Synthesis and Structure–Activity Relationship Studies of 4-((2-Hydroxy-3-methoxybenzyl)amino)benzenesulfonamide Derivatives as Potent and Selective Inhibitors of 12-Lipoxygenase

Abstract

Human lipoxygenases (LOXs) are a family of iron-containing enzymes which catalyze the oxidation of polyunsaturated fatty acids to provide the corresponding bioactive hydroxyeicosatetraenoic acid (HETE) metabolites. These eicosanoid signaling molecules are involved in a number of physiologic responses such as platelet aggregation, inflammation, and cell proliferation. Our group has taken a particular interest in platelet-type 12-(S)-LOX (12-LOX) because of its demonstrated role in skin diseases, diabetes, platelet hemostasis, thrombosis, and cancer. Herein, we report the identification and medicinal chemistry optimization of a 4-((2-hydroxy-3-methoxybenzyl)amino)benzenesulfonamide-based scaffold. Top compounds, exemplified by 35 and 36, display nM potency against 12-LOX, excellent selectivity over related lipoxygenases and cyclooxygenases, and possess favorable ADME properties. In addition, both compounds inhibit PAR-4 induced aggregation and calcium mobilization in human platelets and reduce 12-HETE in β-cells.

Platelet 12-LOX is essential for FcγRIIa-mediated platelet activation

“…This study is the first to demonstrate that 12-LOX is an essential component of FcgRIIa immunemediated platelet activation. Human platelets treated with a highly selective 12-LOX inhibitor, ML355, 27 or FcgRIIa transgenic mouse platelets deficient in 12-LOX, showed significantly attenuated aggregation in response to FcgRIIa-mediated activation. To investigate the underlying mechanism by which 12-LOX regulates FcgRIIa-mediated platelet activation, the activity of multiple signaling intermediates in the FcgRIIa pathway were assessed in the presence of the 12-LOX inhibitor, ML355.…”

“…21,22,24,26 As 12-LOX activity was recently shown to be required for normal GPVI-mediated platelet activation, 21,22 we sought to determine if 12-LOX activity is an essential component of FcgRIIa signaling in platelets. 10 In this study, human platelets were treated with the selective 12-LOX inhibitor, ML-355, 27 or vehicle control prior to FcgRIIa stimulation to determine if 12-LOX plays a role in the FcgRIIa signaling pathway. Pharmacologic inhibition of 12-LOX activity in human platelets attenuated FcgRIIa-mediated platelet aggregation.…”

Selective inhibition of 12-lipoxygenase protects islets and beta cells from inflammatory cytokine-mediated beta cell dysfunction

“…Less-than-desirable aqueous solubility has limited the development of parenteral formulations with which to perform long-term proof-of-concept studies in animal models of diabetes. This limitation is expected to be overcome in future studies following the recent identification of a new chemical class of selective 12-lipoxygenase inhibitors [38].…”

Expression Pattern of 12-Lipoxygenase in Human Islets With Type 1 Diabetes and Type 2 Diabetes

“…Although there are 5 lipoxygenase genes (ALOX-5, ALOX-12S, ALOX-12R, ALOX-15-1 and ALOX- in humans, only ALOX-12S mRNA is expressed in human islets, and plays a role in islet health (4,5). 12-LO has been implicated in the early stages of autoimmune diabetes development. 12/15-LO (functional equivalent for human 12-LO) null mice are fully protected from low-dose streptozotocin-induced and spontaneous diabetes development on the nonobese diabetic (NOD) background (6,7).…”

“…Furthermore, treatment with proinflammatory cytokines has increased expression of 12-LO in human islets, and decreased beta cell function following treatment with the downstream product of 12-LO activation, 12-S-Hydroxyeicosatetraenoic acid (12-S-HETE) (5). Inhibiting 12-LO in human islets decreased 12(S)-HETE levels and improved islet health (12). Mechanisms of 12-LO-induced damage can occur by activating endoplasmic reticulum stress pathways (13), as well as by contributing to increased oxidative stress (8).…”