Abstract 4207: CCN5/WISP-2 upregulates p27Kip1 in breast cancer cell lines through AKT/FOXO3a signaling

Abstract

Abstract CCN5 is a member of the CCN (cysteine rich 61-connective tissue growth factor-nephroblastoma-overexpressed) family of growth factors. Our studies have shown that CCN5 is mainly expressed in less aggressive human breast cancer cells (i.e., MCF-7 and ZR-75-1) and noninvasive lesion (i.e., atypical ductal hyperplasia and ductal carcinoma in situ), whereas its expression is minimally detected in moderately aggressive breast cancer cell lines (i.e., SKBR-3), and it is undetected in triple negative highly aggressive breast cancer cell line (i.e., MDA-MB-231) and invasive lesion. Ectopic expression of CCN5 has been shown to inhibit tumorigenicity in MDA-MB-231-xenograft models therefore suggesting that CCN5 is an anti-invasive molecule. The objective of the present study was to determine how CCN5 overexpression affects cell-cycle progression of breast cancer cells. We found knocking down of CCN5 in non-invasive breast cancer cells significantly downregulated the expression of p27Kip1, a tumor suppressor molecule. In contrast, enforced/ectopic expression of CCN5 overexpression in MDA-MB-231 breast cancer cells caused cell cycle arrest at G1 phase and dramatically reduced proliferation of these cells. CCN5 overexpression results in increased the stability as well as the expression of p27Kip1 protein. The regulation of p27Kip1 by CCN5 is mediated through AKT/FOXO3a signaling. Collectively, the studies suggest that CCN5 exerts its anti-invasive action through the regulation of p27Kip1. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4207. doi:1538-7445.AM2012-4207