Tumor Biology

, Volume 37, Issue 4, pp 5239–5245 | Cite as

A polysaccharide from pumpkin induces apoptosis of HepG2 cells by activation of mitochondrial pathway

  • Weixi Shen
  • Yuanyuan Guan
  • Jingfang Wang
  • Yu Hu
  • Qian Tan
  • Xiaowei Song
  • Yinghua Jin
  • Ying Liu
  • Yanqiao Zhang
Original Article


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.


Pumpkin Polysaccharide Purification Apoptosis Hepatoma Mitochondria 


Compliance with ethical standards

Conflicts of interest



  1. 1.
    Jemal A, Bray F, Center MM, Ferlay J, Ward E, Forman D. Global cancer statistics. CA Cancer J Clin. 2011;61:69–90.CrossRefPubMedGoogle Scholar
  2. 2.
    Chen CJ, Yu MW, Liaw YF. Epidemiological characteristics and risk factors of hepatocellular carcinoma. J Gastroenterol Hepatol. 1997;12:S294–308.CrossRefPubMedGoogle Scholar
  3. 3.
    Zhao X, Shu G, Chen L, Mi X, Mei Z, Deng X. A flavonoid component from Docynia delavayi (Franch.) Schneid represses transplanted H22 hepatoma growth and exhibits low toxic effect on tumor-bearing mice. Food Chem Toxicol. 2012;50:3166–73.CrossRefPubMedGoogle Scholar
  4. 4.
    Yu J, Liu H, Lei J, Tan W, Hu X, Zou G. Antitumor activity of chloroform fraction of Scutellaria barbata and its active constituents. Phytother Res. 2007;21:817–22.CrossRefPubMedGoogle Scholar
  5. 5.
    Zou Y, Xiong H, Xiong H, Lu T, Zhu F, Luo Z, et al. A polysaccharide from mushroom Huaier retards human hepatocellular carcinoma growth, angiogenesis, and metastasis in nude mice. Tumour Biol. 2015;36:2929–36.CrossRefPubMedGoogle Scholar
  6. 6.
    Wang SY, Huang WC, Liu CC, Wang MF, Ho CS, Huang WP, et al. Pumpkin (Cucurbita moschata) fruit extract improves physical fatigue and exercise performance in mice. Molecules. 2012;17:11864–76.CrossRefPubMedGoogle Scholar
  7. 7.
    Nara K, Yamaguchi A, Maeda N, Koga H. Antioxidative activity of water soluble polysaccharide in pumpkin fruits (Cucurbita maxima Duchesne). Biosci Biotechnol Biochem. 2009;73:1416–8.CrossRefPubMedGoogle Scholar
  8. 8.
    Xiong X, Cao J. Study of extraction and isolation of effective pumpkin polysaccharide component and its reducing glycemia function. Chin J Mod Appl Pharm. 2001;18:662–4.Google Scholar
  9. 9.
    Zhang Y, Yao H. Study on effect of hypoglycemia of different type pumpkin. J Chin Food Sci. 2002;23:118–20.Google Scholar
  10. 10.
    Quanhong L, Caili F, Yukui R, Guanghui H, Tongyi C. Effects of protein-bound polysaccharide isolated from pumpkin on insulin in diabetic rats. Plant Foods Hum Nutr. 2005;60:13–6.CrossRefPubMedGoogle Scholar
  11. 11.
    Fu CL, Shi H, Li QH. A review on pharmacological activities and utilization technologies of pumpkin. Plant Foods Hum Nutr. 2006;61:73–80.Google Scholar
  12. 12.
    Staub AM. Removal of protein—Sevag method. Methods Carbohydr Chem. 1965;5:5–6.Google Scholar
  13. 13.
    Dubois M, Gilles KA, Hamilton JK, Rebers PA, Smith F. Colorimetric method for determination of sugars and related substances. Anal Chem. 1956;28:350–6.CrossRefGoogle Scholar
  14. 14.
    Blumenkrantz N, Asboe-Hansen G. New method for quantitative determination of uronic acids. Anal Biochem. 1973;54:484–9.CrossRefPubMedGoogle Scholar
  15. 15.
    Bradford MM. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein binding. Anal Biochem. 1976;72:248–54.CrossRefPubMedGoogle Scholar
  16. 16.
    Erbing B, Jansson PE, Widmalm G, Nimmich W. Structure of the capsular polysaccharide from the Klebsiella K8 reference strain 1015. Carbohydr Res. 1995;273:197–205.CrossRefPubMedGoogle Scholar
  17. 17.
    Guentas L, Pheulpin P, Michaud P, Heyraud A, Gey C, Courtois B, et al. Structure of a polysaccharide from a Rhizobium species containing 2-deoxy-beta-D-arabino-hexuronic acid. Carbohydr Res. 2001;332:167–73.CrossRefPubMedGoogle Scholar
  18. 18.
    Zhang F, Song X, Li L, Wang J, Lin L, Li C, et al. Polygala tenuifolia polysaccharide (PTP) inhibits cell proliferation by repressing Bmi-1 expression and downregulating telomerase activity. Tumour Biol. 2015;36:2907–12.CrossRefPubMedGoogle Scholar
  19. 19.
