Involvement of LPA receptor-5 in the enhancement of cell motile activity by phorbol ester and anticancer drug treatments in melanoma A375 cells

Abstract Lysophosphatidic acid (LPA) signaling through six subtypes of LPA receptors (LPA 1 to LPA 6 ) regulates a variety of biological responses in cancer cells. The aim of our study was to evaluate an involvement of LPA receptors in the activation of cell motility by phorbol ester and anticancer drug treatments in melanoma A375 cells. Cells were treated with 12-O-tetradecanoylphorbol- 13-acetate (TPA) and phorbol-12,13-dibutyrate (PDBu) for 3 days. The cell motile activity of TPA treated cells was significantly higher than that of PDBu treated cells, correlating with LPAR5 expression levels. LPA 5 knockdown suppressed the high cell motile activity induced by TPA. To assess whether the cell motile activity of A375 cells is stimulated through LPA 5 induced by anticancer drugs, the long-term cisplatin (CDDP) and dacarbazine (DTIC) treated cells were generated from A375 cells (A375-CDDP and A375-DTIC cells, respectively). The expression levels of LPA receptor genes were changed in A375-CDDP and A375-DTIC cells. In particular, CDDP and DTIC treatment markedly elevated LPAR5 expressions. The cell motile activities of A375-CDDP and A375-DTIC cells were significantly higher than that of untreated cells. These results suggest that the cell motile activity is regulated through the induction of LPA 5 by phorbol ester and anticancer drug treatments in A375 cells.