title: Enhanced expression of the β4-N-acetylgalactosaminyltransferase 4 gene impairs tumor growth of human breast cancer cells.
abstract: Two β4-N-acetylgalactosaminyltransferases (β4GalNAcTs), β4GalNAcT3 and β4GalNAcT4, have been shown to be involved in the synthesis of the GalNAcβ1 → 4GlcNAc (LacdiNAc) group expressed on the outer branches of N- and/or O-glycans, and only β4GalNAcT4 is expressed in human mammary gland. We found that the expression level of the LacdiNAc group decreases as human breast cancers progress. To investigate biological significances of this disaccharide in human breast cancers, we transfected the FLAG-tagged β4GalNAcT4 cDNA into MDA-MB-231 cells, and obtained several clones showing enhanced expression of the gene. Clones 1 and 2 showed 15 and 9 times more transcript than mock-transfected cells. The FLAG-β4GalNAcT4 protein and its product, the LacdiNAc group, were detected in clone 1 and 2 cells. No change was observed in their growth rates while significant decreases in colony forming and invasive abilities were observed for clone 1 and 2 cells. When clone 1 cells were transplanted subcutaneously into nude mice, no tumors were formed while tumors were formed with mock-transfected cells. These results indicate that the expression of the LacdiNAc group is quite important for the suppression of malignancies of the MDA-MB-231 cells.
authors: Laboratory of Glyco-Bioengineering, The Noguchi Institute, Itabashi, Tokyo 173-0003, Japan. Electronic address: kiyoko.hirano@noguchi.or.jp.
authors: Kiyoko
authors: K
authors: Hirano
authors: Laboratory of Glyco-Bioengineering, The Noguchi Institute, Itabashi, Tokyo 173-0003, Japan.
authors: Akio
authors: A
authors: Matsuda
authors: Laboratory of Glycobiology, Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188, Japan.
authors: Ryo
authors: R
authors: Kuji
authors: Laboratory of Glycobiology, Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188, Japan.
authors: Shiro
authors: S
authors: Nakandakari
authors: Laboratory of Glyco-Bioengineering, The Noguchi Institute, Itabashi, Tokyo 173-0003, Japan.
authors: Takashi
authors: T
authors: Shirai
authors: Laboratory of Glycobiology, Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188, Japan.
authors: Kiyoshi
authors: K
authors: Furukawa
mesh_terms: D001943:Breast Neoplasms / Q000201:enzymology* / Q000473:pathology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D006801:Humans; D017350:N-Acetylgalactosaminyltransferases / Q000378:metabolism*; D009361:Neoplasm Invasiveness; D015854:Up-Regulation
chemical_list: C484901:B4GALNT4 protein, human; D017350:N-Acetylgalactosaminyltransferases
keywords: Human breast cancer cells; LacdiNAc group; Malignant properties; β4GalNAcT4