Takashi Morisaki

Lipopolysaccharide increases cyclo-oxygenase-2 expression in a colon carcinoma cell line through nuclear factor-κB activation

Both nonneoplastic colon epithelium and colon carcinoma cells in situ are continuously exposed to lipopolysaccharide (LPS). Few reports have addressed possible direct effects of LPS in promotion of colon carcinoma and underlying mechanisms. We found evidence that LPS directly stimulated growth of the human colon carcinoma cell line CE-1 through an increase in the production of prostaglandin E2 (PGE2) as a result of cyclo-oxygenase-2 (COX-2) expression. LPS induced significant increases in PGE2 production in CE-1 cells, which were found to express a high-affinity LPS receptor, CD14. Positive correlations were found between PGE2 production and activation of nuclear factor (NF)-κB as well as expression of both COX-2 mRNA and protein in LPS-stimulated CE-1 cells. When CE-1 cells were exposed to exogenous PGE2, DNA synthesis increased. These results indicate that LPS may stimulate DNA synthesis in certain colon carcinoma cells as a result of PGE2 production involving increased COX-2 expression that might result in turn from activation of NF-κB by LPS. Further investigation of the pathways mediating LPS-induced stimulation of colon carcinoma cells may provide insights into LPS effects in in vivo tumor biology.

Laparoscopically assisted distal gastrectomy for early gastric cancer: is it superior to open surgery?

BackgroundThe purpose of this study was to compare clinical outcomes between laparoscopically assisted and open distal gastrectomy for early gastric cancer.MethodsThe records of 21 patients who underwent laparoscopically assisted distal gastrectomy (LG) for preoperative diagnosis of intramucosal gastric carcinoma between January 1996 and August 1998 were reviewed and compared with those of 31 open distal gastrectomy patients during the same period.ResultsAge, gender, and size and histologic differentiation of the lesions were matched. Those located at the body of the stomach (p=0.011) and those macroscopically depressed (p=0.049) were subjected more frequently to open surgery. Laparoscopically assisted gastrectomy required significantly longer operative time (p<0.001) with less extensive lymph node dissection (p<0.001). However, time to start of walking (p=0.032), time to flatus (p=0.002), duration of postoperative fever (p=0.027), and postoperative hospital stay (p=0.001) were significantly shorter in the LG group, and this group had a lower white blood cell count on the first postoperative day (p=0.010). Blood loss and time to oral intake were comparable between the groups. Complications included one conversion to open surgery, one leakage, and one stenosis in the LG group, and two leakages and an atelectasis in the OG group.ConclusionsAlthough LG requires longer surgical time, this retrospective study suggests that it is superior to open surgery in terms of faster postoperative recoveries, shorter hospital stays, and cosmetic outcomes.

Nitric oxide synthase expression and nitric oxide production in human colon carcinoma tissue.

Nitric oxide (NO), the production of which is dependent on NO synthase (NOS), has been shown to contribute to various pathogeneses in cancer. The aim of this study was to determine whether inducible NO synthase (iNOS) is overexpressed in human colon carcinoma tissue, and whether NO is produced in tumor tissue.

Comparison of treatments for hepatolithiasis: hepatic resection versus cholangioscopic lithotomy.

BACKGROUND Hepatic resection and percutaneous transhepatic cholangioscopic lithotomy (PTCSL) are the two main approaches to the treatment of hepatolithiasis, but comparisons of longterm followup results have not been adequately reported. STUDY DESIGN Of 86 patients with hepatolithiasis admitted to our institution between 1980 and 1996, we reviewed 54 patients: 26 who underwent hepatic resection and 28 who underwent PTCSL. Five patients who underwent postoperative cholangioscopic lithotomy were included in the former group. The remainder of the hepatolithiasis patients were not treated by hepatic resection or PTCSL and, therefore, were excluded from this study. Hepatic resections were mainly indicated for left-sided localized intrahepatic calculi, atrophic liver, and possible presence of cholangiocellular carcinoma. PTCSL was performed for right-sided, bilateral or recurrent stones at an average of 6 treatments (range 1 to 20 treatments) for each patient. There were no differences between the two groups in terms of gender or age. The recurrence rate of stones and longterm prognosis were analyzed using the Kaplan-Meier method, and other clinical factors listed below were statistically compared. RESULTS The rate of complete removal of stones was similarly high in each group (96.2% in the hepatic resection group versus 96.4% in the PTCSL group). The complication (38.5% versus 21.4%) and 5-year survival (85.6% versus 100%) rates were comparable. Remaining bile duct stricture (18.2% versus 60.9%, p < 0.01) and 5-year recurrence rates (5.6% versus 31.5%, p < 0.05) were statistically lower in the hepatic resection group than in the PTCSL group. CONCLUSIONS Hepatic resection, when combined with postoperative cholangioscopic lithotomy, is a preferable treatment for left-sided stones with strictures and bilateral stones.

