MDA-7/IL-24-induced cell killing in malignant renal carcinoma cells occurs by a ceramide/CD95/PERK-dependent mechanism
MDA-7/IL-24-induced cell killing in malignant renal carcinoma cells occurs by a ceramide/CD95/PERK-dependent mechanism
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DOI：
10.1158/1535-7163.mct-09-0073
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发表时间：
2009-05-01
影响因子：
5.7
通讯作者：
Dent, Paul
中科院分区：
文献类型：
--
作者：
Park, Margaret A.;Walker, Teneille;Dent, Paul
黑色素瘤分化相关基因-7/白细胞介素-24（mda-7/IL-24）是一种新的细胞因子，在转化细胞中具有选择性的促凋亡活性，而对正常细胞无损伤。本研究旨在探讨谷胱甘肽S-转移酶（GST）-MDA-7在体外对人肾癌细胞存活的影响及其机制。GST-MDA-7引起CD 95的质膜聚集以及CD 95与procaspase-8的关联。GST-MDA-7的致死率抑制caspase-8的抑制或过表达的短形式的细胞FLICE抑制蛋白，但只有微弱的抑制组织蛋白酶。GST-MDA-7诱导的CD 95聚集（和凋亡）被阻断敲低酸性鞘磷脂酶，或在更大程度上，神经酰胺合酶-6的表达。GST-MDA-7的杀伤作用同时依赖于细胞外信号调节激酶1/2的失活以及CD 95诱导的p38丝裂原活化蛋白激酶和c-jun NH 2-末端激酶-1/2信号传导。敲低CD 95表达可消除GST-MDA-7诱导的蛋白激酶R样内质网激酶磷酸化。GST-MDA-7的致死率被显性负性蛋白激酶R样内质网激酶的敲除或表达所抑制，该蛋白激酶R样内质网激酶与减少的c-jun NH 2-末端激酶-1/2和p38丝裂原活化蛋白激酶信号传导相关，并维持细胞外信号调节激酶-1/2磷酸化。GST-MDA-7通过主要依赖于CD 95的机制引起LC 3的空泡化，并且其形成被ATG 5表达的敲低抑制。ATG 5的敲低抑制GST-MDA-7毒性。我们的数据表明，在肾癌细胞中，GST-MDA-7诱导神经酰胺依赖性激活CD 95，这是促进内质网应激反应，激活多种促凋亡途径，减少生存的原因。[Mol癌症治疗2009;8（5）：1280-91]
Melanoma differentiation associated gene-7/interleukin-24 (mda-7/IL-24) is a novel cytokine displaying selective apoptosis-inducing activity in transformed cells without harming normal cells. The present studies focused on clarifying the mechanism(s) by which glutathione S-transferase (GST)-MDA-7 altered cell survival of human renal carcinoma cells in vitro. GST-MDA-7 caused plasma membrane clustering of CD95 and the association of CD95 with procaspase-8. GST-MDA-7 lethality was suppressed by inhibition of caspase-8 or by overexpression of short-form cellular FLICE inhibitory protein, but only weakly by inhibition of cathepsin proteases. GST-MDA-7-induced CD95 clustering (and apoptosis) was blocked by knockdown of acidic sphingomyelinase or, to a greater extent, ceramide synthase-6 expression. GST-MDA-7 killing was, in parallel, dependent on inactivation of extracellular signal-regulated kinase 1/2 and on CD95-induced p38 mitogen-activated protein kinase and c-jun NH2-terminal kinase-1/2 signaling. Knockdown of CD95 expression abolished GST-MDA-7-induced phosphorylation of protein kinase R-like endoplasmic reticulum kinase. GST-MDA-7 lethality was suppressed by knockout or expression of a dominant negative protein kinase R-like endoplasmic reticulum kinase that correlated with reduced c-jun NH2-terminal kinase-1/2 and p38 mitogen-activated protein kinase signaling and maintained extracellular signal-regulated kinase-1/2 phosphorylation. GST-MDA-7 caused vacuolization of LC3 through a mechanism that was largely CD95 dependent and whose formation was suppressed by knockdown of ATG5 expression. Knockdown of ATG5 suppressed GST-MDA-7 toxicity. Our data show that in kidney cancer cells GST-MDA-7 induces ceramide-dependent activation of CD95, which is causal in promoting an endoplasmic reticulum stress response that activates multiple proapoptotic pathways to decrease survival. [Mol Cancer Ther 2009;8(5):1280-91]