title: Enhanced phosphorylation of p53 by microRNA-26a leading to growth inhibition of pancreatic cancer.
abstract: OBJECTIVE
  MicroRNA (miR)-26a has been identified as a tumor suppressor in pancreatic cancer cells. Although wild-type p53 controls cell-cycle progression, its mutant form normally present in pancreatic cancer loses this capability. Phosphorylation is known to restore wild-type activity to mutant p53. We, therefore, examined whether miR-26a treatment can restore wild-type functions of mutant p53 via phosphorylation, resulting in inhibition of cell growth.
  
  
  METHODS
  The human pancreatic cancer cell line BxPc-3 harboring mutant p53 was used for colony formation, cell-cycle, and Western blotting assays. Gene profile analysis was conducted after transfection with pre-miR-26a.
  
  
  RESULTS
  miR-26a expression significantly decreased cell proliferation by 80% along with marked inhibition of colony formation and cell migration. Cell-cycle inhibition at the G0/G1 interface was observed along with enhanced drug retention and increased chemosensitivity to gemcitabine. Mutant p53 was phosphorylated rapidly at its Ser9 and Ser392 residues, but not at Ser15 or Ser20. Gene profile analysis of pre-miR-26a-transfected cells showed a significant increase in gene transcripts promoting apoptosis and p53 activation, with decreased levels of genes involved in cell-cycle progression.
  
  
  CONCLUSIONS
  Delivery of miR-26a may represent a novel strategy for inhibiting pancreatic cancer growth, at least in part by enhancing phosphorylation of mutant p53 to restore its wild-type functions.
authors.affiliation: Wayne State University School of Medicine, Detroit, MI; John D. Dingell VA Medical Center, Detroit, MI; Virocan Therapeutics Pvt. Ltd, Guntur, India. Electronic address: rbatchu@med.wayne.edu.
authors.forename: Ramesh B
authors.initials: RB
authors.lastname: Batchu
authors.affiliation: Wayne State University School of Medicine, Detroit, MI; John D. Dingell VA Medical Center, Detroit, MI.
authors.forename: Oksana V
authors.initials: OV
authors.lastname: Gruzdyn
authors.affiliation: Wayne State University School of Medicine, Detroit, MI; John D. Dingell VA Medical Center, Detroit, MI.
authors.forename: Aamer M
authors.initials: AM
authors.lastname: Qazi
authors.affiliation: Wayne State University School of Medicine, Detroit, MI.
authors.forename: Jaskiran
authors.initials: J
authors.lastname: Kaur
authors.affiliation: Wayne State University School of Medicine, Detroit, MI.
authors.forename: Ebrahem M
authors.initials: EM
authors.lastname: Mahmud
authors.affiliation: Wayne State University School of Medicine, Detroit, MI.
authors.forename: Donald W
authors.initials: DW
authors.lastname: Weaver
authors.affiliation: Wayne State University School of Medicine, Detroit, MI; John D. Dingell VA Medical Center, Detroit, MI.
authors.forename: Scott A
authors.initials: SA
authors.lastname: Gruber
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism*; D015153:Blotting, Western; D021441:Carcinoma, Pancreatic Ductal / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D002453:Cell Cycle / Q000502:physiology; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000502:physiology; D049109:Cell Proliferation / Q000502:physiology*; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D035683:MicroRNAs / Q000378:metabolism*; D009154:Mutation; D014411:Neoplastic Stem Cells; D010190:Pancreatic Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D010766:Phosphorylation; D014162:Transfection; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*
chemical_list: D014408:Biomarkers, Tumor; D035683:MicroRNAs; D016159:Tumor Suppressor Protein p53; C528163:MIRN26 microRNA, human