Comparison of CPT 11- and VP-16- induced topoisomerase I and II cleavage to predicted cleavage sites.

<p>Topoisomerase I and II DNA cleavage was induced by treatment of HTori-3 cells with 10 µM CPT-11 or VP-16, respectively, for 1.5 hours. The location of CPT 11- (n=22) or VP-16- (n=21) induced DNA cleavage within <i>RET</i> intron 11 was detected using LM-PCR and <i>RET</i> primer set 1 and compared to either topoisomerase I (CPT 11) or II (VP-16) predicted cleavage sites. A positive distance indicates the predicted cleavage site is downstream of the drug-induced site, and a negative distance indicates the predicted cleavage site is upstream. The percentage of all drug-induced breakpoints is represented on the y axis.