Synergistic killing effect of arsenic trioxide combined with curcumin on KG1a cells / 中国实验血液学杂志

This study was aimed to explore the effect of arsenic trioxide combined with curcumin on proliferation and apoptosis of KG1a cells and its potential mechanism. The cell survival rate was mesured by MTT; colony formation capacity was examined by methylcellulose colony formation test; flow cytometry was used to analyse the cell surface molecules, cell apoptosis rate and cell cycle; the cell morphology was observed with Wright-Giemsa staining and the protein expression of BCL-2, BAX, PARP was detected by Western blot. The results showed that the phenotype of KG1a cells was CD34(+)CD38(-), while the phenotype of HL-60 cell was CD34(+)CD38(+). The former possessed a stronger colony ability than the latter. Effect of curcumin and arsenic trioxide alone on cell proliferation and inhibition was in dose-dependent manner. Compared with single drug-treatment group, the cell survival rate and colony number were lower, and the apoptosis rate was higher in combined drug-treatment group. Protein expression of BCL-2 and PARP was upregulated, while the protein expression of PARP was downregulated in the combined treatment group. It is concluded that compared with HL-60 cells, KG1a cells are the earlier leukemia stem/progenitor cells. Arsenic trioxide combined with curcumin can effectively inhibit the KG1a cell proliferation and induce apoptosis, which may be associated with the downregulation of BCL-2 and PARP protein expression and the upregulation of BAX protein expression.

Effect of honokiol on proliferation and apoptosis in HL-60 cells and its potential mechanism / 中国实验血液学杂志

This study was aimed to investigate the effect of Honokiol (HNK) on proliferation and apoptosis of acute myeloid leukemia HL-60 cells and its potential mechanism. Inhibitory effect of HNK on the HL-60 cell proliferation was detected by MTT assay. Flow cytometry was used to detect the change of cell cycle and AnnexinV/PI staining was used to detect apoptosis. Western blot was applied to analyze the cell cycle protein (cyclins), cyclin-dependent kinase (CDK), P53, P21, P27, BCL-2, BCL-XL, Bax, caspase-3/9 and proteins for MAPK signal pathway. The results showed that HNK could inhibit the proliferation of HL-60 cells in time- and dose dependent ways. HNK arrested HL-60 cells in G0/G1 phase, and S phase cells decreased significantly (P < 0.05). The expression of cyclin D1, cyclin A, cyclin E and CDK2/4/6 were significantly down-regulated (P < 0.05), the expression of P53 and P21 was significantly upregulated after treating for 24 h with HNK (P < 0.05). After 24 h treatment with HNK, HL-60 cell apoptosis increased significantly with the upregulation of activated caspase-3, -9, BAX expression and the downregulation of BCL-2, BCL-XL expression. The MAPK subfamily, P38 and JNK were not significantly changed, but the expression of MEK1/2-ERK1/2 was significantly downregulated (P < 0.05). It is concluded that HNK arrestes the cells at G0/G1 phase and induces HL-60 cell apoptosis through the intervention of MEK1/2-ERK1/2 signaling pathway.