Abstract: ［Abstract］Objective〖HTSS〗To investigate the effects of norcantharidin(NCTD) on the cell cycle, reactive oxygen species(ROS) and apoptosis in in human melanoma cell strain A375.
  〖WTHZ〗Methods〖HTSS〗The cell cycle of human A375 melanoma cells was determined by flow cytometry after 48 hours of incubation with 10, 20 and 40 μmol/L NCTD. The effects of NCTD on the expression of Cyclin D1 and P21 protein were measured by Western blot. The effects of reactive oxygen species and apoptosis on the cell cycles of A375 was measured by flow cytometric assay.
  〖WTHZ〗Results〖HTSS〗Flow cytometry showed that A375 cells treated with NCTD were blocked at G1 phase in the cell cycles in a dose dependent manner（P＜0.05）. The expression of Cyclin D1，Cyclin A, CDK2 protein was decreased in malignant melanoma cells treated with NCTD, however P21 protein was increased(P＜0.05). The levels of ROS and apoptosis were increased in malignant melanoma cells treated with NCTD in a dose dependent manner（P＜0.05）. While the levels of apoptosis was decreased after treated with the ROS scavenger N-acetylcysteine(P＜0.05).
  〖WTHZ〗Conclusion〖HTSS〗NCTD can inhibit the proliferation of human A375 melanoma cells by blocking the cell cycle of G1, reducing cell cycle of S and can induce the apoptosis of human A375 melanoma cells by inducing a higher level of ROS.

Key words: melanoma, norcantharidin, apoptosis