OBJECTIVETo understand the action mechanisms of artesunate on inhibiting leukaemia cell line K562 on the molecular level.

METHODThe gene chip was used to detect the expression panel of genes of leukaemia cell line K562 treated by dihydroartemisinin. K562 cells were treated with 1 x 10(-5), 4 x 10(-5), 16 x 10(-5), 64 x 10(-5), 256 x 10(-5) mol x L(-1) dihydroartemisinin for 24 h, and then studied the modality changes by invert microscope. The morphological changes of the nucleons were observed by Hoechst33342/PI staining. The cell cycle were examined by flow cytometry analysis (FCM). Total RNA samples were obtained by TRIzol and were reverse transcribed to the cDNA. The cDNA samples were hybridized to our gene chips. Hybridization signal were collected and analyzed following scanning by Gene Pix 4100A.

RESULTThe numbers of drift cells were increased and the density of cells was decreased under invert microscope after K562 cells were treated with dihydroartemisinin for 24 h. Morphological changes of cell apoptosis such as karyopyknosis and conglomeration were observed by Hoechst 33342/PI staining. Flow cytometric analysis showed that cells were arrested in G2 phase. There were 13 differentially expressed genes identified. Hybridization analysis showed up-regulation of chk1 and down-regulation of PCNA, cyclinB1, cyclinD1, cyclinE1, cdk4, cdk2, E2F1, DNA-PK, DNA-Topo I, mcl-1, jNK, VEGF in the dihydroartemisinin-treated K562 cells.

CONCLUSIONDihydroartemisinin can Inhibit the leukaemia cell line K562 and exert its anti-cancer effect by altering the expression of these genes involved in cell cycle; dihydroartemisinin may act via apoptosis pathway.