MicroRNA-765 alleviates the malignant progression of breast cancer via interacting with EZH1.

To detect the expression pattern of microRNA-765 in breast cancer (BCa) and its regulatory effect on the disease progression. Expression level of microRNA-765 in 66 paired BCa tissues and matched normal tissues was detected by qRT-PCR. The relationship between microRNA-765 level and clinical data of BCa patients was analyzed. Subsequently, microRNA-765 level in BCa cell lines was examined as well. Changes in proliferative, migratory and invasive abilities in MCF-7 and SKBR3 cells either overexpressing microRNA-765 or not were evaluated. Furthermore, expression level of EZH1 in BCa tissues and cell lines was determined. The regulatory interaction between microRNA-765 and EZH1 was identified. Finally, the role of microRNA-765/EZH1 axis in the progression of BCa was assessed. MicroRNA-765 was downregulated in BCa tissues relative to matched normal ones. BCa patients expressing low expression of microRNA-765 presented higher tumor stage, higher metastatic rate and worse overall survival. Overexpression of microRNA-765 attenuated proliferative, migratory and invasive abilities in MCF-7 and SKBR3 cells. In addition, EZH1 was upregulated in BCa tissues and cell lines. EZH1 level was negatively regulated by microRNA-765 in BCa. Overexpression of EZH1 reversed the inhibitory effects of microRNA-765 on malignant progression of BCa. MicroRNA-765 is downregulated in BCa and closely correlated to tumor stage, lymphatic metastasis, distant metastasis and poor prognosis of BCa patients. Overexpression of microRNA-765 attenuates the malignant progression of BCa through negatively regulating EZH1.