Histone deacetylase (HDAC) proteins are promising targets for cancer treatment, as shown by the approval of two HDAC inhibitors for the treatment of cutaneous T-cell lymphoma. HDAC1 in particular has been linked to cell growth and cell cycle regulation and is therefore an attractive target for anticancer drugs. The HDAC1 active site contains a hydrophobic 11 Å active-site channel, with a 14 Å internal cavity at the bottom of the active site. Several computational and biochemical studies have proposed an acetate-escape hypothesis where the acetate byproduct of the deacetylation reaction escapes via the 14 Å internal cavity. Selective HDAC inhibitors that bind to the 14 Å cavity have also been created. To understand the influence of amino acids lining the HDAC1 14 Å cavity in acetate escape and inhibitor binding, we used mutagenesis coupled with acetate competition assays. The results indicate that amino acids lining the 14 Å cavity are critical for catalytic activity and acetate competition, confirming the role of the cavity in acetate escape. In addition, these mutagenesis studies will aid in HDAC1-inhibitor design that exploits the 14 Å cavity.

The work aimed to improve both absorption and hepatic availability of sofosbuvir. Bilosomes and galactose-anchored bilosomes were investigated as potential nanocarriers for this purpose. Sofosbuvir is a class III drug with high solubility and low permeability. Thus, the drug entrapment into lipid-based galactose-anchored carriers would enhance drug permeability and improve its liver availability. The galactosylated taurocholate was designed and synthesized based on molecular docking studies, where both galactose and taurocholate molecules were connected in a way to avoid affecting crucial interactions and avoid steric clashes with their cellular uptake receptors. The suggested nano-carriers were prepared using a thin-film hydration technique with sodium taurocholate and span 60 as stabilizers. The prepared formulae were statistically optimized using a central composite design. The optimized plain and galactosylated formulae, composed of SAA to drug ratio of 1:1 w/w and sodium taurocholate to span ratio of 10:1 w/w, have a vesicular size, zeta potential and entrapment efficiency in the range of 140–150 nm, −50 mV and 85%, respectively. The optimized formulae were lyophilized to increase their physical stability and facilitate accurate drug dosing. In vivo results showed that Sofosbuvir availability in the liver was significantly increased after oral administration of the plain and the galactosylated bilosomal formulae when compared to the oral drug solution with relative targeting efficiencies (RTIs) of 1.51 and 3.66, respectively. These findings confirmed the hypothesis of considering the galactosylated bilosomes a promising nanocarrier to efficiently target sofosbuvir to the liver.

In this work, design, synthesis, and screening of thiophene carboxamides 4–13 and 16–23 as dual vascular endothelial growth factor receptors (VEGFRs) and mitotic inhibitors was reported. All compounds were screened against two gastrointestinal solid cancer cells, HepG-2 and HCT-116 cell lines. The most active cytotoxic derivatives 5 and 21 displayed 2.3- and 1.7-fold higher cytotoxicity than Sorafenib against HepG-2 cells. Cell cycle and apoptosis analyses for compounds 5 and 21 showed cells accumulation in the sub-G1 phase, and cell cycle arrest at G2/M phase. The apoptotic inducing activities of compounds 5 and 21were correlated to the elevation of p53, increase in Bax/Bcl-2 ratio, and increase in caspase-3/7.Compounds 5 and 21 showed potent inhibition againstVEGFR-2 (IC₅₀ = 0.59 and 1.29 μM) and β-tubulin polymerization (73% and 86% inhibition at their IC₅₀ values).Molecular docking was performed with VEGFR-2 and tubulin binding sites to explain the displayed inhibitory activities. Graphical Abstract