Ethanol Extract of Lycopodium serratum Thunb. Attenuates Lipopolysaccharide-Induced C6 Glioma Cells Migration via Matrix Metalloproteinase-9 Expression.

OBJECTIVE: To elucidate how ethanol extract of L. serratum (ELS) could exert anti-migratory effects on glioma with the suppression of nuclear factor kappa B (NF-κB) downstream pathway. METHODS: Cell viability of ELS on C6 glioma was detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Nitric oxide (NO) assay and 2',7'-dichlorofluorescin diacetate (DCFH-DA) assay were applied to measure NO production and reactive oxygen species (ROS) generation on lipopolysaccharide (LPS)-induced C6 glioma cells. NF-κB, mitogen-activated protein kinase (MAPK), inducible nictric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) protein were determined by Western blot. Wound healing assay was used to investigate the inhibitory effect of ELS on fetal bovine serum (FBS)-induced migration and matrix metalloproteinase (MMP)-9 and -2 activity was examined by zymography. RESULTS: ELS suppressed LPS-induced phosphorylation of extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38 through inhibiting the expression of chemokine CCL2 (or monocyte chemoattractant protein-1, MCP-1). In addition, ELS inhibited the expression of iNOS, COX-2, and the production of NO by LPS in C6 glioma cells. ELS also significantly decreased serum-induced migration of C6 glioma cells in scratch wound healing in a dose-dependent manner (P<0.01). The activity of MMP-9 and -2 were also significantly attenuated by ELS with LPS treatment (P<0.01). CONCLUSIONS: Our results suggest that downregulation of MMP-9 gene expression might be involved in the anti-migration effect of ELS against LPS-induced C6 glioma cells.

Antioxidants delay clinical signs and systemic effects of ENU induced brain tumors in rats.

According to our previous study suggesting that antioxidant properties of phytochemicals in the diet decrease glioma aggressiveness, we used a SUVIMAX-like diet ("Supplementation en VItamines et Minéraux AntioXydants") (enriched with alpha-tocopherol, beta carotene, vitamin C, zinc, and sodium selenite), adapted to rats. The present results showed that each of the antioxidants inhibited growth of glioma cells in vitro. When used in combination for in vivo studies, we showed a highly significant delay in the clinical signs of the disease, but not a statistical significant difference in the incidence of glioma in an Ethyl-nitrosourea (ENU)-model. The SUVIMAX-like diet decreased candidate markers of tumoral aggressiveness and gliomagenesis progression. The mRNA expressions of 2 common markers in human glioma: Mn-SOD (Manganese Superoxide Dismutase) and IGFBP5 (insulin growth factor binding protein) were reduced in the tumors of rats fed the antioxidant diet. In addition, the transcripts of two markers linked to brain tumor proliferation, PDGFRb (platelet-derived growth factor receptor beta) and Ki-67, were also significantly decreased. On the whole, our results suggest a protective role for antioxidants to limit aggressiveness and to some extent, progression of gliomas, in a rat model.

Replication-deficient vaccinia virus gene therpay vector: evaluation of exogenous gene expression mediated by PUV-inactivated virus in glioma cells.

BACKGROUND: Mild psoralen and UV (PUV) treatments inactivate viral DNA replication, but the virus retains its ability to infect cells. Thus, PUV treatment of vaccinia virus (VV) vectors may increase the safety of gene delivery and extend the duration of gene expression. Although the first studies on PUV-inactivated VV (PUV-VV) for the delivery of suicide or cytokine genes to cancer cells were promising, the efficiency and kinetics of exogenous gene expression have not been fully evaluated. Furthermore, these studies should be extended to other gene therapy strategies, e.g. tumor suppressor genes. METHODS: We constructed VV recombinants carrying the luciferase (luc) gene, or the tumor suppressor p53 gene, to analyze exogenous gene expression after PUV treatment. Apoptosis induction and antitumor effects were examined in glioma cell culture and in an animal model, respectively. RESULTS: PUV-VV induced efficient PE/L-driven expression of luc and p53 exogenous genes in infected cells. A surprising prolonged p53 protein production was measured in glioma cells infected with PUV-VV expressing p53 (VV-TK-53) on Days 5-7 post-infection, reaching a maximal level of 9 microg/ml. VV-TK-53 induced apoptosis in 88% and 77.6% of infected C6 and 9L glioma cells, respectively. In contrast, 80% of cells infected with the PUV-inactivated control virus remained viable. Finally, ex vivo infection of C6 glioma cells with PUV-inactivated VV-TK-53 significantly reduced subsequent tumor growth in nude mice. CONCLUSIONS: Replication-deficient PUV-VV is safe and very efficient in prolonged foreign gene expression. Therefore PUV-VVs are recommended as vectors for applications in cancer gene therapy and recombinant vaccine development.

Case-control study of intracranial tumors among employees at a petrochemical research facility.

