Mechanism of interaction of CC-1065 (NSC 298223) with DNA.
CC-1065 (NSC 298223), a potent new antitumor antibiotic produced by Streptomyces zelensis, interacts strongly with double-stranded DNA and appears to exert its cytotoxic effects through disruption of DNA synthesis. We undertook this study to elucidate the sites and mechanisms of CC-1065 interaction with DNA. The binding of CC-1065 to synthetic and native DNA was examined by differential circular dichroism or by Sephadex chromatography with photometric detection. The binding of CC-1065 with calf thymus DNA was rapid, being complete within 2 hr, and saturated at 1 drug per 7 to 11 base pairs. The interaction of CC-1065 with synthetic DNA polymers indicated a specificity for adenine- and thymine-rich sites. Agarose gel electrophoresis of CC-1065-treated supercoiled DNA showed that CC-1065 did not intercalate. Site exclusion studies using substitutions in the DNA grooves showed CC-1065 to bind primarily in the minor groove. CC-1065 did not cause DNA breaks; it inhibited susceptibility of DNA to nuclease S1 digestion. It raised the thermal melting temperature of DNA, and it inhibited the ethidium-induced unwinding of DNA. Thus, in contrast to many antitumor agents, CC-1065 stabilized the DNA helix. DNA helix overstabilization may be relevant to the mechanism of action of CC-1065.
D000818:Animals; D000876:Anthramycin / Q000378:metabolism; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology*; D002417:Cattle; D002942:Circular Dichroism; D004247:DNA / Q000378:metabolism; D003851:Deoxyribonucleases / Q000494:pharmacology; D000080890:Duocarmycins; D004587:Electrophoresis, Agar Gel; D006358:Hot Temperature; D007211:Indoles; D007933:Leucomycins / Q000378:metabolism / Q000494:pharmacology*; D013950:Thymus Gland / Q000378:metabolism
D000903:Antibiotics, Antineoplastic; D000080890:Duocarmycins; D007211:Indoles; D007933:Leucomycins; D000876:Anthramycin; C018782:CC 1065; D004247:DNA; D003851:Deoxyribonucleases