Odontogenic epithelial proliferation is correlated with COX-2 expression in dentigerous cyst and ameloblastoma.

Investigation of cyclooxygenase (COX)-2 in dentigerous cyst and ameloblastoma may help to improve understanding of the nature and behavior of odontogenic cysts and tumors, and in addition may eventually represent a definitive target for a pharmacological approach in the management of these lesions. The aim of this study was to evaluate COX-2 expression and its correlation with the proliferation of odontogenic epithelium in these lesions. Dentigerous cysts (n=16) and ameloblastomas (n=17) were evaluated. Detection of Ki-67 and COX-2 protein expression was conducted by immunohistochemistry. Data were statistically analyzed using Mann-Whitney U test and Spearman's rank correlation coefficient. No significant differences were found in the expression of Ki-67 and COX-2 between dentigerous cysts and ameloblastomas (P>0.05). A significant positive correlation (P=0.018) and highly significant positive correlation (P=0.004) were found between Ki-67 and COX-2 expression in the odontogenic epithelium of dentigerous cyst and ameloblastoma, respectively. COX-2 was expressed in the odontogenic epithelium of dentigerous cyst and ameloblastoma. It may contribute to local extension of these lesions by increasing the proliferation of their odontogenic epithelial cells.

Trichostatin A, an inhibitor of histone deacetylase, inhibits smooth muscle cell proliferation via induction of p21(WAF1).

The proliferation of vascular smooth muscle cells (VSMCs) can contribute to a variety of pathological states, including atherosclerosis and post-angioplasty restenosis. The p21(WAF1) cyclin-dependent kinase inhibitor regulates cell-cycle progression, senescence, and differentiation in injured blood vessels. Histone deacetylase (HDAC) inhibitors have shown utility in controlling proliferation in a wide range of tumor cell lines, possibly by inducing the expression of p21(WAF1). Our goal was to investigate the effect of trichostatin A (TSA), a specific and potent HDAC inhibitor, on the proliferation of vascular smooth muscle cells (VSMCs) isolated from rat thoracic aorta. TSA suppressed the HDAC activity of VSMCs in a dose-dependent manner and inhibited VSMC proliferation as demonstrated by cell number counting and the degree of [3H] thymidine incorporation. Further, TSA reduced the phosphorylation of Rb protein, a regulator of cell-cycle progression. TSA treatment also induced the expression of p21(WAF1) but not of p16(INK4), p27(KIP1) or p53. Finally, TSA inhibited HDAC activity of VSMCs from p21(WAF1) knock-out mice but had no effect on VSMC proliferation in these animals. In conclusion, TSA inhibits VSMC proliferation via the induction of p21(WAF1) expression and subsequent cell-cycle arrest with reduction of the phosphorylation of Rb protein at the G1-S phase.

The lipoprotein fraction between VLDL and LDL detected by biphasic agarose gel electrophoresis reflects serum remnant lipoprotein and Lp(a) concentrations.

We analyzed lipoprotein profiles in 616 Japanese by biphasic agarose gel electrophoresis using Chol/Trig Combo(TM) to yield HDL, VLDL, LDL and CM fractions which were stained with cholesterol and triglyceride reagents, respectively. To further evalute the pattern of electrophoresis, we analyzed the fraction between VLDL and LDL to confirm the possibility of a MidBand by using an automatic-five-fraction function. The cholesterol concentrations in MidBand (MidBand-C) showed a good correlation to remnant-like particle-cholesterol (RLP-C) (r = 0.95) in 23 consecutive samples (TC < 220 mg/dl, Lp(a) < 30 mg/dl). However, MidBand-C concentrations of subjects with high Lp(a) levels (Lp(a) > 30 mg/dl) were also high compared to RLP-C concentrations. The average MidBand-C levels in elderly normolipidemic control subjects (TC < 220, TG < 150) were 5.2 +/- 2.4 mg/dl in 30 males (mean age, 70 +/- 10 years) and 5.4 +/- 2.0 mg/dl in 40 females (64 +/- 11 years). The average MidBand-C levels of normolipidemic patients with coronary artery diseases (CAD; TC < 220, TG < 150) were 9.4 +/- 4.1 mg/dl in 126 males (mean age, 66 +/- 10 years) and 9.1 +/- 4.0 mg/dl in 44 females (67 +/- 10 years). These levels were significantly higher than control values (p < 0.0001). Areas under ROC curves were greater for MidBand-C than for TC, LDL-C and TG when used to discriminate between the patients with CAD and normolipidemic control subjects for each sex. There results suggest that the MidBand-C level may be useful as an indicator of risk for CAD.

