Comparison of the patterns of DNA alkylation by phenol and amino seco-CBI-TMI compounds: use of a PCR method for the facile preparation of single end-labelled double-stranded DNA.
Both 5-hydroxy- and 5-amino-seco-CBI-TMI minor groove alkylators are very potent cytotoxins. The patterns of alkylation of the two enantiomers of both compounds were compared on a section of the gpt gene. All of the compounds alkylated only at adenines, with the amino compounds being slightly more selective. Consensus alkylation sequences for both S (natural) enantiomers were identical, but for the R (unnatural) enantiomers these varied slightly. The consensus sequences suggest that the S enantiomers bind lying in the 3'-->5' direction from the alkylated adenine, but there was no clear indication of which direction the R enantiomers lie on the DNA. Both S enantiomers were 10- to 100-fold more efficient alkylators than the R enantiomers, and the amino compounds were somewhat more efficient than the corresponding phenols. The S enantiomers were more cytotoxic then the R in both the phenol and amino series. The large amounts of end-labelled DNA required for this work was obtained by first end-labelling appropriate primer oligonucleotides, then amplifying by PCR. Compared with other methods in use, this is a simple and flexible one-step procedure for the preparation of labelled DNA of any sequence. An improvement in the synthesis of 5-hydroxy-seco-CBI-TMI is reported.
Gieseg
M A
MA
Auckland Cancer Society Research Centre, Faculty of Medicine and Health Science, University of Auckland, New Zealand.
Matejovic
J
J
Denny
W A
WA
D000225:Adenine / Q000378:metabolism; D000478:Alkylation; D000818:Animals; D018906:Antineoplastic Agents, Alkylating / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D016466:CHO Cells; D002470:Cell Survival / Q000187:drug effects; D016384:Consensus Sequence; D006224:Cricetinae; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D018983:DNA Footprinting; D006801:Humans; D007211:Indoles / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013237:Stereoisomerism; D014407:Tumor Cells, Cultured
D018906:Antineoplastic Agents, Alkylating; D007211:Indoles; D004247:DNA; D000225:Adenine