Figure 4

A: HuR apoptotic cleavage is not present in MCF-7 cells. Western blotting analysis on HeLa and MCF-7 whole cell lysate sampled after an overnight exposure to doxo at different doses 1, 10, 50 μM (+) or not (-). The cleaved form is present in HeLa cells but only in minimal part in MCF-7 cells. B: Active caspase 3 is present in MCF-7 cells. Western blotting analysis on HeLa and MCF-7 whole cell lysate sampled after an overnight exposure to doxorubicine 10 μM (+) or not (-). Active caspase 3 is present in MCF-7 cells. C: HuR translocates onto the translational active polyribosomes. Western blotting analysis on polysomal fractionation samples (1-9). Fractionation was performed on MCF-7 cells grown in standard condition (FCS), starved or treated with doxorubicin 10 μM for 4 h and samples were investigated for the presence of HuR or PAIP2. In the upper part of the panel is reported a polysomal profile indicating which fractions are enriched in unbound ribosomes (unb), single ribosomes (mono), low molecular weight polysomes (LMW) or high molecular weight polysomes (HMW). The HMW are the fractions where the translational active polyribosomes sedimentate and the HuR western bloltting signal after doxorubicin treatment localizes. PAIP2 is used as control since localization is not affected.