Lead optimization and biological evaluation of diazenylbenzenesulfonamides inhibitors against glyoxalase-I enzyme as potential anticancer agents.

In a previous report, we described the discovery of (E)-5-((8-hydroxyquinolin-5-yl)diazenyl)-2-methylbenzenesulfonamide as a potent inhibitor of GLO-I enzyme with IC50 of 1.28 ± 0.12 µM. Herein, lead optimization of this compound was achieved through targeting the central zinc atom and hydrophilic amino acid residues in the active site of the enzyme. Among the synthesized compounds, compound TS010 showed the most potent inhibitory activity with IC50 of 0.57 ± 0.04 µM. Compound TS013 also showed comparable activity to that of the lead compound with IC50 of 1.14 ± 0.03 µM. Molecular docking studies disclosed the binding mode of the compounds inside the active side of GLO-I enzyme.

Novel Chrysin-De-Allyl PAC-1 Hybrid Analogues as Anticancer Compounds: Design, Synthesis, and Biological Evaluation.

New chrysin-De-allyl-Pac-1 hybrid analogues, tethered with variable heterocyclic systems (4a-4o), were rationally designed and synthesized. The target compounds were screened for in vitro antiproliferative efficacy in the triple-negative breast cancer (TNBC) cell line, MDA-MB-231, and normal human mammary epithelial cells (HMECs). Two compounds, 4g and 4i, had the highest efficacy and selectivity towards MDA-MB-231 cells, and thus, were further evaluated by mechanistic experiments. The results indicated that both compounds 4g and 4i induced apoptosis by (1) inducing cell cycle arrest at the G2 phase in MDA-MB-231 cells, and (2) activating the intrinsic apoptotic pathways in a concentration-dependent manner. Physicochemical characterizations of these compounds suggested that they can be further optimized as potential anticancer compounds for TNBC cells. Overall, our results suggest that 4g and 4i could be suitable leads for developing novel compounds to treat TNBC.

Identification of Human Leukotriene A4 Hydrolase Inhibitors Using Structure-Based Pharmacophore Modeling and Molecular Docking.

Leukotriene B4 (LTB4) is a potent, proinflammatory lipid mediator implicated in the pathologies of an array of inflammatory diseases and cancer. The biosynthesis of LTB4 is regulated by the leukotriene A4 hydrolase (LTA4H). Compounds capable of limiting the formation of LTB4, through selective inhibition of LTA4H, are expected to provide potent anti-inflammatory and anti-cancer agents. The aim of the current study is to obtain potential LTA4H inhibitors using computer-aided drug design. A hybrid 3D structure-based pharmacophore model was generated based on the crystal structure of LTA4H in complex with bestatin. The generated pharmacophore was used in a virtual screen of the Maybridge database. The retrieved hits were extensively filtered, then docked into the active site of the enzyme. Finally, they were consensually scored to yield five hits as potential LTA4H inhibitors. Consequently, the selected hits were purchased and their biological activity assessed in vitro against the epoxide hydrolase activity of LTA4H. The results were very promising, with the most active compound showing 73.6% inhibition of the basal epoxide hydrolase activity of LTA4H. The results from this exploratory study provide valuable information for the design and development of more potent and selective inhibitors.

Synthesis of C3' modified nucleosides for selective generation of the C3'-deoxy-3'-thymidinyl radical: a proposed intermediate in LEE induced DNA damage.

DNA damage pathways induced by low-energy electrons (LEEs) are believed to involve the formation of 2-deoxyribose radicals. These radicals, formed at the C3' and C5' positions of nucleotides, are the result of cleavage of the C-O phosphodiester bond through transfer of LEEs to the phosphate group of DNA oligomers from the nucleobases. A considerable amount of information has been obtained to illuminate the identity of the unmodified oligonucleotide products formed through this process. There exists, however, a paucity of information as to the nature of the modified lesions formed from degradation of these sugar radicals. To determine the identity of the damage products formed via the 2',3'-dideoxy-C3'-thymidinyl radical (C3'(dephos) sugar radical), phenyl selenide and acyl modified sugar and nucleoside derivatives have been synthesized, and their suitability as photochemical precursors of the radical of interest has been evaluated. Upon photochemical activation of C3'-derivatized nucleosides in the presence of the hydrogen atom donor tributyltin hydride, 2',3'-dideoxythymidine is formed indicating the selective generation of the C3'(dephos) sugar radical. These precursors will make the identification and quantification of products of DNA damage derived from radicals generated by LEEs possible.