Dong J, Naito M, Mashima T, Jang W H, Tsuruo T
Institute of Molecular and Cellular Biosciences, University of Tokyo, Japan.
J Cell Physiol. 1998 Feb;174(2):179-85. doi: 10.1002/(SICI)1097-4652(199802)174:2<179::AID-JCP5>3.0.CO;2-L.
Tumor necrosis factor-alpha (TNF-alpha) is a cytokine that induces apoptosis in various cell systems by binding to the TNF receptor (TNFR). To study TNF-alpha-induced apoptosis, we isolated and characterized a novel TNF-alpha-resistant variant, U937/TNF clone UA, from human monocytic leukemia U937 cells. The UA cells resist apoptosis induced by TNF-alpha and anti-Fas antibody but not by anticancer drugs, such as VP-16 and Ara-C. Somatic cell hybridization between U937 and UA showed that apoptosis resistance to TNF-alpha in UA was genetically recessive. The hybridization analysis also showed that UA and another recessive mutant clone, UC, belong to different complementation groups in TNF-alpha-induced apoptosis signaling. In UA cells, TNF-alpha-induced disruption of mitochondrial membrane potential and CPP32 activation were abrogated. Expression of TNFR, Fas, and Bcl-2 family proteins was not changed in UA cells. These results suggest that the apoptosis resistant UA cells could have a functional defect in apoptosis signaling from the TNFR to mitochondria and interleukin-1beta converting enzyme (ICE) family protease activation. UA cells could be used to study signaling linkage between cell death-inducing receptor and mitochondria.
肿瘤坏死因子-α（TNF-α）是一种细胞因子，通过与TNF受体（TNFR）结合在多种细胞系统中诱导细胞凋亡。为了研究TNF-α诱导的细胞凋亡，我们从人单核细胞白血病U937细胞中分离并鉴定了一种新型的TNF-α抗性变体U937/TNF克隆UA。UA细胞对TNF-α和抗Fas抗体诱导的细胞凋亡具有抗性，但对抗癌药物如VP-16和阿糖胞苷诱导的细胞凋亡不具有抗性。U937和UA之间的体细胞杂交表明，UA对TNF-α的凋亡抗性是隐性遗传的。杂交分析还表明，UA和另一个隐性突变克隆UC在TNF-α诱导的细胞凋亡信号传导中属于不同的互补组。在UA细胞中，TNF-α诱导的线粒体膜电位破坏和CPP32激活被消除。UA细胞中TNFR、Fas和Bcl-2家族蛋白的表达没有变化。这些结果表明，抗凋亡的UA细胞在从TNFR到线粒体和白细胞介素-1β转化酶（ICE）家族蛋白酶激活的凋亡信号传导中可能存在功能缺陷。UA细胞可用于研究细胞死亡诱导受体与线粒体之间的信号联系。
