Benzene-mediated protein kinase C activation.

Extracellular ligands transfer information into the cell through several pathways that operate in an integrated fashion. Protein kinase C, and enzyme that plays a pivotal role in signal transduction, is the molecular target for tumor promoters from the series of phorbol esters. A number of structurally unrelated tumor promoters also enhance protein kinase C, interacting or not interacting with the phorbol ester binding site. Evidence is provided that benzene potently activate protein kinase C in vitro, as well as in intact platelets. The drug does not compete for the phorbol ester binding site and probably affects the hydrophobic environment requires for full enzyme activation. Toluene is equally active. The relevance of the presented findings in the carcinogenic effects of benzene is discussed.