Inactivation of protein farnesyltransferase by active-site-targeted dicarbonyl compounds

Abstract

Upon farnesylation by protein farnesyltransferase (FTase), key proteins become compartmentalized in cells. For example, cell membrane localization is essential for the mitogenic role of mutant Ras protein, which acts as a switch for cancer cell proliferation. We report that α-dicarbonyl compounds derived from the isoprenoid skeleton or other hydrophobic groups potently obstruct farnesylation of a Ras model peptide by human recombinant FTase in vitro. A geranyl-derived isoprenoid diketone, 5,9-dimethyl-8-decene-2,3-dione, at 17 μM caused a 62% reduction in FTase activity after 30 minutes. A farnesyl-derived isoprenoid diketone, 5,9,13-trimethyl-8,12-tetradecadiene-2,3-dione, at 93 μM caused a 94% reduction after 30 minutes. Other dicarbonyl compounds found to be effective against FTase in vitro were (±)-6-(camphorquinone-10-sulfonamido)-hexanoic acid, 4,4′-biphenyldiglyoxaldehyde, dehydroascorbic acid 6-palmitate, 2-oxododecanal, and phenylglyoxal. Higher concentrations of the α-dicarbonyl compound resulted in more rapid and more extensive inactivation. These findings demonstrate that α-dicarbonyl compounds targeted to FTase interfere with protein farnesylation in vitro and may lead to derivatives that have utility as chemotherapeutic agents.