Down-Regulation of GD3 Ganglioside and Its O-Acetylated Derivative by Stable Transfection with Antisense V

Effects on Cellular Growth, Melanogenesis, and Dendricity

Authors

  • Stéphane Birklé,

    1. Department of Biochemistry and Molecular Biophysics, Medical College of Virginia Campus of Virginia Commonwealth University, Richmond, Virginia, U.S.A.
    Search for more papers by this author
  • Luoyi Gao,

    1. Department of Biochemistry and Molecular Biophysics, Medical College of Virginia Campus of Virginia Commonwealth University, Richmond, Virginia, U.S.A.
    Search for more papers by this author
  • Guichao Zeng,

    1. Department of Biochemistry and Molecular Biophysics, Medical College of Virginia Campus of Virginia Commonwealth University, Richmond, Virginia, U.S.A.
    Search for more papers by this author
  • Robert K. Yu

    1. Department of Biochemistry and Molecular Biophysics, Medical College of Virginia Campus of Virginia Commonwealth University, Richmond, Virginia, U.S.A.
    Search for more papers by this author

  • International Society for Neurochemistry

  • The hamster GD3-synthase cDNA sequence has been deposited in the GenBank databases (accession no. AF141657).

  • Abbreviations used: BSA, bovine serum albumin; GD3-synthase, CMP-NeuAc:GM3 α2,8 sialyltransferase; mAb, monoclonal antibody; NeuAc, N-acetylneuraminic acid; PBS, phosphate-buffered saline. The ganglioside nomenclature is based on that of Svennerholm (1963): GM3, NeuAcα2→3Galβ1→4Glcβ1→1′Cer; GD3, NeuAcα2→8NeuAcα2→3Galβ1→4Glcβ1→1′Cer; O-acetyl-GD3, acetyl-O-NeuAcα2→8NeuAcα2→3Galβ1→4Glcβ1→1′Cer; GD1a, NeuAcα2→3Galβ1→3GalNAcβ1→4Gal(α2→3NeuAc)β1→4Glcβ1→1′Cer; GD1b, Galβ1→3GalNAcβ1→4Gal(α2→3NeuAc8→2αNeuAc)β1→4Glcβ1→1′Cer; GT1b, NeuAcα2→3Galβ1→3GalNAcβ1→4Gal(α2→3NeuAc8→2αNeuAc)β1→4Glcβ1→1′Cer.

Address correspondence and reprint requests to Dr. R. K. Yu at Department of Biochemistry and Molecular Biophysics, Medical College of Virginia Campus of Virginia Commonwealth University, Richmond, VA 23298-0614, U.S.A. E-mail: rkyu@hsc.vcu.edu

Abstract

Abstract: The expression of gangliosides in hamster melanoma cells is closely related to cellular growth and degree of differentiation, with slow-growing, highly differentiated melanotic melanoma cells expressing GM3 and fast-growing, undifferentiated amelanotic Ab melanoma cells having a preponderance of GD3 and O-acetyl-GD3. We recently showed that down-regulation of O-acetyl-GD3 expression in hamster melanoma cells by introducing the influenza C virus O-acetylesterase cDNA into the cells resulted in induction of dendricity, with a concomitant increased expression of GD3. To examine the effect of the increased GD3 expression in the plasma membrane on the dendricity of the AbC-1 cells, we first established the cDNA coding for hamster GD3-synthase. We then targeted the sialyltransferase gene expression by the antisense knockdown experiment, and the results showed that inhibition of the expression of gangliosides GD3 and O-acetyl-GD3 induced dendricity in the hamster melanoma AbC-1 cell line. These GD3- and O-acetyl-GD3-depleted cells also demonstrated a decreased rate of cell growth, but their melanogenic potential was not affected. These results rule out the possibility that GD3 may serve as an active molecule for dendrite outgrowth in this cell line and suggest that the enhanced expression of O-acetyl-GD3 ganglioside may stimulate cellular growth and suppress certain differentiated phenotypes such as dendrite formation, but not melanogenesis, in our system.

Ancillary