title: Helicobacter pylori-induced cell death is counteracted by NF-κB-mediated transcription of DARPP-32.
abstract: DARPP-32is a frequently amplified and overexpressed gene that promotes several oncogenic functions in gastric cancer. Herein, we investigated the relationship betweenHelicobacter pyloriinfection, proinflammatory NF-κB activation and regulation of DARPP-32.
  
  
  
  The study usedin vivoandin vitroexperiments. Luciferase reporter, quantitative real-time PCR, immunoblot, chromatin immunoprecipitation (ChIP), cell viability,H. pyloriinfection, tissue microarrays and immunohistochemical assays were used.
  
  
  
  Our results indicated thatH. pyloriinfection increased the DARPP-32 mRNA and protein levels in gastric cancer cell lines and gastric mucosa of mice.H. pyloriinfection increased the activity of NF-κB reporter and p-NF-κB (S536) protein levelin vitroandin vivo. To investigate the transcriptional regulation of DARPP-32, we cloned a 3019 bp of theDARPP-32promoter into the luciferase reporter (pGL3-Luc). BothH. pyloriinfection and tumour necrosis factor-α treatment induced DARPP-32 reporter activity (p<0.01). Using deletion constructs ofDARPP-32promoter and ChIP assay, we demonstrated that the sequence -996 to -1008 bp containing putative NF-κB-binding sites is the most active region. The induction of DARPP-32 expression byH. pyloriinfection counteractedH. pylori-induced cell death through activation of serine/threonine-specific protein kinase (AKT), as determined by ATP-Glo and clonogenic survival assays. Immunohistochemistry analysis demonstrated a significant positive correlation between NF-κB and DARPP-32 expression levels in gastric cancer tissues (r2=0.43, p<0.01).
  
  
  
  Given the high frequency of DARPP-32 overexpression and its prosurvival oncogenic functions, the induction of DARPP-32 expression followingH. pyloriinfection and activation of NF-κB provides a link between infection, inflammation and gastric tumourigenesis.
authors: Department of Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
authors: Shoumin
authors: S
authors: Zhu
authors: Department of Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
authors: Mohammed
authors: M
authors: Soutto
authors: Department of Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
authors: Zheng
authors: Z
authors: Chen
authors: Department of Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
authors: DunFa
authors: D
authors: Peng
authors: Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
authors: Judith
authors: J
authors: Romero-Gallo
authors: Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
authors: Uma S
authors: US
authors: Krishna
authors: Department of Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
authors: Abbes
authors: A
authors: Belkhiri
authors: Department of Pathology, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
authors: M Kay
authors: MK
authors: Washington
authors: Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
authors: Richard
authors: R
authors: Peek
authors: Department of Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA.|Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, Tennessee, USA.|Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, Tennessee, USA.
authors: Wael
authors: W
authors: El-Rifai
mesh_terms: D000818:Animals; D016923:Cell Death; D045744:Cell Line, Tumor; D002470:Cell Survival; D051937:Dopamine and cAMP-Regulated Phosphoprotein 32 / Q000032:analysis / Q000235:genetics* / Q000378:metabolism*; D005753:Gastric Mucosa / Q000378:metabolism*; D016481:Helicobacter Infections / Q000235:genetics / Q000378:metabolism*; D016480:Helicobacter pylori; D006801:Humans; D051379:Mice; D016328:NF-kappa B / Q000032:analysis / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*; D015398:Signal Transduction; D013274:Stomach Neoplasms / Q000737:chemistry*; D014158:Transcription, Genetic / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: D051937:Dopamine and cAMP-Regulated Phosphoprotein 32; D016328:NF-kappa B; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D051057:Proto-Oncogene Proteins c-akt
keywords: GASTRIC CANCER; GASTRIC INFLAMMATION; HELICOBACTER PYLORI