RESUMEN
AIM:To observe the expression of Akt/GSK-3β/Snail signaling pathway-related molecules in cis-platin-resistant cell line A549/DDP mediated by transforming growth factor-β1 (TGF-β1), and to explore the association of Akt/GSK-3β/Snail signaling pathway with epithelial-mesenchymal transition (EMT). METHODS:The A549/DDP cells were divided into TGF-β1(+) group, TGF-β1(-) group and LY294002 group. The morphological changes of A549/DDP cells treated with TGF-β1 were observed under microscope. The protein expression of E-cadherin and N-cadherin was determined by the methods of immumofluorescence and Western blot. The protein levels of Akt, p-Akt, GSK-3β, p-GSK-3βSer9 and Snail were also detected by Western blot. RESULTS:The A549/DDP cells in TGF-β1(+) group were disper-sive, showed a spindle-like shape and developed pseudopodia. This transformation was conformed to classic EMT markers. Compared with TGF-β1(-) group, the protein expression of E-cadherin in TGF-β1(+) group was significantly decreased (P<0.05), and N-cadherin was significantly increased (P<0.05). The protein levels of p-Akt, p-GSK-3βSer9 and Snail were also significantly increased ( P<0.05). Compared with TGF-β1(+) group, the protein levels of p-Akt, p-GSK-3βSer9 and Snail were significantly decreased in LY294002 group (P<0.05). No difference of Akt and GSK-3β expression between TGF-β1(-) group and TGF-β1(+) group was observed. CONCLUSION:The mechanism of EMT in A549/DDP cells might be related to Akt/GSK-3β/Snail signaling pathway activated by TGF-β1.
RESUMEN
AIM:To investigate the function of microRNA-125a-5p (miR-125a-5p) on epithelial-mesenchy-mal transition ( EMT) of breast cancer cells via GSK-3β/Snail signaling pathway. METHODS:The expression of miR-125a-5p in normal breast epithelial cells and breast cancer cells, as well as the transfection efficiency of miR-125a-5p plas-mid in MDA-MB-231 cells was detected by RT-qPCR. The chemotaxis ability and invasion ability were detected by chemo-taxis assay and Transwell invasion assay. The changes of EMT-related markers, the protein level of phosphorylated glycogen synthase kinase-3β (p-GSK-3β) and the nuclear translocation of Snail were determined by Western blot. RESULTS:The expression of miR-125a-5p in the breast cancer cells was significantly lower than that in the normal breast epithelial cells. The expression of miR-125a-5p was significantly higher in MDA-MB-231/miR-125a-5p cells than that in MDA-MB-231/NC cells. The ability of epithelial growth factor (EGF) at 10 μg/L to induce chemotaxis of MDA-MB-231 cells was the stron-gest. Compared with MDA-MB-231/NC group, stimulation of EGF decreased the invasion ability of MDA-MB-231/miR-125a-5p cells, and resulted in the increase in E-cadherin expression, while significantly decreased the protein levels of vi-mentin and p-GSK-3β. Meanwhile, the nuclear localization of Snail was significantly inhibited. The invasion capacity of MDA-MB-231/miR-125a-5p+GAB2 cells was significantly enhanced compared with MDA-MB-231/miR-125a-5p +Con cells, the expression of E-cadherin was decreased, and the protein levels of vimentin and p-GSK-3β were significantly in-creased, while the nuclear localization of Snail was promoted. CONCLUSION:miR-125a-5p suppresses EMT via GSK-3β/Snail signaling pathway, thus inhibiting the invasion ability of breast cancer cells.