| Background The antitumor properties of Sargassum fusiforme (Harv.)Setchess have been known since ancient times. SFPS, which contained fucoidan,laminaran, algin and so on,are the polysaccharides extracted from Sargassumfusiforme (Harv.) Setchess. It is main component of water extraction from Sargassumfusiforme. FCD is composed of fucose, xylose, mannose and galactose. Themolecular weight range of FCD is 42000 and 95000, and fraction of SFPS is 3500-10000, which can pass the cell membrane freely.SFPS has been comfirmed to possess anti-tumor, immunity enhancing, anti-lipid-peroxidation effects. SFPS can remove the free radicals, increases in the enzyme activities of CAT, SOD .enhance erythrocyle immune function and obviously prolong the survival duration of mice suffering from tumour and inhibit neoplastic proliferation.Apoptosis has been a hotspot in research of tumor therapy. The mechanism of many anti-tumor medicines is to induce the tumor cells to apoptosis. The anti-tumor effects and mechanism of polysaccharides isolated from Chinese herbs have been studied more and more. Apoptosis of tumor cells induced by polysaccharides was studied and the researches found that polysaccharides had an inhibitory effect on topoisomerase-l, which is known to digger apoptolic celldeath, showed up-regulation effects on Bax, Fas, and FasL expression and an inhibitory effect on the telomerase activity, markedly increased the phosphotiansferase activity of c-Jun N-terminerlkinase 1(JNK 1 )/stress-activated protein kinase activation, increased TNF a and IFN release and their mRNA expression in PM and T lymphocytes. .But these studies were limited on animals and little is known about the effects and mechanism of apoptosis induced by SFPS. Reference related to apoptosis is only one, which was reported that SFPS can increase the expression of P53 gene in mice. Objective In this study, we chose human HL-60 promyeloid leukemia cells and colorectal cancer cells(lovo) as objects to explore the antitumor effects and mechanism of SFPS and investigate the apoptosis of HL-60 cells and lovo cells induced by SFPS.Methods Inhibition of proliferation was measured by MTT assay. SFPS-induced apoptosis in HL-60 and lovo cells was observed by electron microscopy, flow cytometry and DNA electrophoresis.Results SFPS exhibited antiproliferative activity which depended on dosage and time. After incubation for 24,36,48 and mg/L,402 mg/L,421mg/L and lovo cells with IC50 of. 375 mg/L ,355 mg/L ,178 mg/L ,60 mg/L . 24 hours after treated by 5mg/L and 50mg/L SFPS, HL-60 cells showed no DNA ladder while lovo cells demonstrated on agarose gel electrophoresis a ladder-like pattern of DNA fragmentation. 24 hours after treated by 300mg/L SFPS, both of the two cells showed DNA ladder and the fragments were integral of 180~200bp. With 500mg/L SFPS, HL-60 and lovo showed mistiness DNA ladder and smear, while the DNA ladder produced by lovo cells was clearer than HL-60. When the centrantion was 1000mg/l, DNA ladder disappeared entirely and both of the two cells showed smear. Morphological examination by electron microscopy showed HL-60 and lovo cells with chromatin condensation and margination, cell shrinkage and the presence of "apoptosis bodies". When treated by SFPS with concentrations higher than 50mg/L for 12,24,48,72 hours, HL-60 cells showed Apo peaks in the DNA content analysis of FCM and observed time- and dosage-dependent manner in a range of concentration. In addition, 62 period ratio was increased. Lovo cells demonstrated Apo peaks and observed dose- dependent after treated by SFPS of different concentrations for 12 hours,but the cell cycle didn't change observedly .Conclusion (I) SFPS is an effective anti-tumor medicine and the antitumor effect of SFPS is relative to cell apoptosis.The antitumor effect of SFPS on HL-60 cells is relative to the blocking of G2/M period cells, while it is not relative to cell cycle when inducing lovo cells.(2) The effect of SFPS is relativ... |
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