Interaction of aliphatic cap group in inhibition of histone deacetylases by cyclic tetrapeptides

Biocatalytic routes to anti-viral agents and their synthetic intermediates

An assessment of biocatalytic strategies for the synthesis of anti-viral agents, offering guidelines for the development of sustainable production methods for a future COVID-19 remedy.

Design and synthesis of mono and bicyclic tetrapeptides thioester as potent inhibitor of histone deacetylases

Inhibitors of histone deacetylases (HDACs) are a promising class of anticancer agents that have an effect on gene regulation. The naturally occurring cyclic depsipeptide FK228 containing disulfide and Largazole possessing thioester functionalities act as pro-drugs and share the same HDAC inhibition mechanism in cell. Inspired from these facts, we have reported bicyclic tetrapeptide disulfide HDAC inhibitors resembling FK228 with potent activity and enhanced selectivity. In the present study, we report the design and synthesis of several mono and bicyclic tetrapeptide thioester HDAC inhibitors that share the inhibition mechanism similar to Largazole. Most of the compounds showed HDAC1 and HDAC4 inhibition and p21 promoting activity in nanomolar ranges. Among these the monocyclic peptides 1, 2 and bicyclic peptide, 4 are notable demanding more advanced research to be promising anticancer drug candidates.

Bicyclic tetrapeptides as potent HDAC inhibitors: effect of aliphatic loop position and hydrophobicity on inhibitory activity

Several histone deacetylase (HDAC) inhibiting bicyclic tetrapeptides have been designed and synthesized through intramolecular ring-closing metathesis (RCM) reaction and peptide cyclization. We designed bicyclic tetrapeptides based on CHAP31, trapoxin B and HC-toxin I. The HDAC inhibitory and p21 promoter assay results showed that the aliphatic loop position as well as the hydrophobicity plays an important role toward the activity of the bicyclic tetrapeptide HDAC inhibitors.

Bicyclic peptides as potent inhibitors of histone deacetylases: optimization of alkyl loop length

Bicyclic tetrapeptide hydroxamic acids were prepared as histone deacetylase (HDAC) inhibitors, and the evaluated inhibitory activity shows that they are potent against HDAC1 and HDAC4. The in vivo activity depends on alkyl loop length.

Design, synthesis, and biological activity of boronic acid-based histone deacetylase inhibitors

Guided by the proposed catalytic mechanism of histone deacetylases (HDACs), we designed and synthesized a series of boronic acid-based HDAC inhibitors bearing an alpha-amino acid moiety. In this series, compounds (S)-18, 20, and 21 showed potent HDAC-inhibitory activity, highlighting the significance of the (S)-amino acid moiety. In cancer cell growth inhibition assays, compounds (S)-18, 20, and 21 exerted strong activity, and the values of the ratio of the concentration causing 50% growth inhibition (GI(50)) to the concentration causing 50% enzyme inhibition (IC(50)), i.e., GI(50)/IC(50), were low. The potency of these compounds was similar to that of clinically used suberoylanilide hydroxamic acid (SAHA) (2). The results of Western blot analysis indicated that the cancer cell growth-inhibitory activity of compounds (S)-18, 20, and 21 is the result of HDAC inhibition. A molecular modeling study suggested that the hydrated boronic acid interacts with zinc ion, Tyr residue, and His residue in the active site of HDACs. Our findings indicate that these boronic acid derivatives represent an entry into a new class of HDAC inhibitors.