AIM:To investigate whether early endothelial progenitor cells (early-EPCs) expressβ2-adrenergic receptor (β2 AR) in the chronic obstructive pulmonary disease ( COPD) patients and the effect of β2 AR expression on the migration of early-EPCs.METHODS:Venous blood samples (20 mL) were obtained from antecubital vein of COPD pa-tients or healthy controls .Peripheral blood mononuclear cells were isolated by standard Ficoll gradient centrifugation , and purified by CD34 positive selection cocktail .The mRNA expression of β2 AR in the early-EPCs was detected by RT-PCR. The protein levels of β2 AR were assessed by Western blotting and flow cytometry .Chemotaxis was studied by Transwell as-say.Cultured early-EPCs were treated with ICI118551, norpinephrine (NE) or monoclonal antibody of β2AR (mAb-β2 AR) for 24 h.The number of migratory cells was counted under a light microscope .RESULTS:The level of β2 AR ex-pression in the COPD patients was higher than that in the controls .The number of migratory early-EPCs to stromal cell-de-rived factor 1αwas significantly improved by ICI 118551 compared with other COPD groups .When early-EPCs from the COPD patients or the controls were treated with different concentrations of mAb-β2 AR for 24 h, the number of migratory early-EPCs from the COPD patients and the controls treated with NE at concentration of 100 nmol/L was significantly re-duced.However, a marked decrease in the number of migratory early-EPCs from the COPD patients treated with NE was observed compared with control group .Before treated with ICI118551 or NE for 24 h, the early-EPCs were co-incubated with mAb-β2 AR for 40 min, and the number of migratory early-EPCs was not significantly different between COPD group and control group .Genetic down-regulation of β2 AR promoted the migration of early-EPCs in COPD group .CONCLU-SION:The level of β2 AR expression in the COPD patients is increased compared with the controls .The down-regulation ofβ2 AR improves the migration of early-EPCs.

AIM:To investigate the effect of ionizing radiation on epithelial-mesenchymal transition in lung cancer cell line A549 and its possible mechanism.METHODS:The lung cancer A549 cells were irradiated with different doses (0 Gy, 1 Gy, 2 Gy, 4 Gy and 8 Gy) of X-ray for different time.The morphological changes of the cells were observed under inverted microscope at time points of 12 h, 24 h and 48 h.The expression of vimentin, N-cadherin, E-cadherin and transcription factor c-Myc was detected by Western blot at the time points of 12 h and 24 h.RESULTS:After ionizing radiation, the contours of the A549 cells were unclear, the protrusions increased, and the edges were irregular, with fried egg-like collapses.The mesenchymal morphology of the A549 cells was most obvious after irradiation at 8 Gy for 48 h.Compared with 0 Gy irradiation group, the expression of vimentin was down-regulated seemingly 12 h after irradiation, but up-regulated in 2 Gy, 4 Gy and 8 Gy irradiation groups for 24 h, and the most obvious effect was observed in 2 Gy irradiation group (P<0.01).Compared with 0 Gy irradiation group, the expression of N-cadherin was up-regulated in 1 Gy, 2 Gy and 4 Gy irradiation groups for 24 h (P<0.05), while the expression of E-cadherin was not influenced.The up-regulation of vimentin expression in lung cancer cell line A549 was positively correlated with c-Myc expression.CONCLUSION:Ionizing radiation may promotes epithelial-mesenchymal transition in the lung cancer cell line A549 by up-regulating the c-Myc expression.