The effects of RKIP gene expression on the biological characteristics of human triple-negative breast cancer cells in vitro

The purpose of this study was to investigate the effect of Raf kinase inhibitor protein (RKIP) on the growth, proliferation, invasion and metastasis of triple-negative breast cancer (TNBC) cells to provide experimental evidence for developing future therapies against human TNBC. The pcDNA3.1-RKIP eukaryotic expression vector was constructed and transfected into the TNBC cell line MDA-MB-231. The alterations of the biological characteristics of RKIP-transfected MDA-MB-231 cells were analyzed using the following approaches: a growth curve, a 3-(4,5-dimethylthiazol-2-Yl)-2,5-diphenyltetrazolium bromide (MTT) assay, bromodeoxyuridine (BrdU) staining and a cell migration assay. The effects of the RKIP gene on MMP-1 and MMP-2 expression were also examined. The pcDNA3.1 empty vector-transfected and mock-transfected MDA-MB-231 cells were used as control groups. Compared with the empty vector-transfected and mock-transfected cells, the cell growth of RKIP-transfected MDA-MB-231 cells was significantly reduced. The empty vector-transfected group was not significantly different compared with the mock-transfected MDA-MB-231 cells. The results of the MTT and BrdU assays demonstrated that the proliferation of pcDNA3.1-RKIP-transfected cells was significantly reduced compared to the control cells (P < 0.05). The result of the cell migration assay suggested that the cross-membrane migration rate of the pcDNA3.1-RKIP-transfected cells was significantly lower than that of the control MDA-MB-231 cells (P < 0.05). We also demonstrated that RKIP may inhibit MMP-1 and MMP-2 expression in MDA-MB-231 cells. The RKIP gene may play a role in inhibiting cellular proliferation. The RKIP gene may also have some inhibitory effects on the invasiveness and metastatic capability of human TNBC cells.