Apoptosis Induced by Inhibition of Cyclic AMP Response Element–Binding Protein in Vascular Smooth Muscle Cells

Background—The balance between apoptosis and proliferation of vascular smooth muscle cells (VSMCs) is believed to contribute to the vascular remodeling process. Cyclic AMP response element–binding protein (CREB) is a critical transcription factor for the survival of neuronal cells and T lymphocytes. However, the role of CREB in blood vessels is incompletely characterized. Methods and Results—Nuclear staining with Hoechst 33258 or propidium iodine showed an increase in apoptotic cells with activation of caspase-3 in VSMCs infected with adenovirus expressing the dominant-negative form of CREB (AdCREBM1). Basal expression of Bcl-2 and Bcl-2 promoter activity were decreased by infection with AdCREBM1. Immunohistochemistry revealed that CREB was mainly induced and activated in the neointimal &agr;-smooth muscle actin–positive cells of rat carotid artery after balloon injury. Infection with AdCREBM1 suppressed neointimal formation (intima-media ratio) by 33.8% after 14 days of injury, which was accompanied by an increase in apoptosis as indicated by terminal deoxynucleotidyl transferase–mediated dUTP nick end-labeling–positive cells and a decrease in bromodeoxyuridine incorporation. Conclusions—These results suggest that CRE-dependent gene transcription might play an important role in the survival and proliferation of VSMCs. CREB might be a novel transcription factor mediating the vascular remodeling process and a potential therapeutic target for atherosclerotic disease.

Phospholipase A2 mediates nitric oxide production by alveolar macrophages and acute lung injury in pancreatitis.

OBJECTIVE Reportedly, nitric oxide (NO) derived from alveolar macrophages (AMs) and increased serum phospholipase A2 (PLA2) activity are associated with the pathogenesis of lung injury in acute pancreatitis. The authors examined the possibility that PLA2 causes, in part, the induction of NO production by AMs in pancreatitis. METHODS Pancreatitis was induced in rats by selective pancreatic duct ligation (SPL). AMs were stimulated with PLA2 or SPL rat serum, with or without administration of the PLA2 inhibitor quinacrine. Then NO production from the AMs was measured by the Griess method, inducible NO synthase mRNA expression of AMs was analyzed by the reverse transcription-polymerase chain reaction, and cytotoxic effects of AMs on human umbilical vein endothelial cells was examined by a 51Cr release assay. In vivo, the effect of quinacrine on lung injury was determined by measuring the arterial blood oxygen pressure (PaO2), lung weight, and lung permeability using Evans blue dye concentration of SPL rat. RESULTS In vitro, the serum with high PLA2 activity induced NO production by rat AMs. PLA2 (50 ng/ml) induced significant amounts of NO production, inducible NO synthase mRNA expression, and cytotoxicity toward the human umbilical vein endothelial cells in normal rat AMs, and these activities were significantly inhibited by quinacrine. In vivo, rats with pancreatitis that were given quinacrine showed decreased concentrations of NO2- and NO3- in the bronchoalveolar lavage fluid, and the PaO2, lung edema, and lung permeability were improved significantly. CONCLUSION PLA2 induces AMs to release NO, which contributes to lung injury in acute pancreatitis. This lung injury was prevented by the administration of the PLA2 inhibitor quinacrine.

Protein-bound polysaccharide PSK inhibits tumor invasiveness by down-regulation of TGF-β1 and MMPs

Transforming growth factor β1 (TGF-β1) and matrix metalloproteinases (MMPs) produced by tumor cells play important roles in tumor invasion. PSK, a protein-bound polysaccharide, is widely used in Japan as an immunopotentiating biological response modifier for cancer patients. In this study, we focused on the effects of PSK on invasiveness, TGF-β1 production, and MMPs expression in two human tumor cell lines, pancreatic cancer cell line (NOR-P1) and gastric cancer cell line (MK-1P3). PSK significantly decreased the invasiveness of both cell lines through Matrigel-coated filters but did not affect cell viability, proliferation, or adhesion. Decreased invasion was associated with the inhibition of TGF-β1, MMP-2, and MMP-9 at both mRNA and protein levels as assessed by reverse transcriptase-polymerase chain reaction, gelatin zymography, and enzyme-linked immunosorbent assay. Antibody against TGF-β1 neutralized the MMP activities of both cell lines. PSK also suppressed the expression of urokinase plasminogen activator (uPA) and uPA receptor but did not change plasminogen activator inhibitor-1 (PAI-1) expression. Western blot analysis showed that PSK reduced uPA protein expression but not PAI-1 expression in the both cell lines. These results indicate that PSK suppresses tumor cell invasiveness through down-regulation of several invasion-related factors including TGF-β1, uPA, MMP-2, and MMP-9.

