Vol. 62, Issue 2, 297-303, August 2002

trans-Activation and Repression Properties of the Novel Nonsteroid Glucocorticoid Receptor Ligand 2,5-Dihydro-9-hydroxy-10-methoxy-2,2,4-trimethyl-5-(1-methylcyclohexen-3-y1)-1H-[1]benzopyrano[3,4-f]quinoline (A276575) and Its Four Stereoisomers

Chun Wel Lin, Masaki Nakane, Mike Stashko, Doug Falls, Jane Kuk, Loan Miller, Ruth Huang, Curtis Tyree, Jeffrey N. Miner, John Rosen, Philip R. Kym, Mike J. Coghlan, George Carter, and Ben C. Lane

Immunoscience Department, Pharmaceutical Discovery Division, Abbott Laboratories, Abbott Park, Illinois (C.W.L., M.N., M.S., D.F., J.K., L. M., R.H., P.K., G.C., B.C.L.); Ligand Pharmaceuticals, San Diego, California (C.T., J.N.M., J.R.); and Eli Lilly and Co., Lilly Corporate Center, Indianapolis, Indiana (M.J.C.)

Glucocorticoids are potent anti-inflammatory and immunosuppressant agents. However, they also produce serious side effects that limit their usage. It has been proposed that anti-inflammatory properties of glucocorticoids are caused mostly by repression of activator protein 1- and nuclear factor -stimulated synthesis of inflammatory mediators, whereas most of their adverse effects are associated with trans-activation of genes involved with metabolic processes. Our laboratories have sought to discover novel glucocorticoid receptor (GR) ligands that have high repression but low trans-activation activities. We describe here cellular properties of 2,5-dihydro-9-hydroxy-10-methoxy-2,2,4-trimethyl-5-(1-methylcyclohexen-3-y1)-1H-[1]benzopyrano[3,4-f]quinoline (A276575) and its four enantiomers. Similar to dexamethasone, A276575 exhibited high affinity for GR and potently repressed interleukin (IL) 1-stimulated IL-6 production in human skin fibroblasts, prostaglandin (PG) E₂ production in A549 human lung epithelial cells, and concanavalin A-induced monocyte proliferation. In contrast to dexamethasone, A276575 caused smaller induction of aromatase activity in human skin fibroblasts and antagonized dexamethasone-induced activation of an mouse mammary tumor virus-glucocorticoid-response element (GRE) reporter gene construct. Among the four enantiomers of A276575, the two ()-enantiomers showed 10- to 30-fold higher affinities for GR than their respective (+)-enantiomers. Both ()-Syn and ()-Anti enantiomers of A276575 were potent inhibitors of IL-1-stimulated PGE2 production in A549 lung epithelial cells; unexpectedly, however, only the ()-Anti enantiomer inhibited regulated on T-cell activation, normal T-cell expressed and secreted (RANTES) production in A549 cells. In summary, A276575 is a novel, nonsteroidal GR ligand that possesses high repression activities against inflammatory mediator production but has lower GRE trans-activation activities than traditional steroids. Differential repression of RANTES and PGE2 production in a cell by the two ()-enantiomers of A276575 illustrates the complexity of repression by GR.