Figure 3.

A. Representative gel of the TOP1‐mediated DNA cleavage assay. From left to right: Lane 1, DNA alone; lane 2, DNA and TOP1 without drug; lane 3, DNA and TOP1 with CPT (1 μM); lane 4, DNA and TOP1 with LMP744 (1 μM); lanes 5–16, DNA and TOP1 with the tested compounds at 0.1, 1.0, 10, and 100 μM concentrations, respectively. The arrows and numbers at left indicate the cleavage site positions. LMP744 is the positive non‐camptothecin indenoisoquinoline control. B. Sequence of the 3′‐[³²P]‐labelled 117‐bp DNA (labeled Guanine in red) with the indicated TOP1 cleavage site positions. ^[68]