The role of DNA synthesis inhibition in the cytotoxicity of 2′,2′-difluoro-2′-deoxycytidine

Abstract

Cytotoxicity from the anticancer drug 2′,2′-difluoro-2′-deoxycytidine (dFdCyd) has been correlated with its incorporation into DNA. However, cytotoxicity may also result from inhibition of DNA synthesis, due to either (1) dFdCyd diphosphate-mediated inhibition of ribonucleotide reductase, or (2) direct inhibition of DNA polymerases by the 5′-triphosphate of dFdCyd (dFdCTP). To elucidate the role of DNA synthesis inhibition in the cytotoxicity of dFdCyd, we compared dFdCyd to hydroxyurea (HU), a ribonucleotide reductase inhibitor, and aphidicolin, an inhibitor of DNA polymerases, in the U251 and D54 human glioblastoma cell lines.