Design of selective and soluble inhibitors of tumor necrosis factor-alpha converting enzyme (TACE)

A program to improve upon the in vitro, in vivo, and physicochemical proper ties of N-hydroxyformamide TACE inhibitor GW 3333 (1) is described. Using t he primary structure of pro-TNF-alpha, along with a homology model of the c atalytic domain of TACE based on the X-ray diffraction coordinates of adama lysin, we synthesized N-hydroxyformamide TACE inhibitors containing a P2' a rginine side chain. Introduction of nitro and sulfonyl electron-withdrawing groups covalently bound to the P2' guanidine moiety rendered the inhibitor s electronically neutral at cellular pH and led to potent inhibition of TNF -alpha release from stimulated macrophages. Inhibitors containing these arg inine mimetics were found to have increased solubility in simulated gastric fluid (SGF) relative to 1, allowing for the incorporation of lipophilic P1 ' side chains which had the effect of retaining potent TACE inhibition, but reducing potency against matrix metalloproteases (MMPs) thus increasing ov erall selectivity against MMP1, MMP3, and MMP9. Selected compounds showed g ood to excellent in vivo TNF inhibition when administered via subcutaneous injection. One inhibitor, 28a, with roughly 10x selectivity over MMPI and M MP3 and high solubility in SGF, was evaluated in the rat zymosan-induced pl euisy model of inflammation and found to inhibit zymosan-stimulated pleural TNF-alpha elevation by 30%.