Effects of β-Arabinofuranosyladenine on the Growth and Repair of Potentially Lethal Damage in Ehrlich Ascites Tumor Cells

β-D-Arabinofuranosyladenine (β-araA) inhibits the growth of Ehrlich ascites tumor cells by selective inhibition of DNA synthesis via DNA polymerases. RNA and protein synthesis are not significantly affected. Addition of β-araA to the cells after irradiation resulted in a concentration-dependent decrease in survival, presumably due to the inhibition of the repair of potentially lethal damage. Since β-araA selectively inhibits DNA polymerases it is suggested that repair of potentially lethal damage involves steps at the DNA level which require some polymerization. These repair steps take place in the DNA with a velocity comparable to that of the repair of potentially lethal damage. The inhibition of the repair of potentially lethal damage by β-araA was modified by the addition of deoxyadenosine; this supports the finding that β-araA acts competitively against dATP at the molecular level. The inhibition of the repair of potentially lethal damage by β-araA, which is partly reversible, resulted in a concentrat...