title: Effect and mechanism of nociceptin/orphanin FQ reversing multi-drug resistance in K562/ADM cell.
abstract: OBJECTIVE
  To investigate the effect and mechanism of nociceptin/orphanin FQ (OFQ) reversing multi-drug resistance of K562/ADM cells in vitro.
  
  
  METHODS
  MTT assay, Wright staining, flow cytometry, transmission electron microscope and gel electrophoresis were used to evaluate the effect and mechanism of OFQ in reversing multi-drug resistance of K562/ADM cells.
  
  
  RESULTS
  OFQ could time-dependently reverse the ADM resistance of K562/ADM cell. After treatment with OFQ (1 x 10(-7) mol x L(-1)), K562/ADM cells were cultured for 24, 48 and 72 h. The reversal index (RI) was 1.33, 1.42 and 1.53, respectively. Furthermore, OFQ significantly increased the intracellular accumulation of ADM in K562/ADM cells and percentage apoptosis in K562/ADM cells. OFQ down-regulated the level of P-gp time-dependently, while the level of Fas and FasL were up-regulated. There were evidently significant differences compared with the control (P < 0.01). After treating K562/ADM cells with OFQ (1 x 10(-7) mol x L(-1)) and ADM (20 microg x ml(-1)) for 48 hours, the cells showed apoptotic nuclear fragmentation, which was characterized by the appearance of a DNA ladder pattern in genomic DNA gel electrophoresis.
  
  
  CONCLUSIONS
  OFQ can reverse the ADM resistance of K562/ADM cells. The mechanism involves OFQ up-regulating the expression of Fas/FasL, down-regulating the level of P-gp, and decreasing the intracellular level of calcium in K562/ADM cells.
authors.affiliation: Key Laboratory of Preclinical Study for New Drugs of Gansu Province, Institute of Biochemistry and Molecular Biology, School of Life Science, Lanzhou University, Lanzhou, China.
authors.forename: Zhao
authors.initials: Z
authors.lastname: Li
authors.forename: Lan-Xia
authors.initials: LX
authors.lastname: Zhou
authors.forename: Bao-Hong
authors.initials: BH
authors.lastname: Zhang
authors.forename: Xiang
authors.initials: X
authors.lastname: Yan
authors.forename: Juan
authors.initials: J
authors.lastname: Li
authors.forename: Ya-Li
authors.initials: YL
authors.lastname: Peng
authors.forename: Min
authors.initials: M
authors.lastname: Chang
authors.forename: Shou-Liang
authors.initials: SL
authors.lastname: Dong
authors.forename: Rui
authors.initials: R
authors.lastname: Wang
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism; D017302:Annexins / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D020552:Comet Assay; D004247:DNA / Q000235:genetics; D053938:DNA Fragmentation / Q000187:drug effects; D004317:Doxorubicin / Q000378:metabolism; D018432:Drug Resistance, Multiple / Q000187:drug effects*; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D053222:Fas Ligand Protein / Q000378:metabolism; D005434:Flow Cytometry; D016650:Fluorescein-5-isothiocyanate; D006801:Humans; D020014:K562 Cells; D018847:Opioid Peptides / Q000494:pharmacology*; D013050:Spectrometry, Fluorescence; D019014:fas Receptor / Q000378:metabolism; D000097629:Nociceptin
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D017302:Annexins; D002118:Calcium; D004247:DNA; D004317:Doxorubicin; D053222:Fas Ligand Protein; D016650:Fluorescein-5-isothiocyanate; D018847:Opioid Peptides; D019014:fas Receptor; D000097629:Nociceptin