Synthesis and biological study of class I selective HDAC inhibitors with NO releasing activity.

Based on the multi-mechanism antitumor strategy and the regulatory effect of nitric oxide (NO) on histone deacetylases (HDACs), a series of N-acyl-o-phenylenediamine-based HDAC inhibitors equipped with the phenylsulfonylfuroxan module as NO donor was designed, synthesized and biologically evaluated. The in vitro HDAC inhibitory assays revealed that compared with the clinical class I selective HDAC inhibitor MS275, compounds 7c, 7d and 7e possessed similar HDAC inhibitory potency and selective profile, which were confirmed by the results of western blot analysis. The western blot analysis also showed that NO scavenger N-acetyl cysteine (NAC) could weaken the intracellular HDAC inhibitory ability of compound 7c, supporting the HDAC inhibitory effect of NO generated by 7c. It is worth noting that compounds 7c, 7d and 7e exhibited more potent in vitro antiproliferative activities than MS275 against all four tested solid tumor cell lines. The promising in vivo antitumor potency of 7c was demonstrated in a HCT116 xenograft model.

Novel leucine ureido derivatives as aminopeptidase N inhibitors using click chemistry.

The over-expression of aminopeptidase N on diverse malignant cells is associated with the tumor angiogenesis and metastasis. In this report, one new series of leucine ureido derivatives containing the triazole moiety was designed, synthesized and evaluated as APN inhibitors. Among them, compound 13v showed the best APN inhibition with an IC50 value of 0.089 ±â€¯0.007 µM, which was two orders of magnitude lower than that of bestatin (IC50 = 9.4 ±â€¯0.5 µM). Compound 13v also showed dose-dependent anti-angiogenesis activities. Even at the lower concentration (10 µM), compound 13v presented similar anti-angiogenesis activity compared with bestatin at 100 µM in both the human umbilical vein endothelial cells (HUVECs) capillary tube formation assay and the rat thoracic aorta rings test. Moreover, compared with bestatin, 13v exhibited comparable, if not better in vivo anti-metastasis activity in a mouse H22 pulmonary metastasis model.

Discovery of meta-sulfamoyl N-hydroxybenzamides as HDAC8 selective inhibitors.

In the past decade, although research and development of histone deacetylase (HDAC) inhibitors as therapeutic agents have achieved great accomplishments, especially in oncology field, there is still an urgent need for the discovery of isoform-selective HDAC inhibitors considering the side effects caused by nonselective HDAC inhibitors. HDAC8, a unique class I zinc-dependent HDAC, is becoming a potential target in cancer and other diseases. In the current study, a novel series of N-hydroxy-3-sulfamoylbenzamide-based HDAC8 selective inhibitors (12a-12p) were designed and synthesized, among which compounds 12a, 12b and 12c exhibited potent HDAC8 inhibition with two-digit nanomolar IC50 values, and considerable selectivity over HDAC2 (>180-fold) and HDAC6 (∼30-fold) which was confirmed by western blot analysis. It is worth noting that 12a, 12b and 12c displayed highly selective anti-proliferative activity to T-cell leukemia cell lines Jurkat, Molt-4 and neuroblastoma cell line SK-N-BE-(2). Such selective cytotoxicity was also observed in the well-known HDAC8 selective inhibitor PCI-34051 but not in the pan-HDAC inhibitors SAHA and PXD101, indicating that HDAC8 selective inhibitor should have preferable benefit-risk profile in comparison with pan-HDAC inhibitor. Finally, the HDAC8 selectivity of 12a, 12b and 12c was rationalized by molecular docking study.

Nitric oxide donor hybrid compounds as promising anticancer agents.

Nitric oxide (NO) plays important roles in cardiovascular regulation, nerve transmission delivery and immune responses. In the last semicenturry, it has been proved that though low concentration of NO is tumor-promoting, high concentration of NO could exhibit multiple antitumor effects, which led to the research and development of kinds of NO donors and NO donor hybrid compounds as antitumor agents. Herein, the recent development of NO donor hybrid compounds is briefly reviewed.