Research On The Effect Of MiR-320b On TNBC Progress And The Mechanism Explore

Background: MiRNAs are small noncoding RNAs that potentially play a critical role in tumorigenesis.Mounting evidence indicates that one specific miRNA: miR-320b is down regulated in numerous human cancers.Objective:1.Explore miR-320b in triple-negative breast cancer tissues and adjacent normal breast tissues;2.Research the effect of miR-320bon triple-negative breast cancer cells and explore the proper mechanism.Method:1.Use RT-PCR to explore the expression of miR-320b in breast cancer tissues and the adjacent tissues.2.Use the technology of cell transfection to overexpressmiR-320b in MDA-MB-231breast cancer cells;useCCK8,Matrigel Invasion Assay,and Wound Healing experiments to detect the miR-320b’s effects on breast cancer cells.3.Use Western Blotting to test the change of the protein level of Cyclin D1 before and after the transfection of miR-320b mimic.Results:1.The expression of miR-320b was significantly lower in most tumors in patients with triple-negative breast cancer compared to the related normal tissues.2.The expression of miR-320bincreased after transfection in human breast cancer MDA-MB-231 cells;breast cancer cell proliferation,the invasion abilityand transfer ability was inhibited.3.The aberrant increased protein level of Cyclin D1 was reversed by miR-320btransfection.Conclusions:Decrease of miR-320b was found in most patients with triple-negative breast cancer tissues.Selective miR-320b overexpression by transfection resulted in the inhibition oftumor cell growth,invasion and transferin MDA-MB-231 cells,also miR-320b mimic could reduce the protein level of Cyclin D1.Our findings suggest that miR-320b plays a critical role in triple-negative breast cancer progression and may serve as a novel therapeutic target in breast cancer.