Tohru Oyama

Enhanced production of vascular endothelial growth factor by human monocytic cells stimulated with endotoxin through transcription factor SP-1

The effect of endotoxin on the regulation of vascular endothelial growth factor (VEGF) mRNA expression in human monocytic (THP-1) cells was examined. Endotoxic lipopolysaccharide (LPS) from Escherichia coli and synthetic E. coli-type lipid A (LA-15-PP) enhanced VEGF mRNA expression. LPS-induced VEGF mRNA accumulation was regulated, at least in part, at the transcriptional level. Enhancement of VEGF gene expression by LPS was shown by gel shift analysis and use of transcription factor inhibitors to be mediated via the activation of SP-1.

Roxithromycin Inhibits Constitutive Activation of Nuclear Factor κB by Diminishing Oxidative Stress in a Rat Model of Hepatocellular Carcinoma

Purpose: Recently, 14-member macrolide antibiotics such as clarithromycin and roxithromycin have been shown to have anticancer and antiangiogenic effects. We investigated the suppressive effect of roxithromycin on accelerated hepatocellular carcinoma growth in a rat hepatocarcinogenetic model and compared results with effects from TNP-470. Experimental Design: Tumor was induced by oral diethylnitrosamine administration for 17 weeks. Normal saline, TNP-470 (50 mg/kg), or roxithromycin (40 or 100 mg/kg) was administered i.p. thrice per week from week 10 to 17. Results: Carcinomatous tissue growing outside dysplastic nodules and a marked expression of placental glutathione S-transferase were detected in rats with induced carcinogenesis. Tumor growth was accompanied by augmented expression of inducible nitric oxide synthase, activation of nuclear factor κB, and increased lipid peroxidation level. All these effects were absent in animals that received roxithromycin or TNP-470. The inhibitory effect of roxithromycin was dose dependent and no clear differences were noted between groups given roxithromycin 100 mg/kg and TNP-470 50 mg/kg. Conclusions: Our results indicate that roxithromycin inhibits oxidative stress, nitric oxide production, and nuclear factor κB activation induced by experimental hepatocarcinogenesis. The data provide additional evidence for the potential use of roxithromycin in treatment of hepatocellular carcinoma prevention.

Anandamide Induces Matrix Metalloproteinase-2 Production through Cannabinoid-1 Receptor and Transient Receptor Potential Vanilloid-1 in Human Dental Pulp Cells in Culture

INTRODUCTION Anandamide (N-arachidonoylethanolamine [AEA]) is one of the main endocannabinoids. Endocannabinoids are implicated in various physiological and pathologic functions, inducing not only nociception but also regeneration and inflammation. The role of the endocannabinoid system in peripheral organs was recently described. The aim of this study was to investigate the effect of AEA on matrix metalloproteinase (MMP)-2 induction in human dental pulp cells (HPC). METHODS We examined AEA-induced MMP-2 production and the expression of AEA receptors (cannabinoid [CB] receptor-1, CB2, and transient receptor potential vanilloid-1 [TRPV1]) in HPC by Western blot. MMP-2 concentrations in supernatants were determined by enzyme-linked immunosorbent assay. We then investigated the role of the AEA receptors and mitogen-activated protein kinase in AEA-induced MMP-2 production in HPC. RESULTS AEA significantly induced MMP-2 production in HPC. HPC expressed all 3 types of AEA receptor (CB1, CB2, and TRPV1). AEA-induced MMP-2 production was blocked by CB1 or TRPV1 antagonists and by small interfering RNA for CB1 or TRPV1. Furthermore, c-Jun N-terminal kinase inhibitor also reduced MMP-2 production. CONCLUSIONS We demonstrated for the first time that AEA induced MMP-2 production via CB1 and TRPV1 in HPC.

Runt‐related gene 2 is involved in the inhibition of matrix metalloproteinase‐13 expression by roxithromycin in human gingival epithelial cell cultures

BACKGROUND AND OBJECTIVE Matrix metalloproteinase (MMP)-13 has wide substrate specificity compared with other MMPs and appears to be involved in periodontitis. Previously, we reported that roxithromycin (RXM) inhibits vascular endothelial growth factor expression induced by tumour necrosis factor-alpha in human periodontal ligament cells, but little is known about the effect of RXM on MMP-13 expression in human gingival epithelial cells. We therefore examined the effect of RXM on MMP-13 mRNA expression and production in cultured human gingival epithelial cells. MATERIAL AND METHODS Human epithelial cell lines (Ca9-22, TU4, SCCTF and HSC-3) were plated in tissue culture dishes. Then, the culture supernatants and sediments were collected and the production of MMP-13 was analysed using enzyme-linked immunosorbent assay; the expression of MMP-13 mRNA and runt-related gene 2 mRNA was assessed using reverse transcriptase-polymerase chain reaction (RT-PCR) and real-time RT-PCR. We also studied the effect of Runx2 short interfering RNA (siRNA) on the induction of MMP-13. RESULTS Roxithromycin downregulated the induction of MMP-13 in Ca9-22 cells. Roxithromycin suppressed the expression of MMP-13 mRNA not only in Ca9-22 cells, but also in other human epithelial cell lines. Roxithromycin strongly inhibited the expression of Runx2 mRNA. Furthermore, Runx2 siRNA inhibited the induction of MMP-13 in Ca9-22 cells. CONCLUSION These results indicate that RXM suppresses MMP-13 via the downregulation of Runx2 in human gingival epithelial cell cultures.