title: A polysaccharide from pumpkin induces apoptosis of HepG2 cells by activation of mitochondrial pathway.
abstract: Purified white polysaccharide (PPW) is a homogenous polysaccharide isolated from pumpkin, with an average molecular weight of 34 kDa. In this study, we aimed at examining the anti-proliferative activity of PPW against hepatocellular carcinoma (HCC) HepG2 cells and the underlying mechanisms. We found that PPW-induced inhibition of cell proliferation in HepG2 cells was associated with the induction of apoptosis. Exposure of HepG2 cells to PPW (100, 200, and 400 μg/mL) resulted in a loss of mitochondrial membrane potential (Δψm) and the release of cytochrome c from the mitochondria to the cytosol. Also, Western blot analysis revealed dose-dependent increase of pro-apoptotic Bax protein and decrease of anti-apoptotic Bcl-2 protein in PPW-treated cells. Besides, caspase-9 and caspase-3 activities were also enhanced in HepG2 cells followed by PPW treatment. Additionally, the cleavage of poly (ADP-ribose) polymerase (PARP) was observed in PPW-treated HepG2 cells, which altogether account for apoptotic cell death. These results suggested that PPW-induced apoptosis involved a caspase-3-mediated mitochondrial pathway and may have potential as a cancer chemopreventive and therapeutic agent for the prevention and treatment of HCC.
authors.affiliation: Department of Oncology, The Second Affiliated Hospital of Harbin Medical University, Harbin, 150086, China.
authors.forename: Weixi
authors.initials: W
authors.lastname: Shen
authors.affiliation: Department of Allergy, The First Affiliated Hospital of Harbin Medical University, Harbin, 150001, China.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Guan
authors.affiliation: Department of Oncology, The Second Affiliated Hospital of Harbin Medical University, Harbin, 150086, China.
authors.forename: Jingfang
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Oncology, The Second Affiliated Hospital of Harbin Medical University, Harbin, 150086, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Department of Oncology, The Second Affiliated Hospital of Harbin Medical University, Harbin, 150086, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Tan
authors.affiliation: Department of Oncology, The Second Affiliated Hospital of Harbin Medical University, Harbin, 150086, China.
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Song
authors.affiliation: Department of Oncology, The Second Affiliated Hospital of Harbin Medical University, Harbin, 150086, China.
authors.forename: Yinghua
authors.initials: Y
authors.lastname: Jin
authors.affiliation: Department of Oncology, The Second Affiliated Hospital of Harbin Medical University, Harbin, 150086, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Oncology, The Third Affiliated Hospital of Harbin Medical University, Harbin, 150081, China. zhyanqiao@126.com.
authors.forename: Yanqiao
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy* / Q000473:pathology; D053148:Caspase 3 / Q000235:genetics; D028464:Cucurbita / Q000737:chemistry; D056945:Hep G2 Cells; D006801:Humans; D008113:Liver Neoplasms / Q000188:drug therapy* / Q000473:pathology; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects / Q000235:genetics; D011134:Polysaccharides / Q000008:administration & dosage* / Q000737:chemistry; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D011134:Polysaccharides; D053148:Caspase 3
keywords: Apoptosis; Hepatoma; Mitochondria; Polysaccharide; Pumpkin; Purification