Fig. 2.

Idarubicin and irinotecan are not toxic to IMR-32 neuroblastoma cells at sub-micromolar concentration and enhance neurite outgrowth of cerebellar granule cells in a concentration-dependent manner. (a) Representative images of irinotecan-treated IMR-32 cells and control cells and quantification of cell survival after treatment of cells with different concentrations of irinotecan. Three wells per treatment group were used to determine the number of live cells (mean ± SEM) and the experiment was repeated thrice (n = 3). Asterisks signify statistically significant differences as compared to untreated control (p < 0.05, one-way ANOVA with Holm Sidak post-hoc test). (b) Representative images of mouse cerebellar granule cells left untreated (-), treated with 1 nM idarubicin or epirubicin, 0.01 nM irinotecan or 30 μg/ml colominic acid (CA). Bar diagram shows the average neurite length (mean + SEM) from the longest neurite of 300 cells (n = 300 cells from 6 wells out of 3 independent experiments) treated with different concentrations of idarubicin and irinotecan, or treated with epirubicin and CA as positive controls. Experiments were performed 3 independent times. Asterisks signify statistically significant differences versus untreated neurons (-) as determined by one-way ANOVA with Fisher's PLSD test (F=27.744, p<0.0001; PLSD *p<0.05). Scale bar, 25 μm.