title: Stimulation of autophagic activity in human glioma cells by anti-proliferative ardipusilloside I isolated from Ardisia pusilla.
abstract: OBJECTIVE
  Ardipusilloside I (ADS-I), a triterpenoid saponin isolated from Ardisia pusilla A.DC (Myrsinaceae), has been recently tested for cancer treatment including brain cancer. However, the mechanism of its action remains elusive. The present study was to investigate the role of autophagy activation in the anti-tumor activities of ADS-I in human glioma cells.
  
  
  METHODS
  The tetrazolium dye (MTT) colorimetric assay was used for the measurement of cell proliferation in cultured glioma cells, transmission electron microscopy (TEM) for the examination of autophagic activity, flow cytometric analysis for the determination of cell cycle and apoptotic cells, and immunocytochemistry and Western blot for protein expression of microtubule-associated protein light-chain 3 (LC3) and Beclin 1.
  
  
  RESULTS
  ADS-I significantly inhibited the proliferation of both U373 and T98G glioma cells in cultures in a dose-dependent manner. The cytotoxic activity of ADS-I against glioma cell growth was associated not only with the induction of cell cycle arrest at G2/M phase and cell apoptosis in flow cytometric analysis, but also with the activation of autophagy, indicated by the formation of autophagosomes and up-regulated expression of both autophagic protein Beclin 1 and LC3 in glioma cells. Additionally, the treatment with chloroquine, an autophagy inhibitor, reduced ADS-1-mediated cell death.
  
  
  CONCLUSIONS
  These data suggest that the anti-proliferative activity of ADS-I in human glioma cells is associated with the activation of autophagy in addition to cell cycle arrest and apoptosis, and the antagonistic effect of chloroquine suggests an important role of autophagy in ADS-I-mediated cell death against tumor growth.
authors.affiliation: Department of Pharmacy, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China; Department of Pharmacology, Xi'an Jiaotong University College of Medicine, Xi'an, Shaanxi 710061, China.
authors.forename: Rong
authors.initials: R
authors.lastname: Wang
authors.affiliation: Department of Pharmacy, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Xiao
authors.affiliation: Department of Pharmacy, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China.
authors.forename: Peng-Yuan
authors.initials: PY
authors.lastname: Wang
authors.affiliation: Department of Pharmacy, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Urologic Sciences, University of British Columbia, Vancouver, BC V6H 3Z6, Canada.
authors.forename: Qiunong
authors.initials: Q
authors.lastname: Guan
authors.affiliation: Department of Urologic Sciences, University of British Columbia, Vancouver, BC V6H 3Z6, Canada. Electronic address: caigan@mail.ubc.ca.
authors.forename: Caigan
authors.initials: C
authors.lastname: Du
authors.affiliation: Department of Pharmacy, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China. Electronic address: wxjyh231@fmmu.edu.cn.
authors.forename: Xiao-Juan
authors.initials: XJ
authors.lastname: Wang
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D051017:Apoptosis Regulatory Proteins / Q000235:genetics; D031644:Ardisia / Q000737:chemistry*; D001343:Autophagy / Q000187:drug effects*; D000071186:Beclin-1; D001932:Brain Neoplasms / Q000188:drug therapy* / Q000473:pathology; D002453:Cell Cycle / Q000187:drug effects; D059447:Cell Cycle Checkpoints / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002738:Chloroquine / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005434:Flow Cytometry; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D005910:Glioma / Q000188:drug therapy* / Q000473:pathology; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics; D009828:Oleanolic Acid / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000302:isolation & purification / Q000494:pharmacology; D012503:Saponins / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D051017:Apoptosis Regulatory Proteins; C491997:BECN1 protein, human; D000071186:Beclin-1; D008565:Membrane Proteins; D012503:Saponins; C087799:ardipusilloside I; D009828:Oleanolic Acid; D002738:Chloroquine
keywords: Apoptosis; Ardipusilloside I; Ardisia pusilla; Autophagy; Human glioblastoma; Natural compound; Triterpenoid saponin