A selective inhibitor of N8-acetylspermidine deacetylation in mice and HeLa cells without effects on histone deacetylation.
The inhibitory effects of 7-[N-(3-aminopropyl)amino]heptan-2-one (APAH) on N8-acetylspermidine deacetylation were studied. In in vitro studies, APAH produced inhibition (apparent Ki of 0.18 microM) of N8-acetylspermidine deacetylation by the 100,000g supernatant fraction of rat liver. This apparent Ki was 60-fold less than the apparent Km (11 microM) for deacetylation of the substrate, N8-acetylspermidine, suggesting that APAH could be a potent, effective inhibitor in vivo. APAH was administered to mice by intraperitoneal injection at a dose of 200 mg/kg, and polyamine and acetylpolyamine levels in liver and spleen were measured. In tissues of control mice, N8-acetylspermidine was not detectable but increased to detectable levels 30-360 min after APAH treatment. These data are consistent with inhibition of the deacetylase by APAH. Increases in putrescine and N1-acetylspermidine levels occurred in liver after APAH treatment with increases in N1-acetylspermidine levels observed in spleen. In HeLa cells, a significant increase in N8-acetylspermidine was observed following 24 h exposure to 10 microM APAH while no change occurred in the acetylation level of HeLa cell histones. In contrast, 24 h exposure to 10 mM sodium butyrate produced no change in N8-acetylspermidine levels and an increase in the acetylation level of histones H4 and H2B. These results suggest that APAH has a relatively selective inhibitory effect on N8-acetylspermidine but not histone deacetylation. This is the first report of significant levels of N8-acetylspermidine in animal tissues and of the effects of in vivo inhibition of N8-acetylspermidine deacetylase.
Department of Pharmacology, School of Pharmacy, University of the Pacific, Stockton, California 95211.
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Marchant
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Dredar
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Manneh
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Alshabanah
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Matthews
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Fries
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Blankenship
D000107:Acetylation; D000581:Amidohydrolases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D003720:Densitometry; D003959:Diamines / Q000494:pharmacology* / Q000633:toxicity; D006367:HeLa Cells; D006657:Histones / Q000378:metabolism*; D006801:Humans; D008099:Liver / Q000032:analysis / Q000201:enzymology; D008297:Male; D051379:Mice; D011700:Putrescine / Q000032:analysis; D013095:Spermidine / Q000031:analogs & derivatives* / Q000032:analysis / Q000378:metabolism; D013154:Spleen / Q000032:analysis / Q000201:enzymology
D003959:Diamines; D006657:Histones; C060477:7-(N-(3-aminopropyl)amino)heptan-2-one; C030223:N(8)-acetylspermidine; D000581:Amidohydrolases; C018738:acetylspermidine deacetylase; D013095:Spermidine; D011700:Putrescine