receptor and human epidermal growth factor receptor-2 expression. Of the 132 cases, 12 (9.1%) were triple-negative breast cancer (TNBC) cases. Using the mouse TNBC cell line 4T1, which expresses MAS1, we found that cell growth, anti-apoptotic survival, and invasion were suppressed by A1-7 treatment and enhanced by MAS1 knockdown. Combination treatment with cisplatin, an ACE2 activator, and an A-II type 1 receptor blocker showed synergic effects on tumor growth inhibition. These findings suggest that MAS1 might be a pivotal molecular target for TNBC.Note: This abstract was not presented at the meeting.Citation Format: Yi Luo, Yasuhiko Kitadai, Yukiko Nishiguchi, Rina Fujiwara, Takamitsu Sasaki, Hitoshi Ohmori, Hiroki Kuniyasu. Expression of MAS1 in triple-negative breast cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1868. doi:10.1158/1538-7445.AM2015-1868