Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0017638 (glioma)
 30,880 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have examined the metabolism of ketone bodies in neuroblastoma C1300 and glioma C6 cells, two established lines of neural origin. The three ketone body-metabolizing enzymes are present in cells of both lines in the relative proportions normally found in brain (D-3-hydroxybutyrate dehydrogenase less than acetoacetyl-CoA thiolase less than 3-ketoacid CoA-transferase), the activities of the first two are higher in glioma cells than in neuroblastoma, and that of the third is 2-fold higher in neuroblastoma cells than in glioma cells. The specific activity of 3-ketoacid CoA-transferase (EC 2.8.3.5) in both cell lines increased as the cultures achieved confluence, then decreased. Ketone bodies and especially acetoacetate are preferred substrates for synthesis of neural lipids in cells of both lines. The incorporation of glucose carbon into lipids is significantly reduced in cells of both lines in the presence of ketone bodies. Addition of acetoacetate but not DL-3-hydroxybutyrate to the culture medium resulted in a significant increase in the activity of 3-ketoacid CoA-transferase and also in the rate of acetoacetate oxidation in neuroblastoma cells but not glioma cells. These findings indicate that specific differences exist in the capacity of these two cell lines to metabolize ketone bodies and also that substrate-level regulation of the ketone body-metabolizing pathway exists. These two lines therefore provide a potentially useful system in which the mechanisms of regulation of these enzymes may be examined.
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PMID:Ketone-body metabolism in glioma and neuroblastoma cells. 611 69

The specific activity of succinyl-CoA:3-oxo-acid CoA-transferase (3-oxoacid CoA-transferase, EC 2.8.3.5) increases significantly during growth in culture in both mouse neuroblastoma N2a and rat glioma C6 cells. To investigate the mechanism(s) responsible for this, antibody specific for rat brain 3-oxoacid CoA-transferase was raised in rabbits. Immunotitrations of 3-oxoacid CoA-transferase from neuroblastoma and glioma cells on days 3 and 7 of growth after subculture showed that the ratio of 3-oxoacid CoA-transferase activity to immunoprecipitable enzyme protein remained constant, indicating that differences in specific activity of the enzyme at these times in both cell types reflect differences in concentration of enzyme protein. In glioma cells, the relative rate of 3-oxoacid CoA-transferase synthesis was about 0.04-0.05% throughout 9 days in culture. In contrast, the relative rate of synthesis of 3-oxo-acid CoA-transferase in neuroblastoma cells was about 0.07-0.08% on days 3, 5 and 7 after subculture, but fell to 0.052% on day 9. The degradation rates of total cellular protein (t1/2 = 28 h) and 3-oxoacid CoA-transferase (t1/2 = 46-50 h) were similar in both cell lines. The rise in specific activity of the enzyme in both cell lines from days 3 to 7 without a significant increase in the relative rate of synthesis reflects a slow approach to steady-state conditions for the enzyme secondary to its slow degradation. Differences in 3-oxoacid CoA-transferase specific activity between the two cell lines are apparently due to a difference of about 60% in relative rates of enzyme synthesis. The presence of 0.5 mM-acetoacetate in the medium significantly increased the specific activity of 3-oxoacid CoA-transferase in neuroblastoma cells during the early exponential growth phase. This treatment increased the relative rate of synthesis of 3-oxoacid CoA-transferase by 23% (P less than 0.025) in these cells on day 3, suggesting that substrate-mediated induction of enzyme synthesis is a mechanism of regulation of 3-oxoacid CoA-transferase.
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PMID:Turnover of succinyl-CoA:3-oxoacid CoA-transferase in glioma and neuroblastoma cells. Specific influence of acetoacetate in neuroblastoma cells. 659 97