隐丹参酮对白血病细胞伊马替尼敏感性和P-糖蛋白表达作用的研究

Effect of cryptotanshinone on imatinib sensitivity and P-glycoprotein expression of chronic myeloid leukemia cells

隐丹参酮是丹参中主要的脂溶性活性化合物之一,对白血病等多种恶性肿瘤有显著的抑制作用,并可有效提高伊马替尼的化疗效果,但其发挥功能的分子机制仍未阐明。该文利用白血病细胞K562及其伊马替尼耐药株K562-R,系统研究了隐丹参酮对细胞伊马替尼的敏感性和P-糖蛋白表达的影响。利用MTT法检测隐丹参酮对伊马替尼增殖抑制功能的影响,Annexin V-FITC/PI双标记流式细胞术检测细胞凋亡率的变化,Western blot检测细胞凋亡调控蛋白Caspase-3,Caspase-9,PARP的活性变化情况;梯度浓度的隐丹参酮处理细胞后,Western blot和流式细胞仪检测细胞中P-糖蛋白的表达水平变化,高效液相色谱法检测伊马替尼的胞内药物浓度的变化。结果隐丹参酮预处理后,显著增强了伊马替尼对K562和K562-R细胞的增殖抑制和凋亡诱导作用,细胞的促凋亡蛋白Caspase-3,Caspase-9,PARP的降解产物表达水平显著提高,与对照组相比有显著性差异(P<0.01)。而隐丹参酮对白血病细胞中P-糖蛋白表达和伊马替尼胞内药物积累没有影响。结果表明隐丹参酮可提高CML细胞对伊马替尼的化疗敏感性,其作用机制不依赖于对P-糖蛋白表达的抑制和胞内药物浓度的提高。

Cryptotanshinone （CPT）, a lipid soluble active compound in Salvia miltiorrhiza, has a significant inhibitory effect on multiple malignant tumors, e.g. chronic m.yeloid leukemia （CML） ceils and can effectively enhance imatinib＇s chemotherapeutic effect. However, its functional molecular mechanism remained unclear. In this experiment, the authors conducted a systematic study on the effect of CPT on the imatinib sensitivity and P-glycoprotein （P-gp） expression in CML cells by using CML cells K562 and imatinib persister K562-R. The MTT assays were performed to determine CPT＇s impact on the inhibitory effect of imatinib. Annexin V-FITC/PI staining analysis was used to detect the changes in the cell apoptosis rate. The active changes in apoptosis regulatory proteins Caspase-3, Caspase-9 and PARP were determined by Western blot. After the cells were pretreated with the gradient concentration of CPT, the expression of P-gp was analyzed by Western blot and flow cytometry. The changes in intracellular concentrations of imatinib were determined by HPLC analysis. The results indicated that the pretreatment with CPT significantly increased the proliferation inhibiting and apoptosis inducing effects of imatinib on K562 and K562-R cells as well as the degradation product expression of pro-apoptotic proteins Caspase-3, Caspase-9 and PARP, with a significant difference with the control group （P 〈 0.01 ）. However, CPT showed no impact on the P-gp expression in CML cells and the intracellular concentrations of imatinib. In summary, the findings suggested that CPT enhanced the sensitivity of CML cells to imatinib. Its mechanism is not dependent on the inhibition in P-gp expression and the in- crease in intracellular drug concentration.