Abstract: Objective To investigate the effects of norcantharidin on the proliferation and apoptosis related proteins Bax and Bcl-2 of human melanoma M14 cells. Methods Melanoma M14 cell line cultured in vitro was treated with concentrations of 50, 100 and 500 μg / L norcantharidin respectively, and untreated cells were used as control. Cell proliferation was detected by CCK-8 method after treatment for 24 h and 48 h. Morphology of cells was observed under inverted microscope. DAPI nuclear staining was used to observe the morphological changes of apoptosis under fluorescence microscope. The expressions of Bax and Bcl-2 were detected by Western blot assay. Results CCK-8 results showed that concentrations of 100 and 500 μg/L norcantharidin inhibited the proliferation of melanoma M14 cells after treatment for 24 h and 48 h (P＜0.05), and the higher the concentration, the more significant the inhibitory effect. The cells showed irregular contours, nucleus shrinkage, small volume, and poor cell adhesion of apoptosis changes under inverted microscope and fluorescence microscope. Western blot analysis showed that the relative expression of Bcl-2 decreased gradually with the increased concentration of norcantharidin (P＜0.05), and the relative expression of Bax increased gradually (P＜0.05).Conclusion Norcantharidin can inhibit the proliferation of melanoma M14 cells, and its mechanism may be related to the promotion of apoptosis.

Key words: melanoma, experimental, apoptosis, antineopl agents, phytogenic, Bcl-2-associated X protein, norcantharidin, Bax