Figure 5

Adjuvant treatment with niacinamide significantly increases the radiation response of PC-3 cells. A) PC3 cells were incubated with varying concentrations of the PARP inhibitor niacinamide for 8 days and cell colonies of greater than 50 cells were counted. Cell survival percentages were calculated relative to the number of colonies counted in the untreated population. Error bars represent standard error of the mean from 3 biological replicates. p-values determined by one way ANOVA. B) PC-3 cells were incubated with or without niacinamide for 24 hours prior to and 8 days following exposure to 0, 2, 4 or 8 Gy irradiation. Following incubation, colonies of greater than 50 cells were counted, and cell survival percentages were calculated relative to the appropriate non-irradiated colony counts. Error bars represent standard error of the mean from 3 biological replicates. p-values as determined by two way ANOVA and Sidak’s post test.