Figure 4.

Inhibition of RAD51 expression and Etoposide induces apoptosis in sphere cultures. (a) HeLa SPhere culture was exposed to 30 nM of siRAD51 and 5.8 μg/mL of VP16. By MTT assay, cell viability was affected in the presence of both compounds, but not when they were added independently. The absence of RAD51 protein decreased the cell viability of spheres exposed to VP16. HeLa SP culture exposed to VP16 and 30 nM of random siRNA (scrambled) was used as control. (b and c) Apoptosis was evaluated by Annexin-V assay (see Materials and Methods) under identical conditions; the highest level of apoptosis was exhibited in the presence of both VP16 and siRAD51. The absence of RAD51 protein sensitized spheres to VP16. (d and e) Control indicating that treatment with siRAD51 and Etoposide induces apoptosis in ML cells. ^∗∗ p < 0.01 and ^∗∗∗ p < 0.001.