Design, synthesis, and antitumor efficacy of novel 5-deazaflavin derivatives backed by kinase screening, docking, and ADME studies.

Novel 5-deazaflavins were designed as potential anticancer candidates. Compounds 4j, 4k, 5b, 5i, and 9f demonstrated high cytotoxicity against MCF-7 cell line with IC50 of 0.5-190nM. Compounds 8c and 9g showed preferential activity against Hela cells (IC50: 1.69 and 1.52 µM respectively). However, compound 5d showed notable potency against MCF-7 and Hela cell lines of 0.1 nM and 1.26 µM respectively. Kinase profiling for 4e showed the highest inhibition against a 20 kinase panel. Additionally, ADME prediction studies exhibited that compounds 4j, 5d, 5f, and 9f have drug-likeness criteria to be considered promising antitumor agents deserving of further investigation. SAR study showed that substitutions with 2-benzylidene hydra zino have a better fitting into PTK with enhanced antiproliferative potency. Noteworthy, the incorporation of hydrazino or ethanolamine moieties at position 2 along with small alkyl or phenyl at N-10, respectively revealed an extraordinary potency against MCF-7 cells with IC50 values in the nanomolar range.

Generation of a cell-permeable cycloheptapeptidyl inhibitor against the peptidyl-prolyl isomerase Pin1.

Cyclic peptides are capable of binding and modulating challenging drug targets including protein-protein interactions. However, their lack of membrane permeability prevents their application against intracellular targets. In this study, we show that it is possible to design a cell-permeable and biologically active cycloheptapeptide inhibitor against the intracellular enzyme peptidyl-prolyl isomerase Pin1 by integrating cell-penetrating and target-binding sequences.

Direct Inhibitors of Ras-Effector Protein Interactions.

Activating Ras mutations are associated with ~30% of all human cancers, which often respond poorly to standard therapies. The four Ras isoforms are therefore highly attractive targets for anticancer drug discovery. However, Ras proteins function through protein-protein interactions and their surfaces lack any major pockets for small molecules to bind; as a result they have been declared "undruggable" for the past 30 years. Several breakthroughs during the past few years may finally remove Ras from the list of undruggable proteins. This mini-review discusses the current approaches to developing inhibitors especially cyclic peptides that physically block the interaction between Ras and its downstream effector proteins, which is potentially the most effective approach for treating Ras mutant cancers.