Ribrag V, Massade L, Faussat A M, Dreyfus F, Bayle C, Gouyette A, Marie J P
Service de Médecine C, Institut Gustave-Roussy, Villejuif, France.
Leukemia. 1996 Dec;10(12):1944-9.
Peripheral blood samples from 18 patients with chronic lymphocytic leukemias (CLL) who were either untreated but who were later sensitive to chlorambucil (CLL S) or resistant to a combination containing doxorubicin, vincristine, cyclophosphamide and prednisone (CLL R) were studied for glutathione system, P-glycoprotein, PCNA and topoisomerase II expression. P-glycoprotein expression detected by an immunocytochemical technique using MRK 16 antibody was present at the same level in CLL S and CLL R. The percentage of cells positive for P-gp was below 5% in all samples tested. Topoisomerase IIalpha level was quantified by Western blot analysis. None of the 18 CLL samples had detectable topoisomerase IIalpha protein. In addition, 12 CLL were tested for PCNA staining and no samples had more than 1% of positive cells at immunocytochemical detection indicating that CLL cells were not engaged in the cell cycle. Some differences were found between CLL S and CLL R in the glutathione system. Glutathione concentration (GSH) and GST activity was the same in CLL S and CLL R. The glutathione-S-transferase (GST) isoenzyme profile was different in the two CLL groups. The mean GST-pi and GST-alpha quantitation were twice as high as in CLL R compared to CLL S, but this difference did not reach statistical significance because of large variations between CLL samples. A significant correlation was observed between GST-pi expression and GST activity using CDNB as the substrate. GST-mu was detected in only one of seven CLL before therapy and in six of 11 resistant to chemotherapy. No correlation was found between P-glycoprotein expression, GST activity and the different GST isoenzymes studied. These results suggest that the glutathione system could play a role in the resistance of anticancer agents in chronic lymphocytic leukemia. The role of the other drug resistance mechanisms (P-glycoprotein and topoisomerase IIalpha) seems to be of limited importance.
对18例慢性淋巴细胞白血病（CLL）患者的外周血样本进行了研究，这些患者要么未经治疗但后来对苯丁酸氮芥敏感（CLL S），要么对包含阿霉素、长春新碱、环磷酰胺和泼尼松的联合治疗耐药（CLL R），研究内容包括谷胱甘肽系统、P-糖蛋白、增殖细胞核抗原（PCNA）和拓扑异构酶II的表达。使用MRK 16抗体通过免疫细胞化学技术检测到的P-糖蛋白表达在CLL S和CLL R中处于相同水平。在所有测试样本中，P-糖蛋白阳性细胞的百分比均低于5%。通过蛋白质印迹分析对拓扑异构酶IIα水平进行定量。18例CLL样本中均未检测到拓扑异构酶IIα蛋白。此外，对12例CLL进行了PCNA染色检测，在免疫细胞化学检测中，没有样本的阳性细胞超过1%，这表明CLL细胞未进入细胞周期。在谷胱甘肽系统方面，CLL S和CLL R之间存在一些差异。CLL S和CLL R中的谷胱甘肽浓度（GSH）和谷胱甘肽S-转移酶（GST）活性相同。两个CLL组的谷胱甘肽S-转移酶（GST）同工酶谱不同。与CLL S相比，CLL R中GST-π和GST-α的平均定量高出两倍，但由于CLL样本之间差异较大，这种差异未达到统计学意义。以1-氯-2,4-二硝基苯（CDNB）为底物时，观察到GST-π表达与GST活性之间存在显著相关性。在7例治疗前的CLL中仅检测到1例GST-μ，在11例化疗耐药的CLL中有6例检测到GST-μ。在所研究的P-糖蛋白表达、GST活性和不同GST同工酶之间未发现相关性。这些结果表明，谷胱甘肽系统可能在慢性淋巴细胞白血病对抗癌药物的耐药性中起作用。其他耐药机制（P-糖蛋白和拓扑异构酶IIα）的作用似乎有限。