Chylomicron remnants upregulate CD40 expression via the ERK pathway and a redox-sensitive mechanism in THP-1 cells.

CD40 is a 48kDa phosphorylated transmembrane glycoprotein that belongs to the tumor necrosis factor receptor superfamily and may play a role in formation of atherosclerotic plaques. Here, we investigated the effect of chylomicron remnants on CD40 expression in the human premonocytic cell line, THP-1 cells. Chylomicron remnants upregulated the expression of CD40 protein and mRNA in a dose- and time-dependent manner. Further, chylomicron remnants increased the generation of reactive oxygen species as determined by an increasing level of 2',7'-dichlorofluorescein. Pretreatment with the antioxidant, N-acetylcysteine, inhibited chylomicron remnant-induced CD40 protein expression by 60%. On the other hand, chylomicron remnants transiently increased the phosphorylation of extracellular signal-regulated kinase (ERK 1/2) and p38 mitogen-activated protein kinase (MAPK). Pretreatment with the MAPK kinase inhibitor, U0126, completely inhibited chylomicron remnants-induced CD40 protein expression, whereas the p38 MAPK inhibitor, SB203580, had no effect. Pretreatment with N-acetylcysteine had no effect on chylomicron remnant-induced ERK 1/2 phosphorylation. These data suggest that CD40 expression stimulated by chylomicron remnants in THP-1 cells is dependent on ERK 1/2-mediated pathway, which is followed by redox-sensitive mechanism-dependent and independent pathway. Thus, chylomicron remnants may contribute to the formation of atherosclerotic plaques via their immunological and proinflammatory effects.

Chylomicron remnants regulate early growth response factor-1 in vascular smooth muscle cells.

Early growth response factor-1 (Egr-1) is a zinc-finger transcription factor that induces genes that promote atherosclerosis. The goal of the present study was to determine whether Egr-1 expression is modulated by atherogenic, triglyceride rich lipoproteins known as chylomicron remnants. Chylomicron remnants induced Egr-1 mRNA and protein expression in rat cultured vascular smooth muscle cells (VSMCs) and activated extracellular signal-regulated kinase (ERK) 1/2 in VSMCs. Further, chylomicron remnant-induced Egr-1 expression was inhibited by PD98059, a selective inhibitor of MAPK kinase (MEK), suggesting that the action of chylomicron remnants on Egr-1 was dependent on the ERK/MEK pathway. Chylomicron remnants also induced mRNA expression of the pro-inflammatory cytokines, IL-2 and IFN-gamma in VSMCs. We conclude that chylomicron remnants act as atherogenic lipoproteins via induction of Egr-1 expression and via cytokine-mediated inflammation.

Involvement of NF-kappaB and mitochondrial pathways in docetaxel-induced apoptosis of human oral squamous cell carcinoma.

Apoptosis induced by docetaxel that interferes with microtubule polymerization dynamics and is used clinically to treat advanced cancers, has not been fully defined in squamous cell carcinoma. In this study, apoptotic events involved in docetaxel treatment were investigated. When the human oral squamous cell carcinoma cell line HSC-3 was exposed to docetaxel for 72 h, a dose-dependent effect was observed in apoptosis using the TUNEL method. We observed activation of caspase cascade including activities like caspase-3, -8, and -9. And the pan-caspase inhibitor z-VAD-fmk prevented apoptosis induced by docetaxel (0.1 microM), showing participation of caspases in this process. Since an antagonistic CD95-antibody (ZB4) exerted no effect on docetaxel-induced apoptosis, CD95/CD95L interaction was not involved in this pathway. The caspase-8-like activity was inhibited not only by IETD-fmk (caspase-8) but also by DEVD-fmk (caspase-3). The results indicate that the caspase-8-like activation occurred downstream of DEVDase. Docetaxel promoted the formation of reactive oxygen species (ROS) in mitochondria, and preincubation of cells with anti-oxidants such as N-acetyl cysteine and pyrrolidine dithiocarbamate, protected against apoptosis mediated by docetaxel. Furthermore, treatment with docetaxel elicited reduction of mitochondrial membrane potential, and release of cytochrome c to cytosol, after 48 h of treatment. We observed binding activity to NF-kappaB consensus site and interference with the mitochondrial function via NF-kappaB after docetaxel treatment. Preventing pro-apoptotic property of NF-kappaB inhibited docetaxel-induced apoptosis. Thus, these results suggest that, following the activation of NF-kappaB by docetaxel, apoptosis is elicited through a mitochondria-dependent pathway.

