αVβ3 integrin regulates heregulin (HRG)-induced cell proliferation and survival in breast cancer
- 14 March 2005
- journal article
- Published by Springer Science and Business Media LLC in Oncogene
- Vol. 24 (23), 3759-3773
- https://doi.org/10.1038/sj.onc.1208452
Abstract
Alpha(v)beta(3) integrin-overexpression in tumor associated vasculature is a marker of poor prognosis in breast cancer. A positive correlation between alpha(v)beta(3) integrin and overexpression of Heregulin (HRG), a growth factor associated with breast cancer aggressiveness was recently demonstrated. Here, we addressed the role of alpha(v)beta(3) in the proliferation and survival of HRG-overexpressing breast cancer models. Expression of the RGD-binding integrins alpha(v)beta(3), alpha(v)beta(5) and alpha(v)beta(6) was assessed in the HRG-overexpressing breast cancer cells MDA-MB-231, Hs578T (231/WT and Hs578T/WT, respectively) and derived cells transfected with the antisense orientation of the HRG-beta2 full-length cDNA (231/ASPOOL, 231/AS31 and Hs578T/AS15). Interestingly, only alpha(v)beta(3) expression was noticeably decreased by blockade of HRG expression in the 231/ASPOOL, 231/AS31 and Hs578T/AS15 cells. Small RGD-based peptidomimetic alpha(v)beta(3) antagonists significantly decreased cell viability and anchorage-dependent cell growth of HRG-overexpressing cells, while the low-HRG-expressing 231/AS31 cells did not show a significant response. Mechanistically, functional blockade of alpha(v)beta(3) impaired HRG-promoted hyperactivation of ERK1/ERK2 MAPK without altering the activation of AKT. Flow cytometric analysis of the cell cycle demonstrated that alpha(v)beta(3) antagonists significantly decreased S- and G2/M-phase subpopulations of 231/WT and control 231/VEC cells. Comparable, this effect was linked to an increase in the levels and nuclear translocation of the CDKs inhibitor p27(Kip1). Besides downregulating alpha(v)beta(3) and its driven signaling, HRG blockade led to decreased levels of CYR61 in 231/ASPOOL and 231/AS31 cells. Considering that CYR61 is sufficient to upregulate the expression of alpha(v)beta(3), we then assessed alpha(v)beta(3) levels in MDA-MB-231 cell derivatives expressing the antisense orientation of the CYR61 cDNA (231/CYR61AS-5 and 231/CYR61AS-8). Remarkably, downregulation of CYR61 drastically decreased the levels of alpha(v)beta(3) in the 231/CYR61-5 and 231/CYR61-8 cells, providing further evidence of a key role for CYR61 in HRG-dependent alpha(v)beta(3) overexpression. Moreover, blockade of CYR61 expression impaired the HRG-induced hyperactivation of ERK1/ERK2 MAPK without altering the activation status of AKT in MDA-MB-231 cells, thus resembling the effects exerted by the downregulation of HRG expression as well as by functional blockade of alpha(v)beta(3). These results indicate that HRG is regulating alpha(v)beta(3) levels as well as alpha(v)beta(3)-triggered signaling through its downstream effector, CYR61, in highly invasive breast cancer cells. Altogether, the data presented here provide evidence of a CYR61-regulatory role on alpha(v)beta(3) integrin expression in the modulation of uncontrolled growth of HRG-overexpressing breast carcinomas. This work supports additional studies concerning the use of integrin antagonists as dual therapeutic agents in breast cancer, targeting both, endothelial and tumor cells.Keywords
This publication has 27 references indexed in Scilit:
- Cyr61 Expression Confers Resistance to Apoptosis in Breast Cancer MCF-7 Cells by a Mechanism of NF-κB-dependent XIAP Up-RegulationJournal of Biological Chemistry, 2004
- Endothelial cell integrins and COX-2: mediators and therapeutic targets of tumor angiogenesisBiochimica et Biophysica Acta (BBA) - Reviews on Cancer, 2004
- Bimolecular Interaction of Insulin-Like Growth Factor (IGF) Binding Protein-2 with αvβ3 Negatively Modulates IGF-I-Mediated Migration and Tumor GrowthCancer Research, 2004
- αv integrins regulate cell proliferation through integrin-linked kinase (ILK) in ovarian cancer cellsOncogene, 2003
- ERK1 Associates with αvβ3 Integrin and Regulates Cell Spreading on VitronectinPublished by Elsevier BV ,2003
- Activation of metalloproteinases and their association with integrins: an auxiliary apoptotic pathway in human endothelial cellsCell Death & Differentiation, 2002
- Cyr61 promotes breast tumorigenesis and cancer progressionOncogene, 2002
- Integrin αvβ3 expression confers on tumor cells a greater propensity to metastasize to boneThe FASEB Journal, 2002
- Concept and progress in the development of RGD‐containing peptide pharmaceuticalsPeptide Science, 1995
- Integrins: Versatility, modulation, and signaling in cell adhesionCell, 1992