The Anticancer Agent Di-2-pyridylketone 4,4-Dimethyl-3-thiosemicarbazone ( Dp44mT) Overcomes Prosurvival Autophagy by Two Mechanisms PERSISTENT INDUCTION OF AUTOPHAGOSOME SYNTHESIS AND IMPAIRMENT OF LYSOSOMAL INTEGRITY
The Anticancer Agent Di-2-pyridylketone 4,4-Dimethyl-3-thiosemicarbazone ( Dp44mT) Overcomes Prosurvival Autophagy by Two Mechanisms PERSISTENT INDUCTION OF AUTOPHAGOSOME SYNTHESIS AND IMPAIRMENT OF LYSOSOMAL INTEGRITY
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DOI：
10.1074/jbc.m114.599480
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发表时间：
2014-11-28
影响因子：
4.8
通讯作者：
Jansson, Patric J.
中科院分区：
文献类型：
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作者：
Gutierrez, Elaine;Richardson, Des R.;Jansson, Patric J.
自噬作为细胞应激期间的存活机制起作用，并有助于对抗癌剂的抗性。选择性抗肿瘤和抗转移螯合剂二-2-吡啶基酮4，4-二甲基-3-缩氨基硫脲（Dp 44 mT）引起溶酶体膜透化和细胞死亡。考虑到溶酶体在自噬和细胞死亡中的不可或缺的作用，重要的是评估Dp 44 mT对自噬的影响，以进一步了解其作用机制。值得注意的是，Dp 44 mT通过两种机制影响自噬。首先，在具有抗增殖活性的同时，Dp 44 mT由于诱导自噬体合成而增加了经典自噬标志物LC 3-II的表达。第二，这种作用通过减少自噬体降解来补充，如自噬底物和受体p62的积累所示。相反，经典的铁螯合剂去铁胺仅通过抑制自噬体降解诱导自噬体积累。具有氧化还原活性的铁或铜Dp 44 mT复合物的形成对于其对自噬的双重作用至关重要。细胞保护性抗氧化剂N-乙酰半胱氨酸抑制Dp 44 mT诱导的自噬体合成和p62积累。重要的是，Dp 44 mT通过溶酶体破坏抑制自噬体降解。这种作用阻止了溶酶体与自噬体融合形成自溶体，这对于完成自噬过程至关重要。Dp 44 mT的抗增殖活性被Beclin 1和ATG 5沉默抑制，表明持续的自噬体合成在Dp 44 mT诱导的细胞死亡中的作用。这些研究表明，Dp 44 mT可以克服癌细胞中自噬的促生存活性，通过利用这一过程来加强细胞死亡。
Autophagy functions as a survival mechanism during cellular stress and contributes to resistance against anticancer agents. The selective antitumor and antimetastatic chelator di-2-pyridylketone 4,4-dimethyl-3-thiosemicarbazone (Dp44mT) causes lysosomal membrane permeabilization and cell death. Considering the integral role of lysosomes in autophagy and cell death, it was important to assess the effect of Dp44mT on autophagy to further understand its mechanism of action. Notably, Dp44mT affected autophagy by two mechanisms. First, concurrent with its antiproliferative activity, Dp44mT increased the expression of the classical autophagic marker LC3-II as a result of induced autophagosome synthesis. Second, this effect was supplemented by a reduction in autophagosome degradation as shown by the accumulation of the autophagic substrate and receptor p62. Conversely, the classical iron chelator desferrioxamine induced autophagosome accumulation only by inhibiting autophagosome degradation. The formation of redox-active iron or copper Dp44mT complexes was critical for its dual effect on autophagy. The cytoprotective antioxidant N-acetylcysteine inhibited Dp44mT-induced autophagosome synthesis and p62 accumulation. Importantly, Dp44mT inhibited autophagosome degradation via lysosomal disruption. This effect prevented the fusion of lysosomes with autophagosomes to form autolysosomes, which is crucial for the completion of the autophagic process. The antiproliferative activity of Dp44mT was suppressed by Beclin1 and ATG5 silencing, indicating the role of persistent autophagosome synthesis in Dp44mT-induced cell death. These studies demonstrate that Dp44mT can overcome the prosurvival activity of autophagy in cancer cells by utilizing this process to potentiate cell death.