六亚甲基二乙酰胺诱导HL-60细胞分化及其分子机制的研究

本研究探讨六亚甲基二乙酰胺（HMBA）对髓系白血病HL-60细胞分化的作用及其分子机制。应用MTT比色法观察不同浓度HMBA在不同时间点对细胞增殖的抑制作用，采用Wright—Giemsa染色观察细胞形态学变化，运用流式细胞仪测定细胞分化抗原CD11b的表达，并进行细胞周期分析，半定量RT—PCR分析c-myc、mad1、p21、p27、hTERT、HDAC1基因mRNA的表达。结果表明：HL-60细胞经不同浓度（0．5、1、2mmol/L）HMBA处理后细胞增殖受到较明显的抑制，并随时间延长、剂量增大抑制作用明显增强。HL-60细胞经2mmol／L HMBA处理后，细胞形态学上趋于分化成熟，细胞停滞于G0／G1期；CD11b表达显著增高；c-myc、hTERT mRNA表达显著下调，mad1、p21、p27mRNA表达显著上调，而HDAC1 mRNA表达无明显变化。结论：HMBA能诱导HL-60细胞分化，其分子机制可能是通过调节c-myc／mad1开关引起p21、p27上调，并且下调hTERT mRNA表达，与HDAC1活性抑制无关。

Molecular Mechanism Underlying Differentiation of HL-60 Cells Induced by Hexamethylene Bisacetamid

The objective of this study was to investigate the effect of hexamethylene bisacetamid(HMBA) on differentiation of HL-60 cells and its possible molecular mechanism.HL-60 cells were co-cultured with different concentrations of HMBA(0.5,1,2 mmol/L) for 4 days,then the proliferation was assayed by MTT at different time points.Wright-Giemsa staining was used to observe the change in morphology.Cell differentiation antigen CD11b expression and the altered distribution of cell cycle in HL-60 induced by HMBA were analyzed by flow cytometry.The expressions of c-myc,mad1,p21,p27,hTERT and HDAC1 mRNA were detected by RT-PCR.The results indicated that the proliferation of HL-60 cells was inhibited by HMBA in a time-and-dose-dependent manner.Upon 2 mmol/L HMBA treatment,the HL-60 cells arrested at G0/G1 phase and differentiated into granular line in morphology,with the up-regulation of CD11b expression.The expression of c-myc and hTERT mRNA obviously down-regulated,the expression of p21,p27 and mad1 mRNA up-regulated,while there was no change of the expression of hTERT mRNA.It is concluded that effect of HMBA on the differentiation of HL-60 cells may partly contribute to switch from c-myc to mad1 expression,to up-regulate expressions of p21 and p27 mRNA,and down-regulate hTERT mRNA expression,while there is no relation with the expression of HDAC1 mRNA.