S-methyl-KE-298 is an active metabolite of KE-298. KE-298 inhibits matrix metalloproteinase (MMP-1) production from rheumatoid arthritis (RA) synovial cells.
S-methyl-KE-298 is a methyl conjugate of deacetyl-KE-298 is plasma[1]. In vitro protein binding of KE-298 and its plasma metabolites, deacetyl-KE-298 (M-1) and S-methyl-KE-298 (M-2), is high in rat (>97%), dog (>89%) and human plasma (>99%), respectively[2]. KE-298 blocks this IL-1β-induced pro-MMP-2 activation and MT1-MMP expression, but does not affect IL-1β-induced tissue inhibitor of metalloproteinase-2 (TIMP-2) secretion from rheumatoid synovial cells. KE-298 inhibits MMP-1 production from rheumatoid arthritis (RA) synovial cells by affecting a transcription factor, AP-1. KE-298 inhibits the basal levels of MT1-MMP expression of unstimulated rheumatoid synovial cells[3].
[1]. Yoshida H, et al. Identification of metabolites of KE-298, a new antirheumatic drug, and its physiological properties in rats. Biol Pharm Bull. 1996 Mar;19(3):424-9. [2]. Endo H, et al. Stereoselectivity and species difference in plasma protein binding of KE-298 and its metabolites. Biol Pharm Bull. 2001 Jul;24(7):800-5. [3]. Honda S, et al. Expression of membrane-type 1 matrix metalloproteinase in rheumatoid synovial cells. Clin Exp Immunol. 2001 Oct;126(1):131-6.