Abstract: Objective The purpose of this study is to investigate the effects of miRNA-181 and transcription homeobox factor (Prox-1) on proliferation and apoptosis of breast cancer cells. Methods The expression of miRNA-181 was detected by quantitative PCR in normal breast tissue, breast ductal carcinoma in situ tissue and breast invasive ductal carcinoma tissue. pRFP-miRNA-181-inhibitor plasmid was transfected into breast cancer cell line MCF-7, and the mRNA and protein levels of Prox1 were detected by quantitative PCR and Western-blot. Cell proliferation was evaluated by EdU assay, and apoptosis state was detected by TUNEL kit. Results Compared with normal breast tissues, the expression of miR-181 was upregulated in intraductal carcinoma and invasive ductal carcinoma (p<0.01). After the expression of miRNA-181 was inhibited in MCF-7 cells, the protein level of Prox1 was significantly upregulated (p<0.05). Morever, the proliferation ability was weakened (p<0.05) and the apoptosis ability was enhanced of MCF-7 cell (p<0.05). Conclusions miRNA-181 may play an important role in the pathogenesis of breast cancer by promoting the proliferation and inhibiting apoptosis through Prox1.

Key words: miRNA, breast cancer, proliferation, apoptosis