Enhancive effect of HMGB1 gene silence on adriamycin-induced apoptosis in K562/A02 drug resistance leukemia cells / 中华血液学杂志

ABSTRACT

<p><b>OBJECTIVE</b>To investigate the effect of high mobility group boxl (HMGBI) gene silence on adriamycin (ADM)-induced apoptosis in K562/A02 drug resistance leukemia cells.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>(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.</p><p><b>CONCLUSION</b>HMGB1 gene silence can enhance sensitivity of K562/A02 cells to ADM and reverse cell resistant to ADM.</p>