title: [Reverse effect of genetically modified adenovirus H101 on drug-resistance of A549/DDP cells to cisplatin].
abstract: OBJECTIVE
  Multidrug resistance is one of the main causes of treatment failure of chemotherapy. Reversal agents may be used to reverse drug-resistance. To date, no appropriate reversal agent is used clinically. This study was to evaluate reverse effect of genetically modified adenovirus H101 on drug-resistance of A549/DDP cells to cisplatin (DDP), and to explore its mechanisms.
  
  
  METHODS
  Lung adenocarcinoma cell line A549 and its DDP-resistant cell line A549/DDP were treated with DDP and H101. Reverse effect of H101 on drug-resistance of A549/DDP to DDP was tested by MTT assay. The levels of cellular multidrug resistant protein 1 (MRP1), glutathione-S-transferase (GST), and topoisomerase-II (TOPO-II) were detected by flow cytometry (FCM). The level of intracellular glutathione (GSH) was measured by fluorescence-Coomassie light blue method. The intracellular concentration of platinum was measured by atomic absorption spectrometry.
  
  
  RESULTS
  The resistance index of A549/DDP cells to DDP was 14.3. After infection of H101, the 50% inhibitory concentration (IC(50)) of DDP to A549/DDP cells reduced from 352.4 micromol/L to 61.6 micromol/L by 5.7 folds. Protein levels of GST and TOPO-II were higher in A549/DDP cells than in A549 cells, which were markedly decreased in A549/DDP cells after infection of H101. No MRP1 protein was detected in both A549 cells and A549/DDP cells. Intracellular amount of GSH in A549/DDP cells was 2 times higher than that in A549 cells, which was significantly decreased after infection of H101. The concentration of platinum in A549 cells was 3 times higher than that in A549/DDP cells. After infection of H101, the concentration of platinum in A549 cells had no significant change, but that in A549/DDP cells was significantly increased.
  
  
  CONCLUSIONS
  H101 may reverse drug-resistance of A549/DDP cells to DDP through down-regulating GST and TOPO-IIand increasing intracellular cumulation of platinum.
authors.affiliation: Skate Key Laboratory of Oncology in Southern China, Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong, P. R. China. ruihuaxu@163.com
authors.forename: Rui-Hua
authors.initials: RH
authors.lastname: Xu
authors.forename: Zhong-Yu
authors.initials: ZY
authors.lastname: Yuan
authors.forename: Zhong-Zhen
authors.initials: ZZ
authors.lastname: Guan
authors.forename: Su
authors.initials: S
authors.lastname: Li
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism / Q000473:pathology*; D000256:Adenoviridae / Q000235:genetics* / Q000502:physiology; D000970:Antineoplastic Agents / Q000494:pharmacology; D045744:Cell Line, Tumor; D002945:Cisplatin / Q000494:pharmacology*; D004250:DNA Topoisomerases, Type II / Q000378:metabolism; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D020128:Inhibitory Concentration 50; D008175:Lung Neoplasms / Q000378:metabolism / Q000473:pathology*; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000378:metabolism*; D050504:Oncolytic Viruses / Q000235:genetics / Q000502:physiology; D010984:Platinum / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D002945:Cisplatin; D004250:DNA Topoisomerases, Type II; D005982:Glutathione Transferase; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D010984:Platinum; C421109:multidrug resistance-associated protein 1