OBJECTIVETo explore the apoptosis-inducing effects of isoalantolactone on chronic myeloid leukemia drug-resistant cell line K562/A02.

METHODSK562/A02 cells were treated with 0, 6.25, 12.5, 25, 50, and 100 µmol/L isoalantolactone for 12 h, 24 h, and 48 h. The cell viability was analyzed with CCK8 assay. The effects of isoalantolactone on mitochondrial membrane potential (MMP), reactive oxygen species(ROS) and apoptosis of K562/A02 cells were measured by flow cytometry. The apoptosis related proteins were analyzed by using Western blot after treatment with isoalantolactone.

RESULTSIsoalantolactone effectively inhibited the proliferation of K562/A02 cells in dose- and time-dependent manner, the ICvalue of isoalantolactone in K562/A02 cells at 24 h was about (15±1.42) µmol/L (P<0.05). Flow cytometric analysis displayed that after treatment of K562/A02 cells with 0, 10, 15, and 20 µmol/L of isoalantolactone, apoptotic rate were 1.35±0.52%, 18.07±4.03%, 27.53±3.01%, and 34.99±4.91%, respectively, mitochondrial membrane potential was 96.42±3.59%, 74.25±6.91%, 60.97±5.69%, and 31.28±4.95%, respectively. Otherwise, isoalantolactone induced accumulation of intracellular reactive oxygen species(ROS) in K562/A02 cells (5.03±1.43%, 17.55±3.85%, 32.09±3.23%, and 44.38±5.92%). Meanwhile, isoalantolactone significantly down-regulated the expression of BCL-2 protein and up-regulated the expression of BAX, cytochrome C, cleaved-caspase-9, cleaved-caspase-3, and cleaved-PARP.

CONCLUSIONIsoalantolactone significantly inhibits K562/A02 cell proliferation mainly via caspase-dependent apoptotic pathway.