Figure 2

Dose-dependent activation of HIV-1 replication by class I-selective HDACIs and corresponding toxicity in U1 and ACH-2 cells. Panels A, B: Concentration-dependent stimulation of HIV-1 p24 production in the latently infected cell lines U1 (A) and ACH-2 (B) at 72 hours of incubation with MS-275, MC2211, MC2113 (class I-selective HDACIs) and SAHA (a non-class-selective HDACI used as a positive control). Mean values are from three independent experiments (error bars are not shown for better clarity). Dotted lines represent the average p24 levels found in untreated controls in the same experiments. Panel C. Effective concentrations for increasing viral replication to 500% of the basal levels of untreated controls (EC₅₀₀). Panel D: Cell viability of ACH-2 cells, as measured by the methyl tetrazolium (MTT) method. Results are presented as a percentage of the O.D. (λ = 550) of untreated controls subtracted for background (means ± SEM; 3 experiments). Panel E: Cell viability of uninfected Jurkat T cells incubated for 72 hours with the same drugs is shown as comparison. Panel F. 50% cytotoxic concentrations (CC₅₀). For the symbols in panels D, E, the reader should refer to those of panels A, B.