Abstract
Phosphatidic acid (PA) is a key bioactive glycerophospholipid that is implicated in the regulation of vital cell functions such as cell growth, differentiation, and migration, and is involved in a variety of pathologic processes. However, the molecular mechanisms by which PA exerts its pathophysiological actions are incompletely understood. In the present work, we demonstrate that PA stimulates the migration of the human non-small cell lung cancer (NSCLC) A549 adenocarcinoma cells, as determined by the transwell migration assay. PA induced the rapid phosphorylation of mitogen-activated protein kinases (MAPKs) ERK1-2, p38, and JNK, and the pretreatment of cells with selective inhibitors of these kinases blocked the PA-stimulated migration of cancer cells. In addition, the chemotactic effect of PA was inhibited by preincubating the cells with pertussis toxin (PTX), a Gi protein inhibitor, suggesting the implication of a Gi protein-coupled receptor in this action. Noteworthy, a blockade of LPA receptor 1 (LPA1) with the specific LPA1 antagonist AM966, or with the selective LPA1 inhibitors Ki1645 or VPC32193, abolished PA-stimulated cell migration. Moreover, PA stimulated the phosphorylation of the transcription factor STAT3 downstream of JAK2, and inhibitors of either JAK2 or STAT3 blocked PA-stimulated cell migration. It can be concluded that PA stimulates lung adenocarcinoma cell migration through an interaction with the LPA1 receptor and subsequent activation of the MAPKs ERK1-2, p38, and JNK, and that the JAK2/STAT3 pathway is also important in this process. These findings suggest that targeting PA formation and/or the LPA1 receptor may provide new strategies to reduce malignancy in lung cancer.