Biochimica et biophysica acta
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Biochim. Biophys. Acta · Jul 1997
Effects of bizelesin (U-77,779), a bifunctional alkylating minor groove binder, on replication of genomic and simian virus 40 DNA in BSC-1 cells.
Bizelesin, an AT-specific DNA-alkylating antitumor drug, is a potent inhibitor of genomic DNA replication in BSC-1 cells. Fifty percent inhibition of DNA synthesis was observed at 10 nM bizelesin compared to 160 nM needed for 50% inhibition of RNA synthesis while no inhibition of protein synthesis was observed up to 200 nM. Sedimentation analysis of nascent genomic DNA showed that bizelesin inhibited new replicon initiation and had significantly less effect on replicon maturation. ⋯ Only one bizelesin adduct per several SV40 molecules was needed for a potent inhibition of intracellular SV40 replication. In contrast, only partial inhibition of SV40 replication in vitro was observed with bizelesin-treated naked SV40 DNA as a template. Overall, the results indicate that infrequent bizelesin lesions impede the cellular replication apparatus at the level of the initiation of new replicons.