Recent studies show that dysregulated miRNAs play an important role in breast cancer initiation and progression. Here, we identified upregulated expression of miR-1307-3p in breast cancer tissues and that increased level of miR-1307-3p was closely correlated with lower survival rate in breast cancer patients. Consistent with clinical data, our in vitro data show that expression level of miR-1307-3p was significantly increased in breast cancer cell lines compared to human mammary epithelial cell line MCF10A. Overexpression of miR-1307-3p in MCF10A stimulated cell proliferation and caused their growth in soft agar and tumor formation in nude mice. In contrast, inhibition of miR-1307-3p suppressed breast cancer cell proliferation and their growth in soft agar and inhibited tumor formation in nude mice. Further, we identified that miR-1307-3p plays its oncogenic role through targeting SET and MYND domain-containing 4 (SMYD4) expression in breast cancer. Taken together, our findings suggest that miR-1307-3p is a oncogenic miRNA that significantly contributes to breast cancer development and progression, and inhibition of miR-1307-3p may be a novel strategy for inhibits breast cancer initiation and progression.
Keywords: SMYD4; breast cancer; miR-1307-3p; tumorigenesis.