A, DNMT1 activity assay in the presence of compounds 5175328, 5175323, and quinacrine. 5-fluorouracil (5-FU) was a negative control. Each assay was performed in duplicate in every experiment. Data from a representative experiment are shown. Normalized absorbance was calculated by subtracting the 655 nm OD from the 450 nm OD. Full description of each bar: DNMT1 (1), DNMT1+DMSO (2), DNMT1 + 100 μM 5FU (3), 10 μg/ml 5175328 without DNMT1 (4), DNMT1+0.1μg/ml 5175328 (5), DNMT1+0.3μg/ml 5175328 (6), DNMT1+1μg/ml 5175328 (7), DNMT1 + 3 μg/ml 5175328 (8), DNMT1 + 10 μg/ml 5175328 (9), 10 μg/ml 5175323 without DNMT1 (10), DNMT1+0.1μg/ml 5175323 (11), DNMT1+0.3μg/ml 5175323 (12), DNMT1+1μg/ml 5175323 (13), DNMT1 + 3 μg/ml 5175323 (14), DNMT1 + 10 μg/ml 5175323 (15), 100 μg/ml quinacrine without DNMT1 (16), DNMT1+1μg/ml quinacrine (17), DNMT1+3μg/ml quinacrine (18), DNMT1+10μg/ml quinacrine (19), DNMT1 + 30 μg/ml quinacrine (20), DNMT1 + 100 μg/ml quinacrine (21). B, DNA intercalation assay of 5175328, 5175323, and quinacrine. Ethidium bromide was a positive control, and 5238219 a negative control. For each compound the following concentrations were used (μg/ml): 0.1, 1, 5, 50, and 500.