miR‑365 overexpression promotes cell proliferation and invasion by targeting ADAMTS-1 in breast cancer.

MicroRNAs (miRNAs) have important roles in the initiation and progression of human cancer, including breast cancer. We evaluated miR‑365 expression in breast cancer tissues, and investigated its effects on cell growth, cell cycle, cell invasion, and expression of its target gene ADAMTS-1. miR‑365 expression levels were analyzed in breast cancer tissues and adjacent normal tissues using qRT-PCR. CCK-8, cell cycle, and invasion assays were used to explore the role of miR‑365 expression in breast cancer cells. We conducted luciferase reporter and western blot assays to test whether ADAMTS-1 is a direct target of miR‑365. We found that miR‑365 expression levels were significantly higher in breast cancer tissues compared with adjacent non-tumor tissues (P<0.05). These relatively high expression levels were significantly associated with advanced clinical stages (P<0.05). In breast cancer cell lines, transfection with miR‑365 inhibitor suppressed proliferation and invasion, and resulted in cell cycle arrest. Subsequent experiments indicated that miR‑365 bound the 3'-UTR of ADAMTS-1 and downregulated its expression. Our findings indicated that the inhibition of miR‑365 reduced cell proliferation and cell invasion. Additionally, miR‑365 may function as a novel oncogene in breast cancer through targeting ADAMTS-1. These findings provide insight into the mechanism of breast cancer pathogenesis.