A DNA topoisomerase I and II inhibitor (IC50s = 2 and 6.5 µM, respectively); stabilizes topoisomerase I-DNA and topoisomerase II-DNA cleavable complexes in KB cells at 3 µM; cytotoxic to P388 and KB cells (IC50s = 1.1 and 9.6 nM, respectively); reduces pulmonary metastasis in murine B16-BL6 melanoma and UV-2237M fibrosarcoma models of lung metastasis at 15, 26, and 45 mg/kg per day; reduces tumor growth in a variety of human cancer mouse xenograft models