MiR-1271 as a tumor suppressor in breast cancer proliferation and progression via targeting SPIN1.

OBJECTIVE: As breast cancer has become the most common malignant tumor in women worldwide and several microRNAs involved in the mechanism of breast cancer development and progression have been identified, we aimed at investigating the role of miR-1271 in breast cancer. PATIENTS AND METHODS: By quantitative Real-time polymerase chain reaction (qRT-PCR), miR-1271 expression levels in 94 pairs of breast cancer tissue samples and five breast cancer-derived cell lines were detected. Using miR-1271 mimics and inhibitors, the effects of miR-1271 over-expression and knockdown on the proliferation, invasion and migration of MCF-7 cells were analyzed, respectively. Dual-luciferase activity assay was recruited to examine the potential target gene SPIN1 that was predicted by several databases. Protein level was studied using Western blotting. RESULTS: MiR-1271 was significantly lowly expressed in breast cancer tissue samples and cell lines. Over-expression of miR-1271 in MCF-7 cells significantly decreased the cell proliferation, invasion, and migration abilities while down-regulation of miR-1271 in MDA-MB-453 cells increased these abilities oppositely. Dual-luciferase and Western blotting were used to confirm SPIN1 as a target gene of miR-1271. Furthermore, up-regulation SPIN1 reserved the suppressive effect of miR-1271 over-expression on cell growth and progression. CONCLUSIONS: miR-1271 can suppress breast cancer cell proliferation and progression via SPIN1, which may provide a potential therapeutic target in treatment for breast cancer.