Glucocorticoids inhibits the repair of airway epithelial cells via the activation of wnt pathway.

BACKGROUND: The purpose of this study was to explore the effect of Wnt pathway on the inhibition of airway epithelial cells repair by glucocorticoid. MATERIALS AND METHODS: The expression of E-cadherin in asthma mice model was detected by immunocytochemistry. XAV939 was used to treat 16HBE, and the expressions of related genes were determined by western blotting and quantitative real-time polymerase chain reaction (qRT-PCR). Cell viability, migration and cell cycle were analyzed by methylthiazolyldiphenyl-tetrazolium bromide, wound healing and flow cytometry, respectively. RESULTS: In asthma mice model, the lung tissue was impaired. After dexamethasone treatment, the airway inflammation was relieved and the expression of E-cadherin was reduced. Dexamethasone increased the expressions of Wnt7b, LRP5, ß-catenin and CyclinD1, inhibited cell viability and migration and arrested cell cycle, whereas XAV939 produced the opposite effects. In addition, XAV939 suppressed Wnt pathway that activated by dexamethasone. CONCLUSION: Glucocorticoid could inhibit cell proliferation and migration via regulating Wnt pathway to affect cell cycle, thus inhibiting the repair of airway epithelial after injury.

Resveratrol induces apoptosis of leukemia cell line K562 by modulation of sphingosine kinase-1 pathway.

To explore the effects of resveratrol in a human myelogenous leukemia cell line K562 and its potential molecular mechanisms. The anti-proliferation effect of resveratrol-induced apoptosis on K562 cells were detected using MTT assay. Western blotting was performed for detecting changes of SphK1 expression in total cell protein and membrane/cytosol protein in K562 cells respectively after exposure to resveratrol. A biochemical assay was used to measure the activity of SphK after treatment of resveratrol, and then S1P and ceramide levels were examined using ELISA kits. Hochest 33258 staining and flow cytometry were applied to detect the apoptosis condition of K562 cells treated with resveratrol. Resveratrol inhibited the proliferation and induced apoptosis in K562 cells in a dose and time-dependent manner. Western blotting revealed that resveratrol did not affect total SphK1 expression level in K562 cells, but significantly changed the translocation of SphK1, the membrane SphK1 was decreased while cytosol SphK1 level was elevated. The activity of SphK1 in resveratrol treated groups was decreased compared to control group with a significant decrease of S1P and increase of ceramide level. Furthermore, Hoechst 33258 staining and Annexin V-FITC analysis confirmed the notable apoptotic effect of resveratrol in its anti-leukemia process. Resveratrol-induced proliferation inhibition of K562 cells might be mediated through its modulation activity of SphK1 pathway by regulating S1P and ceramide levels, which then affected the proliferation and apoptosis process of leukemia cells. SphK1/S1P pathway represents a target of resveratrol in human leukemia.