title: High expression of N-acetylglucosaminyltransferase IVa promotes invasion of choriocarcinoma.
abstract: BACKGROUND
  Gestational trophoblastic diseases (GTDs) are related to trophoblasts, and human chorionic gonadotropin (hCG) is secreted by GTDs as well as normal placentas. However, the asparagine-linked sugar chains on hCG contain abnormal biantennary structures in invasive mole and choriocarcinoma, but not normal pregnancy or hydatidiform mole. N-acetylglucosaminyltransferase-IV (GnT-IV) catalyses β1,4-N-acetylglucosamine branching on asparagine-linked oligosaccharides, which are consistent with the abnormal sugar chain structures on hCG.
  
  
  METHODS
  We investigated GnT-IVa expression in GTDs and placentas by immunohistochemistry, western blot, and RT-PCR. We assessed the effects of GnT-IVa knockdown in choriocarcinoma cells in vitro and in vivo.
  
  
  RESULTS
  The GnT-IVa was highly expressed in trophoblasts of invasive mole and choriocarcinoma, and moderately in extravillous trophoblasts during the first trimester, but not in hydatidiform mole or other normal trophoblasts. The GnT-IVa knockdown in choriocarcinoma cells significantly reduced migration and invasive capacities, and suppressed cellular adhesion to extracellular matrix proteins. The extent of β1,4-N-acetylglucosamine branching on β1 integrin was greatly reduced by GnT-IVa knockdown, although the expression of β1 integrin was not changed. In vivo studies further demonstrated that GnT-IVa knockdown suppressed tumour engraftment and growth.
  
  
  CONCLUSIONS
  These findings suggest that GnT-IVa is involved in regulating invasion of choriocarcinoma through modifications of the oligosaccharide chains of β1 integrin.
authors.affiliation: Department of Obstetrics and Gynecology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Niimi
authors.forename: E
authors.initials: E
authors.lastname: Yamamoto
authors.forename: S
authors.initials: S
authors.lastname: Fujiwara
authors.forename: K
authors.initials: K
authors.lastname: Shinjo
authors.forename: T
authors.initials: T
authors.lastname: Kotani
authors.forename: T
authors.initials: T
authors.lastname: Umezu
authors.forename: H
authors.initials: H
authors.lastname: Kajiyama
authors.forename: K
authors.initials: K
authors.lastname: Shibata
authors.forename: K
authors.initials: K
authors.lastname: Ino
authors.forename: F
authors.initials: F
authors.lastname: Kikkawa
mesh_terms: D000328:Adult; D014408:Biomarkers, Tumor / Q000378:metabolism*; D015153:Blotting, Western; D002465:Cell Movement; D049109:Cell Proliferation; D002822:Choriocarcinoma / Q000201:enzymology* / Q000473:pathology*; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000378:metabolism; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D015972:Gene Expression Regulation, Neoplastic; D031901:Gestational Trophoblastic Disease / Q000201:enzymology* / Q000473:pathology*; D006801:Humans; D002820:Hydatidiform Mole, Invasive / Q000201:enzymology / Q000473:pathology; D007150:Immunohistochemistry; D019012:Integrin beta1 / Q000378:metabolism; D017350:N-Acetylgalactosaminyltransferases / Q000378:metabolism; D017351:N-Acetylglucosaminyltransferases / Q000378:metabolism*; D009361:Neoplasm Invasiveness; D011247:Pregnancy; D060888:Real-Time Polymerase Chain Reaction; D015854:Up-Regulation; D014594:Uterine Neoplasms / Q000201:enzymology* / Q000473:pathology*
chemical_list: D014408:Biomarkers, Tumor; D018997:Chorionic Gonadotropin, beta Subunit, Human; D019012:Integrin beta1; D017350:N-Acetylgalactosaminyltransferases; D017351:N-Acetylglucosaminyltransferases; C038111:alpha-1,3-mannosylglycoprotein beta-1,4-N-acetylglucosaminyltransferase; C023220:(N-acetylneuraminyl)-galactosylglucosylceramide N-acetylgalactosaminyltransferase