RESUMO
BACKGROUND: Breast cancer is a highly prevalent disease worldwide, and early diagnosis and treatment could reduce the mortality rate of breast cancer patients. microRNAs (miRNA) have been shown to regulate the occurrences and progression of many types of cancers. Thus, it is crucial to find novel biomarkers in breast cancer. miR-449c-5p acted as a biomarker in non-small cell lung cancer, gastric carcinoma, and so forth. ERBB2 is an ideal target for breast cancer therapy. However, the molecular mechanisms between miR-449c-5p and ERBB2 in breast cancer remain poorly understood. Our study focused on the regulatory role of miR-449c-5p in breast cancer and its targeting relationship with ERBB2. METHODS: The miR-449c-5p expression in breast cancer tissue and normal tissue was searched from the online database (Starbase). The clinical prognosis of miR-449c-5p and ERBB2 was predicted by using the Kaplan-Meier analysis method. The expression of miR-449c-5p mimics and inhibitors was measured by qRT-PCR. T47D cells were transfected with miR-449c-5p mimics and miR-449c-5p inhibitors. After that, CCK-8, colony formation assays and Transwell assays were used to evaluate the cell proliferation ability, migration and invasion. Whether ERBB2 was the target gene of the miR-449c-5p was predicted by Starbase and verified by dual-luciferase activity assay. In addition, protein levels and the relationship between signalling pathways were measured and validated using western blotting analysis. RESULTS: We confirmed that miR-449c-5p was highly expressed in breast cancer tissue, and its downregulation was linked with poor prognosis. Overexpression of miR-449c-5p inhibited the proliferation, migration and invasion of breast cancer cells. ERBB2 was a target of miR-449c-5p. The invasion, migration, and proliferation of breast cancer cells were inhibited by miR-449c-5p/ERBB2 through JAK-STAT. CONCLUSION: This study demonstrated that miR-449c-5p inhibits breast cancer cell proliferation, migration and invasion by targeting ERBB2 via JAK/STAT, which means miR-449c-5p, is a potential biomarker for breast cancer and provides a novel insight for diagnosis.
