Effect of RBV on cell viability of seven cell lines.

<p>To determine the relative toxicity of increasing concentrations of RBV in different cell lines, 80%-confluent uninfected cells were treated with RBV for 24 h and tested for viability using MTT cell viability assay (A) or CellTiter-Glo Luminescent Cell Viability Assay (B) or by cell counting using trypan blue dye exclusion as an indicator of live cells (C) as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0011265#s2" target="_blank">Materials and Methods</a>. To determine the sensitivity of the MTT assay, serial dilutions of A549 and HeLa cells were plated [lower left and right graphs in (A)], grown for 24 h, cells from separate wells were trypsinized and counted using a hemocytometer (36,000 cells for HeLa and 38,000 cells for A549 formed 100% confluent monolayers), and MTT assay was conducted as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0011265#s2" target="_blank">Materials and Methods</a>. (A–C) The data (done in triplicate) represent the mean ± standard deviation and are expressed as a percentage of the untreated control. Statistical analysis was done using one-way ANOVA with Tukey's post hoc test (GraphPad Prism 4, San Diego, CA). ***P<0.001, **P<0.01, *P<0.05, as compared to mock-treated cells (indicated as 0 µM RBV).