Stress Cellulaire, Parc Scientifique et Technologique de Luminy, Marseille, France.
Clin Cancer Res. 2012 Oct 1;18(19):5234-46. doi: 10.1158/1078-0432.CCR-12-0026. Epub 2012 Aug 16.
The limited supply of oxygen and nutrients is thought to result in rigorous selection of cells that will eventually form the tumor.
Nupr1 expression pattern was analyzed in human tissue microarray (TMA) and correlated with survival time of the patient. Microarray analysis was conducted on MiaPaCa2 cells subjected to metabolic stress in Nupr1-silenced conditions. DNA repair and cell cycle-associated gene expression was confirmed by real-time quantitative PCR (qRT-PCR). Nupr1 and AURKA protective role were analyzed using RNA interference (RNAi) silencing or overexpression. DNA damage and autophagy were analyzed by Western blot analysis and immunofluorescence.
We showed that both Nupr1 and HIF1α are coexpressed in human pancreatic ductal adenocarcinoma (PDAC) samples and negatively correlate with survival time. PDAC-derived cells submitted to hypoxia and/or glucose starvation induce DNA damage-dependent cell death concomitantly to the overexpression of stress protein Nupr1. Affymetrix-based transcriptoma analysis reveals that Nupr1 knockdown enhances DNA damage and alters the expression of several genes involved in DNA repair and cell-cycle progression. Expression of some of these genes is common to hypoxia and glucose starvation, such as Aurka gene, suggesting that Nupr1 overexpression counteracts the transcriptional changes occurring under metabolic stress. The molecular mechanism by which hypoxia and glucose starvation induce cell death involves autophagy-associated, but not caspase-dependent, cell death. Finally, we have found that AURKA expression is partially regulated by Nupr1 and plays a major role in this response.
Our data reveal that Nupr1 is involved in a defense mechanism that promotes pancreatic cancer cell survival when exposed to metabolic stress.
氧气和营养物质的有限供应被认为导致了最终形成肿瘤的细胞的严格选择。
分析了 Nupr1 在人组织微阵列（TMA）中的表达模式，并与患者的生存时间相关联。对代谢应激下沉默 Nupr1 的 MiaPaCa2 细胞进行了微阵列分析。通过实时定量 PCR（qRT-PCR）确认了 DNA 修复和细胞周期相关基因的表达。通过 RNA 干扰（RNAi）沉默或过表达分析了 Nupr1 和 AURKA 的保护作用。通过 Western blot 分析和免疫荧光分析分析了 DNA 损伤和自噬。
我们表明，Nupr1 和 HIF1α 在人胰腺导管腺癌（PDAC）样本中均共表达，与生存时间呈负相关。缺氧和/或葡萄糖饥饿诱导的 PDAC 衍生细胞诱导 DNA 损伤依赖性细胞死亡，同时应激蛋白 Nupr1 过表达。基于 Affymetrix 的转录组分析显示，Nupr1 敲低增强了 DNA 损伤，并改变了几个参与 DNA 修复和细胞周期进程的基因的表达。这些基因中的一些表达是缺氧和葡萄糖饥饿共有的，例如 Aurka 基因，这表明 Nupr1 过表达抵消了代谢应激下发生的转录变化。缺氧和葡萄糖饥饿诱导细胞死亡的分子机制涉及自噬相关但不依赖于半胱天冬酶的细胞死亡。最后，我们发现 AURKA 的表达部分受 Nupr1 调节，并在该反应中起主要作用。
我们的数据表明，Nupr1 参与了一种防御机制，当暴露于代谢应激时，该机制促进了胰腺癌细胞的存活。
