Tetsuya Ota

nm23-H1 reduces in vitro cell migration and the liver metastatic potential of colon cancer cells by regulating myosin light chain phosphorylation.

The nm23‐H1 gene is known as a potential metastasis suppressor gene in various types of carcinomas. However, the role of nm23‐H1 in colorectal carcinoma still remains controversial and the cellular mechanisms by which its protein may modulate the metastatic phenotype are not yet known. We transfected nm23‐H1 cDNA into the human colon cancer cell line, HT‐29, to test the effects and cellular biological mechanism of nm23 protein in colon cancer. We found that nm23‐H1 strongly inhibited the liver metastasis of HT‐29 cells in nude mice and inhibited the epidermal growth factor (EGF)‐induced cell migration in vitro. Furthermore, we clarified the regulation of the myosin light chain (MLC) phosphorylation by nm23‐H1, which has been demonstrated as having potential role in cell migration.

Attenuation of Liver and Lung Injury after Hepatic Ischemia and Reperfusion by a Cytokine-Suppressive Agent, FR167653

Background: Hepatic ischemia/reperfusion (I/R) injury is an important clinical problem and leads to the release of the proinflammatory cytokines, TNF-α and IL-1. These cytokines play important roles in the induction of polymorphonuclear neutrophil (PMN) activation and infiltration, and induce not only localized hepatic injury but also remote organ injury, especially pulmonary injury. Using a total hepatic ischemia model in rats, we tested our hypothesis that suppression of TNF-α and IL-1 by FR167653 ameliorates I/R injury in the liver and lung. Methods: Male Wistar rats, weighing 240–280 g, were divided into 3 groups, an FR group, a control group and a sham group. In the FR group, FR167653 (1 mg/kg/h) was administered continuously to the animals for 30 min prior to the onset of ischemia and for 2 h after reperfusion. The control group received normal saline. A porto-systemic shunt was placed between the cecal branch of the portal vein and the jugular vein, and total hepatic ischemia was produced for 90 min. The sham group was treated with placement of the porto-systemic shunt only. The 1-week survival rate, liver enzyme activity, hepatic tissue blood flow (HTBF), cytokine mRNA expression, myeloperoxidase (MPO) activity and histological results were studied. Results: The 1-week survival rate and HTBF were significantly higher in the FR group than in the control group. Serum AST, ALT, and LDH levels were significantly lower in the FR group at 30 min, 1 h and 3 h after reperfusion. MPO levels in liver and lung tissue were also significantly lower in the FR group. The expression of IL-1β mRNA remarkably decreased up to 6 h after reperfusion in the FR group. Conclusions: We concluded that the inflammatory cytokines, IL-1β, play important roles in hepatic I/R injury. FR167653 might ameliorate I/R injury and be useful in liver surgery with ischemia.

Endothelin-1 levels in portal venous blood in relation to hepatic tissue microcirculation disturbance and hepatic cell injury after ischemia/reperfusion.

This study was conducted to clarify the role of endothelin-1 in the portal vein after hepatic ischemia/reperfusion and to ascertain whether it is related to hepatic microcirculation disturbance. Using a canine ischemic liver model, the portal and systemic endothelin-1 levels were measured before ischemia, then after 1h and 2h of reperfusion, and comparatively evaluated with the serum levels of GOT and lactic dehydrogenase (LDH). As an indicator of liver tissue microcirculation, tissue blood flow volume (TBF) was also measured in the site subjected to ischemia. The animals were divided into: group 1, which received ischemia for 30 min; group 2, which received ischemia for 60 min; and group 3, which received a sequence repeated four times of 15 min ischemia and 10 min reperfusion. The portal endothelin-1 level became significantly elevated after reperfusion compared to that before ischemia in all groups, being significantly higher in group 2 than in the other groups. The systemic endothelin-1 level also increased after reperfusion; significantly in group 2. The portal endothelin-1 level was generally higher than the systemic level, which again was statistically significant in group 2. After 2h of reperfusion, a significant positive correlation was found between the portal endothelin-1 level and serum LDH, whereas a significant negative correlation was found between the portal endothelin-1 level and TBF. The finding that the portal endothelin-1 level became elevated after hepatic ischemia/reperfusion suggests that it probably plays an essential role in hepatic ischemia/ reperfusion injury by adversely influencing tissue microcirculation.

Experimental Evaluation of the Effects of the Intraportal Administration of Cyclic Guanosine Monophosphate on Ischemia / Reperfusion in the Porcine Liver

This study was done to examine the protective effects of cyclic guanosine monophosphate (cGMP), a second messenger of nitric oxide, for ischemia/reperfusion injury of the liver, since it is known to induce vasodilatation and to inhibit platelet aggregation. Using an experimental model of porcine liver ischemia, 8-bromoguanosine 3′,5′ monophosphate, a cGMP analog, was continuously administered into the portal vein before ischemia and after reperfusion 30 min for each in the cGMP group (n=6). Saline water was administered in the same way in the control group (n=6). The cardiac output (CO), mean arterial blood pressure (MAP), portal venous flow (PVF), hepatic arterial flow (HAF), hepatic tissue blood flow (HTBF), and hepatic tissue cGMP level were determined. Hepatic enzymes and the bile discharge were also assessed as indicators of hepatic function. The hepatic tissue cGMP level was significantly higher, and PVF, HTBF, and the bile discharge were significantly greater in the cGMP group, while there were no remarkable differences between the groups with CO, MAP, HAF, and hepatic enzymes. In conclusion, the continuous supplementation of cGMP into the portal vein was found to be beneficial for preserving both the hepatic circulation and, consequently, the hepatic function of after warm ischemia of porcine liver.

Thymidine Phosphorylase and Dihydropyrimidine Dehydrogenase Expression Levels in Tumor and Normal Tissue Specimens of T3 Human Colorectal Carcinoma

PurposeThymidine phosphorylase (TP) and dihydropyrimidine dehydrogenase (DPD) are important enzymes related to the metabolism of 5-fluorouracil and its derivatives. We evaluated the association between the clinicopathological factors and these enzymes in patients with T3 colorectal carcinoma.MethodsThe TP and DPD expression levels in 15 patients with T3 colorectal carcinomas were measured in tumor and adjacent normal tissue specimens by enzyme-linked immunosorbent assay. Correlations between each enzyme and clinicopathological factors were also statistically evaluated.ResultsThe TP levels in tumor and normal tissue specimens were 77.9 ± 33.6 and 24.7 ± 10.3, respectively (P < 0.001). The DPD levels in tumor and normal tissue specimens were 44.1 ± 18.2 and 53.1 ± 24.1, respectively (P = 0.46). The TP/DPD ratios in tumor and normal tissue specimens were 1.84 ± 0.52 and 0.53 ± 0.26, respectively (P < 0.001). The tumor/normal ratios of TP level in patients with and without liver metastasis were 1.79 ± 0.91 and 4.67 ± 2.51, respectively (P = 0.024).ConclusionThe measurement of the enzyme expression levels of TP and DPD is considered to be useful for better understanding the conditions of tumor progression. The mechanisms of regulation of these enzymes thus require further evaluation.