Effects of miR-511-5p/FEM1C axis on proliferation and invasion of breast cancer cells by activating autophagy
Objective To explore the effect of microRNA-511-5p(miR-511-5p)on breast cancer cells and its underlying mechanism.Methods The expression levels of miR-511-5p in breast cancer tissues and cell lines were detected with real-time quantitative PCR(qPCR).Breast cancer cells were transfected with miR-511-5p mimics,miR-511-5p inhibitor and/or FEM1C overexpression vector(FEM1C),as well as the corresponding blank control vector.Next,CCK-8 was used to detect the cell proliferation.Transwell assay was used to detect the cell invasion ability.Flow cytometry was used to analyze the cell apoptosis,and Western blotting was used to detect the expression of autophagy related proteins(LC3Ⅱ,Beclin1 and p62)and key proteins of PI3K/AKT pathway.The binding site of miR-511-5p with fem-1 homolog C(FEM1C)was predicted by TargetScan database and verified by dual luciferase reporter gene analysis.In addition,the xenograft tumor model was established by subcutaneous injection of mimics NC and miR-511-5p mimics transfected breast cancer cells into nude mice to reveal the role of miR-511-5p in tumor growth.Results The expression of miR-511-5p was significantly down-regulated in breast cancer tissues and cells(P<0.05).Compared with other cell lines,miR-511-5p expression was the lowest in MDA-MB-231 cell line.Compared with the mimics NC group,the autophagy of miR-511-5p mimics group was enhanced,the ability of cell proliferation and invasion were significantly down-regulated,and cell apoptosis was significantly up-regulated(P<0.05).Compared with miR-511-5p mimics group,autophagy was weakened,cell proliferation and invasion were significantly upregulated,and cell apoptosis was significantly down-regulated in miR-511-5p mimics+ autophagy inhibitor 3-Methyladenine(3-MA)group(P<0.05).FEM1C was the target gene of miR-511-5p,and the expression of both was negatively correlated.Functionally,miR-511-5p significantly inhibited the ratio of p-PI3K/PI3K and p-AKT/AKT and increased the level of autophagy by targeting FEM1C(P<0.05).Overexpression of FEM1C significantly promoted cell proliferation and invasion,inhibited cell apoptosis(P<0.05),and reversed the effect of miR-511-5p mimics on MDA-MB-231 cells.In vivo result showed that miR-511-5p overexpression inhibited tumor growth.Conclusion miR-511-5p induces autophagy and blocks the PI3K/AKT signaling pathway by down-regulating the expression of FEM1C,thereby inhibiting cell proliferation and invasion and promoting cell apoptosis.This study provides a new target for the treatment of breast cancer.
Breast cancerMiR-511-5pFEM1CPI3K/AKT signaling pathwayAutophagy
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