Licochalcone D induces apoptosis and inhibits migration and invasion in human melanoma A375 cells

The aim of the present study was to determine the effects of Licochalcone D (LD) on the apoptosis and migration and invasion in human melanoma A375 cells. Cell proliferation was determined by sulforhodamine B assay. Apoptosis was assessed by Hoechst 33258 and Annexin V-FITC/PI staining and JC-1 assay. Total intracellular reactive oxygen species (ROS) was examined by DCFH-DA. Wound healing and Transwell assays were used to detect migration and invasion of the cells. The activities of matrix metalloproteinase (MMP-2 and MMP-9) were assessed via gelatin zymography. Tumor growth in vivo was evaluated in C57BL/6 mice. RT-PCR, qPCR, ELISA and western blot analysis were utilized to measure the mRNA and protein levels. Our results showed that LD inhibited the proliferation of A375 and SK-MEL-5 cells in a concentration-dependent manner. After treatment with LD, A375 cells displayed obvious apoptotic characteristics, and the number of apoptotic cells was significantly increased. Pro-apoptotic protein Bax, caspase-9 and caspase-3 were upregulated, while anti-apoptotic protein Bcl-2 was downregulated in the LD-treated cells. Meanwhile, LD induced the loss of mitochondrial membrane potential (ΔΨm) and increased the level of ROS. ROS production was inhibited by the co-treatment of LD and free radical scavenger N-acetyl-cysteine (NAC). Furthermore, LD also blocked A375 cell migration and invasion in vitro which was associated with the downregulation of MMP-9 and MMP-2. Finally, intragastric administration of LD suppressed tumor growth in the mouse xenograft model of murine melanoma B16F0 cells. These results suggest that LD may be a potential drug for human melanoma treatment by inhibiting proliferation, inducing apoptosis via the mitochondrial pathway and blocking cell migration and invasion.