calcimycin and Leukemia--Mast-Cell

The aim of the present study was to determine whether dehydroleucodine, xanthatin and 3-benzyloxymethyl-5H-furan-2-one inhibit the activation of human leukemic LAD2 mast cells induced by compound 48/80 or the calcium ionophore A23187. LAD2 cells were preincubated in the presence of test drugs and then challenged with the secretagogues. This study provides the first evidence in favor of the view that dehydroleucodine and xanthatin inhibit the degranulation of LAD2 cells, thus acting as human mast cell stabilizers. These molecules could be effective in the treatment of human diseases associated with inappropriate mast cell activation.

Topics: beta-N-Acetylhexosaminidases; Calcimycin; Calcium Ionophores; Cell Degranulation; Cell Line, Tumor; Furans; Humans; Kinetics; Lactones; Leukemia, Mast-Cell; Mast Cells; Microscopy, Electron, Scanning; Microscopy, Electron, Transmission; p-Methoxy-N-methylphenethylamine; Sesquiterpenes

Schisandra fructus has been used for treatment of cough and thirst in Korea. However, its therapeutic mechanisms remain largely unclear. To investigate the biological effect of Schisandra fructus water extract (SFWE), we examined the effect of SFWE on the phorbol 12-myristate 13-acetate (PMA) and calcium ionophore A23187-induced pro-inflammatory cytokine secretion in the human mast cell line HMC-1. HMC-1 cells were stimulated with PMA plus A23187 in the presence or absence of SFWE. Tumor necrosis factor (TNF)-alpha, interleukin 6 (IL-6), and granulocyte-macrophage colony-stimulating factor (GM-CSF) productions were measured by enzyme-linked immunosorbent assay and reverse transcription-polymerase chain reaction. Inhibitory IkappaB/nuclear factor-kappaB (NF-kappaB) expression was assessed by western blot. SFWE suppressed PMA plus A23187-induced TNF-alpha, IL-6, and GM-CSF production in dose-dependent manners. Furthermore, SFWE inhibited IkappaB degradation and NF-kappaB nuclear translocation. These results suggest that SFWE inhibits the secretion of pro-inflammatory cytokines in HMC-1 cells through blockade of IkappaB degradation and NF-kappaB activation. Taken together, these findings may help elucidate the mechanism of action of this medicine in the modulation of mast cell activation in inflammatory conditions.

Topics: Calcimycin; Cell Line, Tumor; Culture Media, Conditioned; Cytokines; Gene Expression; Granulocyte-Macrophage Colony-Stimulating Factor; Humans; I-kappa B Proteins; Interleukin-6; Leukemia, Mast-Cell; Mast Cells; NF-kappa B; Plant Extracts; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Schisandra; Tetradecanoylphorbol Acetate; Tumor Necrosis Factor-alpha; Water

Topics: Antibodies, Anti-Idiotypic; Calcimycin; Cytokines; Histamine Release; Humans; Immunoglobulin E; Interleukin-8; Ionophores; Leukemia, Mast-Cell; Mast Cells; RNA, Messenger; Stem Cell Factor; Tumor Cells, Cultured; Tumor Necrosis Factor-alpha

Hepatocyte growth factor (HGF) was originally characterized as a strong inducer of liver regeneration. However, it is now clear that HGF and its receptor, the proto-oncogene c-met, can be expressed in many other tissues, and that HGF can mediate diverse biological activities. We investigated the expression and function of c-met in a human mast cell line (HMC-1). We found that HMC-1 cells express c-met and that c-met expression can be upregulated by treatment of the cells with phorbol 12-myristate 13-acetate (PMA). Although HGF did not detectably influence the proliferation or morphology of HMC-1 cells, HGF inhibited the cells' ability to release tumor necrosis factor-alpha (TNF-alpha) in response to stimulation with PMA and the calcium ionophore, A23187. These results add the inhibition of TNF-alpha production to the other recognized effects of HGF/c-met on cellular function.

Topics: Calcimycin; Hepatoblastoma; Humans; Leukemia, Mast-Cell; Liver Neoplasms; Proto-Oncogene Mas; Proto-Oncogene Proteins c-met; RNA, Messenger; Tetradecanoylphorbol Acetate; Transcription, Genetic; Tumor Cells, Cultured; Tumor Necrosis Factor-alpha

Recent reports have indicated that ADP-ribosylation factor (ARF) plays a role in the regulation of phospholipase D (PLD) activity in the in vitro assay system. Since a fungal metabolite brefeldin A (BFA) is known to interfere with ARF function, the effect of BFA on antigen-induced PLD activation was examined in rat basophilic leukemia (RBL-2H3) cells. BFA inhibited the antigen-induced formation of phosphatidylbutanol (PBut), a specific and stable metabolite produced by PLD activity in a concentration-dependent manner. The maximal inhibition obtained at 10 micrograms/ml of the drug was nearly 70% and further inhibition was not observed at higher concentrations. Ca(2+)-ionophore A23187-mediated PLD activation was also prevented by BFA. In contrast, BFA failed to inhibit PLD activation in response to 4 beta-phorbol 12-myristate 13-acetate (PMA), an activator of protein kinase C (PKC). This indicates that there are BFA-sensitive and BFA-insensitive pathways leading to PLD activation in RBL-2H3 cells and also that the PKC-mediated pathway may be insensitive to BFA treatment, suggesting the existence of PLD isozymes. BFA inhibited Ag-induced serotonin release at a concentration 20-fold lower than that needed for the inhibition of PLD. Moreover, PMA caused a marked production of PBut, but it failed to elicit secretory response. This implies that PLD may be not a crucial element for secretory responses.

Topics: Animals; Antigens; Brefeldin A; Calcimycin; Cyclopentanes; Enzyme Activation; Leukemia, Mast-Cell; Phospholipase D; Rats; Serotonin; Tetradecanoylphorbol Acetate; Tumor Cells, Cultured