VEGFR2 is selectively expressed by FOXP3high CD4+ Treg

CD25+ FOXP3+CD4+ T cells (Treg) have been considered to play an important role in immune tolerance against several tumor antigens. It has also been indicated that high‐level expression of FOXP3 (FOXP3high) is sufficient to confer suppressive activity to normal non‐Treg. Here, we showed for the first time that vascular endothelial growth factor receptor 2 (VEGFR2) is selectively expressed by FOXP3high but not FOXP3low Treg. Such VEGFR2+ Treg exist in several tissues including PBMC and malignant effusion‐derived lymphocytes. In conclusion, VEGFR2 may be a novel target for controlling Treg with highly suppressive function.

Association of Enhanced Cyclooxygenase-2 Expression With Possible Local Immunosuppression in Human Colorectal Carcinomas

Background: Prostaglandin (PG) E2 has an influence on antitumor lymphocyte reactions and causes local immunosuppression at tumor sites. The contribution of cyclooxygenase (COX), a key enzyme in PGE2 synthesis, to this effect is still unclear. We examined if cyclooxygenase (COX)-2 is involved in local immunosuppression in human colon carcinoma cell lines and in clinical tumor specimens.Methods: PGE2 concentrations were measured in culture media from a highly COX-2-expressing human colon carcinoma cell line (CE-1) and other cell lines. Lymphocyte proliferation in response to a mitogen was used to evaluate immunosuppression in tumor cell-lymphocyte cocultures with and without selective COX-2 inhibitor NS-398. We also evaluated expression of COX-2 mRNA in surgical specimens of colorectal carcinoma by reverse transcription polymerase chain reaction (RT-PCR) and COX-2 protein by immunohistochemistry, correlating COX-2 expression with clinicopathologic features.Results: CE-1 cells produced large amounts of PGE2, which was significantly inhibited by NS-398. The proliferation index of lymphocytes cocultured with CE-1 cells was significantly less than that of control lymphocytes; again, this effect was inhibited by NS-398. While human colorectal carcinoma tissue expressed more COX-2 mRNA and protein than nonneoplastic tissue, no significant correlation was found between COX-2 levels and clinicopathologic features.Conclusions: Overexpression of COX-2 in colon cancer may cause local immunosuppression, and COX-2 inhibitors might be therapeutically useful against these tumors.

Expression of inducible nitric oxide synthase in circulating neutrophils of the systemic inflammatory response syndrome and septic patients.

Abstract. There is increasing evidence that nitric oxide (NO) is an important factor in the pathogenesis of septic shock. It is known that polymorphonuclear neutrophils (PMNs) are activated during sepsis or after surgical stress, and they then release various toxic mediators including free radicals. It has not been clear whether NO synthesis can be induced in circulating PMNs. Blood samples were obtained from 11 patients with sepsis, 23 patients with systemic inflammatory response syndrome (SIRS), and 16 patients without SIRS (nonSIRS) who underwent operation. We examined mRNA expression of inducible NO synthase (iNOS) in circulating PMNs from those patients pre- and postoperatively using the reverse transcriptase polymerase chain reaction (RT-PCR) method and measured their serum nitrate (NO 2 \- ) + nitrate (NO 3 \- ) concentration, peripheral blood white blood cell (WBC) count, and serum C-reactive protein (CRP) level. The frequency of iNOS expression in PMNs increased in sepsis (100%) and SIRS (70%) patients compared to that in nonSIRS patients (18%) (p < 0.001). The peripheral WBC count and CRP level were significantly higher in iNOS-positive patients than in iNOS-negative patients (p < 0.05 andp < 0.01, respectively). Postoperatively, the serum NO2\-+ NO3\- concentration increased in 87% of septic patients and in 56% of patients with SIRS (p < 0.05 for both). Our study indicated that iNOS mRNA expression is induced in human circulating PMNs of patients with postoperative sepsis and SIRS and may be involved in the pathogenesis of the sepsis syndrome.