(2E)-5-[3-[(phenylsulfonyl)amino]phenyl]-pent-2-en-4-ynohydroxamic acid and its derivatives as novel and potent inhibitors of ras transformation

Conformational analogues of Oxamflatin as histone deacetylase inhibitors

Conformational analogues of the hydroxamic acid Oxamflatin compounds, have been synthesised to enable evaluation of the impact of varying the linking section on histone deacetylase inhibition. Preliminary testing indicates treatment of leukaemia cells with each of the analogues leads to significant inhibition of histone deacetylase and reduction in cell growth and proliferation.

Differential effects of histone deacetylase inhibitors in tumor and normal cells-what is the toxicological relevance?

Histone deacetylase (HDAC) inhibitors target key steps of tumor development: They inhibit proliferation, induce differentiation and/or apoptosis, and exhibit potent antimetastatic and antiangiogenic properties in transformed cells in vitro and in vivo. Preliminary studies in animal models have revealed a relatively high tumor selectivity of HDAC inhibitors, strenghtening their promising potential in cancer chemotherapy. Until now, preclinical in vitro research has almost exclusively been performed in cancer cell lines and oncogene-transformed cells. However, as cell proliferation and apoptosis are essential for normal tissue and organ homeostasis, it is important to investigate how HDAC inhibitors influence the regulation of and interplay between proliferation, differentiation, and apoptosis in primary cells as well. This review highlights the discrepancies in molecular events triggered by trichostatin A, the reference compound of hydroxamic acid-containing HDAC inhibitors, in hepatoma cells and primary hepatocytes (which are key targets for drug-induced toxicity). The implications of these differential outcomes in both cell types are discussed with respect to both toxicology and drug development. In view of the future use of HDAC inhibitors as cytostatic drugs, it is highly recommended to include both tumor cells and their healthy counterparts in preclinical developmental studies. Screening the toxicological properties of compounds early in their development process, using a battery of different cell types, will enable researchers to discard those compounds bearing undesirable adverse activity before entering into expensive clinical trials. This will not only reduce the risk for harmful exposure of patients but also save time and money.

Chromatin Modifications as Targets for New Anticancer Drugs

Chromatin proteins undergo diverse posttranslational modifications, esp. acetylation and methylation, that contribute to the control of transcriptional processes. The result of these modifications in its various states is called the histone code. This review presents an overview of those modifications of chromatin proteins that affect the side chains of lysines and arginines and define variations of the chromatin acetylome and methylome. The relevant enzymes are presented and the feasibility to influence their activity by inhibition or activation is discussed. The manipulation of these enzymes is an exciting strategy towards an increased understanding of their role in the functionality of a cell. Additionally, this may lead to new approaches for the treatment of diseases that are based on a dysregulation of transcription, especially cancer.

Stereodefined and polyunsaturated inhibitors of histone deacetylase based on (2E,4E)-5-arylpenta-2,4-dienoic acid hydroxyamides

Syntheses of (2E,4E)-5-arylpenta-2,4-dienoic acid hydroxyamides are described, some of which are potent inhibitors of histone deacetylase, a double bond conferring more than a 10-fold increase in potency compared with the triple bond analogue oxamflatin. Variation of substituents on the aromatic ring has a marked effect on potency, in vitro IC(50) values down to 50 nM being obtained.

Development of potential antitumor agents. Synthesis and biological evaluation of a new set of sulfonamide derivatives as histone deacetylase inhibitors

A series of sulfonamide hydroxamic acids and anilides have been synthesized and studied as histone deacetylase (HDAC) inhibitors that can induce hyperacetylation of histones in human cancer cells. The inhibition of HDAC activity represents a novel approach for intervening in cell cycle regulation. The lead candidates were screened in a panel of human tumor and normal cell lines. They selectively inhibit proliferation, cause cell cycle blocks, and induce apoptosis in human cancer cells but not in normal cells. The structure-activity relationships, the antiproliferative activity, and the in vivo efficacy are described.