Lysophosphatidic acid signaling via LPA 1 and LPA 3 regulates cellular functions during tumor progression in pancreatic cancer cells.

Lysophosphatidic acid (LPA) signaling via G protein-coupled LPA receptors exhibits a variety of biological effects, such as cell proliferation, motility and differentiation. The aim of this study was to evaluate the roles of LPA1 and LPA3 in cellular functions during tumor progression in pancreatic cancer cells. LPA1 and LPA3 knockdown cells were generated from PANC-1 cells. The cell motile and invasive activities of PANC-1 cells were inhibited by LPA1 and LPA3 knockdown. In gelatin zymography, LPA1 and LPA3 knockdown cells indicated the low activation of matrix metalloproteinase-2 (MMP-2) in the presence of LPA. Next, to assess whether LPA1 and LPA3 regulate cellular functions induced by anticancer drug, PANC-1 cells were treated with cisplatin (CDDP) for approximately 6 months. The cell motile and invasive activities of long-term CDDP treated cells were markedly higher than those of PANC-1 cells, correlating with the expression levels of LPAR1 and LPAR3 genes. In soft agar assay, the long-term CDDP treated cells formed markedly large sized colonies. In addition, the cell motile and invasive activities enhanced by CDDP were significantly suppressed by LPA1 and LPA3 knockdown as well as colony formation. These results suggest that LPA signaling via LPA1 and LPA3 play an important role in the regulation of cellular functions during tumor progression in PANC-1 cells.