title: Effects of multidrug resistance, antisense RNA on the chemosensitivity of hepatocellular carcinoma cells.
abstract: BACKGROUND
  Multidrug resistance is a major obstacle in cancer chemotherapy. We examined whether the antisense RNA of multidrug resistance gene 1 (mdr1) could reverse multidrug resistance in the human hepatocellular carcinoma (HCC) cell line SMMC7721/ADM.
  
  
  METHODS
  The recombinant adenoviruses pAdEasy-GFP-ASmdr1 product was produced by the adenoviral vector AdEasy system, which can express antisense RNA against the mdr1 gene. Following that, the recombinant adenovirus was transfected into the P-glycoprotein-producing multidrug resistance cell line, SMMC7721/ADM human HCC cells resistant to adriamycin (ADM) and daunorubicin (DNR). In order to investigate the reversal of multidrug resistance phenotype, we measured the expression of mdr1 mRNA by RT-PCR and the production of P-glycoprotein by flow cytometry. The sensitivities for ADM and DNR SMMC7721/ADM cells were examined by [3-(4, 5-dimethylthi-azol-2-yl)-2,5 diphenyl-terazolium bromide] (MTT) analysis.
  
  
  RESULTS
  The low-level expression of mdr1 mRNA and P-glycoprotein production were observed in parental sensitive cells SMMC/7721 in addition to the overexpression of mdr1 mRNA and P-glycoprotein in SMMC7721/ADM cells. The transfection of antisense-RNA into SMMC7721/ADM cells resulted in decreases of mdr1 mRNA and P-glycoprotein, but increase of drug sensitivities. The sensitivities of transfected SMMC7721/ADM cells to ADM and DNR in IC50 reduced by 31.25% and 62.96% respectively.
  
  
  CONCLUSIONS
  Mdr1 antisense RNA can increase the sensitivities of SMMC7721/ADM cells to anticancer drug by decreasing the expression of the mdr1 gene and inhibiting P-glycoprotein expression. This strategy may be applicable to cancer patients with P-glycoprotein mediated multidrug resistance.
authors.affiliation: Department of Hepatobiliary Surgery, Second Affiliated Hospital, Chongqing University of Medical Sciences, Chongqing 400010, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Li
authors.forename: Tian
authors.initials: T
authors.lastname: Ye
authors.forename: Lei
authors.initials: L
authors.lastname: Zhao
authors.forename: De-Hua
authors.initials: DH
authors.lastname: Li
authors.forename: Xing-Hua
authors.initials: XH
authors.lastname: Gou
authors.forename: Lan-Ying
authors.initials: LY
authors.lastname: Zhao
authors.forename: Lei
authors.initials: L
authors.lastname: Han
authors.forename: Lin
authors.initials: L
authors.lastname: Chen
authors.forename: Lu-Nan
authors.initials: LN
authors.lastname: Yan
authors.forename: Jian-Ping
authors.initials: JP
authors.lastname: Gong
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism; D000256:Adenoviridae / Q000235:genetics; D006528:Carcinoma, Hepatocellular / Q000235:genetics*; D045744:Cell Line, Tumor; D018432:Drug Resistance, Multiple / Q000235:genetics; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D019450:Genes, MDR; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics*; D010957:Plasmids; D016372:RNA, Antisense; D012333:RNA, Messenger / Q000378:metabolism; D014170:Transformation, Genetic
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D016372:RNA, Antisense; D012333:RNA, Messenger