McGahon A J, Costa Pereira A P, Daly L, Cotter T G
Department of Biochemistry, University College, Cork, Ireland.
Br J Haematol. 1998 Jun;101(3):539-47. doi: 10.1046/j.1365-2141.1998.00745.x.
The potential role of the Fas (CD95/APO-1) receptor/ligand system in chemotherapeutic drug-induced apoptosis was examined in a number of human leukaemic cell lines. Flow cytometric profiles of doxorubicin-treated HL-60, K562, U937 and Jurkat cells failed to show any significant increase in Fas or Fas ligand expression over 24 h, despite the induction of significant levels of apoptosis in these cells. Although preincubation of human leukaemic cells with a neutralizing anti-Fas IgG antibody blocked anti-Fas IgM-induced apoptosis, this strategy failed to inhibit chemotherapeutic drug-induced apoptosis. To determine whether recruitment of the Fas/Fas ligand complex during drug-induced apoptosis was a cell-specific event we utilized the CEM cell line. Doxorubicin treatment of CEM cells over 24 h failed to show any up-regulation in Fas or Fas ligand protein levels as detected by flow cytometry. Furthermore, neutralizing anti-Fas IgG Ab failed to inhibit chemotherapeutic drug-induced apoptosis in CEM cells. The present studies do, however, demonstrate a role for anti-Fas IgM Ab in producing a cytotoxic synergistic effect when used in combination with chemotherapeutic drugs. Low-dose anti-Fas IgM treatment in combination with doxorubicin, methotrexate, camptothecin and etoposide produced an augmented cytoxicity in CEM cells. Taken together these observations demonstrate that although recruitment of the Fas/APO-1/CD95 receptor/ligand system is not a necessary requirement for chemotherapeutic drug-induced apoptosis, combination of anti-Fas IgM and drug treatment produces a synergistic cytotoxic effect which may prove useful in the treatment of human leukaemias.
在多种人类白血病细胞系中研究了Fas（CD95/APO-1）受体/配体系统在化疗药物诱导的细胞凋亡中的潜在作用。阿霉素处理的HL-60、K562、U937和Jurkat细胞的流式细胞术分析结果显示，尽管这些细胞中诱导了显著水平的细胞凋亡，但在24小时内Fas或Fas配体的表达未出现任何显著增加。虽然用中和性抗Fas IgG抗体对人类白血病细胞进行预孵育可阻断抗Fas IgM诱导的细胞凋亡，但该策略未能抑制化疗药物诱导的细胞凋亡。为了确定在药物诱导的细胞凋亡过程中Fas/Fas配体复合物的募集是否是细胞特异性事件，我们使用了CEM细胞系。流式细胞术检测结果显示，阿霉素处理CEM细胞24小时后，Fas或Fas配体蛋白水平未出现任何上调。此外，中和性抗Fas IgG抗体未能抑制CEM细胞中化疗药物诱导的细胞凋亡。然而，本研究确实证明了抗Fas IgM抗体与化疗药物联合使用时在产生细胞毒性协同效应方面的作用。低剂量抗Fas IgM与阿霉素、甲氨蝶呤、喜树碱和依托泊苷联合处理可增强CEM细胞的细胞毒性。综上所述，这些观察结果表明，虽然Fas/APO-1/CD95受体/配体系统的募集不是化疗药物诱导细胞凋亡的必要条件，但抗Fas IgM与药物联合治疗可产生协同细胞毒性效应，这可能对人类白血病的治疗有用。
