Roth W, Fontana A, Trepel M, Reed J C, Dichgans J, Weller M
Department of Neurology, University of Tübingen, School of Medicine, Germany.
Cancer Immunol Immunother. 1997 Mar;44(1):55-63. doi: 10.1007/s002620050355.
Malignant glioma cells are susceptible to CD95(Fas/APO-)-mediated apoptosis triggered by agonistic antibody. Here we examined the proapoptotic effects of the natural CD95 ligand, a cytotoxic cytokine homologous to tumor necrosis factor, on malignant glioma cell lines LN-229, LN-308 and T98G. We assessed whether glioma cell killing is synergistically enhanced by cotreatment with CD95 ligand and chemotherapeutic agents, including doxorubicin, carmustine, vincristine, etoposide, teniposide, 5-fluorouracil and cytarabine. Synergy was examined at low concentrations of cytotoxic drugs and CD95 ligand with a defined effect level (IC15). Short-term-cytotoxicity assays showed prominent killing of the glioma cells by CD95 ligand but not by the drugs at relevant concentrations. CD95 ligand induced apoptosis in the acute toxicity paradigm was augmented by doxorubicin and vincristine. Growth-inhibition assays revealed prominent synergy between CD95 ligand and all drugs examined. The best synergy was obtained with CD95 ligand and doxorubicin, vincristine or teniposide. The strong synergistic antiproliferative effects were observed at much lower concentrations of CD95 ligand and cytotoxic drugs than the moderate synergistic acute cytotoxic effects. All cell lines examined express the Bcl-2 protein. LN-229 has partial wild-type p53 activity. T98G has mutant p53, LN-308 has a deleted p53 gene and lacks p53 protein expression. Thus, synergistic effects of CD95 ligand and cytotoxic drugs were observed in cell lines exhibiting two features thought to play a role in the chemoresistance of human malignant glioma cells: loss of wild-type p53 activity and acquisition of bcl-2 expression. Ectopic expression of murine bcl-2 conferred partial protection from CD95 ligand and drugs when administered alone but did not interfere with the mechanisms underlying the synergistic effects of CD95 ligand and chemotherapeutic drugs.
恶性胶质瘤细胞对激动性抗体触发的CD95（Fas/APO-）介导的凋亡敏感。在此，我们研究了天然CD95配体（一种与肿瘤坏死因子同源的细胞毒性细胞因子）对恶性胶质瘤细胞系LN-229、LN-308和T98G的促凋亡作用。我们评估了CD95配体与化疗药物（包括阿霉素、卡莫司汀、长春新碱、依托泊苷、替尼泊苷、5-氟尿嘧啶和阿糖胞苷）联合治疗是否能协同增强对胶质瘤细胞的杀伤作用。在低浓度的细胞毒性药物和CD95配体以及确定的效应水平（IC15）下检测协同作用。短期细胞毒性试验显示，在相关浓度下，CD95配体能显著杀伤胶质瘤细胞，而药物则不能。阿霉素和长春新碱增强了CD95配体在急性毒性模式下诱导的凋亡。生长抑制试验显示，CD95配体与所有检测药物之间存在显著的协同作用。CD95配体与阿霉素、长春新碱或替尼泊苷的协同作用最佳。与中等协同急性细胞毒性作用相比，在低得多的CD95配体和细胞毒性药物浓度下就观察到了强烈的协同抗增殖作用。所有检测的细胞系均表达Bcl-2蛋白。LN-229具有部分野生型p53活性。T98G具有突变型p53，LN-308具有缺失的p53基因且缺乏p53蛋白表达。因此，在表现出被认为在人类恶性胶质瘤细胞化疗耐药中起作用的两个特征的细胞系中观察到了CD95配体与细胞毒性药物的协同作用：野生型p53活性丧失和bcl-2表达获得。单独给药时，小鼠bcl-2的异位表达赋予了对CD95配体和药物的部分保护作用，但不干扰CD95配体与化疗药物协同作用的潜在机制。
