Effect and mechanism of nociceptin/orphanin FQ reversing multi-drug resistance in K562/ADM cell.
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.
Li
Zhao
Z
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.
Zhou
Lan-Xia
LX
Zhang
Bao-Hong
BH
Yan
Xiang
X
Li
Juan
J
Peng
Ya-Li
YL
Chang
Min
M
Dong
Shou-Liang
SL
Wang
Rui
R
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
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