    Zhang F, Song X, Li L, Wang J, Lin L, Li C, et al. Polygala tenuifolia polysaccharide PTP induced apoptosis in ovarian cancer cells via a mitochondrial pathway. Tumour Biol. 2015;36:2913–9.CrossRefPubMedGoogle Scholar
  20. 20.
    Miao S, Mao X, Pei R, Miao S, Xiang C, Lv Y, et al. Lepista sordida polysaccharide induces apoptosis of Hep-2 cancer cells via mitochondrial pathway. Int J Biol Macromol. 2013;61:97–101.CrossRefPubMedGoogle Scholar
  21. 21.
    Zhang Y, Sun S, Chen J, Ren P, Hu Y, Cao Z, et al. Oxymatrine induces mitochondria dependent apoptosis in human osteosarcoma MNNG/HOS cells through inhibition of PI3K/Akt pathway. Tumour Biol. 2014;35:1619–25.CrossRefPubMedGoogle Scholar
  22. 22.
    Susin SA, Lorenzo HK, Zamzami N, Marzo I, Snow BE, Brothers GM, et al. Molecular characterization of mitochondrial apoptosis-inducing factors. Nature. 1999;397:441–6.CrossRefPubMedGoogle Scholar
  23. 23.
    Green DR. Apoptotic pathways: the roads to ruin. Cell. 1998;94:695–8.CrossRefPubMedGoogle Scholar
  24. 24.
    Hengartner MO. The biochemistry of apoptosis. Nature. 2006;407:770–6.CrossRefGoogle Scholar
  25. 25.
    Orrenius S. Mitochondrial regulation of apoptotic cell death. Toxicol Lett. 2004;149:19–23.CrossRefPubMedGoogle Scholar
  26. 26.
    Scorrano L, Korsmeyer SJ. Mechanisms of cytochrome c release by proapoptotic Bcl-2 family members. Biochem Biophys Res Commun. 2003;304:437–44.CrossRefPubMedGoogle Scholar
  27. 27.
    Kluck R, Bossy-Wetzel E, Green DR, Newmeyer DD. The release of cytochrome c from mitochondria: a primary site for Bcl-2 regulation of apoptosis. Science. 1997;275:1132–6.CrossRefPubMedGoogle Scholar
  28. 28.
    Shen DY, Kang JH, Song W, Zhang WQ, Li WG, Zhao T, et al. Apoptosis of human cholangiocarcinoma cell lines induced by β-escin through mitochondrial caspase-dependent pathway. Phytother Res. 2011;25:1519–26.CrossRefPubMedGoogle Scholar
  29. 29.
    Sun Z, Huang K, Fu X, Zhou Z, Cui Y, Li H. A chemically sulfated polysaccharide derived from Ganoderma lucidum induces mitochondrial-mediated apoptosis in human osteosarcoma MG63 cells. Tumour Biol. 2014;35:9919–26.CrossRefPubMedGoogle Scholar
  30. 30.
    Yakovlev AG, Wang G, Stoica BA, Boulares HA, Spoonde AY, Yoshihara K, et al. A role of the Ca2+/Mg2+-dependent endonuclease in apoptosis and its inhibition by poly (ADP-ribose) polymerase. J Biol Chem. 2000;275:21302–8.CrossRefPubMedGoogle Scholar
  31. 31.
    Qin H, Du XY, Zhang Y, Wang R, Platycodin D. A triterpenoid saponin from Platycodon grandiflorum, induces G2/M arrest and apoptosis in human hepatoma HepG2 cells by modulating the PI3K/Akt pathway. Tumour Biol. 2014;35:1267–74.CrossRefPubMedGoogle Scholar
  32. 32.
    Li P, Nijhawan D, Budihardjo I, Srinivasula SM, Ahmad M, Alnemri ES, et al. Cytochrome c and dATP-dependent formation of Apaf-1/caspase-9 complex initiates an apoptotic protease cascade. Cell. 1997;91:479–89.CrossRefPubMedGoogle Scholar
  33. 33.
    Wang X, Chen Y, Wang J, Liu Z, Zhao S. Antitumor activity of a sulfated polysaccharide from Enteromorpha intestinalis targeted against hepatoma through mitochondrial pathway. Tumour Biol. 2014;35:1641–7.CrossRefPubMedGoogle Scholar
  34. 34.
    Decker P, Muller S. Modulating poly (ADP-ribose) polymerase activity: potential for the prevention and therapy of pathogenic situations involving DNA damage and oxidative stress. Curr Pharm Biotechnol. 2002;3:275–83.CrossRefPubMedGoogle Scholar

Copyright information

© International Society of Oncology and BioMarkers (ISOBM) 2015

Authors and Affiliations

  • Weixi Shen
    • 1
  • Yuanyuan Guan
    • 2
  • Jingfang Wang
    • 1
  • Yu Hu
    • 1
  • Qian Tan
    • 1
  • Xiaowei Song
    • 1
  • Yinghua Jin
    • 1
  • Ying Liu
    • 1
  • Yanqiao Zhang
    • 3
  1. 1.Department of OncologyThe Second Affiliated Hospital of Harbin Medical UniversityHarbinChina
  2. 2.Department of AllergyThe First Affiliated Hospital of Harbin Medical UniversityHarbinChina
  3. 3.Department of OncologyThe Third Affiliated Hospital of Harbin Medical UniversityHarbinChina

Personalised recommendations