Figure 4.

Effects of siRNAnNOShum_4400 on the viability of American Type Culture Collection U87MG cells injured by TMZ. Bars express mean ± standard error of the mean regarding the results of MTT assays. Cells were first transfected with siRNAnNOShum_4400 (37.5 nM) for 24 h. Then, cells received TMZ (250 or 500 µM). Cell viability was determined at 48 h post-TMZ by MTT assay in four independent experiments. Bars represent the absorbance values determined in treated groups normalized to the mock control group. *P<0.05 (one-way analysis of variance followed by Tukey's post hoc test) for the following groups: (A) Pretreated with siRNAnNOShum_4400 followed by TMZ 250 µM treatment vs. TMZ 250 µM treatment alone and (B) pretreated with siRNAnNOShum_4400 followed by TMZ 500 µM treatment vs. TMZ 500 µM treatment alone. siRNAnNOShum_4400 improved the effects of TMZ on cells for both drug concentrations. siRNA, small interfering RNA; nNOS, neuronal nitric oxide synthase; hum, human; TMZ, temozolomide.