Effect And Mechanism Of Silencing MicroRNA-10b On Biological Behavior Of Human Triple-negative Breast Cancer Cell

BackgroundMicroRNAs are a class of small endogenous noncoding RNAs, which modulatetarget gene expression by binding with target mRNA sequences in the3’untranslatedregion (UTR) with full or partial complementarity way that cleavage of targetmRNAs or inhibit mRNA translation. As a member of the miRNAs family,microRNA-10b participate in the biology process of a wide variety of tumors. But theexact function of miR-10b in breast cancer has been always controversial. Threenegative breast cancer is a subtype of breast cancer that is clinically negative forexpression of estrogen receptor (ER), progesterone receptor (PR) and epidermalgrowth factor receptor2(Her-2), which is characterized highly aggressive, highlyhistologic classification, poorer prognosis and lack of targeted therapies, etc. To clearexplain miR-10b biological characteristics in three negative breast cancer cells, thisstudy selected human triple-negative breast cancer MDA-MB-231cell as a specimens,and investigate the effect of silencing miR-10b on the proliferation, apoptosis, invasion and migration and the influence of TIAM1target gene expression in threenegative breast cancer cells.ObjectiveTo investigate the effection on the biological behavior of human triple-negativebreast cancer MDA-MB-231cell and expression of target TIAM1gene after silencingmiR-10b.Methods1.MDA-MB-231cell were transfected with artificially synthesized miR-10binhibitor, blank cell group and nonsence sequence-transfected group were establishedas a control. Real-time quantitative polymerase chain reaction (Real-time PCR) wasconducted to detect the expression of miR-10b after transfection48h．2.CCK-8assays, flow cytometry and Transwell chamber assays were used todetect variations in cell proliferation, apoptosis, invasion and migration respectively.3.Real-time PCR and Western blotting were used to detect expression of TIAM1mRNA and protein levels respectively.Results1.Real-time PCR results showed that as compared with control group, therelative expression of miR-10b inhibitor-transfected group (0.26±0.01) wassignificantly reduced (P<0.01), this show the expression of miR-10b was suppressedby miR-10b inhibitor successfully.2.CCK-8assays results showed that the proliferation rate at48h (409.10±8.38)%and the proliferation rate at72h (610.70±17.59)%were significantly increased(P<0.01) after silencing miR-10b, proliferation effect occured at48h and it continuedto72h.3.Flow cytometry results showed that early apoptosis rate1.77%and late apoptosis rate1.61%were significantly reduced after silencing miR-10b (P<0.05).4.Transwell chamber assays results showed that the number of invasion(212.17±13.57) and migration (322.67±8.62) cells was significantly increased aftertransfection48h (P<0.01).5.Real-time PCR and Western blotting results showed that TIAM1gene has nosignificant changes at mRNA level (P>0.05), but up-regurated expression at proteinlevel (P<0.05).ConclusionSilencing miR-10b could promote proliferation, invasion, migration and inhibitapoptosis acivity of MDA-MB-231cell, the probable mechanism was the negativelyregulation of TIAM1protein expression at the post-transcriptional1evel.