尿多酸肽联合环腺苷酸诱导维甲酸耐药急性早幼粒细胞白血病细胞凋亡的实验研究

In vitro study of the effects of CDA- Ⅱ combined with cAMP on apoptosis induction in retinoic acid resistant acute promyelocytic leukemia cells

目的探讨尿多酸肽（CDA-Ⅱ）单独和联合环腺苷酸（cAMP）对维甲酸耐药的急性早幼粒细胞白血病（APL）细胞的作用。方法以维甲酸耐药的APL细胞株NIM—R2为体外模型，观察使用CDA—Ⅱ单独和联合cAMP处理前后细胞生长和形态的改变；同时利用流式细胞术检测细胞的凋亡特征，包括细胞内DNA含量的分布、亚二倍体（sub—G1）细胞群所占比例、凋亡相关蛋白Bcl-2的表达水平等；并通过电泳鉴定因基因组DNA非随机性降解导致的梯状DNA。结果CDA-Ⅱ可以通过降低细胞内抗凋亡蛋白Bcl-2的水平，诱导NB4-R2细胞发生凋亡；cAMP则能显著加强CDA—Ⅱ的这一促凋亡作用1g／LCDA-Ⅱ联合100μmol／LcAMP共同处理NB4-R2细胞48h和72h时Bcl-2阳性细胞比例分别下降至（15．1±4．8）％和（7．3±2．9）％。100μmol／L cAMP单独作用可使MB4-R2细胞的Bcl-2阳性率由（92．0±0．6）％下降至（75．3±2．0）％。结论尿多酸肽CDA—Ⅱ联合cAMP对于维甲酸耐药的APL细胞株具有强烈的诱导凋亡效应。

Objective To investigate the effects of CDA- Ⅱ alone or combined with cAMP on the retinoic acid （RA）-resistant acute promyelocytic leukemia （APL） cells. Methods The RA-resistant cell line NB4-R2 was used as an in vitro model and treated with CDA- Ⅱ alone or in combination with cAMP. Cell apoptosis was assessed by morphology observation, distribution of cellular DNA contents and sab-G1 cell population. The level of Bcl-2 was detected by flow cytometry, DNA ＂ladder＂ was detected by agarose-electrophoresis. Results CDA- Ⅱ could induce NB4-R2 cell apoptosis through decreasing the level of cellular anti-apoptotic protein Bcl-2. cAMP could significantly enhance the role of CDA- Ⅱ. Bcl-2 positive cell rates decreased to （15.1±4.8）% and （7.3 ±2.9）% in NB4-R2 cells treated with 1 mg/ml CDA-Ⅱ plus 100 μmol/L cAMP for 48 h and 72 h, respectively. While 100 μmol/L of cAMP could decrease Bcl-2 positive NB4-R2 cells from （92.0± 0.6） % to （75.3 ± 2.0） %. Conclusions CDA-Ⅱ combined with cAMP could exert potent apoptotic effect on RA-resistant APL cells.