Phosphorylation of Fas-associated death domain contributes to enhancement of etoposide-induced apoptosis in prostate cancer cells
Phosphorylation of Fas-associated death domain contributes to enhancement of etoposide-induced apoptosis in prostate cancer cells
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DOI：
10.1111/j.1349-7006.2002.tb01219.x
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发表时间：
2002-10-01
期刊：
影响因子：
--
通讯作者：
Konishi, N
中科院分区：
文献类型：
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作者：
Shimada, K;Nakamura, M;Konishi, N
Fas相关死亡结构域（FADD）在Fas（CD 95/APO-1）介导的细胞凋亡中起着重要的衔接分子作用，并参与抗癌药物诱导的细胞毒性。我们用足叶乙甙治疗了三种人前列腺癌细胞系，足叶乙甙是一种对包括前列腺癌在内的各种肿瘤具有活性的拓扑异构酶II抑制剂。我们发现，FADD的过度表达通过快速激活c-Jun氨基末端激酶（JNK）和随后的caspase 3来敏化依托泊苷诱导的细胞凋亡。此外，FADD在丝氨酸194处的磷酸化与这种致敏作用一致。用半胱天冬酶3抑制剂N-乙酰-Asp-Glu-Val-Asp-醛（DEVD-CHO）或过表达促分裂原活化蛋白激酶激酶（MKK）7或Bcl-xL治疗可取消FADD介导的对依托泊苷诱导的细胞凋亡的敏感性。此外，用半胱天冬酶8抑制剂苄氧基-羰基-Val-Ala-Asp-氟甲基酮（z-IETD-fetoxin）或来自马疱疹病毒2型E8的病毒FLICE/半胱天冬酶-8-抑制蛋白（FLIP）过表达治疗也具有抑制作用，支持主要参与半胱天冬酶8依赖性线粒体途径。有趣的是，FADD被磷酸化，依托泊苷诱导的JNK/caspase激活和凋亡在G2/M转换被逮捕的细胞中增强，但不是在那些过度表达突变FADD，其中194丝氨酸被丙氨酸取代。我们的研究结果表明，磷酸化的FADD依赖性激活JNK/caspase途径在前列腺癌细胞对依托泊苷诱导的凋亡的敏感性中起着关键作用。
Fas-associated death domain (FADD) plays an important role as an adapter molecule in Fas (CD95/APO-1)-mediated apoptosis and contributes to anticancer drug-induced cytotoxicity. We treated three human prostate cancer cell lines with etoposide, a toposiomerase II inhibitor with activity against various tumors including prostate cancer. We found that the overexpression of FADD sensitizes etoposide-induced apoptosis through a rapid activation of c-Jun NH2-terminal kinase (JNK) and, subsequently, of caspase 3. In addition, phosphorylation of FADD at serine 194 coincided with this sensitization. Treatment with the caspase 3 inhibitor, N-acetyl-Asp-Glu-Val-Asp-aldehyde (DEVD-CHO), or overexpression of either mitogen-activated protein kinase kinase (MKK) 7 or Bcl-xL canceled FADD-mediated sensitization to etoposide-induced apoptosis. Moreover, treatment with the caspase 8 inhibitor, benzyloxy-carbonyl-Val-Ala-Asp-fluoromethylketone (z-IETD-fmk), or overexpression of viral FLICE/caspase-8-inhibitory protein (FLIP) from equine herpesvirus type 2 E8 also had an inhibitory effect, supporting a major involvement of a caspase 8-dependent mitochondrial pathway. Interestingly, FADD was phosphorylated, and etoposide-induced JNK/caspase activation and apoptosis were enhanced in the cells arrested at G2/M transition, but not in those overexpressing mutant FADD, in which 194 serine was replaced by alanine. Our results demonstrate that phosphorylated FADD-dependent activation of the JNK/caspase pathway plays a pivotal role in sensitization to etoposide-induced apoptosis in prostate cancer cells.