title: Low concentrations of beta-carotene stimulate the proliferation of human pancreatic duct epithelial cells in a PKA-dependent manner.
abstract: BACKGROUND
  Pancreatic ductal adenocarcinoma (PDAC) is among the most common causes of cancer death. Preclinical and clinical studies on the preventive effects of beta-carotene or other retinoids have used dietary supplements that yielded high systemic concentrations (1-50 microM). While some of the preclinical data suggested cancer preventive effects of these agents, they have disappointed in clinical investigations.
  
  
  METHODS
  The effects of low concentrations (10 fM-200 nM)of beta-carotene on the proliferation, intracellular cAMP levels, PKA activation status and phosphorylation of EGFR-specific tyrosine kinases and ERK1/2 in immortalized human pancreatic duct epithelial cells was investigated.
  
  
  RESULTS
  Our data show significant concentration-dependent and PKA-dependent stimulation of all measured endpoints. Similar responses were achieved with forskolin. Our data indicate that low concentrations of beta-carotene stimulate the proliferation of the putative origin of PDAC, pancreatic duct epithelial cells via cAMP and PKA-dependent transactivation of the EGFR pathway. This could potentially have promoting effects on the development of PDAC.
authors.affiliation: Experimental Oncology Laboratory, Department of Pathobiology, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996, USA.
authors.forename: Hussein A N
authors.initials: HA
authors.lastname: Al-Wadei
authors.forename: Mourad
authors.initials: M
authors.lastname: Majidi
authors.forename: Ming-Sound
authors.initials: MS
authors.lastname: Tsao
authors.forename: Hildegard M
authors.initials: HM
authors.lastname: Schuller
mesh_terms: D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D005576:Colforsin / Q000494:pharmacology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D004790:Enzyme Induction / Q000187:drug effects; D004847:Epithelial Cells / Q000187:drug effects* / Q000201:enzymology*; D066246:ErbB Receptors / Q000378:metabolism; D006801:Humans; D019950:Mitogen-Activated Protein Kinase 1 / Q000096:biosynthesis; D048052:Mitogen-Activated Protein Kinase 3 / Q000096:biosynthesis; D010183:Pancreatic Ducts / Q000166:cytology* / Q000187:drug effects* / Q000201:enzymology; D010766:Phosphorylation / Q000187:drug effects; D019207:beta Carotene / Q000494:pharmacology*
chemical_list: D019207:beta Carotene; D005576:Colforsin; D066246:ErbB Receptors; D017868:Cyclic AMP-Dependent Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3