Identification and characterization of novel sirtuin inhibitor scaffolds

Abstract

The sirtuin proteins are broadly conserved NAD + -dependant deacetylases that are implicated in diverse biological processes including DNA recombination and repair, transcriptional silencing, longevity, apoptosis, axonal protection, insulin signaling and fat mobilization. Because of these associations, the identification of small molecule sirtuin modulators has been of significant interest. Here we report on high throughput screening against the yeast sirtuin, Hst2, leading to the identification of four unique inhibitor scaffolds that also inhibit the human sirtuins, SIRT1, SIRT2 and SIRT3. The identified inhibitor scaffolds range in potency from IC 50 values of 6.5-130 μ M against Hst2. Each of the inhibitor scaffolds binds reversibly to the enzyme, and kinetic analysis reveals that each of the inhibitors is non-competitive with respect to both acetyl-lysine and NAD + binding. Limited SAR analysis of the scaffolds also identifies which functional groups may be important for inhibition. These sirtuin inhibitors are low molecular weight and well-suited for lead molecule optimization, making them useful chemical probes to study the mechanism and biological roles of sirtuins and potential starting points for optimization into therapeutics.

PPAR control: it's SIRTainly as easy as PGC

“…SRT1720 treatment of Zucker fa/fa rats also impoves glucose and insulin responses during an oral glucose tolerance test (Milne et al 2007). In addition, the recent identification of four unique lowmolecular-weight inhibitor scaffolds that inhibit the human sirtuins, including SIRT1, by binding reversibly and noncompetitively with respect to both acetyl-lysine and NAD C binding highlights further potential therapeutic tools (Sanders et al 2009). …”

Rejuvenating Sirtuins: The Rise of a New Family of Cancer Drug Targets

“…The fluorescence of the wells is then measured using a fluorometric reader and the percentage of inhibition exerted by each compound is calculated. The most recent sirtuin inhibitors identified by these assay kits include: indoles [68]; a non-peptide molecule containing an N-thioacetyl lysine [59]; four novel scaffolds [113]; tri- and tetrecyclic pyrimidinediones [114]; molecules containing N(epsilon)-modified lysine [58]; tenovins [24]; pseudopeptidic compounds [88]; JGB1741, a small molecule developed on sirtinol structure [115] and other sirtinol analogues [116]; cambinol analogs [117]; 2-anilinobenzamide derivatives [118]. It has been suggested that the aminomethylcoumarin moiety of the fluorogenic substrates used in the SIRT1 Fluor de Lys ® assay can affect the binding of other small molecules to the enzyme [102, 103].…”

Writers and Readers of Histone Acetylation: Structure, Mechanism, and Inhibition

“…Although subnanomolar HDAC inhibitors are available, they show poor selectivity among the class I, II, and IV HDACs (Marsoni et al 2008), and although potent sirtuin activators and inhibitors have been reported they also show modest selectivity (Sanders et al 2009). HDAC-specific inhibitors are thus actively being pursued, but obtaining them may be particularly challenging because the class I, II, IV, and class III HDACs each share a highly homologous active site and catalytic mechanism (Marsoni et al 2008).…”