Differential effects of sphingomyelinase and cell-permeable ceramide analogs on proliferation of Swiss 3T3 fibroblasts

Ana Olivera, Amy Romanowski, C. S. Sheela Rani, Sarah Spiegel

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25 Scopus citations

Abstract

Metabolites of sphingomyelin, ceramide and sphingosine, have previously been implicated in cell growth regulation. Here we show that cell-permeable ceramide analogs and treatment with sphingomyelinase, which hydrolyzes sphingomyelin located on the outer leaflet of the bilayer, increase the progression of quiescent Swiss 3T3 fibroblasts through the S phase of the cell cycle leading to an increase in cell division. Although both potentiate the mitogenic effects of several growth factors [14], sphingomyelinase treatment antagonized the mitogenic effect of the tumor promoter, 12-O-tetradecanoylphorbol 13-acetate (TPA), while ceramide analogs had no effect, and sphingosine, a further metabolite of ceramide, potentiated the mitogenic effect of TPA. Concomitantly, sphingomyelinase, but not ceramide analogs, blunted the rapid increase in membrane-associated protein kinase C (PKC) activity induced by TPA without affecting the translocation of PKC α, δ, ε or ζ isoforms. Moreover, in contrast to sphingosine which activates phospholipase D (PLD) leading to an increase in phosphatidic acid levels, sphingomyelinase, but not ceramide analogs, reduced TPA-stimulated PLD activity. Our results suggest that the signaling pathways utilized by sphingomyelinase differ from those of cell-permeable ceramide analogs, and both act differently than sphingosine. The differential effects of exogenous short-chain ceramide analogs and sphingomyelinase call for caution in using these analogs as tools to study the role of ceramide in diverse cellular functions.

Original languageEnglish (US)
Pages (from-to)311-323
Number of pages13
JournalBiochimica et Biophysica Acta - Lipids and Lipid Metabolism
Volume1348
Issue number3
DOIs
Publication statusPublished - Oct 18 1997

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Keywords

  • Cellular proliferation
  • Ceramide
  • Phospholipase D
  • Protein kinase C
  • Sphingomyelinase

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Endocrinology

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