[Effect of hypoxia inducible factor1-α inhibitor on reversal of multidrug resistance of K562/A02 cell line].
OBJECTIVE
To study the reversal effect of the hypoxia inducible factor (HIF)-1α inhibitor, YC-1, on multidrug resistance of K562/A02 cells and its mechanism.


METHODS
Pre- and post- incubation with adriamycin (ADM) alone or in combination with YC-1 for 48 h, the proliferation capacity of K562/A02 and K562 cells were evaluated by MTT assay. The apoptosis rate of K562/A02 cells after treated with 0, 5, 10 and 20 µmol/L YC-1 alone or in combination with 1 mg/L ADM and intracellular ADM concentration were analyzed by flow cytometry (FCM). The mRNA levels of HIF-1α and mdr1 genes were determined by semi-quantitative RT-PCR. The protein levels of HIF-1α and P-glycoprotein (P-gp) were detected by Western blot.


RESULTS
The IC(50) of ADM for K562 and K562/A02 cells were (1.56 ± 0.07) mg/L and (42.98 ± 3.15) mg/L respectively. The resistance of K562/A02 cells to ADM was 27.55- fold higher of that of K562 cells. After treatment with YC-1 (5 µmol/L, 10 µmol/L, 20 µmol/L) for 48h, the resistances of K562/A02 cells to ADM were 24.63-, 16.38- and 10.71- fold increase respectively. After treatment of K562/A02 cell with YC-1 (0 µmol/L, 5 µmol/L, 10 µmol/L, 20 µmol/L) alone or in combination with 1 mg/L ADM for 48 h, the apoptotic rates were (1.9 ± 0.9)%, (4.9 ± 0.9)%, (5.8 ± 1.1)%, and (9.3 ± 1.4)% and (2.3 ± 0.7)%, (8.2 ± 1.2)%, (19.0 ± 1.7)%, and (34.5 ± 2.4)% respectively. The intracellular flucorescence intensity of ADM were 232 ± 33, 1300 ± 219, 1961 ± 240 and 3342 ± 269 in the combined treatment group. With the increase in YC-1 concentration, the levels of mdr1 mRNA reduced, while that of HIF-1α mRNA had no obvious change. Furthermore, the expressions of HIF-1α and P-gp were also decreased in K562/A02 cells.


CONCLUSIONS
YC-1, as a HIF-1 inhibitor, can reverse multidrug resistance of K562/A02 cells through down-regulating HIF-1α and P-gp.
Department of Hematology, the Affliated Zhongda Hospital of Clinical Medical School of Southeast University, Nanjing 210009, China.
Bao-An
BA
Chen
Fei
F
Wang
Jian
J
Cheng
Jia-Hua
JH
Ding
Chong
C
Gao
Yun-Yu
YY
Sun
Jun
J
Wang
Gang
G
Zhao
Wen
W
Bao
Hui-Hui
HH
Song
Feng
F
Gao
Guo-Hua
GH
Xia
Xue-Yun
XY
Shan
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism; D004317:Doxorubicin / Q000494:pharmacology; D018432:Drug Resistance, Multiple / Q000187:drug effects; D019008:Drug Resistance, Neoplasm / Q000187:drug effects; D006801:Humans; D020014:K562 Cells
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D004317:Doxorubicin