Naturally Occurring Alkylresorcinols That Mediate DNA Damage and Inhibit Its Repair

Abstract

A study of di- and trihydroxyalkylbenzenes and bis(dihydroxyalkylbenzenes) revealed that several compounds were capable of both mediating Cu2+-dependent DNA cleavage and strongly inhibiting DNA polymerase β. The most potent DNA polymerase β inhibitors were bis(dihydroxyalkylbenzenes) 5 and 6; compounds 3 and 4 were also reasonably potent. The length of the alkyl substituent was found to be a critical element for DNA polymerase β inhibition, since compounds 1 and 2 had shorter substituents than 3 and were completely inactive. Lineweaver−Burk plots revealed that 3, 4, and 6 exhibited mixed inhibition of DNA polymerase β with respect to both activated DNA and dTTP. Unsaturated bis(dihydroxyalkylbenzene) 5 was a pure noncompetitive inhibitor with respect to both substrates and associated avidly with the enzyme whether or not it was in complex with its substrate(s). Copper(II)-mediated DNA cleavage was the most pronounced for the trihydroxyalkylbenzene 3, consistent with an earlier report [Singh, U. S., Scannell, R. T., An, H., Carter, B. J., and Hecht, S. M. (1995) J. Am. Chem. Soc. 117, 12691−12699]. Unsaturated bis(dihydroxyalkylbenzene) 5 was the next most active DNA cleaving agent, followed by the dihydroxyalkylbenzene 4. The saturated bis(dihydroxyalkylbenzene) (6) did not cleave DNA well in a cell-free system under the conditions studied but nonetheless potentiated the effects of bleomycin to the greatest extent in cell culture studies. Interestingly, compound 5 produced a reduction in the numbers of viable cells when incubated in the presence of bleomycin and a further reduction in the numbers of viable cells in the presence of both bleomycin and Cu2+. The same effect was noted to a lesser extent for compound 3 but not for 4 or 6.

Naturally Occurring Alkylresorcinols That Mediate DNA Damage and Inhibit Its Repair

Citations Over Time

Abstract

Related Papers