title: Acidic extracellular pH induces matrix metalloproteinase-9 expression in mouse metastatic melanoma cells through the phospholipase D-mitogen-activated protein kinase signaling.
abstract: The extracellular pH (pHe) of tumor tissues is often acidic, which can induce the expression of several proteins. We previously showed that production of matrix metalloproteinase-9 (MMP-9) was induced by culturing cells at acidic pHe (5.4-6.5). Here we have investigated the signal transduction pathway by which acidic pHe induces MMP-9 expression. We found that acidic pHe (5.9) activated phospholipase D (PLD), and inhibition of PLD activity by 1-butanol and Myr-ARF6 suppressed the acidic pHe-induced MMP-9 expression. Exogenous PLD, but not phosphatidylinositol-specific PLC or PLA2, mimicked MMP-9 induction by acidic pHe. Western blot analysis revealed that acidic pHe increased the steady-state levels of phosphorylated extracellular signal-regulated kinases 1/2 and p38 and that the PLD inhibitors suppressed these increases. Using 5'-deletion mutant constructs of the MMP-9 promoter, we found that the acidic pHe-responsive region was located at nucleotide -670 to -531, a region containing the NF kappa B binding site. A mutation into the NF kappa B binding site reduced, but not completely, the acidic pHe-induced MMP-9 promoter activity, and NF kappa B activity was induced by acidic pHe. Pharmacological inhibitors specific for mitogen-activated protein kinase kinase 1/2 (PD098059) and p38 (SB203580) attenuated the acidic pHe-induced NF kappa B activity and MMP-9 expression. These data suggest that PLD, mitogen-activated protein kinases (extracellular signal-regulated kinases 1/2 and p38), and NF kappa B mediate the acidic pHe signaling to induce MMP-9 expression. A transcription factor(s) other than NF kappa B may also be involved in the MMP-9 expression.
authors.affiliation: Department of Otolaryngology and Urology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan. yasumasa@kdcnet.ac.jp
authors.forename: Yasumasa
authors.initials: Y
authors.lastname: Kato
authors.forename: Charles A
authors.initials: CA
authors.lastname: Lambert
authors.forename: Alain C
authors.initials: AC
authors.lastname: Colige
authors.forename: Pierre
authors.initials: P
authors.lastname: Mineur
authors.forename: Agnés
authors.initials: A
authors.lastname: Noël
authors.forename: Francis
authors.initials: F
authors.lastname: Frankenne
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Foidart
authors.forename: Masaya
authors.initials: M
authors.lastname: Baba
authors.forename: Ryu-Ichiro
authors.initials: R
authors.lastname: Hata
authors.forename: Kaoru
authors.initials: K
authors.lastname: Miyazaki
authors.forename: Mamoru
authors.initials: M
authors.lastname: Tsukuda
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D015971:Gene Expression Regulation, Enzymologic; D006863:Hydrogen-Ion Concentration; D048031:JNK Mitogen-Activated Protein Kinases / Q000502:physiology; D020780:Matrix Metalloproteinase 9 / Q000235:genetics*; D008546:Melanoma, Experimental / Q000201:enzymology* / Q000556:secondary; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000502:physiology; D048052:Mitogen-Activated Protein Kinase 3 / Q000502:physiology; D020928:Mitogen-Activated Protein Kinases / Q000502:physiology*; D016328:NF-kappa B / Q000378:metabolism; D010739:Phospholipase D / Q000502:physiology*; D011401:Promoter Regions, Genetic; D015398:Signal Transduction / Q000502:physiology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000502:physiology
chemical_list: D016328:NF-kappa B; D048031:JNK Mitogen-Activated Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D010739:Phospholipase D; D020780:Matrix Metalloproteinase 9