Actinomycin D specifically inhibits the interaction between transcription factor Sp1 and its binding site.
The mode of action of many anticancer drugs involves DNA interactions. We here examine the ability of actinomycin D to alter the specific binding of transcription factors Spl and NFkappaB to their DNA sequences. Employing an electrophoretic mobility shift assay, it is shown that actinomycin D inhibits complex formation between nuclear proteins present in the extracts from stimulated human umbilical vein endothelial cells and the Sp1-binding site. Actinomycin D is also able to induce disruption of preformed DNA-protein complexes, pointing to the importance of an equilibrium of three components: actinomycin D, protein and DNA for drug action. The effect of actinomycin D is sequence-specific, since no inhibition is observed for interaction of nuclear proteins with the NFkappaB binding site. The results support the view that DNA-binding drugs displaying high sequence-selectivity can exhibit distinct effects on the interaction between DNA and different DNA-binding proteins.
Department of General Chemistry, Institute of Physiology and Biochemistry, Medical University of Lódź, Poland. mczyz@psk2.am.lodz.pl
M
M
Czyz
M
M
Gniazdowski
D000903:Antibiotics, Antineoplastic / Q000494:pharmacology*; D001665:Binding Sites; D002478:Cells, Cultured; D003609:Dactinomycin / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007364:Intercalating Agents / Q000494:pharmacology*; D016328:NF-kappa B / Q000378:metabolism*; D011485:Protein Binding; D014157:Transcription Factors / Q000378:metabolism*
D000903:Antibiotics, Antineoplastic; D007364:Intercalating Agents; D016328:NF-kappa B; D014157:Transcription Factors; D003609:Dactinomycin