| Objective:To study the effects of Wnt/β-catenin signaling pathway in lung adenocarcinoma A549 cells.Methods:After A549 cells were stimulated with Lithium Chloride (LiCl) or transfected withβ-catenin interference plasmids, real time PCR was employed to detect the expression ofβ-catenin, cyclin D1 (a target gene of Wnt/β-catenin pathway) and OCT-4. Western blot was used to measure the expression of P-catenin and the stem cell marker OCT-4. A MTT cell proliferation assay was performed to study the proliferating capacity. Flow cytometry was used for cell cycle analysis. Clone formation and Millicell chamber experiments were performed to evaluate the clone formation and migration capacities of cells. Drug resistance experiments were performed to study the drug resistance capacity.Results:Stimulating A549 cells with 10 mmol/L Lithium Chloride (LiCl) for 24 h resulted in accumulation ofβ-catenin and upregulation of a typical Wnt target gene cyclin D 1(0.023±0.006 vs 0.007±0.003, P<0.05). This stimulation also significantly enhanced proliferation, clone formation[(22.875±2.115)% vs (11.455±4.274)%, P<0.01], migration (52.5±4.041 vs 27.250±2.500, P< 0.01) and drug resistance abilities in A549 cells. Moreover, the upregulation of OCT-4, a stem cell marker, was observed through real time PCR and western blot. In a reverse approach, Wnt signaling pathway was inhibited by knocking down the expression ofβ-catenin using RNA interference technology. This inhibition resulted in down-regulation of the Wnt target gene cyclin D1 (0.005±0.002 vs 0.042±0.004, P<0.05) as well as the proliferation, clone formation [(31.6±7.7)% vs (46.9±7.3)%, P<0.05], migration (16.0±3.8 vs 32.7±3.1, P<0.01) and drug resistance abilities. Meanwhile, the expression of OCT-4 was reduced after the inhibition of Wnt/β-catenin signaling.Conclusions:Wnt signaling plays an important role in lung cancer stem cell properties and the expression of OCT-4, which may be a new target for lung cancer therapy.
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