Synthesis, conformational analysis, and biological evaluation of 1-hexylindolactam-V10 as a selective activator for novel protein kinase C isozymes

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 mu M. These results suggest that 5 could be useful for the functional analysis of novel PKC isozymes.