The Function Of MiR-411-5p In Proliferation And Metastasis Of Breast Cancer Cells

MicroRNAs(miRNAs)are small noncoding RNAs that have a pivotal role in the post-transcriptional regulation of gene expression by sequence-specifically targeting multiple mRNAs.MiR-411-5p(previously called miR-411)is severely involved in human diseases,however,the relationship between miR-411-5p and breast cancer has not been investigated thoroughly.Here,we found that the expression levels of miR-411-5p were downregulated in breast cancer tissues compared to their matched adjacent non-neoplastic tissues.In addition,the expression of miR-411-5p was also lower in breast cancer cell lines in contrast with the normal mammary epithelial cell line(MCF-10A).We found that the overexpression of miR-411-5p inhibited breast cancer cell proliferation and metastasis mainly by targeting GRB2(Growth factor receptor-bound protein 2)in vitro and in vivo,and we demonstrated the involvement of GRB2 and Ras activation.Ectopic expression of miR-411-5p suppressed the breast cancer cell proliferation migration and invasion while low expression of miR-411-5p had the opposite effect.Furthermore,GRB2 is significantly overexpressed in breast cancer tissues compared with normal breast tissues,and low expression of GRB2 has a longer overall survival compared with high expression of GRB2 in breast cancer.In general,our study has shed light on miR-411-5p regulated mechanism and,miR-411-5p/GRB2/Ras is potential to be targeted for breast cancer management.