title: RhoA mediates the expression of acidic extracellular pH-induced matrix metalloproteinase-9 mRNA through phospholipase D1 in mouse metastatic B16-BL6 melanoma cells.
abstract: Solid tumors are characterized by acidic extracellular pH (pHe). The present study examined the contribution of small GTP-binding proteins to phospholipase D (PLD) activation of acidic pHe-induced matrix metalloproteinase-9 (MMP-9) production. Acidic pHe-induced MMP-9 production was reduced by C3 exoenzyme, which inhibits the Rho family of GTPases; cytochalasin D, which inhibits actin reorganization; and simvastatin, which inhibits geranylgeranylation of Rho. Small interfering RNA (siRNA) against RhoA, but not against Rac1 or Cdc42, significantly inhibited acidic pHe induction of MMP-9. Pull-down assays showed that acidic pHe increased the activated form of RhoA. Forced expression of constitutively active RhoA induced MMP-9 production, even at neutral pHe. RhoA siRNA also reduced acidic pHe induced PLD activity. Specific inhibition of PLD1 and Pld1 gene knockout significantly reduced acidic pHe-induced MMP-9 expression. In contrast, PLD2 inhibition or knockout had no effect on MMP-9 expression. These findings suggested that RhoA-PLD1 signaling is involved in acidic pHe induction of MMP-9.
authors.affiliation: Department of Oral Function and Molecular Biology, Ohu University School of Dentistry, Koriyama 963‑8611, Japan.
authors.forename: Toyonobu
authors.initials: T
authors.lastname: Maeda
authors.affiliation: Department of Oral Function and Molecular Biology, Ohu University School of Dentistry, Koriyama 963‑8611, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Yuzawa
authors.affiliation: Department of Oral Function and Molecular Biology, Ohu University School of Dentistry, Koriyama 963‑8611, Japan.
authors.forename: Atsuko
authors.initials: A
authors.lastname: Suzuki
authors.affiliation: Department of General Clinical Medicine, Ohu University School of Dentistry, Koriyama 963‑8611, Japan.
authors.forename: Yuh
authors.initials: Y
authors.lastname: Baba
authors.affiliation: Kyushu University Graduate School of Pharmaceutical Sciences, Fukuoka 812-8582, Japan.
authors.forename: Yukio
authors.initials: Y
authors.lastname: Nishimura
authors.affiliation: Department of Oral Function and Molecular Biology, Ohu University School of Dentistry, Koriyama 963‑8611, Japan.
authors.forename: Yasumasa
authors.initials: Y
authors.lastname: Kato
mesh_terms: D000199:Actins / Q000737:chemistry; D000818:Animals; D015638:Cytochalasin D / Q000737:chemistry; D015971:Gene Expression Regulation, Enzymologic; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D006863:Hydrogen-Ion Concentration; D020780:Matrix Metalloproteinase 9 / Q000235:genetics / Q000378:metabolism*; D008546:Melanoma, Experimental / Q000378:metabolism*; D051379:Mice; D009362:Neoplasm Metastasis; D009479:Neuropeptides / Q000378:metabolism; D010739:Phospholipase D / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D034741:RNA, Small Interfering / Q000378:metabolism; D015398:Signal Transduction; D019821:Simvastatin / Q000737:chemistry; D020764:cdc42 GTP-Binding Protein / Q000378:metabolism; D020830:rac1 GTP-Binding Protein / Q000378:metabolism; D020741:rho GTP-Binding Proteins / Q000378:metabolism*; D020742:rhoA GTP-Binding Protein
chemical_list: D000199:Actins; C581598:Cdc42 protein, mouse; D009479:Neuropeptides; D034741:RNA, Small Interfering; C484602:Rac1 protein, mouse; D015638:Cytochalasin D; D019821:Simvastatin; D010739:Phospholipase D; C106801:phospholipase D1; D020780:Matrix Metalloproteinase 9; C501830:Mmp9 protein, mouse; C526380:RhoA protein, mouse; D020764:cdc42 GTP-Binding Protein; D020830:rac1 GTP-Binding Protein; D020741:rho GTP-Binding Proteins; D020742:rhoA GTP-Binding Protein