[(DIMETHYLAMINO)METHYL]-10,11,14,15-TETRAHYDRO-4,9 ,4-H][1,4,13]OXADIAZACYCLOHEXADECENE-1,3(2H)-DIONE (LY333531) AND RELATED ANALOGS - ISOZYME-SELECTIVE INHIBITORS OF PROTEIN-KINASE C-BETA/

Protein kinase C (PKC) is a family of closely related serine and threo nine kinases. Overactivation of some PKC isozymes has been postulated to occur in several disease states, including diabetic complications. Selective inhibition of overactivated PKC isozymes may offer a unique therapeutic approach to disease states such as diabetic retinopathy. A novel series of 14-membered macrocycles containing a N-N'-bridged bis indolylmaleimide moiety is described. A panel of eight cloned human PK C isozymes (alpha, beta I, beta II, gamma, delta, epsilon, zeta, eta) was used to identify the series and optimize the structure and associa ted activity relationship. The dimethylamine analogue LY333531 (1), 4- h][1,4,13]oxadiazacyclohexadecene-1,3(2H)-dione, inhibits the PKC beta I (IC50 = 4.7 nM) and PKC beta II (IC50 = 5.9 nM) isozymes and was 76 - and 61-fold selective for inhibition of PKC beta I and PKC beta II i n comparison to PKC alpha, respectively. The additional analogues desc ribed in the series are also selective inhibitors of PKC beta. LY33353 1 (1) exhibits ATP dependent competitive inhibition. of PKC beta I and is selective for PKC in comparison to other ATP dependent kinases (pr otein kinase A, calcium calmodulin, caesin kinase, src tyrosine kinase ). The cellular activity of the series was assessed using bovine retin al capillary endothelial cells. Retinal endothelial cell dysfunction h as been implicated in the development of diabetic retinopathy. Plasmin ogen activator activity stimulated by a phorbol ester (4 beta-phorbol 12,13-dibutyrate) in endothelial cells was inhibited by the compounds in the series with ED(50) values ranging from 7.5 to 0.21 mu M. A comp arison of the PKC isozyme and related ATP dependent kinase inhibition profiles is provided for the series and compared to the profile for st aurosporine, a nonselective PKC inhibitor. The cellular activity of th e series is compared with that of the kinase inhibitor staurosporine.