Design, synthesis, bioevaluation of LFC- and PA-tethered anthraquinone analogues of mitoxantrone.

The clinical application of mitoxantrone (MTZ), a DNA-intercalating topoisomerase II (topo II) poison, has been largely limited by the risk of secondary tumor and severe myelosuppression. To develop more effective antineoplastic agents with less toxicity, a spectrum of anthraquinone analogues of MTZ were herein designed and synthesized based on the concept of 'enhancing protein backbone-binding', by rationally introducing hydrophobic long fatty acid chain (LFC) and hydrophilic polyamine (PA) components, which are reported to function as effective tumor-targeting tethers. The SAR exploration implicated that in our synthesized molecules, the introduction of both lipophilic LFC and hydrophilic PA fragment is plausibly beneficial to the anti-proliferative potency, with a certain degree of selectivity between the hematopoietic and solid malignant cells, which still need to be further accurately confirmed. Meanwhile, many compounds, the LFC-tethered 5d2 and PA-bridged 8c in particular, provided satisfactory topo IIα inhibition by acting as DNA non-intercalators, largely attributable to their strong adaptability to three binding regions (pocket I, II and III) and also the generated H-bonding interactions between inhibitors and key residues of topo IIα. In brief, 5d2 and 8c might be promising hits for further exploitation of more potent topo IIα inhibitors.

Recent Research Advances in Selective Matrix Metalloproteinase-13 Inhibitors as Anti-Osteoarthritis Agents.

Matrix metalloproteinase-13 (MMP-13) plays a key role in the degradation of type II collagen in cartilage and bone in osteoarthritis (OA). The subtle differences between the S1' loop of MMP-13 and that of other MMPs offer a structural base for the design of selective MMP-13 inhibitors to mitigate the unperceived risk associated with inhibiting other MMP isoforms. In this review, we summarize zinc-binding and non-zinc-binding selective MMP-13 inhibitors. The zinc-binding MMP-13 inhibitors contain a small set of zinc-binding groups (ZBGs), including hydroxamic acid, pyrimidinetrione, reversed hydroxamic acid and hydantoin, carboxylic acid, 1,2,4,-triazole, and 1,2,4,-triazolone. The non-zinc-binding MMP-13 inhibitors have different structural scaffolds, including diphenyl ethers, biaryls (aryltetrazoliums, arylfurans, pyrazole-indoles), pyrimidines, and aryl/cycloalkyl-fused pyrimidines. This review provides a systematic overview of recent developments in MMP-13 inhibitors for the treatment of OA, with emphasis on their enzyme inhibitory potency, selectivity, and biological activities, and highlights the various binding modes of typical inhibitors with MMP-13.