In the HCT116 human colon cancer xenograft model, administration of 50 and 100 mg/kg SNS-314 leads to dose-dependent inhibition of histone H3 phosphorylation for at least 10 h. SNS-314 shows significant tumor growth inhibition in a dose dependent manner under a variety of dosing schedules including weekly, bi-weekly, and 5 days on/9 days off.