乌苯美司增强全反式维甲酸诱导急性早幼粒细胞白血病细胞分化的体外研究

目的探讨氨肽酶N抑制剂乌苯美司（ubenimex）对全反式维甲酸（ATRA）诱导人急性早幼粒细胞白血病（APL）细胞分化的影响及可能机制。方法采用流式细胞术检测细胞表面分化抗原CD11b，四氮唑蓝（NBT）还原实验检测细胞分化；Western blot法检测细胞c—Myc、ERK1／2及P—ERK1/2 、p38MAPK及p—p38MAPK蛋白表达。结果ubenimex单独应用对NB4细胞的NBT还原能力及CD11b表达无明显影响，但ubenimex能增强ATRA诱导NB4细胞的NBT还原能力及CD11b的表达。100μg／mlubenimex能增强10nmol／LATRA诱导原代APL细胞的NBT还原能力。100μg／mlubenimex增强10nmol／LATRA下调NB4细胞c—Myc蛋白的表达；抑制10nmol／LATRA引起的NB4细胞的p38MAPK磷酸化。结论ubenimex能够增强ATRA对APL细胞的诱导分化作用，可能与抑制p38MAPK的磷酸化及对原癌基因c—Myc表达的调控有关。

Experimental study of the enhancement effect of aminopeptidase N inhibitor ubenimex on the differentiation induction activity of all-trans-retinoic acid in acute promyelocytic leukemia cells and its mechanism

OBJECTIVE: To investigate the effect of aminopeptidase N inhibitor ubenimex on differentiation induction of all-trans-retinoic acid (ATRA) in acute promyelocytic leukemia (APL) cells and its mechanism. METHODS: The expression of CD11b was analyzed by flow cytometry and nitroblue-tetrazolium (NBT) reduction assay was performed to determine the cell differentiation of APL cells. The expressions of c-Myc, ERK1/2, p38MAPK protein and the phosphorylation of ERK1/2, p38MAPK protein in NB4 cells were detected by Western blot assay. RESULTS: Ubenimex alone induced no significant changes in NBT reduction activity and CD11b expression but potentiated the differentiation induction activity of ATRA in APL cells. 100 microg/ml of ubenimex could enhance the NBT reduction activity induced by 10 nmol/L of ATRA, intensify the down-regulation of c-Myc protein expression and inhibit the phosphorylation of p38MAPK protein induced by 10 nmol/L of ATRA in NB4 cells. CONCLUSIONS: Ubenimex could potentiate ATRA induced differentiation in APL cells, which may be correlated with the inhibition of p38 MAPK protein phosphorylation and regulation of c-Myc protein expression.