Fig. 5.

Cytotoxicity analysis in OLA1-knockdown cells pretreated with protein synthesis inhibitor cycloheximide (CHX). (A) HeLa cells were pretreated with CHX (20 μg/ml, 1 h) and then the oxidants tBH or diamide were added (in the presence of CHX) for an additional 5 h; cells were then assayed for viability (MTS). Data represent ED₅₀ values of tBH and diamide with or without the cotreatment of CHX (means ± SD, n = 3–5). **, P < 0.01, as compared with control cells. (B) Western blot analysis of OLA1 and p53 proteins in the cells treated with CHX (20 μg/ml, 4 h). The OLA bands are significantly decreased in the “Ola1 siRNA” transfected cells compared to the “Control siRNA” transfected cells, indicating a successful knockdown of the OLA1 protein (Top); suppression of the p53 bands in the CHX (+) group suggests that the CHX blocked protein synthesis successfully (Middle); β-actin was used as loading control (Bottom).