title: Sialidase NEU3 contributes neoplastic potential on colon cancer cells as a key modulator of gangliosides by regulating Wnt signaling.
abstract: The plasma membrane-associated sialidase NEU3 is a key enzyme for ganglioside degradation. We previously demonstrated remarkable up-regulation of NEU3 in various human cancers, with augmented malignant properties. Here, we provide evidence of a close link between NEU3 expression and Wnt/β-catenin signaling in colon cancer cells by analyzing tumorigenic potential and cancer stem-like characteristics. NEU3 silencing in HT-29 and HCT116 colon cancer cells resulted in significant decrease in clonogenicity on soft agar and in vivo tumor growth, along with down-regulation of stemness and Wnt-related genes. Analyses further revealed that NEU3 enhanced phosphorylation of the Wnt receptor LRP6 and consequently β-catenin activation by accelerating complex formation with LRP6 and recruitment of GSK3β and Axin, whereas its silencing exerted the opposite effects. NEU3 activity-null mutants failed to demonstrate the activation, indicating the requirement of ganglioside modulation by the sialidase for the effects. Under sphere-forming conditions, when stemness genes are up-regulated, endogenous NEU3 expression was found to be significantly increased, whereas NEU3 silencing suppressed sphere-formation and in vivo tumor incidence in NOD-SCID mice. Increased ability of clonogenicity on soft agar and sphere formation by Wnt stimulation was abrogated by NEU3 silencing. Furthermore, NEU3 was found to regulate phosphorylation of ERK and Akt via EGF receptor and Ras cascades, thought to be additionally required for tumor progression. The results indicate an essential contribution of NEU3 to tumorigenic potential through maintenance of stem-like characteristics of colon cancer cells by regulating Wnt signaling at the receptor level, in addition to tumor progression via Ras/MAPK signaling.
authors: Division of Cancer Glycosylation Research, Institute of Molecular Biomembrane and Glycobiology, Tohoku Pharmaceutical University, Sendai.|Division of Cancer Molecular Biology, Graduate School of Medicine, Tohoku University, Sendai, Japan.
authors: Kohta
authors: K
authors: Takahashi
authors: Division of Cell Recognition Study, Institute of Molecular Biomembrane and Glycobiology, Tohoku Pharmaceutical University, Sendai.
authors: Masahiro
authors: M
authors: Hosono
authors: Division of Pathology, Miyagi Cancer Center Research Institute, Natori.
authors: Ikuro
authors: I
authors: Sato
authors: Division of Cancer Glycosylation Research, Institute of Molecular Biomembrane and Glycobiology, Tohoku Pharmaceutical University, Sendai.
authors: Keiko
authors: K
authors: Hata
authors: Division of Cancer Glycosylation Research, Institute of Molecular Biomembrane and Glycobiology, Tohoku Pharmaceutical University, Sendai.
authors: Tadashi
authors: T
authors: Wada
authors: Division of Molecular and Cellular Oncology, Miyagi Cancer Center Research Institute, Natori.
authors: Kazunori
authors: K
authors: Yamaguchi
authors: Division of Cancer Molecular Biology, Graduate School of Medicine, Tohoku University, Sendai, Japan.
authors: Kazuo
authors: K
authors: Nitta
authors: Division of Cancer Molecular Biology, Graduate School of Medicine, Tohoku University, Sendai, Japan.
authors: Hiroshi
authors: H
authors: Shima
authors: Division of Cancer Glycosylation Research, Institute of Molecular Biomembrane and Glycobiology, Tohoku Pharmaceutical University, Sendai.
authors: Taeko
authors: T
authors: Miyagi
mesh_terms: D000818:Animals; D003110:Colonic Neoplasms / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology; D005732:Gangliosides / Q000378:metabolism*; D045325:HCT116 Cells; D057809:HEK293 Cells; D019073:HT29 Cells; D064593:Heterografts; D006801:Humans; D060488:Low Density Lipoprotein Receptor-Related Protein-6 / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D016688:Mice, Inbred NOD; D008819:Mice, Nude; D016513:Mice, SCID; D009363:Neoplasm Proteins / Q000378:metabolism; D009439:Neuraminidase / Q000378:metabolism*; D039904:Pluripotent Stem Cells / Q000378:metabolism / Q000473:pathology; D051820:TCF Transcription Factors / Q000378:metabolism; D060449:Wnt Signaling Pathway; D051176:beta Catenin / Q000378:metabolism
chemical_list: C495270:CTNNB1 protein, human; D005732:Gangliosides; C555475:LRP6 protein, human; D060488:Low Density Lipoprotein Receptor-Related Protein-6; D009363:Neoplasm Proteins; D051820:TCF Transcription Factors; D051176:beta Catenin; C465436:Neu3 protein, human; D009439:Neuraminidase
keywords: Wnt signaling; colon cancer; gangliosides; sialidase; stem cells