The role of Bcl-xL and nuclear factor-kappaB in the effect of taxol on the viability of dendritic cells

Taxol has been used effectively in cancer therapies. Our previous study demonstrated that taxol induced altered maturation and improved viability of dendritic cells (DCs). However, the effects of taxol on DC viability have not been fully elucidated. In the present study, flow cytometric analyses revealed that taxol treatment significantly increased the number of viable DCs and the expression levels of a representative anti-apoptotic protein Bcl-xL. Furthermore, mobilization of the p65 subunit of nuclear factor-kappaB (NF-kappaB) from the cytosol to the nucleus in DCs was observed by confocal microscopy. An inhibition assay using N-p-tosyl-L-phenylalanine chloromethyl ketone confirmed that NF-kappaB was intimately involved in the effects of taxol on DC viability. In addition, we investigated the mechanisms of taxol enhancement of DC viability. Since taxol is a popular anticancer agent used in clinic, this study may provide a rationale for the use of taxol in DC immunotherapy to treat cancer patients. Taken together, these results confirm that taxol increases DC viability, and this information may provide new insights for new clinical applications of both taxol and DCs.

Effect of N-tosyl-L-phenylalnylchloromethyl ketone and dexamethasone on expression of nuclear transcription factor-kappaB in childhood acute lymphoblastic leukemia and its significance / 中国实验血液学杂志

In order to investigate the effect of N-tosyl-L-phenylalnylchloromethyl ketone (TPCK) and dexamethasone (Dex) on expression of nuclear transcription factor-kappaB (NF-kappaB) in childhood acute lymphoblastic leukemia (ALL) and its significance, so as to provide the experimental basis for corresponding clinical treatment of ALL, in which NF-kappaB is taken as a target. The biotin-streptavidin method was used to detect the expression of NF-kappaB P65 protein and the effects of TPCK and Dex at clinically relevant dosage on activity of NF-kappaB P65 protein in 20 childhood ALL patients. The results indicated that the expression of NF-kappaB P65 protein was strongly diminished and reached to negative level at 2 hours by treatment with 40 micromol/L TPCK, the positive expression of NF-kappaB P65 protein was (2.5 +/- 1.6)%. TPCK had a time-dependent inhibitory effect on ALL cells cultured in vitro. The expression of NF-kappaB P65 protein in ALL cells was strongly inhibited by clinically relevant concentration of dexamethasone 5.0 microg/ml for 24 hours in vitro. The positive expression was (25.0 +/- 3.0)%, there was significant difference, as compared with untreated ALL cells (T=55, P<0.01). It is concluded that TPCK and Dex can inhibit NF-kappaB activity. Inhibition of NF-kappaB activity may be one of the effect mechanism of dexamethasone on ALL cells. Inhibition of NF-kappaB conduction pathway may have a significant value in childhood ALL treatment.

Effect of CD14, Toll-like receptors, cytoskeletal inhibitors and NF-kappaB inhibitor on MMP-8 release from human neutrophils induced by E. coli lipopolysaccharides / 대한치주과학회지

OBJECTIVE: MMP-8 is a neutrophil enzyme and its level increases in some inflammatory diseases, including periodontal disease. We knew that the lipopolysaccharide of E.coli(E-LPS) induced MMP-8 release from human neutrophils. E-LPS is known to induce the production and release of inflammatory cytokines through CD14, Toll-like receptor(TLR). In the present study, we investigated whether MMP-8 release by E-LPS is induced via CD14-TLR pathway and the cellular mechanism of MMP-8 release in human neutrophils. MATERIAL AND METHODS: Human neutrophils were isolated from the peripheral blood of healthy donors and pre-incubated in medium containing antibodies against CD14, anti-TLR2 and anti-TLR4 or several inhibitors of microtubules and microfilaments and then incubated with E-LPS. The cells were treated TPCK and E-LPS simultaneously. The MMP-8amount in the culture medium was determined using ELISA. RESULTS: E-LPS increased MMP-8release from neutrophils and its induction was inhibited by anti- CD14 and anti-TLR4 but not by anti-TLR2 antibodies. The inhibitors of micro- tubule and microfilament polymerization significantly decreased E-LPS-induced MMP- 8release. TPCK inhibited E-LPS-induced MMP-8 release. CONCLUSION: These results suggest that MMP-8 release is induced by E-LPS via the CD14-TLR4 signal pathway in human neutrophils and may be depedent on microtubule and microfilament systems and NF-kappaB pathway.

