[Role of WAVE1 in drug resistance of K562/A02 leukemia cells].
OBJECTIVE
To investigate if WAVE1 is involved in mult drug-resistance (MDR) of human leukemia cell line K562/A02.


METHODS
The level of WAVE1 in K562 and K562/A02 cells was assayed by Western blot and RT-PCR; K562 cells and K562/A02 cells were transient transfected with pEFBOS-WAVE1 reconstructed plasmid or specifically siRNA to WAVE1. 50% inhibition concentration (IC50) of doxorubicin on K562/A02 was determined by WST-8 assay. Hoechst33258 staining was used to examine cell morphological changes and to calculate percentage of apoptotic nuclei. The mRNA level of mdrl was assayed by RT-PCR. The Bcl-2 protein was assayed by Western blot.


RESULTS
1. The WAVE1 expression at mRNA and protein level in K562/A02 cells was increased by about 70% and 63% respectively as compared with that in K562 cells. 2. Overexpression of WAVE1 in K562 cells by transient transfection significantly increased the resistance to doxorubicin, and increased IC50 from (0.05 +/- 0.00) microg/ml to (2.99 +/- 0.12) microg/ml, and at 1 microg/ml or 5 microg/ml of doxorubicin treatment, cell apoptotic nuclei rate was decreased by 30% or 35% respectively. 3. Suppression of WAVE1 in K562/A02 cells by siRNA resulted in a reversal of MDR to doxorubicin, and decreased IC50 from (4.29 +/- 0.15) microg/ml to (1.85 +/- 0.07) microg/ml, and at 1 microg/ml or 5 microg/ml of doxorubicin treatment, cell apoptotic nuclei rate was increased by 24% or 21% respectively. 4. Overexpression of WAVE1 in K562 cells significantly increased the mdrl mRNA and the Bcl-2 protein, and suppression of WAVE1 in K562/A02 cells by siRNA decreased the mRNA and the protein.


CONCLUSIONS
WAVE1 involves in the MDR mechanisms in K562/A02 leukemia cells through regulation the level of mdrl and Bcl-2.
Kang
Rui
R
Department of Pediatrics, Xiangya Hospital, Central South University, Changsha 410008, China.
Cao
Li-zhi
LZ
Yu
Yan
Y
Hu
Ting
T
Wang
Zhuo
Z
Xu
Wang-qiong
WQ
Xie
Min
M
D017209:Apoptosis; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm; D005822:Genetic Vectors; D006801:Humans; D020014:K562 Cells; D010957:Plasmids / Q000235:genetics; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics; D014162:Transfection; D051300:Wiskott-Aldrich Syndrome Protein Family / Q000235:genetics* / Q000378:metabolism
D012333:RNA, Messenger; C114864:WASF1 protein, human; D051300:Wiskott-Aldrich Syndrome Protein Family