ABSTRACT
Necroptosis is reported to play a critical role in contributing to a variety of human pathologies. The benzoxazepinone GSK'772 is a potent necroptosis inhibitor optimized using a hit from a DNA-encoded library, which is currently in phase II clinical trials for psoriasis, rheumatoid arthritis, and ulcerative colitis. In the present study, the bioisosterism strategy was applied to replace the amide and benzene ring of GSK'772 based on the co-crystal structure of GSK'772 with its binding target RIPK1. As a result, the novel thio-benzoxazepinones exhibited higher anti-necroptosis activity in a human HT-29 cell necroptosis model. The effect on anti-necroptosis activity by the chirality was significantly reduced in the thio-benzoxazepinones, which was explained by the ligand conformation calculation. Among these analogues, compound 11 (S) and 12 (R) specifically inhibited necroptosis rather than apoptosis with EC50 values of 2.8 and 22.6 nM. They blocked necrosome formation by inhibiting the phosphorylation of RIPK1, RIPK3 and MLKL in necroptotic cells. Collectively, the highly potent thio-benzoxazepinones represent promising lead structures for further development of necroptosis-related diseases.
Subject(s)
Drug Design , Necroptosis/drug effects , Oxazepines/pharmacology , Sulfhydryl Compounds/pharmacology , Cell Survival/drug effects , Dose-Response Relationship, Drug , Humans , Models, Molecular , Molecular Structure , Oxazepines/chemical synthesis , Oxazepines/chemistry , Structure-Activity Relationship , Sulfhydryl Compounds/chemical synthesis , Sulfhydryl Compounds/chemistry , Tumor Cells, CulturedABSTRACT
Necroptosis is a form of programmed cell death that contributes to the pathophysiology of cerebral ischemia/reperfusion (I/R) injury. In this study, bardoxolone (CDDO, 7) was an inhibitor of necroptosis identified from an in-house natural product library. Further optimization led to identify a more potent analogue 20. Compound 20 could effectively protect against necroptosis in human and mouse cells. The antinecroptotic effect could also be synergized with other necroptosis inhibitors. It blocked necrosome formation by targeting Hsp90 to inhibit the phosphorylation of RIPK1 and RIPK3 in necroptotic cells. In vivo, this compound was orally active to alleviate TNF-induced systemic inflammatory response syndrome (SIRS) and cerebral I/R injury. Our results suggested that 20 could be a lead compound for discovering necroptosis inhibitors in I/R treatment.
Subject(s)
Drug Discovery , Infarction, Middle Cerebral Artery/drug therapy , Oleanolic Acid/analogs & derivatives , Systemic Inflammatory Response Syndrome/drug therapy , Administration, Oral , Animals , Cell Survival/drug effects , Cells, Cultured , Dose-Response Relationship, Drug , Female , Humans , Infarction, Middle Cerebral Artery/metabolism , Infarction, Middle Cerebral Artery/pathology , Male , Mice , Mice, Inbred C57BL , Molecular Structure , Necroptosis/drug effects , Oleanolic Acid/administration & dosage , Oleanolic Acid/chemistry , Oleanolic Acid/pharmacology , Rats , Rats, Sprague-Dawley , Structure-Activity Relationship , Systemic Inflammatory Response Syndrome/metabolism , Systemic Inflammatory Response Syndrome/pathologyABSTRACT
Piperlongumine (PL) is a natural alkaloid with broad biological activities. Twelve analogues have been designed and synthesized with non-substituted benzyl rings or heterocycles in this work. Most of the compounds showed better anticancer activities than the parent PL without apparent toxicity in normal cells. Elevation of cellular ROS levels was one of the main anticancer mechanisms of these compounds. Cell apoptosis and cell cycle arrest for the best compound ZM90 were evaluated and similar mechanism of action with PL was demonstrated. The SAR was also characterized, providing worthy directions for further optimization of PL compounds.
