LPA-mediated migration of ovarian cancer cells involves translocalization of Gαi2 to invadopodia and association with Src and β-pix

Lysophosphatidic acid (LPA) plays a critical role in the migration and invasion of ovarian cancer cells. However, the downstream spatiotemporal signaling events involving specific G protein(s) underlying this process are largely unknown. In this report, we demonstrate that LPA signaling causes the translocation of G alpha(i2) into the invadopodia leading to its interaction with the tyrosine kinase Src and the Rac/CDC42-specific guanine nucleotide exchange factor, beta-pix. Our results establish that G alpha(i2) activates Rac1 through a p130Cas-dependent pathway in ovarian cancer cells. Moreover, our report reveals that knockdown of G alpha(i2) leads to loss of beta-pix and active-Rac association in the invadopodia. We also show that knockdown of G alpha(i2) leads to the complete loss of translocation to p130Cas to focal adhesions. Finally, when G alpha(i2) is knocked down, this led to the total distribution of Src being shifted primarily from invadopodia and the leading edge of the cells to the perinuclear region, suggesting that Src is inactive in the absence of G alpha(i2). Overall, our report provides tantalizing evidence that G alpha(i2) is a critical signaling component of a large signaling complex in the invadopodia that if disrupted could serve as an excellent target for therapy in ovarian and potentially other cancers. (C) 2014 Elsevier Ireland Ltd. All rights reserved.