Downregulation of KLF4 Inhibits Proliferation and Promotes Apoptosis of Melanoma A375 and SK-Mel-28 Cells Through p21/Cyclin D1/E2F1 Signaling Pathway

Malignant melanoma is one of the most common malignant tumors of the skin with rapidly increasing incidence. To investigate the role of Kruppel-like factor 4 (KFL4) in this severe disease, vectors with low and high levels of KLF4 expression were constructed and used to transfect human melanoma cells A375 and SK-Mel-28. Western blotting, RT-qPCR, cell counting, Transwell assay and flow cytometry were used to detect the changes in characteristics of these cells. In comparison with controls, the sh-KLF4 group (with low expression of KLF4) showed reduced expression of KLF4 at the mRNA and protein levels, as well as decreased migration and invasion ability of the cells. In addition, flow cytometry showed that the cell cycle was arrested in G1 phase and the proportion of apoptotic cells increased significantly. The results of the mimics-KLF4 group (with high expression of KLF4) were opposite to those observed in the sh-KLF4 group. Therefore, downregulation of KLF4 expression inhibits proliferation and promotes apoptosis of human malignant melanoma A375 and SK-Mel-28 cells through p21/cyclin D1/E2F1 signaling pathway, and inhibits their migration and invasion. Thus, the KLF4 gene act as an oncogene in human melanoma.