Nupr1-aurora kinase A pathway provides protection against metabolic stress-mediated autophagic-associated cell death.
OBJECTIVE
The limited supply of oxygen and nutrients is thought to result in rigorous selection of cells that will eventually form the tumor.


METHODS
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.


RESULTS
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.


CONCLUSIONS
Our data reveal that Nupr1 is involved in a defense mechanism that promotes pancreatic cancer cell survival when exposed to metabolic stress.
Stress Cellulaire, Parc Scientifique et Technologique de Luminy, Marseille, France.
Tewfik
T
Hamidi
Carla E
CE
Cano
Daniel
D
Grasso
Maria Noé
MN
Garcia
Maria José
MJ
Sandi
Ezequiel L
EL
Calvo
Jean-Charles
JC
Dagorn
Gwen
G
Lomberk
Raul
R
Urrutia
Sandro
S
Goruppi
Arkaitz
A
Carracedo
Guillermo
G
Velasco
Juan L
JL
Iovanna
D000230:Adenocarcinoma / Q000378:metabolism / Q000473:pathology; D064096:Aurora Kinase A; D064127:Aurora Kinases; D001343:Autophagy; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism; D021441:Carcinoma, Pancreatic Ductal / Q000378:metabolism / Q000473:pathology; D015687:Cell Hypoxia; D045744:Cell Line, Tumor; D002470:Cell Survival; D015972:Gene Expression Regulation, Neoplastic; D005947:Glucose / Q000378:metabolism; D006801:Humans; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D013312:Stress, Physiological
D064096:Aurora Kinase A; D064127:Aurora Kinases; D051792:Basic Helix-Loop-Helix Proteins; D005947:Glucose; D009363:Neoplasm Proteins; D017346:Protein Serine-Threonine Kinases; C491643:NUPR1 protein, human; C576917:AURKA protein, human