title: Reversal of P-glycoprotein-mediated multidrug resistance of human hepatic cancer cells by Astragaloside II.
abstract: OBJECTIVE
  Chemoresistance is the main obstacle encountered in cancer treatment and is frequently associated with multidrug resistance (MDR). Astragaloside is a saponin which is widely used in traditional Chinese medicine. It has been reported that Astragaloside has antitumour effects on hepatocellular carcinoma Bel-7402 cells in vitro and in vivo. The purpose of this study was to examine the effects of Astragaloside II on the reversal of MDR and its molecular mechanism in vitro.
  
  
  METHODS
  In this study, Bel-7402 and Bel-7402/FU cell lines were used as the experimental model. Drug sensitivity was determined using the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay, accumulation and efflux of Rh123 were analyzed by flow cytometer, the mRNA level of mdr1 was determined by RT-PCR and the protein levels of P-glycoprotein (P-gp) and mitogen-activated protein kinase were determined by Western blot.
  
  
  RESULTS
  Astragaloside II (0.08 mg/ml) showed strong potency to increase 5-fluorouracil cytotoxicity toward 5-fluorouracil-resistant human hepatic cancer cells Bel-7402/FU. The mechanism of Astragaloside II on P-gp-mediated MDR demonstrated that Astragaloside II significantly increased the intracellular accumulation of rhodamine 123 via inhibition of P-gp transport function. Based on the analysis of P-gp and mdr1 gene expression using Western blot and RT-PCR, the results revealed that Astragaloside II could downregulate the expression of the P-gp and mdr1 gene. In addition, Astragaloside II suppressed phosphorylation of extracellular signal regulated kinase 1/2, p38 and c-Jun N-terminal kinase.
  
  
  CONCLUSIONS
  The results suggested that Astragaloside II is a potent MDR reversal agent and may be a potential adjunctive agent for hepatic cancer chemotherapy.
authors.affiliation: School of Pharmacy, Anhui Medical University, The First Affiliated Hospital of Anhui Medical University, China.
authors.forename: Can
authors.initials: C
authors.lastname: Huang
authors.forename: Dujuan
authors.initials: D
authors.lastname: Xu
authors.forename: Quan
authors.initials: Q
authors.lastname: Xia
authors.forename: Peipei
authors.initials: P
authors.lastname: Wang
authors.forename: Chao
authors.initials: C
authors.lastname: Rong
authors.forename: Yong
authors.initials: Y
authors.lastname: Su
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics / Q000378:metabolism*; D000964:Antimetabolites, Antineoplastic / Q000627:therapeutic use; D000972:Antineoplastic Agents, Phytogenic / Q000302:isolation & purification / Q000494:pharmacology / Q000627:therapeutic use; D027883:Astragalus Plant / Q000737:chemistry*; D001692:Biological Transport / Q000187:drug effects; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy* / Q000378:metabolism; D045744:Cell Line, Tumor; D015536:Down-Regulation; D018432:Drug Resistance, Multiple / Q000187:drug effects*; D005472:Fluorouracil / Q000627:therapeutic use; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D008113:Liver Neoplasms / Q000188:drug therapy* / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D010766:Phosphorylation; D008517:Phytotherapy; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use; D020112:Rhodamine 123 / Q000378:metabolism; D012503:Saponins / Q000302:isolation & purification / Q000494:pharmacology / Q000627:therapeutic use*
chemical_list: C513055:ABCB1 protein, human; D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000964:Antimetabolites, Antineoplastic; D000972:Antineoplastic Agents, Phytogenic; D010936:Plant Extracts; D012503:Saponins; C580601:astragaloside II; D020112:Rhodamine 123; D020928:Mitogen-Activated Protein Kinases; D005472:Fluorouracil