[Study on the apoptosis of HL-60 human promyeloid leukaemia cells induced by SFPS].

The inhibition effects of Sargassum fusiforme Polysaccharides (SFPS) on proliferation of human HL-60 promyeloid leukemia cells were measured by MTT assay. SFPS-induced apoptosis in HL-60 cells was observed by electron microscopy, flow cytometry and DNA electrophoresis. The results revealed that SFPS exhibited antiproliferative activity which depended on dosage and time. After incubation for 24, 36, 48 and 72 h, SFPS had growth inhibitory effect on HL-60 cells with IC50 of 390, 362, 402 and 421 mg/L. A ladder-like pattern of DNA fragmentation was demonstrated on agarose gel electrophoresis after HL-60 cells induced by SFPS at a dose of 300 mg/L and 500 mg/L. Morphological examination by electron microscopy showed cells with few microvilli on the surface, chromatin condensation and margination, cell shrinkage and the presence of "apoptosis bodies". The DNA content analysis of FCM showed pre-G1 cells and increased G2 period ratio, in addition, it demonstrated that apoptosis induced by SFPS was dose-and time-dependent. In conclusion, the antitumor effect of SFPS is relative to cell apoptosis and the blocking of G2/M period cells.