title: Recruited metastasis suppressor NM23-H2 attenuates expression and activity of peroxisome proliferator-activated receptor δ (PPARδ) in human cholangiocarcinoma.
abstract: BACKGROUND
  Peroxisome proliferator-activated receptor δ (PPARδ) is a versatile regulator of distinct biological processes and overexpression of PPARδ in cancer may be partially related to its suppression of its own co-regulators.
  
  
  OBJECTIVE
  To determine whether recruited suppressor proteins bind to and regulate PPARδ expression, activity and PPARδ-dependent cholangiocarcinoma proliferation.
  
  
  METHODS
  Yeast two-hybrid assays were done using murine PPARδ as bait. PPARδ mRNA expression was determined by qPCR. Protein expression was measured by western blot. Immunohistochemistry and fluorescence microscopy were used to determine PPARδ expression and co-localization with NDP Kinase alpha (NM23-H2). Cell proliferation assays were performed to determine cell numbers.
  
  
  RESULTS
  Yeast two-hybrid screening identified NM23-H2 as a PPARδ binding protein and their interaction was confirmed. Overexpressed PPARδ or treatment with the agonist GW501516 resulted in increased cell proliferation. NM23-H2 siRNA activated PPARδ luciferase promoter activity, upregulated PPARδ RNA and protein expression and increased GW501516-stimulated CCA growth. Overexpression of NM23-H2 inhibited PPARδ luciferase promoter activity, downregulated PPARδ expression and AKT phosphorylation and reduced GW501516-stimulated CCA growth.
  
  
  CONCLUSIONS
  We report the novel association of NM23-H2 with PPARδ and the negative regulation of PPARδ expression by NM23-H2 binding to the C-terminal region of PPARδ. These findings provide evidence that the metastasis suppressor NM23-H2 is involved in the regulation of PPARδ-mediated proliferation.
authors.affiliation: The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.
authors.forename: Fang
authors.initials: F
authors.lastname: He
authors.affiliation: Houston Methodist Research Institute, Weill Cornell School of Medicine, Houston, TX, USA.
authors.forename: J Philippe
authors.initials: JP
authors.lastname: York
authors.affiliation: Houston Methodist Research Institute, Weill Cornell School of Medicine, Houston, TX, USA.
authors.forename: Sherilyn Gordon
authors.initials: SG
authors.lastname: Burroughs
authors.affiliation: Houston Methodist Research Institute, Weill Cornell School of Medicine, Houston, TX, USA.
authors.forename: Lidong
authors.initials: L
authors.lastname: Qin
authors.affiliation: The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.
authors.forename: Jintang
authors.initials: J
authors.lastname: Xia
authors.affiliation: The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.
authors.forename: De
authors.initials: D
authors.lastname: Chen
authors.affiliation: Houston Methodist Research Institute, Weill Cornell School of Medicine, Houston, TX, USA.
authors.forename: Eamonn M
authors.initials: EM
authors.lastname: Quigley
authors.affiliation: Houston Methodist Research Institute, Weill Cornell School of Medicine, Houston, TX, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Webb
authors.affiliation: Division of Gastroenterology and Hepatology, Department of Internal Medicine, East Tennessee State University, Johnson City, TN, USA.
authors.forename: Gene D
authors.initials: GD
authors.lastname: LeSage
authors.affiliation: The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China; Houston Methodist Research Institute, Weill Cornell School of Medicine, Houston, TX, USA. Electronic address: xxia2@tmhs.org.
authors.forename: Xuefeng
authors.initials: X
authors.lastname: Xia
mesh_terms: D000818:Animals; D001650:Bile Duct Neoplasms / Q000235:genetics* / Q000378:metabolism; D001653:Bile Ducts, Intrahepatic; D015153:Blotting, Western; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D018281:Cholangiocarcinoma / Q000235:genetics* / Q000378:metabolism; D015536:Down-Regulation; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D051379:Mice; D054778:NM23 Nucleoside Diphosphate Kinases / Q000235:genetics* / Q000378:metabolism; D047495:PPAR gamma / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*; D034741:RNA, Small Interfering; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015003:Yeasts
chemical_list: D054778:NM23 Nucleoside Diphosphate Kinases; D047495:PPAR gamma; D012333:RNA, Messenger; D034741:RNA, Small Interfering
keywords: Cholangiocarcinoma; Nucleoside diphosphate kinase alpha; Peroxisome proliferator-activated receptor δ