Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0079731 (B-cell lymphoma)
 16,671 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Sphingolipid metabolites are important regulators of cell growth and apoptosis. To clarify the biological roles of cell surface sialylation in the effects of sphingomyelinase (SM) treatment on cell viability, the human diffuse large B cell lymphoma cell line, HBL-2 with or without treatment with Vibrio cholerae neuraminidase, was incubated with exogenous bacterial SM which is a key enzyme of ceramide production from sphingolipids in cell membranes. SM treatment enhanced viability of HBL-2 cells compared to non-treatment after 6 h of incubation. On the other hand, viability of HBL-2 cells was decreased by SM treatment with neuraminidase pre-treatment after 6 and 24 h of incubation, and ceramide production on cell surfaces of SM treated cells was enhanced by neuraminidase treatment as shown by flow cytometric analysis. Furthermore, treatment with D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol, an inhibitor which specifically reduces the activity of UDP-glucose:ceramide glucosyltransferase in combination with SM treatment, causes the viability of HBL-2 cells to be decreased more with neuraminidase pre-treatment than without it. Exogenous C6-ceramide induced HBL-2 cell death, and there was no difference in the effects of C6-ceramide after 6 h of incubation between treatment and non-treatment with neuraminidase. Together these data suggest that alteration in susceptibility of HBL-2 cells to SM by neuraminidase treatment may precede the process of ceramide production, and that cell death through the activation of SM, which induces ceramide production, is regulated by cell surface sialylation in DLBCL.
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PMID:Regulatory roles of cell surface sialylation in susceptibility to sphingomyelinase in human diffuse large B cell lymphoma. 1594 62

We examined the ability of mifepristone to reverse the in vitro drug resistance of human cervical cancer cells resistant to mitomycin-C (HeLa/MMC) cells and investigated the mechanism of this effect. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed to detect the drug resistance of HeLa/MMC cells and the reversed drug resistance in vitro. Expression levels of B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax), and glucosylceramide synthase (GCS) were measured in HeLa and HeLa/MMC cells. The resistance index of HeLa/MMC cells on MMC was reduced from 5.02 to 1.46 after 10 mg/mL mifepristone exposure. A combination of mifepristone upregulated the Bax/Bcl-2 protein expression ratio and apoptosis in HeLa/MMC cells. GCS expression was significantly higher in HeLa/MMC cells than in HeLa cells (P < 0.01), but distinctly declined in both cell lines after mifepristone application (P < 0.01). Mifepristone reversed the resistance of HeLa/MMC cells to MMC in vitro; the overexpression of the GCS gene and the increased expression of apoptosis-related protein Bcl-2 may play important roles in the formation of multidrug resistance in cervical cancer.
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PMID:Mechanism of the reversal effect of mifepristone on drug resistance of the human cervical cancer cell line HeLa/MMC. 2463 86