Eischen C M, Kottke T J, Martins L M, Basi G S, Tung J S, Earnshaw W C, Leibson P J, Kaufmann S H
Department of Immunology, Mayo Clinic, Rochester, MN 55901, USA.
Blood. 1997 Aug 1;90(3):935-43.
The Fas/Fas ligand (FasL) pathway is widely involved in apoptotic cell death in lymphoid and nonlymphoid cells. It has recently been postulated that many chemotherapeutic agents also induce cell death by activating the Fas/FasL pathway. In the present study we compared apoptotic pathways induced by anti-Fas or chemotherapeutic agents in the Jurkat human T-cell leukemia line. Immunoblotting showed that treatment of wild-type Jurkat cells with anti-Fas or the topoisomerase II-directed agent etoposide resulted in proteolytic cleavage of precursors for the cysteine-dependent aspartate-directed proteases caspase-3 and caspase-7 and degradation of the caspase substrates poly(ADP-ribose) polymerase (PARP) and lamin B1. Likewise, affinity labeling with N-(N(alpha)-benzyloxycarbonylglutamyl-N(epsilon)-biotinyllysyl+ ++)aspartic acid [(2,6-dimethyl-benzoyl)oxy]methyl ketone [Z-EK(bio)D-amok] labeled the same five active caspase species after each treatment, suggesting that the same downstream apoptotic pathways have been activated by anti-Fas and etoposide. Treatment with ZB4, an antibody that inhibits Fas-mediated cell death, failed to block etoposide-induced apoptosis, raising the possibility that etoposide does not initiate apoptosis through Fas/FasL interactions. To further explore the relationship between Fas- and chemotherapy-induced apoptosis, Fas-resistant Jurkat cells were treated with various chemotherapeutic agents. Multiple independently derived Fas-resistant Jurkat lines underwent apoptosis that was indistinguishable from that of the Fas-sensitive parental cells after treatment with etoposide, doxorubicin, topotecan, cisplatin, methotrexate, staurosporine, or gamma-irradiation. These results indicate that antineoplastic treatments induce apoptosis through a Fas-independent pathway even though Fas- and chemotherapy-induced pathways converge on common downstream apoptotic effector molecules.
Fas/Fas配体（FasL）途径广泛参与淋巴细胞和非淋巴细胞的凋亡性细胞死亡。最近有人提出，许多化疗药物也通过激活Fas/FasL途径诱导细胞死亡。在本研究中，我们比较了抗Fas或化疗药物在Jurkat人T细胞白血病细胞系中诱导的凋亡途径。免疫印迹显示，用抗Fas或拓扑异构酶II导向剂依托泊苷处理野生型Jurkat细胞，导致半胱氨酸依赖性天冬氨酸导向蛋白酶caspase-3和caspase-7的前体发生蛋白水解切割，以及caspase底物聚（ADP-核糖）聚合酶（PARP）和核纤层蛋白B1降解。同样，用N-（N（α）-苄氧羰基谷氨酰-N（ε）-生物素基赖氨酰 +++）天冬氨酸[（2,6-二甲基-苯甲酰）氧基]甲基酮[Z-EK（bio）D-氨甲环酸]进行亲和标记，在每次处理后标记相同的五种活性caspase，表明抗Fas和依托泊苷激活了相同的下游凋亡途径。用ZB4（一种抑制Fas介导的细胞死亡的抗体）处理未能阻断依托泊苷诱导的凋亡，这增加了依托泊苷不是通过Fas/FasL相互作用启动凋亡的可能性。为了进一步探讨Fas诱导的凋亡与化疗诱导的凋亡之间的关系，用各种化疗药物处理Fas抗性Jurkat细胞。多个独立衍生的Fas抗性Jurkat细胞系在用依托泊苷、阿霉素、拓扑替康、顺铂、甲氨蝶呤、星形孢菌素或γ射线照射后发生凋亡，与Fas敏感的亲本细胞无法区分。这些结果表明，抗肿瘤治疗通过Fas非依赖性途径诱导凋亡，尽管Fas诱导的途径和化疗诱导的途径在共同的下游凋亡效应分子上汇聚。
