The inhibitory effect of simvastatin on growth in malignant gliomas--with special reference to its local application with fibrin glue spray in vivo.

Simvastatin is one of the competitive inhibitors of HMG-CoA reductase. During clinical trials, it has shown the ability to lower serum cholesterol. We investigated the effect of simvastatin on the growth of malignant gliomas in vitro, semi-in vivo, and in vivo. An in-vitro MTT assay revealed that human malignant glioma cell lines: U-251MG, U-373MG, and U-87MG, and rat malignant glioma cell line C6 were well inhibited in growth in a dose-dependent fashion. An anchorage-independent growth assay showed that the number of colonies (more than 100 microM in size) of human (U-373MG) and rat malignant gliomas (C6) was markedly reduced in a dose-dependent fashion. A flow cytometry analysis revealed that simvastatin treatment led U-251MG cells to accumulate in sub G0-G1. Immunostaining by TUNEL method showed that most glioma cells treated by 10 microM simvastatin had nuclear immunostaining, suggesting apoptotic changes of the treated cells. The human umbilical vein endothelial cells and human lung fibroblasts were inhibited in growth by no more than 20% of controls even with a high dose (10 microM) of simvastatin. In the semi-in vivo model, using newborn rat brain slice cultures, the rhodamine-labeled glioma cells were abolished after 7 days of local simvastatin treatment with fibrin glue probably suggesting that simvastatin led the cells to apoptosis. In rat models using subcutaneously inoculated C6, the local application of simvastatin combined with fibrin glue (spray method) was quite effective in inhibiting the growth of the tumor. These data suggest that simvastatin may be a novel anti-glioma drug, and the local application of simvastatin combined with fibrin glue (by spray method) may be a crucial new clinical strategy against glioma growth.

Antidiabetic effect of an acidic polysaccharide (TAP) from Tremella aurantia and its degradation product (TAP-H).

Continuous oral administration of the acidic polysaccharide (TAP) solution (0.5 g/l) and the TAP-H (degradation products of TAP) solution (1.5 g/l) instead of water for 10 weeks were found to depress plasma glucose increases in diabetes using genetically non-insulin-dependent diabetic model (KK-Ay) mice. TAP and TAP-H significantly lowered levels of insulin, total-cholesterol and triglyceride in the blood of the mice. In excretion to feces, TAP and TAP-H significantly increased the total bile acid, while the cholesterol content of both groups was less than that of the control. Furthermore, TAP and TAP-H significantly decreased the plasma lipoperoxide level. The study shows that TAP and TAP-H have an antidiabetic effect on diabetes model mice.

[Significance of neoadjuvant chemotherapy for gastric cancer].

Neoadjuvant chemotherapy for high-risk patients with advanced gastric cancer is important to increase the chance for curative resection and make unresectable gastric cancer tumors resectable by down-staging of the tumor. Tumors with H0, P0, T3, T4, or N3 are the best candidates for this therapy. Randomized controlled phase III studies are needed in conjunction with accurate staging of the disease by laparoscopy. The results of histopathologic evaluation of resected materials following preoperative chemotherapy using oral fluoropyrimidine are thought to be useful as an indicator of chemosensitivity for postoperative adjuvant setting.

Production of hydrogen peroxide in cancerous tissue by intravenous administration of sodium 5,6-benzylidene-L-ascorbate.

We investigated whether the antitumor action of sodium 5,6-benzylidene-L-ascorbate (SBA) is mediated via oxidation-involved mechanism, in three different systems: 3'-methyl-4-dimethylaminoazobenzene (DAB)-induced rat hepatocellular carcinoma (in vivo), its homogenate (semi in vivo), and cultured cells (in vitro). Oral intake of DAB irreversibly produced hepatocellular carcinoma in rats, with a maximum incidence of carcinogenesis after 4 months. Intravenous administration of SBA induced vacuolar, eosinophilic degeneration and nuclear debris, producing greater amounts of ESR signal of ascorbate radical and hydrogen peroxide (H2O2)-derived chemiluminescence (CL) (H2O2-CL) in the cancerous tissue than in the normal tissue. When SBA was directly added to the homogenates, higher amounts of ascorbate radical and H2O2-CL were generated in cancerous tissues. When SBA was added to the RPMI1640 medium supplemented with 10% fetal bovine serum, methionine was oxidized to methionine sulfoxide and H2O2 was produced in amounts that sufficiently induce apoptotic cell death in human promyelocytic leukemic HL-60 cells. Cytotoxic activity of SBA was significantly reduced by catalase. These data suggest that antitumor activity of SBA in vivo might at least in part be due to H2O2, produced from SBA.

Amino acid utilization during cell growth and apoptosis induction.

The amino acid utilization between human promyelocytic leukemia (HL-60), human oral squamous carcinoma (HSC-2, HSC-4, NA), human salivary gland tumor (HSG) and rat neuron cells (PC-12) were compared, using amino acid analyzer. All these cells consumed four essential amino acids (valine, methionine, isoleucine, leucine), glutamine and arginine, whereas they produced glycine, alanine and ammonia, without significantly affecting threonine, tyrosine, phenylalanine, histidine or lysine concentration. Serine and glutamine utilization varied considerably from cell to cell. HL-60 cells consumed serine and arginine at much higher rates than other cells. Serine depletion accumulated the G1 arrested cells, and produced increasing numbers of the apoptotic cells. Supplementation of serine significantly extended the period of logarithmic cell growth. During apoptosis induction of HL-60 cells by dopamine, sodium ascorbate or sodium 5,6-benzylidene-L-ascorbate, the oxidation of methionine to methionine sulfoxide was enhanced, but the consumption of serine, glutamine and arginine was reduced. In the presence of HL-60 cells, the methionine oxidation was significantly inhibited, suggesting the antioxidant action of the cells. These present study suggests the importance of re-evaluation of culture condition for each cell lines.

[The optimal period for orally administered fluoropyrimidines as an adjuvant chemotherapy for gastric cancer--a pilot study using 5-FU tablets compared with surgical operation alone].

Long-term oral administration of fluoropyrimidines such as 5-fluorouracil (5-FU) or tegafur is commonly used as an adjuvant chemotherapy for gastric cancer, but the optimal period or optimal total doses of fluoropyrimidines have not been studied. Two hundred cases of macroscopical Stage II and III curatively resected gastric cancer patients were entered in this study, and divided into three groups (6 months group: mitomycin C was given i.v. at day 0 and day 1 and 5-FU tablets were orally administered at a dose of 200 mg/day for 6 months. 12 months group: MMC was given the same as for the 6 months group and 5-FU tablets were administered for 12 months. Surgery alone group: No chemotherapy, operation only). As the result, 185 cases were eligible. There was no significant difference between the 6 months group and the 12 months group among Stage II patients. Although there was also no significant difference between the 2 groups in Stage III patients, the survival curve of 12 months group was always higher than in the 6 months group. When comparing with surgery alone group, 5-year survival of the 12 months group was always higher than in the surgery alone group of Stage III patients; however, the survival rate in the 6 months group was worse than in the surgery alone group at Stage II and III. These results suggest that MMC i.v. and 12 months or over administration of 5-FU tablets is useful for Stage III gastric cancer patients, and that cooperative study is required comparing with surgery alone in Stage II patients.