Lysophosphatidic acid regulates the motility of MCF10CA1a breast cancer cell sheets via two opposing signaling pathways.

Aberrant cell migration leads to the dispersal of malignant cells. The ubiquitous lipid mediator lysophosphatidic acid (LPA) modulates cell migration and is implicated in tumor progression. Yet, the signaling cascades that regulate LPA's effect on cell motility remain unclear. Using time-lapse imaging and quantitative analyses, we studied the role of signaling cascades that act downstream of LPA on the motility of MCF10CA1a breast cancer cells. We found that LPA alters cell motility via two major signaling pathways. The Rho/ROCK signaling cascade is the predominant pathway that increases E-Cadherin containing cell-cell adhesions and cortical arrangement of actomyosin to promote slow, directional, spatially coherent and temporally consistent movement. In contrast, Gα- and Gα-dependent signaling cascades lessen directionality and support the independent movement of cells. The net effect of LPA on breast cancer cell migration therefore results from the integrated signaling activity of the Rho/ROCK and Gα- and Gα-dependent pathways, thus allowing for a dynamic migratory response to changes in the cellular or microenvironmental context.