title: Up-regulation of alphavbeta3 integrin expression is a novel molecular response to chemotherapy-induced cell damage in a heregulin-dependent manner.
abstract: alpha(v)beta(3) integrin has a dual role in apoptosis. Whereas ligated alpha(v)beta(3) activates cell survival pathways and suppresses pro-apoptotic signals, unligated alpha(v)beta(3) or integrins bound to soluble ligands promote apoptosis. In this study, we assessed the role of alpha(v)beta(3) in chemosensitivity of breast cancer cells expressing different levels of heregulin (HRG). Expression levels of the RGD-binding integrins alpha(v)beta(3) were measured in MDA-MB-231 human breast cancer cells and its low HRG-expressing derivative (MDA-MB-231/AS31) treated with the microtubule-interfering agents (MIAs) paclitaxel and vincristine. Following treatment, only alpha(v)beta(3) levels were significantly increased in MDA-MB-231 cells. Interestingly, alpha(v)beta(3) expression was more significantly up-regulated in the MDA-MB-231/AS31 cells than in the parental cells. This MIA-induced increase of alpha(v)beta(3) expression was correlated with a decrease in cell viability and an increase in apoptosis in MDA-MB-231/AS31 cells, indicating that overexpression of alpha(v)beta(3) is linked to chemotherapy-induced cell death in low HRG-expressing breast cancer models. Moreover, a paclitaxel-induced increase of alpha(v)beta(3) was also observed in MCF-7 cells but not in an doxorubicin-resistant derivative that shows cross-resistance to paclitaxel, further providing evidence that the extent of alpha(v)beta(3) up-regulation is related to cell damage. These results indicate that alpha(v)beta(3) integrin is dramatically up-regulated in low HRG-expressing breast cancer models that are highly responsive to MIAs, thus providing a novel molecular marker of chemosensitivity influenced by HRG levels in breast cancer cells.
authors.affiliation: Department of Medicine, Breast Cancer Translational Research Laboratory, Evanston Northwestern Healthcare Research Institute, 1001 University Place, Evanston, IL, USA.
authors.forename: Luciano
authors.initials: L
authors.lastname: Vellon
authors.forename: Javier A
authors.initials: JA
authors.lastname: Menendez
authors.forename: Hong
authors.initials: H
authors.lastname: Liu
authors.forename: Ruth
authors.initials: R
authors.lastname: Lupu
mesh_terms: D017209:Apoptosis; D001943:Breast Neoplasms / Q000737:chemistry / Q000188:drug therapy* / Q000378:metabolism; D045744:Cell Line, Tumor; D019008:Drug Resistance, Neoplasm; D005260:Female; D006801:Humans; D039302:Integrin alphaVbeta3 / Q000032:analysis / Q000378:metabolism*; D008870:Microtubules / Q000187:drug effects; D020890:Neuregulin-1 / Q000032:analysis / Q000378:metabolism*; D017239:Paclitaxel / Q000494:pharmacology / Q000627:therapeutic use; D050257:Tubulin Modulators / Q000494:pharmacology* / Q000627:therapeutic use; D015854:Up-Regulation; D014750:Vincristine / Q000494:pharmacology / Q000627:therapeutic use
chemical_list: D039302:Integrin alphaVbeta3; D020890:Neuregulin-1; D050257:Tubulin Modulators; D014750:Vincristine; D017239:Paclitaxel