Macrocyclic Bisindolylmaleimides as Inhibitors of Protein Kinase C and Glycogen Synthase Kinase-3 Han-Cheng Zhang, a, * Kimberly B. White, a Hong Ye, a David F. McComsey, a Claudia K. Derian, a Michael F. Addo, a Patricia Andrade-Gordon, a Annette J. Eckardt, a Bruce R. Conway, b Lori Westover, b Jun Z. Xu, b Richard Look, b Keith T. Demarest, b Stuart Emanuel b and Bruce E. Maryanoff a a Drug Discovery, Johnson & Johnson Pharmaceutical Research & Development, Spring House, PA 19477-0776, USA b Drug Discovery, Johnson & Johnson Pharmaceutical Research & Development, Raritan, NJ 08869-0602, USA Received 28 March 2003; accepted 24 April 2003 Abstract—Efficient methods were developed to synthesize a novel series of macrocyclic bisindolylmaleimides containing linkers with multiple heteroatoms. Potent inhibitors (single digit nanomolar IC 50 ) for PKC-b and GSK-3b were identified, and compounds showed good selectivity over PKC-a,-g,-d,-e,and-z. Representative compound 5a also had high selectivity in a screening panel of 10 other protein kinases. In cell-based functional assays, several compounds effectively blocked interleukin-8 release induced by PKC-bII and increased glycogen synthase activity by inhibiting GSK-3b. # 2003 Elsevier Ltd. All rights reserved. Protein phosphorylation and dephosphorylation are important processes in the regulation of protein func- tion. Phosphorylation occurs on serine, threonine, and tyrosine residues and is catalyzed by protein kinases, thereby mediating various cellular signaling events that can be associated with human diseases. 1 Given the > 500 protein kinases identified in the human genome, there is a rich mother lode of drug discovery targets for exploration. 2 We have been interested in finding inhibi- tors of enzymes in the protein kinase C (PKC) and gly- cogen synthase kinase-3 (GSK-3) classes as potential therapeutic agents. PKC represents a family of serine/threonine kinases that play a critical role in intracellular signal transduction, gene expression, and the control of cell differentiation and growth. There are at least 11 isozymes that are classified into three subfamilies on the basis of their cofactor requirements: conventional (a, bI, bII, g), novel (d, e, Z, y, m), and atypical (z, i). PKC enzymes regulate vascular tone, permeability, and proliferation, and they are involved in cardiovascular disease, cancer, ischemia, inflammation, and CNS disorders. 3 The b isoform, which is induced in response to hyperglycemia in cardiac, aortic, renal, and retinal tissues, is associated with diabetic complications, particularly retinopathy, angiopathy, nephropathy, macular edema, neuropathy, and cardiomyopathy. 4 GSK-3 is a serine/threonine protein kinase composed of two isoforms (a and b) with high homology (ca. 90%) at the catalytic domain. 5 GSK-3b plays a critical role in glucose homeostasis, CNS function (via the proteins tau and b-catenin), and cancer (via angiogenesis, apoptosis, and tumorigenesis). 6 Inhibition of GSK-3-dependent phosphorylation should activate insulin-dependent gly- cogen synthesis, thereby mimicking the action of insulin to lower plasma glucose. Thus, inhibitors of GSK-3b would afford a novel mode of treating type II diabe- tes. 4b,7 Additionally, GSK-3 inhibitors have therapeutic potential for treating neurodegenerative diseases, bipo- lar disorder, stroke, cancer, and chronic inflammatory diseases. 8 Several PKC inhibitors, such as UCN-01, CGP-41251 and LY-317615, are now in clinical trials as anticancer agents. 9 Ruboxistaurin (LY-333531) is a selective inhi- bitor of PKC-b that is in Phase 3 clinical trials for the 0960-894X/$ - see front matter # 2003 Elsevier Ltd. All rights reserved. doi:10.1016/S0960-894X(03)00644-9 Bioorganic & Medicinal Chemistry Letters 13 (2003) 3049–3053 *Corresponding author. Tel.: +1-215-628-5988; fax: +1-215-628- 4985; e-mail: hzhang@prdus.jnj.com