Impact of increasing diabetes on coronary artery disease in the past decade.

We studied the coronary risk factors of hospitalized patients with coronary artery disease (CAD) in the Department of Cardiovascular Internal Medicine of Kobe University Hospital in 1993, 1996, 1999 and 2003, and examined trends in the factors over the past decade. The prevalences of diabetes mellitus (DM) (24.7%, 33.6%, 41.1% and 44.7%, respectively) and impaired glucose tolerance (IGT) (5.9%, 8.0%, 9.3% and 11.0%, respectively) steadily increased, whereas dyslipidemia (high total cholesterolemia, high triglyceridemia, or low high-density lipoproteinemia) and hypertension remained unchanged. We also revealed an increase in hemoglobin A1c levels (5.8%, 5.9%, 6.2% and 6.4%, respectively), in contrast to modest improvements in lipid levels and blood pressure levels. Additionally, patients with multi-vessel disease (MVD, stenosis in more than two major coronary vessels) significantly increased from 44.7% in 1993 to 58.8% in 2003 (p < 0.01). In 1993, DM and dyslipidemia were significant predictors for MVD (Odds Ratio: 2.72 and 2.68, respectively). On the other hand, in 2003, the significant predictor for MVD shifted to DM alone (Odds Ratio: 2.38). In conclusion, the prevalence rate of DM among CAD patients significantly increased in this decade, and the consequent increase in the prevalence of MVD should be recognized as the most important problem clinically.

Dual role of NF-kappaB in apoptosis of THP-1 cells during treatment with etoposide and lipopolysaccharide.

One of the mechanisms repressing apoptosis in tumor cells can involve the expression of anti-apoptotic NF-kappaB target genes. In this study, we demonstrated that a potent NF-kappaB inhibitor, Nalpha-tosyl-L-lysinyl chloromethyl ketone (TLCK), inhibits apoptosis of THP-1 cells triggered by etoposide (VP16), and actinomycin D (ACT D) or cycloheximide inhibits apoptosis. However, persistent activation of NF-kappaB by lipopolysaccharide (LPS) led to the survival of leukemic cells against VP16-induced apoptosis. Thus, the molecular events (Bax/X-chromosome-linked IAP (XIAP)) occurring downstream of NF-kappaB activation during VP16 and/or LPS stimulation may become important to understand the multiple effects of NF-kappaB.

Chylomicron remnants induce monocyte chemoattractant protein-1 expression via p38 MAPK activation in vascular smooth muscle cells.

Chylomicron remnants, major lipoproteins at postprandial hyperlipidemia, have been considered to be proatherogenic lipoproteins. However, the mechanisms by which chylomicron remnants enhance atherosclerosis have not been fully understood. Monocyte chemoattractant protein-1 (MCP-1) is a chemokine which stimulates migration of monocytes and plays a critical role in the development of atherosclerosis. In this study, we investigated the effect of chylomicron remnants on MCP-1 expression in cultured vascular smooth muscle cells (VSMCs). We prepared chylomicrons from the lymph of gastrostomized rats fed with egg solution and obtained chylomicron remnants from the plasma of hepatectomized rats which were injected with chylomicrons. Treatment of VSMC with chylomicron remnants resulted in a significant increase of the expression of MCP-1 mRNA and protein in a time-and a dose-dependent manner. Further, chylomicron remnants activated p38 mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinase (ERK1/2). Pretreatment of VSMCs with p38 MAPK inhibitors, SB203580 and SB202190, resulted in a dose-dependent inhibition of chylomicron remnants-induced MCP-1 mRNA and protein expression, whereas a MAPK kinase inhibitor, PD98059, had no effect on these responses. MCP-1 secretion by chylomicron remnants was much more pronounced than those by chylomicrons, oxidized low-density lipoproteins, or lysophosphatidylcholine. These results indicated that chylomicron remnants stimulated MCP-1 expression in VSMCs, and suggested that chylomicron remnants might contribute to the formation of atherosclerosis through this proinflammatory effect.

