Role of phospholipase D in laminin-induced production of gelatinase A (MMP-2) in metastatic cells.
Metastatic spread depends critically upon the invasiveness of tumor cells, i.e. their ability to breach basement membranes by elaborating and secreting specific proteolytic enzymes such as gelatinase A (MMP-2). Laminin is a major constituent of the extracellular matrix that can trigger production of MMP-2 in metastatic cells, but not in non-metastatic cells. The present study was designed to examine the role of phospholipase D (PLD) and its product, phosphatidic acid, in the intracellular signal transduction mechanisms that mediate induction of MMP-2 by laminin. Here we show that stimulation of tumor cells with laminin results in a time- and dose-dependent activation of PLD. Laminin-induced production of MMP-2 is attenuated by 1-butanol, a competitive substrate of PLD that reduces PLD-catalyzed production of PA. Moreover, phosphatidic acid itself can induce production of MMP-2 in metastatic tumor cells. MMP-2 can also be induced by exposing the cells to exogenous bacterial PLD. Elevated cellular phosphatidic acid induces MMP-2 in metastatic ras-transformed 3T3 fibroblasts but, like laminin, fails to do so in normal cells. These data indicate that laminin-induced activation of PLD and consequent generation of phosphatidic acid are involved in a signal propagation pathway leading to induction of MMP-2 and enhanced invasiveness of metastatic tumor cells.
Reich
R
R
Department of Pharmacology, Hebrew University of Jerusalem, Israel.
Blumenthal
M
M
Liscovitch
M
M
D016475:3T3 Cells; D000818:Animals; D005354:Fibrosarcoma / Q000201:enzymology; D018093:Gelatinases / Q000096:biosynthesis*; D006801:Humans; D007797:Laminin / Q000494:pharmacology*; D020778:Matrix Metalloproteinase 2; D008666:Metalloendopeptidases / Q000096:biosynthesis*; D051379:Mice; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D010739:Phospholipase D / Q000502:physiology*; D014407:Tumor Cells, Cultured
D007797:Laminin; D010739:Phospholipase D; D018093:Gelatinases; D008666:Metalloendopeptidases; D020778:Matrix Metalloproteinase 2