Abstract: Objective To investigate the role of Hsa-miR-148a-3p in regulating biological behaviors of breast cancer cells and explore the mechanism. Methods TCGA database was used to identify the differential miRNAs and mRNAs in breast cancer, and the protein-protein interaction (PPI) network was constructed using String and Cytoscape to screen the top 10 hub genes and construct the miRNA-TOP10hub network. RT-qPCR was used to detect the expressions of Hsa-miR-148a-3p and DUSP1 in breast cancer tissues and cell lines. The effects of Hsa-miR-148a-3p mimic and inhibitor on proliferation, migration, invasion and apoptosis of MCF-7 cells were analyzed, and luciferase reporter gene experiment was performed to verify the binding of Hsa-miR-148a-3p to DUSP1. The effect of Hsa-miR-148a-3p overexpression on breast cancer cell xenograft growth was evaluated in nude mice. Kaplan-Meier survival curve analysis was used to analyze the survival of the tumor-bearing mice, and the expression level of DUSP1 in the xenografts was detected using immunohistochemistry. Results A total of 54 differential miRNAs and 799 differential mRNAs were identified in breast cancer; 3716 target genes were intersected with the differential mRNA, resulting in 150 intersected genes. The top 10 hub genes were downregulated in breast cancer tissues in the PPI network. Double luciferase reporter gene experiment confirmed that Hsa-miR-148a-3p was capable of binding to DUSP1. Hsa-miR-148a-3p was up-regulated and DUSP1 was down-regulated significantly in breast cancer tissues and cells (P<0.01). In breast cancer cells, Hsa-miR-148a- 3p mimic strongly promoted cell proliferation, migration and invasion and inhibited cell apoptosis (P<0.01). Hsa-miR-148a-3p overexpression obviously promoted xenograft growth in nude mice (P<0.01), shortened survival time of the mice (P<0.01), and reduced the expression of DUSP1 in the xenografts (P<0.01). Conclusion Hsa-miR-148a-3p promotes malignant behavior of breast cancer cells by inhibiting the expression of DUSP1.

Key words: Hsa-miR-148a-3p; DUSP1; breast cancer; tumor promotion