title: Increased expression of PHD3 represses the HIF-1 signaling pathway and contributes to poor neovascularization in pancreatic ductal adenocarcinoma.
abstract: BACKGROUND
  Pancreatic ductal adenocarcinoma (PDAC) is known as one of the most malignant potential diseases with poor neovascularization. By comparing PDAC to hepatocellular carcinoma (HCC), which is well vascularized, we investigated the mechanisms and tumor biological significance of the poor neovascularization in PDAC.
  
  
  METHODS
  Surgical specimens from primary PDAC and HCC patients were immunohistologically stained to detect the expressions of CD105, CD44, HIF-1α, PHD3, and Siah2. We also used two PDAC and two HCC cell lines to compare the expressions of HIF-1α, PHD3, and CD44, as well as the production of VEGF in hypoxic condition. The role of PHD3 in regulating HIF-1α expression was further confirmed by siRNA knockdown in a PDAC cell line that highly expressed PHD3.
  
  
  RESULTS
  There were significantly fewer microvessels but more cancer stem cells in PDAC specimens compared to HCC specimens. The expression of CD105 was reversely related to the expression of CD44 in PDAC and HCC specimens. PDAC specimens also showed higher expressions of PHD3 but lower expressions of HIF-1α. Similarly, the expression of PHD3 was observed clearly in PDAC cell lines, but was almost completely negative in HCC cell lines. Hypoxic stimulation clearly enhanced HIF-1α expression and VEGF secretion in both HCC cell lines, but did not significantly change in PDAC cell lines. The knockdown of PHD3 in PDAC cells restored the hypoxic-induced HIF-1α expression, which accordingly stimulated the cells' VEGF secretion.
  
  
  CONCLUSIONS
  The enhanced expression of PHD3 might likely contribute to the poor neovascularization and affect the biological characterization in PDAC cancer cells.
authors.affiliation: Department of Stem Cell Biology, Atomic Bomb Disease Institute, Nagasaki University, 1-12-4 Sakamoto, Nagasaki, 852-8523, Japan, pay-it-forward.197675@hotmail.co.jp.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Tanaka
authors.forename: Tao-Sheng
authors.initials: TS
authors.lastname: Li
authors.forename: Yoshishige
authors.initials: Y
authors.lastname: Urata
authors.forename: Shinji
authors.initials: S
authors.lastname: Goto
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Ono
authors.forename: Miho
authors.initials: M
authors.lastname: Kawakatsu
authors.forename: Hajime
authors.initials: H
authors.lastname: Matsushima
authors.forename: Masataka
authors.initials: M
authors.lastname: Hirabaru
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Adachi
authors.forename: Amane
authors.initials: A
authors.lastname: Kitasato
authors.forename: Mitsuhisa
authors.initials: M
authors.lastname: Takatsuki
authors.forename: Tamotsu
authors.initials: T
authors.lastname: Kuroki
authors.forename: Susumu
authors.initials: S
authors.lastname: Eguchi
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism*; D015703:Antigens, CD / Q000378:metabolism; D015153:Blotting, Western; D006528:Carcinoma, Hepatocellular / Q000378:metabolism* / Q000473:pathology; D021441:Carcinoma, Pancreatic Ductal / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D000071063:Endoglin; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D006801:Humans; D018960:Hyaluronan Receptors / Q000378:metabolism; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism*; D064799:Hypoxia-Inducible Factor-Proline Dioxygenases / Q000378:metabolism*; D007150:Immunohistochemistry; D008113:Liver Neoplasms / Q000378:metabolism* / Q000473:pathology; D009389:Neovascularization, Pathologic; D009687:Nuclear Proteins / Q000378:metabolism; D010190:Pancreatic Neoplasms / Q000378:metabolism* / Q000473:pathology; D034741:RNA, Small Interfering; D011956:Receptors, Cell Surface / Q000378:metabolism; D015398:Signal Transduction; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism; D000098563:Seven in Absentia Proteins
chemical_list: D015703:Antigens, CD; C497483:CD44 protein, human; C064206:ENG protein, human; D000071063:Endoglin; D018960:Hyaluronan Receptors; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D009687:Nuclear Proteins; D034741:RNA, Small Interfering; D011956:Receptors, Cell Surface; C488894:EGLN3 protein, human; D064799:Hypoxia-Inducible Factor-Proline Dioxygenases; D044767:Ubiquitin-Protein Ligases; D000098563:Seven in Absentia Proteins