Inserm, U1065, Centre Méditerranéen de Médecine Moléculaire C3M, équipe 'contrôle métabolique des morts cellulaires', Nice, France.
Cell Death Differ. 2013 Aug;20(8):1043-54. doi: 10.1038/cdd.2013.32. Epub 2013 May 3.
Increased glucose catabolism and resistance to cell death are hallmarks of cancers, but the link between them remains elusive. Remarkably, under conditions where caspases are inhibited, the process of cell death is delayed but rarely blocked, leading to the occurrence of caspase-independent cell death (CICD). Escape from CICD is particularly relevant in the context of cancer as apoptosis inhibition only is often not sufficient to allow oncogenic transformation. While most glycolytic enzymes are overexpressed in tumors, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is of particular interest as it can allow cells to recover from CICD. Here, we show that GAPDH, but no other glycolytic enzymes tested, when overexpressed could bind to active Akt and limit its dephosphorylation. Active Akt prevents FoxO nuclear localization, which precludes Bcl-6 expression and leads to Bcl-xL overexpression. The GAPDH-dependent Bcl-xL overexpression is able to protect a subset of mitochondria from permeabilization that are required for cellular survival from CICD. Thus, our work suggests that GAPDH overexpression could induce Bcl-xL overexpression and protect cells from CICD-induced chemotherapy through preservation of intact mitochondria that may facilitate tumor survival and chemotherapeutic resistance.
葡萄糖分解代谢增加和细胞死亡抵抗是癌症的特征,但它们之间的联系仍然难以捉摸。值得注意的是,在 caspase 被抑制的情况下,细胞死亡过程被延迟但很少被阻断,导致 caspase 非依赖性细胞死亡(CICD)的发生。在癌症的背景下,逃避 CICD 尤为重要,因为凋亡抑制通常不足以允许致癌转化。虽然大多数糖酵解酶在肿瘤中过度表达,但甘油醛-3-磷酸脱氢酶(GAPDH)特别有趣,因为它可以使细胞从 CICD 中恢复。在这里,我们表明,GAPDH(但未测试的其他糖酵解酶)过表达时可以与活性 Akt 结合并限制其去磷酸化。活性 Akt 可防止 FoxO 核定位,从而阻止 Bcl-6 表达并导致 Bcl-xL 过表达。GAPDH 依赖性 Bcl-xL 过表达能够保护一部分线粒体免于透化,这些线粒体对于细胞从 CICD 中存活是必需的。因此,我们的工作表明,GAPDH 过表达可能通过保留完整的线粒体来诱导 Bcl-xL 过表达并保护细胞免受 CICD 诱导的化疗,从而促进肿瘤存活和化疗耐药。