[Reversal of multidrug resistance of leukemia cell line in vitro by antisense phosphorothioate oligonucleotide].
OBJECTIVE
To investigate the effectiveness of 14 mer antisense phosphorothioate oligonucleotide (AS-SODN) complementary to the published multidrug resistance gene (mdr(1) gene) sequence to reverse multidrug resistance of leukemia cell line.


METHODS
50% inhibitory concentration (IC(50)) of K562 cell line resistant to adriamycin (K562/ADM cell line) was determined by the tetrazolium dye, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method, the concentration of daunorubicin (DNR) in the cell by flow cytometry, the level of P170 by immunohistochemical staining technique and the level of mdr(1)-mRNA by half-quantitative RT-PCR (the ratio of mdr(1)/beta(2)-MG).


RESULTS
Treatment of K562/ADM cell line with 2 micromol/L AS-SODN reduced the level of both the mdr(1)-mRNA and P170. The ratio of mdr(1)/beta(2)-MG reduced from (2.07 +/- 0.16) to (1.57 +/- 0.14), and positive rate of P170 expression decreased from (98.26 +/- 1.35)% to (18.30 +/- 6.50)%. Accordingly, the concentration of DNR in cell increased. With these findings, IC(50) to ADM reduced from 25.72 mg/L to 6.97 mg/L and relative efficiency of modulation was 73.01%.


CONCLUSIONS
Antisense oligonucleotide targeting mdr(1) gene can reduce md(1)-mRNA, block P170 expression so as to increase the sensitivity of K562/ADM cell line to chemotherapy drugs.
Chen
Y
Y
Fujian Institute of Hematology, Union Hospital Fujian Medical University, Fuzhou 350001.
Chen
Z
Z
Zhuo
G
G
Hu
J
J
D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics / Q000378:metabolism*; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D003630:Daunorubicin / Q000378:metabolism; D004317:Doxorubicin / Q000494:pharmacology; D018432:Drug Resistance, Multiple / Q000187:drug effects*; D006023:Glycoproteins / Q000378:metabolism; D006801:Humans; D020014:K562 Cells; D016376:Oligonucleotides, Antisense / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics
C513055:ABCB1 protein, human; D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000903:Antibiotics, Antineoplastic; D006023:Glycoproteins; D016376:Oligonucleotides, Antisense; D012333:RNA, Messenger; D004317:Doxorubicin; D003630:Daunorubicin