Effects of diethyldithiocarbamate and endogenous polyamine content on cellular responses to hydrogen peroxide cytotoxicity

P. M. Harari, M. E. Tome, D. J.M. Fuller, S. W. Carper, E. W. Gerner

Research output: Contribution to journalArticle

8 Scopus citations

Abstract

In exponential-phase Chinese-hamster cells, 0.1 mM-diethyldithiocarbamate (DDC) afforded greater than 1 log survival protection to cultures treated before and during exposure to 1 mM-H2O2. Both DDC and H2O2 treatment stimulated the activity of ornithine decarboxylase (ODC), the first enzyme in polyamine synthesis, within 4 h of exposure. DDC, and to a lesser degree H2O2, also stimulated the activity of spermidine N1-acetyltransferase (SAT), the rate-limiting enzyme in polyamine catabolism. The increase in SAT activity, after exposure to DDC or another stress (heat shock), was inhibited in cells depleted of putrescine and spermidine by α-difluoromethylornithine (DFMO), the enzyme-activated suicide inhibitor of ODC. Pretreatment with DFMO or heat shock also induced resistance to H2O2 cytotoxicity. Since SAT activity is low in resting cells, yet stimulation of enzyme activity depends on endogenous spermidine pools, these results suggest that the expression of SAT activity occurs by a mechanism involving a stress-dependent displacement of spermidine into a new intracellular compartment. The stimulation of ODC and SAT activities does not appear to be a necessary component of the mechanism by which DDC protects cells from H2O2 cytotoxicity, although spermidine displacement may be a common facet of the cellular response to stress.

Original languageEnglish (US)
Pages (from-to)487-490
Number of pages4
JournalBiochemical Journal
Volume260
Issue number2
DOIs
StatePublished - 1989

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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