We describe a ligand system that forms either a dinuclear double helicate or a dinuclear double mesocate dependent upon the size of the metal ion or the steric bulk of the ligand strand.
A series of potent histone deacetylase inhibitors is presented that incorporate alkyl or perfluorinated alkyl chains. Several new compounds show greater in vitro antiproliferative activity than the clinically approved inhibitor, SAHA. Furthermore, the new compounds show up to 5-fold greater activity against cancer cells than healthy cells. This selectivity is in contrast to SAHA, which is more active against the healthy cell line than the cancer cell line tested. Finally, we report an increase in activity for SAHA under mild hyperthermia, indicating that it could be an interesting candidate to use in combination with thermal therapy.
Background
Previously, we evaluated the intracellular mycobactericidal activity of the minor groove binder, S-MGB-364 against the clinical Mycobacterium tuberculosis (Mtb) strain HN878 in macrophages.
Objectives
To assess the mycobactericidal activity of S-MGB-364 in Mtb-infected mice. Further, we investigated a plausible DNA binding mechanism of action of S-MGB-364.
Methods
The anti-TB and host immune effects of intranasal S-MGB-364 or S-MGB-364 encapsulated in non-ionic surfactant vesicles (NIV) were assessed in Mtb-infected mice by cfu enumeration, ELISA, histology, and flow cytometry. DNA binding was examined using native mass spectrometry and UV-vis thermal melt determination. S-MGB interference with DNA-centric biological events was assessed using a representative panel of Mtb and human topoisomerase I, and gyrase assays.
Results
S-MGB-364 bound strongly to DNA as a dimer, significantly increasing the stability of the DNA:S-MGB complex compared with DNA alone. Moreover, S-MGB-364 inhibited the relaxation of Mtb topoisomerase I but not the human form. In macrophages, S-MGB-364 or S-MGB-364-NIV did not cause DNA damage as shown by the low γ-H2AX expression. Importantly, in the lungs, the intranasal administration of S-MGB-364 or S-MGB-364-NIV formulation in Mtb-infected mice was non-toxic and resulted in a ∼1 log cfu reduction in mycobacterial burden, reduced the expression of proinflammatory cytokines/chemokines, altered immune cell recruitment, and importantly reduced recruitment of neutrophils.
Conclusions
Together, these data provide proof of concept for S-MGBs as novel anti-TB therapeutics in vivo.
The first examples of RuII and RhIII piano‐stool complex histone deacetylase (HDAC) inhibitors are presented. The novel complexes have antiproliferative activity against H460 non‐small‐cell lung carcinoma cells that is comparable to the clinically used HDAC inhibitor suberoylanilide hydroxamic acid (SAHA). Strong evidence for HDAC inhibition as a primary mechanism of action is provided. The complexes reported here represent an important step towards the design of highly active and selective HDAC inhibitors.
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The histone deacetylase (HDAC) enzymes have emerged as an important class of molecular targets in cancer therapy, with five inhibitors in clinical use. Recently, it has been shown that a lack of selectivity between the 11 Zn-dependent HDAC isoforms may lead to unwanted side-effects. In this paper, we show that piano stool Ru complexes can act as HDAC inhibitors, and variation in the capping arene leads to differences in HDAC isoform selectivity.
This paper describes the design and synthesis of Strathclyde minor groove binders (S-MGBs) that have been truncated by the removal of a pyrrole ring in order to mimic the structure of the natural product, disgocidine.
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