Expression of (pro)renin receptor in breast cancers and its effect on cancercell proliferation

Abstract

(Pro)renin receptor ((P)RR) is a specific receptor for renin and prorenin. The aim of the presentstudy is to clarify expression of (P)RR and pathophysiological roles of (P)RR in human breastcarcinomas. (P)RR expression was studied in 69 clinical cases of breast carcinoma by immunohistochemistry.Effects of (P)RR on cell proliferation were examined in cultured human breast carcinomacells using (P)RR specific small interference RNA. Immunohistochemistry showed that(P)RR immunoreactivity was detected in the breast carcinoma cells in 50 of 69 cases of breastcarcinoma (72%). The analysis on association between (P)RR immunoreactivity and clinicopathologicalparameters showed that the number of (P)RR positive cases was significantly greater inKi-67 (a cell proliferation marker) ≥ 10% group than in Ki-67 < 10% group (P = 0.02). (P)RR wasexpressed in 4 types of human breast carcinoma cell lines. (P)RR specific small interference RNAinhibited proliferation of both MCF-7 (ERα positive) and SK-BR-3 (ERα negative) cells. Thepresent study has shown, for the first time, the expression of (P)RR in human breast carcinomatissues and cultured breast carcinoma cell lines. These findings have raised the possibility that theblockade of the (P)RR signaling may be a novel therapeutic strategy against breast carcinomas.