Abstract
Breast cancer is a major public health concern, due to its increasing incidence and limited effective treatment. The present study aimed to investigate the expression of microRNA (miR)‑194‑5p and its roles in breast cancer. The expression levels of miR‑194‑5p and SRY‑box 17 (SOX17) mRNA were detected in breast cancer tissues and cell lines by reverse transcription‑quantitative polymerase chain reaction. The protein expression levels were determined by western blotting. In addition, MTT, colony formation, scratch and Transwell assays were use to evaluate the characteristics of MCF‑7 cells with miR‑194‑5p knockdown. The target verification of miR‑194‑5p was determined by luciferase reporter assay. Furthermore, tumor‑bearing nude mice with miR‑194‑5p knockdown were used to assess the effects of miR‑194‑5p on tumor activity. In breast cancer tissues, miR‑194‑5p was upregulated, whereas SOX17 was downregulated. In addition, the expression levels of SOX17 and phosphorylated (p)‑β‑catenin in the cytosol and nucleus were increased in the miR‑194‑5p inhibitor group. In addition, cell proliferation, migration and invasion were inhibited in response to miR‑194‑5p knockdown. The luciferase reporter assay confirmed that SOX17 was a target gene of miR‑194‑5p. In the mouse studies, knockdown of miR‑194‑5p suppressed tumor growth and promoted SOX17 expression in nude mice with breast cancer. These findings suggested that knockdown of miR‑194‑5p may increase the expression of SOX17 and regulate the Wnt/β‑catenin signaling pathway in breast cancer cells; therefore, miR‑194‑5p may be considered a potential target for breast cancer prevention.