title: Cdc7 is a potent anti-cancer target in pancreatic cancer due to abrogation of the DNA origin activation checkpoint.
abstract: OBJECTIVE
  Cdc7 is a serine/threonine kinase which is responsible for the 'firing' of replication origins leading to initiation of DNA replication. Inhibition or depletion of Cdc7 in normal cells triggers a DNA origin activation checkpoint causing a reversible G1 arrest. Here we investigate Cdc7 as a novel therapeutic target in pancreatic cancer.
  
  
  METHODS
  Cdc7 target validation was performed by immunoexpression profiling in a cohort of 73 patients with pancreatic adenocarcinoma including 24 controls. Secondly Cdc7 kinase was targeted in Capan-1 and PANC-1 pancreatic cancer cell line models using either an siRNA against Cdc7 or alternatively a small molecule inhibitor (SMI) of Cdc7 (PHA-767491).
  
  
  RESULTS
  Cdc7 was significantly overexpressed in pancreatic adenocarcinoma compared to benign pancreatic tissue (median LI 34.3% vs. 1.3%; P<0.0001). Cdc7 knockdown using siRNA in Capan-1 and PANC-1 cells resulted in marked apoptotic cell death when compared with control cells. A prominent sub-G1 peak was seen on flow cytometry (sub-G1 51% vs. 3% and 45% vs. 0.7% in Capan-1 and PANC-1 cells, respectively). Annexin V labelling confirmed apoptosis in 64% vs. 11% and 75% vs. 8%, respectively. Western blotting showed cleavage of PARP-1 and caspase-3 and presence of γH2A.X. TUNEL assay showed strong staining in treated cells. These results were mirrored following Cdc7 kinase inhibition with PHA-767491.
  
  
  CONCLUSIONS
  Our findings show that Cdc7 is a potent anti-cancer target in pancreatic adenocarcinoma and that Cdc7 immunoexpression levels might be used as a companion diagnostic to predict response to therapeutic siRNAs or SMIs directed against this kinase.
authors.affiliation: UCL Institute for Liver and Digestive Health and UCL Cancer Institute, University College London, London, UK.|The Research Department of Pathology, UCL Cancer Institute, University College London, London, UK.
authors.forename: Matthew T
authors.initials: MT
authors.lastname: Huggett
authors.affiliation: The Research Department of Pathology, UCL Cancer Institute, University College London, London, UK.
authors.forename: Slavica
authors.initials: S
authors.lastname: Tudzarova
authors.affiliation: The Research Department of Pathology, UCL Cancer Institute, University College London, London, UK.
authors.forename: Ian
authors.initials: I
authors.lastname: Proctor
authors.affiliation: The Research Department of Pathology, UCL Cancer Institute, University College London, London, UK.|Oncologica Ltd, The Science Village, Chesterford Research Park, Cambridge, UK.
authors.forename: Marco
authors.initials: M
authors.lastname: Loddo
authors.affiliation: UCL Institute for Liver and Digestive Health and UCL Cancer Institute, University College London, London, UK.
authors.forename: Margaret G
authors.initials: MG
authors.lastname: Keane
authors.affiliation: The Research Department of Pathology, UCL Cancer Institute, University College London, London, UK.
authors.forename: Kai
authors.initials: K
authors.lastname: Stoeber
authors.affiliation: The Research Department of Pathology, UCL Cancer Institute, University College London, London, UK.|Oncologica Ltd, The Science Village, Chesterford Research Park, Cambridge, UK.
authors.forename: Gareth H
authors.initials: GH
authors.lastname: Williams
authors.affiliation: UCL Institute for Liver and Digestive Health and UCL Cancer Institute, University College London, London, UK.
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Pereira
mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D018797:Cell Cycle Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D015331:Cohort Studies; D004261:DNA Replication; D059585:G1 Phase Cell Cycle Checkpoints / Q000187:drug effects / Q000235:genetics; D006801:Humans; D058990:Molecular Targeted Therapy; D010190:Pancreatic Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D010881:Piperidones / Q000494:pharmacology; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D011758:Pyrroles / Q000494:pharmacology; D014162:Transfection
chemical_list: D018797:Cell Cycle Proteins; C531237:PHA 767491; D010881:Piperidones; D011758:Pyrroles; C068619:CDC7 protein, human; D017346:Protein Serine-Threonine Kinases
keywords: Cdc7; DNA replication; cell cycle; pancreatic cancer