High glucose accelerates MCP-1 production via p38 MAPK in vascular endothelial cells.

In diabetes mellitus (DM), hyperglycemia causes cardiovascular lesions through endothelial dysfunction. Monocyte chemoattractant protein-1 (MCP-1) is implicated in the pathogenesis of cardiovascular lesions. By using human umbilical vein endothelial cells, we investigated the effect of hyperglycemia on MCP-1 production and its signaling pathways. Chronic incubation with high glucose increased mRNA expression and production rate of MCP-1 in a time (1-7 days)- and concentration (10-35 mM)-dependent manner. Chronic exposure to high glucose resulted in enhancement of generation of reactive oxygen species (ROS), as determined by increasing level of 2,7-dichlorofluorescein (DCF), and subsequent activation of p38 mitogen-activated protein kinase (MAPK). Neither c-Jun NH(2)-terminal kinase nor extracellular signal-regulated kinase1/2 was affected. SB203580 or FR167653, p38 MAPK specific inhibitors, completely suppressed MCP-1 expression. Catalase suppressed p38 MAPK phosphorylation and MCP-1 expression. These results indicate that hyperglycemia can accelerate MCP-1 production through the mechanism involving p38 MAPK, ROS-sensitive signaling pathway, in vascular endothelial cells.

A case of severe hyperlipidemia caused by long-term tube feedings.

A 77-year-old woman with type II diabetes mellitus was admitted to our hospital in August/ 1995 with severe hyperlipidemia. She had taken feedings through a nasogastric tube with 1000 ml (1000 kcal) of Ensureliquid daily since 1993 because of the muscle weakness after rhabdomyolysis. Her serum total cholesterol was 515 mg/dl and triglyceride was 3378 mg/dl despite administration of 10 mg of simvastatin daily. After substitution of a standard diet starting August 21, we found significant decreases of total cholesterol from 725 mg/dl to 194 mg/dl and triglyceride from 4680 mg/dl to 550 mg/dl within 37 days. We also found a severe decrease in her serum total carnitine level of 22 micromol/l (normal range 45-91 micromol/l) before changing the diet, suggesting secondary carnitine deficiency. Severe hyperlipidemia was reversed by changing the carnitine deficient diet (Ensureliquid) to a carnitine-containing diet. We suggested that the development of hyperlipidemia was related to the carnitine deficiency.

Mouse genetic evidence that tranilast reduces smooth muscle cell hyperplasia via a p21(WAF1)-dependent pathway.

OBJECTIVE: N-(3'4'-dimethoxycinnamoyl)-anthranilic acid (tranilast) is a drug that has been shown to reduce the incidence of restenosis after angioplasty in middle-scale clinical trials. Despite clinical interest in this drug, the pharmacological actions of tranilast remain relatively unexplored at a molecular level. METHODS AND RESULTS: We evaluated the effects of tranilast on vascular smooth muscle cell (VSMC) proliferation in wild-type mice and in mice lacking a cyclin-dependent kinase inhibitor, p21(WAF1) (p21). Tranilast potently inhibited the proliferation of VSMC cultures derived from wild-type mice, but VSMCs derived from p21-deficient (p21-/-) mice were unaffected by this treatment. In a mouse femoral artery model of vascular injury, tranilast administration to wild-type mice led to an upregulation of p21 expression and a decrease in the number of proliferating VSMCs, as determined by immunostaining for proliferating cell nuclear antigen. In contrast, tranilast had no effect on the number of proliferating cell nuclear antigen-positive cells in the injured arteries of p21-/- mice. Administration of tranilast significantly reduced the neointimal VSMC hyperplasia in wild-type mice at 4 weeks but had no effect on lesion formation in p21-/- mice. CONCLUSIONS: Our findings provide genetic evidence that tranilast inhibits intimal hyperplasia via a p21-dependent pathway, an activity that may contribute to its efficacy in the prophylactic treatment of postangioplasty restenosis.