Effects of miR-7 on bone metastasis of breast cancer cells

CUI Li-qun; WANG Xiao-rui; JIANG Zhong-min; ZHANG Ming; YANG Zhi-cheng; CHEN Jin-gang; MA Rui; SHENG Feng; LIU Xiao-zhi

Abstract：Objective To study the molecular mechanisms of miR-7 inhibiting bone metastasis of breast cancer cells.Methods The miR-7 gene sequence embedded GFP expression plasmid was transfected into MDA-MB-231 breast cancer cells, while fluorescence microscope was used to detect efficiency of exogenous gene integration.Western blot method was used to detect the protein expression levels of AKT-2, CXCR-4 and MMP-9, while transwell system was applied for detection of breast tumor cell migration.After a breast cancer bone metastasis model was founded, the pa-thology of bone metastasis was analyzed.The gene prediction software was used to find the potential therapeutic targets of miR-7.Results The plasmid containing GFP/miR-7 gene was efficiently transferred to the breast cancer cells, which significantly down-regulated the protein expression of PI3K, AKT2 and CXCR-4 (P<0.05, P<0.01), with no sig-nificant effect on MMP-9(P>0.05).Distant metastasis was suppressed by miR-7 in breast cancer cells both in vitro and in vivo.The miRNA gene prediction software analysis showed that PI3K was one of the potential targets of miR-7. Conclusion miR-7 may indirectly affect CXCR-4/SDF-1 axis by targeting the PI3K/AKT-2 pathway, thereby in-hibiting bone metastasis of breast cancer cells.