APN/CD13对乌苯美司增强全反式维甲酸诱导急性早幼粒白血病细胞株NB4细胞分化的影响

本研究探讨细胞表面APN/CD13在乌苯美司(bestatin)增强全反式维甲酸(ATRA)诱导急性早幼粒细胞白血病(APL)细胞株NB4细胞分化过程中的作用.采用四氮唑蓝还原实验检测细胞分化;Western blot检测细胞P38MAPK及p-P38MAPK蛋白表达.结果显示:APN/CD13中和抗体WM-15能够完全阻断乌苯美司对ATRA诱导分化作用的增强效应.WM-15能够部分阻断乌苯美司抑制NB4细胞P38 MAPK磷酸化的作用.100μg/ml乌苯美司呈时间依赖性抑制APL细胞株NB4细胞及MR2细胞的P38MAPK磷酸化水平,l00 μg/ml乌苯美司对CD13表达低下的K562细胞的P38 MAPK磷酸化水平无明显影响.100μg/ml乌苯美司不能恢复MR2细胞及难治复发患者原代APL细胞对ATRA的敏感性.结论:氨肽酶N/CD13抑制剂乌苯美司可能通过细胞表面APN/CD13分子的介导抑制NB4细胞P38 MAPK的磷酸化,从而增强ATRA诱导NB4细胞分化的作用.

Effect of APN/CD13 on bestatin enhancing all-trans-retinoic acid-inducing differentiation in NB4 cells

This study was purposed to investigate the effect of aminopeptidase N/CD13 on bestatin enhancing all-trans-retinoic acid（ATRA）-inducing differentiation in NB4 cells.The nitroblue-tetrazolium（NBT） reduction assay was performed to determine the differentiation of NB4 cells,MR2 cells and primary APL blasts.The expression of P38 MAPK protein and the phosphorylation of P38 MAPK protein in NB4,MR2 and K562 cells were detected by Western blot.The results showed that pre-incubation with 5 μg/ml WM-15 blocked the enhancement effect of bestatin on differentiation of NB4 cells induced by ATRA.5 μg/ml CD13 antibody WM-15 partly blocked the inhibition of bestatin on the phosphorylation of P38 MAPK in NB4 cells.100 μg/ml bestatin inhibited the phosphorylation of P38 MAPK in NB4 cells and MR2 cells in a time-dependent manner.100 μg/ml bestatin had no effect on the phosphorylation of P38 MAPK in K562 cells with low level of CD13.Bestatin could not restore the sensitivity to ATRA in ATRA-resistant primary APL blasts and MR2 cells.It is concluded that aminopeptidase N/CD13 inhibitor bestatin may enhance the differentiation-inducing activity of ATRA through inhibiting the phosphorylation of P38 MAPK in NB4 cells mediated by the cell surface APN/CD13.