This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Stimson, L. Articles by Aherne, G. W. Search for Related Content PubMed PubMed Citation Articles by Stimson, L. Articles by Aherne, G. W.

¹ Cancer Research UK Centre for Cancer Therapeutics at the Institute of Cancer Research, Sutton, Surrey, United Kingdom and ² Wellcome Trust/Cancer Research UK Institute of Cancer and Developmental Biology, University of Cambridge, Cambridge, United Kingdom

Requests for reprints: G. Wynne Aherne, Cancer Research UK Centre for Cancer Therapeutics at the Institute of Cancer Research, Haddow Laboratories, 15 Cotswold Road, Sutton, Surrey SM2 5NG, United Kingdom. Phone: 44-208-722-4258; Fax: 44-208-722-4324. E-mail: wynne.aherne{at}icr.ac.uk

Histone acetylation plays an important role in regulating the chromatin structure and is tightly regulated by two classes of enzyme, histone acetyltransferases (HAT) and histone deacetylases (HDAC). Deregulated HAT and HDAC activity plays a role in the development of a range of cancers. Consequently, inhibitors of these enzymes have potential as anticancer agents. Several HDAC inhibitors have been described; however, few inhibitors of HATs have been disclosed. Following a FlashPlate high-throughput screen, we identified a series of isothiazolone-based HAT inhibitors. Thirty-five N-substituted analogues inhibited both p300/cyclic AMP–responsive element binding protein–binding protein–associated factor (PCAF) and p300 (1 to >50 µmol/L, respectively) and the growth of a panel of human tumor cell lines (50% growth inhibition, 0.8 to >50 µmol/L). CCT077791 and CCT077792 decreased cellular acetylation in a time-dependent manner (2–48 hours of exposure) and a concentration-dependent manner (one to five times, 72 hours, 50% growth inhibition) in HCT116 and HT29 human colon tumor cell lines. CCT077791 reduced total acetylation of histones H3 and H4, levels of specific acetylated lysine marks, and acetylation of -tubulin. Four and 24 hours of exposure to the compounds produced the same extent of growth inhibition as 72 hours of continuous exposure, suggesting that growth arrest was an early event. Chemical reactivity of these compounds, as measured by covalent protein binding and loss of HAT inhibition in the presence of DTT, indicated that reaction with thiol groups might be important in their mechanism of action. As one of the first series of small-molecule inhibitors of HAT activity, further analogue synthesis is being pursued to examine the potential scope for reducing chemical reactivity while maintaining HAT inhibition.

The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

Note: P. Workman is a Cancer Research UK Life Fellow.

³ S. Gowan and L. Kelland, unpublished data.

Received 4/28/05; revised 6/14/05; accepted 7/22/05.