Modulation of tryptase and histamine release from human lung mast cells by protease inhibitors.

Inhibition of IgE dependent histamine release from human mast cells by protease inhibitors has been observed in skin, tonsil and synovial tissues. However, little is known about the actions of protease inhibitors on tryptase release from human lung mast cells. We therefore examined the ability of protease inhibitors to modulate tryptase and histamine release from human lung mast cells. IgE dependent tryptase release from dispersed lung mast cells was inhibited to a maximum of approximately 53.8% and 44.5% by N-a-tosyl-L-lysine chloromethyl ketone (TLCK) and N-p-Tosyl-L-phenylalanine chloromethyl ketone (TPCK), respectively. A similar degree of inhibition of calcium ionophore A23187 (CI) induced tryptase release was also observed with these two inhibitors. Preincubation of TLCK or TPCK with the mast cells at 37 degrees C for 20 minutes before addition of anti-IgE or CI did not improve their ability to inhibit anti-IgE and CI induced tryptase release. At a concentration of 10 microg/ml, protamine inhibited anti-IgE or CI induced tryptase release; but at 100 microg/ml, it increased anti-IgE and CI induced release of tryptase from lung mast cells. A concentration dependent inhibition of anti-IgE and CI induced release of histamine from lung mast cells was also observed with TLCK, TPCK and protamine. The maximum inhibition of anti-IgE induced histamine release was approximately 40.7%, 40.2% and 33.4% with TLCK, TPCK and protamine, respectively. At the concentrations tested, TLCK and TPCK by themselves did not stimulate tryptase and histamine release from lung mast cells. A specific inhibitor of aminopeptidase, amastatin, had no effect on anti-IgE induced tryptase and histamine release and was used as control. In conclusion, it was demonstrated that protease inhibitors are able to inhibit IgE dependent tryptase and histamine release from human lung mast cells, which suggested that they could be developed to a novel class of anti-inflammatory drugs to treat allergic conditions in man.

Effect of N-tosyl-L-phenylalanylchloromethyl ketone on tumor necrosis factor-alpha -induced NF-kappaB activation and apoptosis in U937 cell line / 华中科技大学学报（医学）（英德文版）

To investigate the effect of N-tosyl-L-phenylalanylchloromethyl ketone (TPCK) on tumor necrosis factor-alpha-induced NF-kappaB activation and apoptosis in U937 cell line, changes and subcellular localization of NF-kappaB/p65 and IkappaB-alpha were observed by fluorescencemicroscopy and expression and degradation of IkappaB-alpha by flow cytometry. The apoptosis of U937 cells was measured by flow cytometry and electrophoresis of DNA. Immunolfluorescence assay showed that NF-kappaB/p65, IkappaB-alpha only localized in cytoplasm. After TNF-alpha stimulation, p65 was localized only in nuclei, and IkappaB-alpha was only localized in cytoplasm and decreased. The changes of TNF-alpha stimulation were specifically inhibited by TPCK. Flow cytometry also revealed the downregulation of IkappaB-alpha protein during TNF-alpha-induced apoptosis and the down-regulation was specifically inhibited by TPCK. Flow cytometry also showed the apoptosis of U937 cells after TNF-alpha induction. DNA ladder can be detected in cells treated by TNF-alpha. It is concluded that degradation of IkappaB-alpha protein and NF-kappaB/p65 translocation occur during TNF-alpha-induced apoptosis of U937 cells, suggesting the activation of NF-kappaB TPCK-sensitive protease plays an important role in the degradation of IkappaB-alpha protein induced by TNF-alpha in U937 cells. TPCK sensitive protease also plays an important role in the apoptosis of U937 cells induced by TNF-alpha.