Cytotoxicity was assayed by determining lactate dehydrogenase (LDH) release. CTCL cells were left untreated, or were treated for 48 hours with ethanol vehicle, 10−7 M of the indicated compounds, or 10 mM hydroxyurea (HU, positive control). After a 48 hour incubation, the supernatant from cells was removed and assayed for LDH activity (Promega CytoTox 96® Non-Radioactive Cytotoxicity Assay). The total cell activity was determined by lysing untreated cells and assaying the whole cell lysates. Cytotoxcicity was determined as percentage of LDH released, as compared to total activity (total activity set to 1.0) after normalizing for background.