| Objective Prostate cancer is one of the common malignant tumors in the male genitourinary system.Modern studies have shown that pollen has a certain role in the treatment of prostate-related diseases.PI3K/AKT signaling pathway is closely related to the occurrence and development of prostate cancer.In this study,homogeneous polysaccharide was extracted and purified from Chinese wolfberry pollen,and then the apoptosis of DU145 prostate cancer cells and its effect on PI3K/AKT signaling pathway in vitro and vivo after induced by pollen polysaccharides from Chinese wolfberry were investigated.The antitumor mechanism of pollen polysaccharides from Chinese wolfberry were studied in vitro and vivo,which provided a new theoretical basis for the biological value of Chinese wolfberry pollen and the treatment of prostate cancer.Methods In the present study,pollen polysaccharides from Chinese wolfberry(WPPs)were extracted by hot-water extraction and ethanol precipitation,further purified by chromatography on a DEAE-cellulose column and Sephadex G-100 column.Homogeneous polysaccharide CF1 of WPPs was obtained,the molecular weight of which was estimated by HPGPC-ELSD.The monosaccharide compositions of CF1 was estimated by HPLC with PMP derivatization analysis.The antitumor effects of CF1 upon MTT,Tunel assay and flow cytometry assay were investigated in vitro.Western blot was used to detect the expression of PI3 K,AKT,p-AKT,Bcl-2,Bax,Caspase-3 and Caspase-9 in DU145 cells treated with CF1.The nude mouse xenograft model of DU145 prostate cancer cells in vivo were established,pollen polysaccharides from Chinese wolfberry were gavaged,tumor size and tumor inhibition rate were measured,then the apoptosis and the expression of PI3 K,AKT,p-AKT,Bcl-2 and Caspase-3 protein in tumor tissues were detected by Tunel assay and immunohistochemistry,respectively.Results(1)Homogeneous polysaccharide CF1 of WPPs was obtained,the molecular weight of which was estimated to be 1540.10 ± 48.78 kDa by HPGPC-ELSD.HPLC with PMP derivatization analysis indicated that the monosaccharide compositions of CF1 were mannose,glucuronic acid,galacturonic acid,xylose,galactose,arabinose,and trehalose,in a molar ratio of 0.68:0.59:0.27:0.24:0.22:0.67:0.08.(2)The antitumor effects of CF1 upon MTT showed that CF1 exhibited a dose-dependent anti-proliferative effect,with an IC50 value of 374.11 ?g/mL against DU145 prostate cancer cells.(3)Tunel assay and flow cytometry assay showed that the antitumor activity of CF1 was related to apoptosis in vitro.It was found that the apoptosis rate of DU145 cells treated with CF1 was significantly increased compared with the control group(P<0.05).Tunel assay also showed the apoptosis in tumor tissues were increased compared with the model group(P<0.05).(4)In nude mice xenografts,the tumor volume and tumor weight of the pollen polysaccharide group were significantly lower than those of the model group(P<0.05),and the tumor inhibition rates of the low,middle and high dose groups were 40.16%,57.98%,and 62.31%,respectively.However,the tumor inhibition rate was lower than the cyclophosphamide group(66.45%).(5)The expression of related proteins in PI3K/AKT signaling pathway was detected by western blot and immunohistochemistry.We found that the expression levels of PI3 K,AKT,p-AKT and Bcl-2 proteins in DU145 cells and tumor tissues were decreased after treatment with CF1 and the expression level of Caspase-3 was increased(P<0.05).The expression level of Bax,Caspase-9 proteins in DU145 cells were increased,and the ratio of Bcl-2/Bax were decreased(P<0.05).Conclusion CF1 can inhibit the proliferation of prostate cancer DU145 cells by inducing apoptosis and inhibit the growth of tumor in the xenograft model of DU145 prostate cancer cells,reducing the volume and weight of the tumor.The mechanism may be related to inhibit the activity of PI3K/AKT signaling pathway,and down-regulation the expression levels of anti-apoptotic protein Bcl-2,and up-regulation of apoptotic protein Bax,Caspase-9 and Caspase-3. |
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