title: A Novel Polysaccharide Conjugate from Bullacta exarata Induces G1-Phase Arrest and Apoptosis in Human Hepatocellular Carcinoma HepG2 Cells.
abstract: Bullacta exaratahas been consumed in Asia, not only as a part of the normal diet, but also as a traditional Chinese medicine with liver- and kidney-benefitting functions. Several scientific investigations involving extraction of biomolecules from this mollusk and pharmacological studies on their biological activities have been carried out. However, little is known regarding the antitumor properties of polysaccharides fromB. exarata, hence the polysaccharides fromB. exaratahave been investigated here. One polysaccharide conjugate BEPS-IA was isolated and purified fromB. exarata. It mainly consisted of mannose and glucose in a molar ratio of 1:2, with an average molecular weight of 127 kDa. Thirteen general amino acids were identified to be components of the protein-bound polysaccharide. Methylation and NMR studies revealed that BEPS-IA is a heteropolysaccharide consisting of 1,4-linked-α-d-Glc, 1,6-linked-α-d-Man, 1,3,6-linked-α-d-Man, and 1-linked-α-d-Man residue, in a molar ratio of 6:1:1:1. In order to test the antitumor activity of BEPS-IA, we investigated its effect against the growth of human hepatocellular carcinoma cells HepG2 in vitro. The result showed that BEPS-IA dose-dependently exhibited an effective HepG2 cells growth inhibition with an IC50of 112.4 μg/mL. Flow cytometry analysis showed that BEPS-IA increased the populations of both apoptotic sub-G1 and G1 phase. The result obtained from TUNEL assay corroborated apoptosis which was shown in flow cytometry. Western blot analysis suggested that BEPS-IA induced apoptosis and growth inhibition were associated with up-regulation of p53, p21 and Bax, down-regulation of Bcl-2. These findings suggest that BEPS-IA may serve as a potential novel dietary agent for hepatocellular carcinoma.
authors.affiliation: Department of Nutrition and Food Safety, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou 310051, China. nbliao@cdc.zj.cn.
authors.forename: Ningbo
authors.initials: N
authors.lastname: Liao
authors.affiliation: Department of Nutrition and Food Safety, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou 310051, China. lsun@cdc.zj.cn.
authors.forename: Liang
authors.initials: L
authors.lastname: Sun
authors.affiliation: Department of Nutrition and Food Safety, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou 310051, China. jchen@cdc.zj.cn.
authors.forename: Jiang
authors.initials: J
authors.lastname: Chen
authors.affiliation: College of Biosystem Engineering and Food Science, Zhejiang University, Hangzhou 310058, China. bedelight@163.com.
authors.forename: Jianjun
authors.initials: J
authors.lastname: Zhong
authors.affiliation: Department of Nutrition and Food Safety, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou 310051, China. yjzhang@cdc.zj.cn.
authors.forename: Yanjun
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Nutrition and Food Safety, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou 310051, China. rhzhang@cdc.zj.cn.
authors.forename: Ronghua
authors.initials: R
authors.lastname: Zhang
mesh_terms: D000596:Amino Acids / Q000737:chemistry; D000818:Animals; D000970:Antineoplastic Agents / Q000737:chemistry* / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D015415:Biomarkers; D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D059585:G1 Phase Cell Cycle Checkpoints / Q000187:drug effects*; D049851:Gastropoda / Q000737:chemistry*; D056945:Hep G2 Cells; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics / Q000378:metabolism; D008745:Methylation; D018625:Microscopy, Atomic Force; D015689:Oncogene Protein p21(ras) / Q000378:metabolism; D011134:Polysaccharides / Q000737:chemistry* / Q000494:pharmacology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D013057:Spectrum Analysis; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000378:metabolism
chemical_list: D000596:Amino Acids; D000970:Antineoplastic Agents; D015415:Biomarkers; D011134:Polysaccharides; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; D015689:Oncogene Protein p21(ras)
keywords: Bullacta exarata; apoptosis; human hepatocellular carcinoma HepG2 cells; polysaccharide