circ-PRKDC affects the proliferation, apoptosis and radiosensitivity of lung cancer cells by regulating miR-505-3p / 中华放射肿瘤学杂志

ABSTRACT

Objective:To investigate the effect of circ-PRKDC on lung cancer cell proliferation, apoptosis and radiosensitivity and its molecular mechanism.Methods:Normal lung epithelial cells BEAS-2B and lung cancer cell lines NCI-H1299, NCI-H2170, NCI-H1975 were cultured. NCI-H1299 cells were divided into the si-NC, si-PRKDC, pcDNA-NC, pcDNA-PRKDC, miR-NC, miR-505-3p, anti-miR-NC, anti-miR-505-3p, si-PRKDC+ anti-miR-NC and si-PRKDC+ anti-miR-505-3p groups. RT-qPCR was used to detect the expression levels of circ-PRKDC and miR-505-3p. Western blot was employed to measure the protein expression. MTT was used to detect cell proliferation. Flow cytometry was utilized to detect cell apoptosis. Plate clone formation assay was conducted to detect the cell radiosensitivity. Dual luciferase reporter assay was performed to analyze the targeting relationship between circ-PRKDC and miR-505-3p.Results:Compared with normal lung epithelial cells BEAS-2B, the expression levels of circ-PRKDC in the lung cancer cell lines NCI-H1299, NCI-H2170 and NCI-H1975 were significantly up-regulated (3.65, 3.10, 2.67 vs. 1.00, all P<0.05), whereas those of miR-505-3p were significantly down-regulated (0.42, 0.50, 0.54 vs. 1.02, all P<0.05). After low expression of circ-PRKDC, the expression level of CyclinD1 was significantly down-regulated (0.42 vs. 0.81, P<0.05), whereas those of Cleaved-caspase-3(0.71 vs. 0.33, P<0.05) and γ-H 2AX (0.89 vs. 0.46, P<0.05) were significantly up-regulated, the cell A value was significantly decreased (0.413 vs. 0.839, P<0.05), cell apoptosis rate was significantly increased (20.35 vs. 6.21, P<0.05), cell survival fraction was significantly decreased ( P<0.05), and β-catenin expression was significantly down-regulated (0.35 vs. 0.73, P<0.05). After high expression of miR-505-3p, the expression level of CyclinD1 was significantly down-regulated (0.34 vs. 0.83, P<0.05), those of Cleaved-caspase-3(0.65 vs. 0.32, P<0.05) and γ-H 2AX (0.96 vs. 0.45, P<0.05) were significantly up-regulated, the cell A value was significantly decreased (0.386 vs. 0.851, P<0.05), the apoptosis rate was significantly increased (16.38 vs. 6.20, P<0.05), and the cell survival fraction was significantly decreased ( P<0.05). Compared with miR-NC, the luciferase activity of miR-505-3p group transfected with circ-PRKDC wild-type reporter plasmid was significantly decreased (0.44 vs. 1.00, P<0.05). Down-regulation of miR-505-3p could reverse the effect of low expression of circ-PRKDC on the proliferation, apoptosis, radiosensitivity and β-catenin expression of NCI-H1299 cells. Conclusion:Low expression of circ-PRKDC may inhibit lung cancer cell proliferation, promote cell apoptosis and enhance cell radiosensitivity by up-regulating miR-505-3p, which is probably associated with the Wnt/β-catenin signaling pathway.