Macrophage migration inhibitory factor regulating the expression of VEGF-C through MAPK signal pathways in breast cancer MCF-7 cell

Jinnan Zhang, Guangbo Zhang, Sumei Yang, Junli Qiao, Taixun Li, Song Yang, Yong Hong

As a kind of versatility of cytokines, overexpression of macrophage migration inhibitory factor (MIF) and vascular endothelial growth factor-C (VEGF-C) have been reported in a wide variety of tumors. However, the correlation and mechanism between MIF and VEGF-C are still not clear. As an important signal transduction system, MAPK signaling pathways participate in a variety of biological behavior of cells. The purposes of this study are to study the relationship between MIF and VEGF-C and discuss the role of MAPK signal pathway in the relationship. In this study, we first knocked down the MIF using small interfering RNA (siRNA) and built the stable low expression MIF breast cancer cells (siRNA-MIF-MCF-7) and the negative control cells (siRNA-NC-MCF-7). And then, we evaluated the expression of MIF using Western blot to confirm the effect of transfection. Using real-time fluorescent quantitative polymerase chain reaction and enzyme-linked immunosorbent experiment, we respectively examined the different expression of VEGF-C between siRNA-MIF-MCF-7 and siRNA-NC-MCF-7 and breast cancer cells MCF-7. Moreover, we investigated the expression of p38 MAPK, P-p38 MAPK, p44/42 MAPK, and P-p44/42 MAPK in the three kinds of cells by Western blot to analyze the regulatory mechanism to VEGF-C. We found that MIF siRNA markedly reduced the expression of MIF. And the expression level of VEGF-C, p38 MAPK, P-p38-MAPK, p44/42-MAPK, and P-p44/42 MAPK in siRNA-MIF-MCF-7 cells had different degree of decrease compared with siRNA-NC-MCF-7 cells and MCF-7 cells. These results suggest that MIF can regulate the expression of VEGF-C in breast cancer cells. And its regulatory mechanism may work by activating the MAPK signaling pathway.