| Objective Colon cancer is one of the serious threats to human life and health with high morbidity and high mortality.Especially in recent years,with rapid economic development,lifestyle and diet of our society have been changed significantly,leading to colon cancer incidence to increase year by year,and has become the fourth incidence of malignant tumors in China.Therefore,effective control and treatment of colon cancer,has become the focus of medical research.In addition to improving the surgery,radiotherapy and radiotherapy,more efficient and safer compound play an important role in the drug development.Paliurus polysaccharide was originally extracted from woody plants paliurus Cyclocarya paliurus(Batal.)Iljin.,which is considered as one of the main active ingredient in paliurus.Paliurus polysaccharide,as an important natural plant polysaccharides,has been found to be with multiple pharmacological effects,including anti-inflammatory,antioxidant,immune enhancement,and anti-tumor effects.Paliurus polysaccharide as an anti-tumor activity of plant polysaccharides have been preliminary reported.In vitro and in vivo studies have proved that paliurus polysaccharides could inhibit tumor cell proliferation.However,due to the complicated pharmacological effects of polysaccharides paliurus,its mechanisms of anticancer action have not yet been fully elucidated.Therefore,in-depth study of the mechanism of anticancer activity of paliurus polysaccharide,can provide a technical basis for the clinical application of comprehensive treatment of colon cancer.Methods In this study,colon cancer HT29 cells were used for in vitro studies and tumor-bearing mice were used for in vivo studies.MTT assay,flow cytometry,western blotting and immunofluorescence staining techniques were used for the studies of paliurus polysaccharide anti-cancer effect and its mechanism.Results Paliurus polysaccharide(10,50 and 100 mg/kg)could significantly inhibit the tumor growth of HT29 cells in tumor-bearing mice.Paliurus polysaccharide treatment could significantly reduce the weight of tumor tissue(p<0.01),tumor inhibition rates were 15.37%,21.66%and 32.19%,respectively.Paliurus polysaccharide also significantly reduced tumor volume(p<0.05).Paliurus polysaccharide treatment had no significant effect on the blood routine examination and liver and kidney function in tumor-bearing mice(p>0.05),indicating that paliurus polysaccharide treatment showed no obvious toxicity to blood system,liver and kidneys.But after various concentrations of paliurus polysaccharide treatment,tumor-bearing mice immune function parameters has been restored After the treatment of 100mg/kg paliurus polysaccharide,the immune indexes were significantly higher than the negative control group(p<0.05).The impact of paliurus polysaccharide on related protein expression in tumor tissue was different.10-100μg/mL of polysaccharides paliurus treatment can significantly enhance the expression of pro-apoptotic protein Bax;on the contrary,the anti-apoptotic protein Bcl-2 expression was significantly inhibited.In addition,10,50 and 100μg/mL paliurus polysaccharide treatment significantly inhibited the expression of survivin and inhibit the expression of c-myc in a dose-dependent manner.In vitro studies demonstrated that paliurus polysaccharides could significantly inhibited the cell proliferation of human HT29 colon cancer cells in a time and dose dependent manner.But no effects of 10 μg/mL paliurus polysaccharides on normal human cells NCM460.Only 50μg/mL or more concentration could inhibit cell growth.Paliurus polysaccharides could significantly inhibit HT29 cell colony formation rate and significantly reduce the relative survival rate of proliferation of cells(p<0.05).10,50 and 100μg/mL concentration paliurus polysaccharides can significantly reduce cell proliferation relative survival rates were reduced to 78.33%,57.43%and 42.79%.Test results of flow cytometry showed that after 10,50 and 100μg/mL paliurus polysaccharides treatment for 48 h,cell apoptosis rates were increased to 15.07 ±0.74%(p<0.05),28.19 ± 1.14%(p<0.01)and 55.87μ3.27%(p<0.001).The experimental results in vivo were consistent with in vitro experiments.10-100 μg/mL of polysaccharides paliurus treatment can significantly enhance the expression of pro-apoptotic protein Bax;on the contrary,the anti-apoptotic protein Bcl-2 expression was significantly inhibited In addition,10,50 and 100μg/mL paliurus polysaccharide treatment significantly inhibited the expression of survivin and inhibit the expression of c-myc in a dose-dependent manner.Conclusion In summary,paliurus polysaccharide could inhibit tumor growth in tumor-bearing mice and inhibits cancer cell proliferation in vitro in a dose-dependent manner,which may be achieved by the up-regulation of Bax protein,down-regulation of Bcl-2,survivin and c-myc protein,suggesting paliurus polysaccharide is feasible in the treatment of colon cancer,with the potential value in clinical applications. |
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