[Enhancive effect of HMGB1 gene silence on adriamycin-induced apoptosis in K562/A02 drug resistance leukemia cells].
OBJECTIVE
To investigate the effect of high mobility group boxl (HMGBI) gene silence on adriamycin (ADM)-induced apoptosis in K562/A02 drug resistance leukemia cells.


METHODS
K562/ A02 cells were transient transfected with HMGB1- small interference RNA(siRNA) vector, and the levels of HMGB1 gene differential expression pre-and post-transfection were measured by RT-PCR and Western blotting. 50% inhibition concentration (IC50) of ADM on K562/A02 was determined by WST-8 assay. Cell apoptosis was assessed by flow cytometry. The release of Smac/DIABLO from the mitochondria to the cytoplasm was assayed by Western blotting. Activity of Caspase-3 was assayed with a Caspase Colorimetric Assay Kit.


RESULTS
(1) The HMGB1 expression at mRNA and protein levels in HMGB1 siRNA transfected K562/A02 cells were decreased by 86% and 71% respectively compared with control. (2) Suppression of HMGB1 by siRNA in K562/A02 cells resulted in a reversal of the resistance to ADM, and decreased IC50 from (4.83 +/- 0.08) microg/ml to (1.33 +/- 0.10) microg/ml. 1 microg/ml and 5 microg/ml of ADM treatment increased cell apoptotic rate by 27% and 32% respectively. (3) HMGB1 suppression in K562/A02 cells significantly promoted ADM- induced Smac/DIABLO release from the mitochondria to the cytoplasm, and increased the activities of Caspase-3.


CONCLUSIONS
HMGB1 gene silence can enhance sensitivity of K562/A02 cells to ADM and reverse cell resistant to ADM.
Xie
Min
M
Department of Pediatrics, Xiangya Hospital, Central South University, Changsha 410008, China.
Kang
Rui
R
Yu
Yan
Y
Zhu
Shan
S
He
Yu-Lei
YL
Xu
Wang-Qiong
WQ
Tang
Dao-Lin
DL
Cao
Li-Zhi
LZ
D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D004317:Doxorubicin / Q000494:pharmacology*; D020868:Gene Silencing; D024243:HMGB1 Protein / Q000235:genetics*; D006801:Humans; D020014:K562 Cells; D034741:RNA, Small Interfering / Q000235:genetics*
D024243:HMGB1 Protein; D034741:RNA, Small Interfering; D004317:Doxorubicin