目的：探讨小白菊内酯（parthenolide，PTL）对CD34+CD38- KG-1a白血病细胞的增殖、Bcl-2表达及其被同种异体NK（allo-NK）细胞杀伤敏感性的影响。方法：免疫磁珠法从KG-1a细胞中分离CD34+CD38- KG-1a细胞。XTT法检测PTL对CD34+CD38-白血病细胞增殖的影响，Real-time PCR和Western blotting分别检测PTL对CD34+CD38- KG-1a细胞Bcl-2 mRNA和蛋白表达的影响，LDH释放法观察PTL对CD34+CD38- KG-1a细胞被allo-NK细胞杀伤敏感性的影响。结果：PTL对CD34+CD38- KG-1a细胞增殖的抑制呈剂量（2.5~80 μmol/L)依赖性。PTL浓度为2.5 μmol/L时，PTL组CD34+CD38- KG-1a细胞的增殖抑制率显著高于对照组\[（4.89±1.07）% vs 0，P<0.01\]；PTL杀伤CD34+CD38- KG-1a细胞的IC50为20 μmol/L；PTL组CD34+CD38-KG-1a细胞Bcl-2 mRNA \[（0.105±0.007）vs（0.307±0.013），P＜0.01\]与蛋白表达均显著低于对照组。在效靶比为10∶1，20∶1和40∶1时，allo-NK细胞对PTL组CD34+CD38- KG-1a细胞杀伤率逐步升高，且均高于阴性（无PTL处理）对照组\[(19.76±1.01)%，(30.14±0.96)%和(51.48±3.15)% vs (12.50±1.42)%，(16.90±0.93)%和(31.70±1.53)%（均P<0.01）\]；效靶比为40∶1时，allo-NK细胞对PTL组细胞的杀伤效率显著高于阳性（Bcl-2抑制剂ABT-737处理）对照组\[（51.48±3.15）% vs （43.08±2.81）%，P<0.05\]。结论：PTL能抑制CD34+CD38-KG-1a细胞的增殖并增强其被allo-NK细胞杀伤的敏感性，这可能与PTL下调Bcl-2的表达有关。

Objective:To investigate the effects of parthenolide (PTL) on the proliferation, bcl-2 expression and susceptibility of CD34+CD38- KG-1a leukemia cells to cytotoxicity of allogeneic natural killer cells (allo-NK cells). Methods: CD34+CD38- KG-1a cells were separated from KG-1a cells by magnetic activated cell sorting (MACS). The effect of PTL on the proliferation of CD34+CD38- KG-1a cells was assessed by XTT assay. The expression of Bcl-2 mRNA and protein in CD34+CD38- KG-1a cells regulated by parthenolide were evaluated by real-time reverse transcriptase-polymerase chain reaction analysis (RT-PCR) and Western blotting, respectively. LDH-releasing assay was performed to observe the effect of PTL on the cytotoxicity of allo-NK cells against CD34+CD38- KG-1a cells. Results: PTL inhibited the proliferation of CD34+CD38- KG-1a cells with a concentration-dependent manner. As the concentration of PTL was 2.5 μmol/L, the cellular proliferation inhibition rate of CD34+CD38- KG-1a cells in PTL group was significantly higher than that of the control group (\[4.89±1.07\]% vs 0, P＜0.01). The IC50 of PTL to inhibit the proliferation of CD34+CD38- KG-1a leukemia cells was 20 μmol/L. By treated with 20 μmol/L PTL, the expression of bcl-2 mRNA (\[0.105±0007\] vs \[0.307±0.013\], P＜0.01) and protein in CD34+CD38- KG-1a cells were significantly lower than those of the control group. At effect-to-target ratio of 10∶1, 20∶1 and 40∶1, the cytotoxicity rate of allo-NK cell against CD34+CD38- KG-1a cells in the PTL group and in the positive control group was increasing and was higher than that of the negative control group (\[19.76±1.01\]%, \[30.14±0.96\]% and \[51.48±3.15\]% vs \[12.50±1.42\]%, \[16.90±093\]% and \[31.70±1.53\]%; all P<0.01). In addition, at effect-to-target ratio of 40∶1, the cytotoxicity rate of allo-NK cell against CD34+CD38- KG-1a cells in the PTL group was significantly higher than that of the positive control group (\[5148±315\]% vs \[43.08±2.81\]%, P<0.05). Conclusion: PTL can suppress the proliferation of CD34+CD38- KG-1a cells and enhance its susceptibility to the cytotoxicity of allo-NK cells, which may be related with the down-regulation of Bcl-2 by PTL．

广东省医学科研基金资助项目（No. A2012133），广东省自然科学基金资助项目（No.S2012040007108）