Cytotoxicity of the ten tested compounds: Vero cells (96-well plate format, 5 × 104 cells/well, quadruplicates) were incubated with DMEM 5% FBS containing the indicated doses of the inhibitors (3-fold serial dilutions, starting concentration of 1350 µM) (A) Antimycin A, (B) OSU-03012 and Obatoclax, (C) Azaribine, Azauridine, and Pyrazofurin, (D) Mycophenolate mofetil, Mycophenolic acid, and AVN-944, (E) Brequinar, and (F) Aurintricarboxylic acid (ATA). Cell viability assays (MTT and XTT) were performed at 36 h post-treatment and the CC50 for each compound was calculated. Dotted line indicates the 50% toxicity of each of the compounds. Data were expressed as mean and SD from three independent experiments conducted in quadruplicates.