MiR-17-5p mediating cisplatin resistance in breast cancer cells by regulating PTEN/Akt pathway
AIM To investigate the role of miR-17-5p in mediating cisplatin(DDP)resistance in breast cancer cells by regulating the PTEN/Akt pathway.METHODS MCF-7/DDP-resistant cell line was cultured with a gradient of increasing DDP concentrations.The content of miR-17-5p was detected in MCF-7 and MCF-7/DDP cells by RT-qPCR.MCF-7 cells were divided into miR-NC and miR-17-5p groups,and transfected with miR-NC and miR-17-5p mimics plasmids,respectively.MCF-7/DDP-resistant cells were divided into anti-miR-NC and anti-miR-17-5p groups,and transfected with anti-miR-NC and anti-miR-17-5p plasmids,respectively.Transfection efficiency was defined by RT-qPCR.The drug sensitivity of DDP in each group of transfected cells was evaluated by MTT.The direct effect of miR-17-5p on the invasive ability was obtained by Transwell assay.DDP-induced apoptosis of MCF-7 and MCF-7/DDP cells after transfection was analyzed by flow cytometry.The targeting relationship between miR-17-5p and PTEN was verified by double luciferase reporter gene assay.The changes of apoptosis and key proteins of PTEN/Akt pathway under the regulation of miR-17-5p were detected by Western blot.RESULTS Compared with MCF-7 cells,the miR-17-5p expression in MCF-7/DDP-resistant cells was abnormally increased,while the PTEN expression was reduced(P＜0.01).PTEN was regulated by miR-17-5p as a target gene.Compared with the miR-NC group,the proliferation inhibition rate in the miR-17-5p mimics group was significantly declined,the number of invaded cells was enhanced,and the apoptosis rate was also decreased(P＜0.05),and the expressions of tumor suppressor proteins PTEN,p21 and p27 in the PTEN/Akt pathway were decreased,and the expressions of p-Akt308,p-Akt473 and cyclin D1 were increased(P＜0.01).Compared with the anti-miR-NC group,the proliferation inhibition rate was increased in the anti-miR-17-5p group,the number of invaded cells was decreased,and the apoptosis rate was also increased(P＜0.05),and the expression of tumor suppressor proteins PTEN,p21 and p27 was increased,and the expression of p-Akt308,p-Akt473 and cyclin D1 was decreased(P＜0.01).CONCLUSION Knockdown of miR-17-5p can effectively improve the DDP sensitivity of breast cancer cells,attenuate the invasive ability,and induce further apoptosis,which may be related to the regulatory effect of miR-17-5p on the PTEN/Akt pathway.
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