FTI-277抑制急性髓系白血病细胞增生及增强三氧化二砷诱导细胞凋亡的作用

Study on the mechanisms of FTI-277 inhibiting proliferation of acute myeloid leukemia cells and enhancing apoptosis induced by As2O3

目的研究法尼基转移酶抑制剂FTI-277单独或联合三氧化二砷（As2O3）对急性髓系白血病（AML）细胞增生和凋亡的影响及其作用机制。方法以HL-60细胞株、31例初治AML患者骨髓标本为研究对象，用四甲基偶氮唑蓝（MTT）法检测细胞增生，用流式细胞术检测细胞周期、磷酸化ERK1／2表达，用AnnexinV-FITC法、DNA琼脂糖凝胶电泳检测细胞凋亡。结果FTT-277可明显抑制AML细胞增生，对正常细胞无明显抑制增生作用。FTI-277使AML细胞G2／M期百分数显著升高，但亚G1期细胞百分数无明显变化。FTI-277显著下调AML细胞磷酸化ERK1／2的表达，但不影响正常细胞表达。联合组与单用组相比，AML细胞凋亡率明显增高，并可检出梯状DNA条带。结论FTI—277通过阻断AML细胞ERK／MAPK途径，使细胞发生G2／M期阻滞，抑制细胞增生。FTI-277可增强As2O3对AML细胞的凋亡诱导作用。

Objective To investigate the mechanisms of farnesyhransferase inhibitor FTI-277 inhibiting proliferation of acute myeloid leukemia （AML） cells and enhancing apoptosis induced by As2O3. Methods HL-60 cells and bone marrow mononuclear cells （BMMNCs） from 31 AML patients at diagnosis were examined. Cell proliferation was determined by MTT test. Cell cycle and the expression of phospho-ERK1/2 were detected by flow cytometry. Cell apoptosis was determined by DNA agrose gel electrophoresis and annexinV-FiTC/PI double-staining. Results FTI-277 inhibited proliferation of AML cells. However, this inhibitor had little effect on proliferation of normal cells. Incubation with FTI-277 led to an increase of AML cells in G2/M, whereas the sub-G1 fraction remained unchanged. Incubation of AML cells with FTI-277 decreased the expression of phospho-ERK1/2, where the expression of phospho-ERK1/2 in normal cells were unaffected by FTI-277. In the combination group, the percentage of apoptosis was increased with increasing concentration of FTI-277 and the apoptosis ladders were readily observed. Furthermore, FTI-277 and As2O3 in combination significantly induced apoptosis of AML cells compared with either FTI-277 or As2O3. Conclusion FTI-277 exerts proliferation inhibition on AML cells by inhibiting constitutive ERK/MAPK activation and resulting in a G2/M block. FTI-277 doesn＇t inhibit proliferation of normal cells with low steady-state levels of ERK/MAPK activity. FTI-277 can enhance apoptosis induced by As2O3.