This case-control study evaluated the relation between potential exposure to chemical and physical agents and the occurrence of intracranial tumors among employees at a petrochemical research facility. Cases were employees with glioma (n = 6) or benign intracranial tumors (n = 6). Controls (n = 119) were individually matched to cases on gender and birth year, and they were alive and did not have an intracranial tumor at the case's diagnosis date. Exposure information came from interviews with subjects or surrogates and from corporate records on agents used in research projects. Analyses computed matched odds ratios (ORs) and corresponding 95% confidence intervals (CIs) for self-reported exposure to 15 agents and project-based estimates of exposure to 29 agents. For gliomas, the OR was elevated for self-reported exposure to ionizing radiation (OR, 15.7; CI, 1.4 to 179.4), n-hexane (OR, infinity; CI, 1.4 to infinity), organometallics (OR, 9.4; CI, 1.5 to 59.7), and amines other than nitrosamines (OR, 6.0; CI, 1.0 to 35.7). The OR also was elevated for project-based potential use of ionizing radiation (OR, 9.6; CI, 1.7 to 55.2) and for potential use of n-hexane lasting at least 4 years (OR, 16.2; CI, 1.1 to 227.6). For benign intracranial tumors, the OR was elevated only for self-reported exposure to ionizing radiation (OR, 5.4; CI, 1.7 to 43.1) and other amines (OR, 5.2; CI, 0.9 to 29.5). Occupational exposure may have contributed to the glioma excess, but the specific causal agents remain unknown. The study indicated that benign intracranial tumors were unlikely to be work-related.

Effect of dietary vitamin A or N-acetylcysteine on ethylnitrosourea-induced rat gliomas.

It is our hypothesis that low grade gliomas are the glial counterparts of other precancerous lesions such as colon polyps and, therefore, suitable targets for chemoprevention. Steps in the molecular progression of gliomas have been described, indicating that an accumulation of abnormalities is required for progression to a high grade and interruption of this progression might be possible. An animal model of chemical glial carcinogenesis was used to test this hypothesis. Pregnant rats were injected intravenously with ENU (ethylnitrosourea) on the 18th day of gestation to induce gliomas in the offspring, which were randomized to receive control diet, diet supplemented with vitamin A palmitate, or diet supplemented with N-acetylcysteine. Animals exposed to ENU and receiving a control diet developed brain tumors and had a shortened life expectancy compared with rats unexposed to ENU. The animals treated with NAC showed no statistically significant delay in the time to tumor and no change in the histologic grade of the tumors when compared with animals receiving control diet, but the time to death from any cause of NAC treated animals differed significantly from untreated animals. Animals receiving high dose VA had statistically significantly prolonged time to tumor, survived significantly longer than untreated animals, but had no reduction in the total number of tumors or change in the histologic grade of their tumors. The theoretical basis of these results is likely due to the putative mechanism of action of these agents. These data indicate that glioma chemoprevention is possible and deserves further exploration.

Gliomas and meningiomas in men in Los Angeles County: investigation of exposures to N-nitroso compounds.

We conducted a case-control study of primary tumours of the brain and cranial meninges in Los Angeles County to investigate the hypothesis that these tumours are related to occupational exposures. We also collected limited data on diet and personal habits that are likely to involve exposure to N-nitroso compounds (NOC), NOC precursors and modulators of NOC metabolism. Interviews were conducted with 272 men with a brain tumour diagnosed in 1980-84 and with 272 individually matched neighbourhood controls. The study was of sufficient size to allow for separate analyses of the 202 pairs of glioma patients and of the 70 patients of meningioma. Six glioma cases and one control had worked in the rubber industry, in which excesses of brain tumour have been shown in previous studies and where there are high levels of volatile NOC at various work sites. Ten meningioma patients and five controls had used cooling, cutting or lubricating oils, and most had used these daily (eight cases; four controls). Cases and controls were not different, however, with respect to other occupations known to involve exposures to NOC. Cases and controls also did not differ in their consumption of alcoholic beverages or cigarettes or in their passive exposure to cigarette smoke. The most striking dietary finding was a significant protective effect among glioma pairs of use of vitamin supplements, which increased with increasing frequency of use (p for trend = 0.04; odds ratio for use at least twice a day = 0.4 (95% confidence interval = 0.24-0.77)).(ABSTRACT TRUNCATED AT 250 WORDS)

Chronic toxicity/carcinogenicity study of FD & C Blue No. 2 in rats.

FD & C Blue No. 2 was fed to rats in the diet in a long-term toxicity/carcinogenicity study. The study included an in utero phase in which the compound was administered to groups of 60 male and 60 female Charles River CD albino rats at levels of 0.5, 1.0 and 2.0%. Two concurrent control groups, each containing 60 rats of each sex, received the basal diet. After random selection of the F1 animals, the long-term phase was initiated at the same dietary levels, with 70 rats of each sex in each dose group and in each of two control groups. Maximum exposure was 30 months. No consistent compound-related biologically adverse effects were noted. There were random statistically significant differences from the controls with respect to body weight, food consumption and clinical chemistry tests. Food consumption by the test groups showed a dose-related increase. This was probably due to the non-nutritive character of the colouring. A statistically significant increase in gliomas in the high-dose male rats was not found to be biologically significant, since none of the criteria for determining the neurocarcinogenic potential of chemical substances was met. The overall brain-tumour incidence in this study was within the range typical for 2-yr-old CD rats. Under the conditions of this study, FD & C Blue No. 2 did not produce evidence of any toxicity, including carcinogenicity.

The subependymal plate and the genesis of gliomas.

A case of experimentally induced glioma in the rat is described, whose origin is clearly linked with hyperplasia of the subependymal plate.