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- Title
β-Arrestin2 Regulates Lysophosphatidic Acid-Induced Human Breast Tumor Cell Migration and Invasion <i>via</i> Rap1 and IQGAP1.
- Authors
Alemayehu, Mistre; Dragan, Magdalena; Pape, Cynthia; Siddiqui, Iram; Sacks, David B.; Di Guglielmo, Gianni M.; Babwah, Andy V.; Bhattacharya, Moshmi
- Abstract
β-arrestins play critical roles in chemotaxis and cytoskeletal reorganization downstream of several receptor types, including G protein-coupled receptors (GPCRs), which are targets for greater than 50% of all pharmaceuticals. Among them, receptors for lysophosphatidic acid (LPA), namely LPA1 are overexpressed in breast cancer and promote metastatic spread. We have recently reported that β-arrestin2 regulates LPA1-mediated breast cancer cell migration and invasion, although the underlying molecular mechanisms are not clearly understood. We show here that LPA induces activity of the small G protein, Rap1 in breast cancer cells in a β-arrestin2-dependent manner, but fails to activate Rap1 in non-malignant mammary epithelial cells. We found that Rap1A mRNA levels are higher in human breast tumors compared to healthy patient samples and Rap1A is robustly expressed in human ductal carcinoma in situ and invasive tumors, in contrast to the normal mammary ducts. Rap1A protein expression is also higher in aggressive breast cancer cells (MDA-MB-231 and Hs578t) relative to the weakly invasive MCF-7 cells or non-malignant MCF10A mammary cells. Depletion of Rap1A expression significantly impaired LPA-stimulated migration of breast cancer cells and invasiveness in three-dimensional Matrigel cultures. Furthermore, we found that β-arrestin2 associates with the actin binding protein IQGAP1 in breast cancer cells, and is necessary for the recruitment of IQGAP1 to the leading edge of migratory cells. Depletion of IQGAP1 blocked LPA-stimulated breast cancer cell invasion. Finally, we have identified that LPA enhances the binding of endogenous Rap1A to β-arrestin2, and also stimulates Rap1A and IQGAP1 to associate with LPA1. Thus our data establish novel roles for Rap1A and IQGAP1 as critical regulators of LPA-induced breast cancer cell migration and invasion.
- Subjects
CANCER research; ARRESTINS; LYSOPHOSPHOLIPIDS; BREAST cancer treatment; CANCER cells; CELL migration; RAP1 proteins; GTPASE-activating protein; CELLULAR signal transduction
- Publication
PLoS ONE, 2013, Vol 8, Issue 2, p1
- ISSN
1932-6203
- Publication type
Article
- DOI
10.1371/journal.pone.0056174