Abstract 4661: The regulatory mechanism of fibronectin in EGFR and/or HER2 positive breast cancer

Abstract

Abstract Fibronectin (FN) is a glycoprotein of the extracellular matrix and plays a major role in cell adhesion, migration and oncogenic transformation. Aberrant FN expression is associated with poor prognosis in a variety of cancers including breast cancer. However, the regulatory mechanism between FN and HER2 is not fully elucidated in breast cancer. Our clinical data showed that both disease free survival (DFS) and overall survival (OS) was lower in EGFR (+) and HER2 (+) breast cancer patients than in EGFR (+) breast cancer patients. To verify the causing of poor prognosis, we analyzed secreted proteins in EGFR and/or HER2 overexpressed MDA-MB231 cells. Our results showed that the level of FN expression was significantly increased in HER2 overexpressed MDA-MB231 cells. On the other hand, the induction of FN by HER2 overexpression was decreased by trastuzumab (HER2 monoclonal antibody) and AG825 (HER2 inhibitor), respectively. In addition, we observed that the expression of FN was dose-dependently increased by EGFR ligands in SKBR3 cells which are expressed endogenous EGFR and HER2. EGF ligands-induced FN expression also decreased through the suppression of HER2 in SKBR3 cell. However, these effects did not detect in trastuzumab-resistant breast cancer cell line, JIMT-1. Taken together, we demonstrated that the induction of FN by HER2 correlates poor clinical outcome in breast cancer patients. Citation Format: Myeongjin Jeon. The regulatory mechanism of fibronectin in EGFR and/or HER2 positive breast cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4661. doi:10.1158/1538-7445.AM2014-4661