[Study on reversal effect of nilotinib in combination with 5-BrTet on multidrug resistance of K562/A02 cell line].
OBJECTIVE
To investigate the reversible effect of nilotinib, BrTet (5-bromotetrandrine) and their combination on multidrug resistance cell line K562/A02 and its mechanism.


METHODS
Cell proliferation inhibition was assessed by MTT method and cell apoptosis by flow cytometry (FCM). The expression of mdr1 mRNA was determined by RT-PCR, and the expression of P-gp was assessed by Western blot.


RESULTS
After 48 h 5 nmol/L nilotinib or 0.5 µmol/L BrTet treatment, IC(50) of daunorubicin (DNR) to K562/A02 was 4.52 mg/L or 5.41 mg/L respectively; While on combinative treatment, its IC(50) decreased to 2.98 mg/L. Nilotinib or BrTet alone was not able to increase the DNR induced apoptosis rate of K562/A02 cell (P > 0.05), while on combination treatment the apoptosis rate increased remarkably. After 48 h 5 nmol/L nilotinib or 0.5 µmol/L BrTet treatment alone, gray-scale value of mdr1 mRNA was 0.48 ± 0.04 or 0.64 ± 0.01, respectively; while on combinative treatment the value decreased to 0.35 ± 0.04. The P-gp expression level in K562/A02 cells was 0.61 ± 0.05, or 0.52 ± 0.02 when treated with 5 nmol/L nilotinib or 0.5 µmol/L BrTet alone for 48 h, but on combination treatment, the level decreased to 0.44 ± 0.03.


CONCLUSIONS
Nilotinib or BrTet alone can partially reverse drug resistance of K562/A02 cells. The mechanism may be associated with the decrease of mdr1 mRNA and P-gp expression and increase of the apoptosis rate. And there is a synergistic action with these two agants in combination.
Clinical College Affiliated Zhongda Hospital, Southeast University, Nanjing 210009, China.
Bao-An
BA
Chen
Xue-Yun
XY
Shan
Jian
J
Chen
Fei
F
Wang
Jia-Hua
JH
Ding
Chong
C
Gao
Gang
G
Zhao
Xue-Mei
XM
Wang
Wen-Lin
WL
Xu
Feng
F
Gao
Guo-Hua
GH
Xia
Michael
M
Schmitt
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism; D003630:Daunorubicin / 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; D003630:Daunorubicin