ABSTRACT
Conventional and novel protein kinase C (PKC) isozymes are the main targets of tumor promoters. We developed 1-hexylindolactam-V10 ( 5) as a selective activator for novel PKC isozymes that play important roles in various cellular processes related to tumor promotion, ischemia--reperfusion injury in the heart, and Alzheimer's disease. The compound existed as a mixture of three conformers. The trans-amide restricted analogues of 5 ( 14 and 15) hardly bound to PKC isozymes, suggesting that the active conformation of 5 could be that with a cis-amide. Compound 5 selectively translocated novel PKC isozymes over conventional PKC isozymes in HeLa cells at 0.1-1 microM. These results suggest that 5 could be useful for the functional analysis of novel PKC isozymes.
Subject(s)
Enzyme Activators/chemical synthesis , Indoles/chemical synthesis , Lactams/chemical synthesis , Protein Kinase C/metabolism , Cell Membrane/enzymology , Enzyme Activators/chemistry , Enzyme Activators/pharmacology , HeLa Cells , Humans , Indoles/chemistry , Indoles/pharmacology , Isoenzymes/genetics , Isoenzymes/metabolism , Lactams/chemistry , Lactams/pharmacology , Models, Molecular , Molecular Conformation , Mutation , Protein Binding , Protein Kinase C/genetics , Protein Transport , Structure-Activity RelationshipABSTRACT
Benzolactone-V8 (4) is a lactone analogue of the artificial tumor promoter benzolactam-V8 (1). To investigate the effect of hydrophobic substituents at positions 7 and 15 of 4 on binding selectivity for protein kinase C (PKC) isozymes, 7- and 15-decylbenzolactone-V8 (7, 8) were synthesized and their binding affinities for synthetic PKC isozyme C1 peptides were examined. Compound 8 showed moderate selectivity for novel PKC isozymes similar to 9-decylbenzolactone-V8 (5), while 7 was less selective. Compounds 7 and 8 showed no significant selectivity among novel PKC isozymes unlike 8-decylbenzolactone-V8 (6). These results indicate that the introduction of a hydrophobic substituent at position 8 of 4 is most effective in the development of PKC epsilon- and PKCeta-selective binders.
