Antitumor effects of a new diterpene in vitro

AIM To determine the antitumor effects of a new diterpene (petrisolide A, FA) against human promyeloxytic leukemia HL60 and erythroleukemia K562 cell lines in vitro. METHODS Antitumor activity was measured using IC50, cell growth curve and 3HTdR uptake. Simultaneously, the cell cycle was analysed by flow cytometric(FCM) technique and the induced differentiation was tested by nitronblue tetrazolium(NBT) red uction. RESULTS IC50 of FA was 76 mg·L-1 to HL60 and 91 mg·L-1 to K562 respectively when incubation for 24 h. It obviously inhibited the growth curve of HL60 at 4 mg·L-1, the assays of 3HTdR incorporation into DNA showed a slight inhibition and the morphology was showed a cell damage under transmission electron microscopy (TEM) in the tumor cells of treated group. FCM analysis revealed that FA could arrest HL60 cells to G2+M phase and the S and G1 phase were not altered. In the tests of NBT reduction in the presence of FA at 4 mg·L-1 for 4 days, HL60 cells did not show NBT reductive ability. CONCLUSION FA remarkbly inhibited HL60 and K562 cell lines proliferation and showed a high antitumor activity. It was suggested that FA might inhibite mitoses of the cells and have not ability to induce Differentiation.