Alantolactone inhibits the proliferation of K562/ADR cells through regulating expression of cell cycle-related proteins

Abstract

Objective To investigate the effects of alantolactone on cell proliferation, cell-cycle and cell cycle-related proteins in human chronic myelogenous leukemia drug-resistant cell line K562/ADR. Methods K562/ADR cells were treated with 0, 1.0, 2.0, 4.0, 6.0, 8.0, and 10.0 μmol/L of alantolactone for 12, 24 and 48 h, with its cell viability analyzed by MTT assay. Flow cytometry was used to examine the effect of alantolactone on the cell-cycle of K562/ADR cells. The cell cycle-related proteins were analyzed by using Western blot after treatment with alantolactone. Results The results of MTT showed that alantolactone effectively inhibited the proliferation of K562/ADR cells in dose and time-dependent way, and the IC50 value of alantolactone in K562/ADR cells was about 5 μmol/L. Flow cytometric analysis displayed that alantolactone could arrest cell cycle at G2/M phase. The percentage of accumulated cells in the G2/M phase was increased from (15.8±1.7) % in the control group to (21.0±2.4) %, (26.4±2.7) %, and (30.1±3.9) % in cells treated with 2.5, 5.0, and 7.5 μmol/L of alantolactone for 24 h, respectively(P < 0.05). Alantolactone significantly decreased the expression of CDK1 and CyclinB1 and increased the expression of cyclin-dependent kinase inhibitor p21. Meanwhile, the treatment of K562/ADR with alantolactone led to a dose-dependent decrease in bcr-abl protein levels. Conclusion Alantolactone can significantly inhibit the proliferation and cell-cycle arrest in G2/M phase of K562/ADR cells, in which mechanism may be associated with the regulation of cell cycle-related proteins and downregulation of bcr-abl protein. Key words: Alantolactone; Leukemia; Cell proliferation; Cell cycle