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The purpose of this study is to investigate the effect of a purified polysaccharide (PPPF) from pumpkin fruit on the Janus activated kinase (JAK)/signal transducer and activator of transcription (STAT) signaling during apoptotic process. The results showed that PPPF or STAT3 siRNA inhibits the cell growth of HepG2 cells via induction of apoptosis. Moreover, PPPF is able to suppress both constitutive and IL-6-induced phosphorylation of STAT3 (on Tyr705) and subsequent nuclear translocation in cancer cells. Such inhibition is found to be achieved through down-regulation of constitutive phosphorylation of JAK2, but not JAk1, c-Src, ERK1/2, and Akt, which means STAT3 tyrosine phosphorylation in HepG2 cells following PPPF treatment is associated with a reduction in JAK2 activity. In addition, the protein expression of SHP-1 was increased in cells in response to PPPF treatment, whereas SHP-2, SOCS-1 and SCOS-3 protein expression remain unchanged. In vivo animal experiment also indicated that PPPF had a potent inhibitory effect on tumor growth in mice bearing HepG2 xenograft tumors. Thus we can conclude that PPPF directly induces apoptotic cell death of HepG2 cells via down-regulation of the JAK2/STAT3 signal transduction pathways, which may facilitates the development of a therapeutic strategy for treating HCC. [ABSTRACT FROM AUTHOR]

Abstract: In this study, we prepared an acidic polysaccharide (CPPA) from the roots of Codonopsis pilosula. The effects of CPPA on tumor cell growth, invasion, and migration were examined in vitro. The CPPA not only induced a potent inhibitory effect on the invasion and migration potential of human epithelial ovarian cancer HO-8910 cells in vitro, evaluated by wound healing, transwell and cell adhesion assays, but also had an efficient anti-proliferation effect on tumor cells. Moreover, the CD44 expression on the HO-8910 cells was also attenuated by CPPA treatment. Therefore, our results indicate that CPPA may be a potential candidate compound for the prevention of tumor metastasis, presumably by inhibiting invasion, migration and adhesion of tumor cells, as well as the CD44 expression on the tumor cells. [Copyright &y& Elsevier]

Abstract: Two acidic polysaccharide fractions (PTPa and PTPb) extracted from the roots of Polygala tenuifolia, were obtained by DEAE-Sephacel anion-exchange, and Sephadex G-100 gel-permeation chromatography. High-performance liquid chromatography (HPLC) identified that PTPa and PTPb was composed of Ara, Glc, Gal, Man and GlcUA in the proportion of 2.4:1.2:0.6:0.4:1.1 and 2.1:1.7:0.5:0.6:1.7, respectively. Their molecular weight was evaluated to be 5.9×104 (PTPa) and 2.5×104 Da (PTPb) as determined by high performance size exclusion chromatography (HPSEC). Pharmacological studies revealed PTPa and PTPb significantly inhibited the growth of A549 cells in vitro and exhibited significantly higher antitumor activity against solid tumor A549 in vivo than did a blank control. Moreover, treatment with two acidic polysaccharides caused an enhancement of superoxide dismutase (SOD) and catalase (CAT) activities in tumor-bearing mice and a reduction in thiobarbituric acid reactive substances (TBARS) level. Taken together, these results indicated that two acidic polysaccharides from the roots of P. tenuifolia may be useful as potent antitumor agents for the prevention of lung tumorigenesis. [Copyright &y& Elsevier]

Abstract: One polysaccharide PTP was isolated and purified from the roots of Polygala tenuifolia. It consisted of galactose, glucose and galactose in the ratio of 3.1:3.7:2.5, and a small amount of rhamnose, mannose and xylose. 17 general amino acids were identified to be components of the protein-bound polysaccharide analyzed by automatic amino acid analyzer. In order to test the anti-cancer activity of PTP, we investigated its effect against the growth of human ovarian cancer cells SKOV3 in vitro and in ovarian cancer rats. The intracellular reactive oxygen species (ROS) and glutathione (GSH) in SKOV3 cells following PTP treatment were also quantified to explore the possible mechanism underlying the antitumor activity of the polysaccharide. The result showed that PTP is effective on inhibiting the proliferation of SKOV3 cells in a concentration-dependent manner. Furthermore, treatment with PTP caused a rapid depletion of intracellular GSH content and accumulation of intracellular ROS, thus resulting in the apoptosis, which may prove to be a pivotal mechanism for its cancer protection action. In addition, a significant tumor growth inhibition effect was observed in nude mice after PTP administration for 7 weeks. All above indicated PTP could be beneficial towards ovarian cancer therapy. [Copyright &y& Elsevier]