Figure 2: Cytotoxic activity of various HDACi in the presence of an anti-herpesvirus nucleoside analog prodrug, GCV. Three hundred thousand P3HR1 cells were exposed to either 40 μM GCV or vehicle, and the indicated concentrations of individual HDACi, in a 1 mL volume in 24-well plates, in triplicate. Seventy-two hrs later, 800 μL of the media was removed without disturbing the settled cells and 1 mL of fresh growth media containing GCV (40 μM) was added and the cells, which were cultured for another 72 hrs. HDACi studied included butyrate, valproate, apicidin, largazole and its analogs, MS275, oxamflatin, LBH589, SAHA, and Scriptaid. The number above the HDAC+GCV bar represents the percentage of cells surviving, relative to the cultures exposed to that particular HDAC inhibitor alone (assigned a value of 100%). Error bars represent standard deviation.