Figure 5.

Effect of shRNA-mediated inhibition of p62/SQSTM1 expression on cell death induced by ATRA. NB4 cells were transduced with control shRNA or shRNAs that target p62/SQSTM1 (p62#1 shRNA and p62#2 shRNA) and then treated with 1 μM ATRA for 4 days. (a–d) Cell death features were characterized by: (a) evaluation of the appearance of the cleaved forms of caspase 3 and caspase 8 by immunoblot assay; (b) measurement of the loss of mitochondrial transmembrane potential by TMRM staining, representative flow cytometry diagrams are shown. Values are means±S.D. (n=4); (c) assessment of the cell plasma membrane permeability by propidium iodide staining, values are means±S.D. (n=4). (d) NB4-LR1 cells, which are resistant to maturation by ATRA, were treated with 1 μM ATRA and 100 μM 8-CPT-cAMP alone or in combination for 4 days and then subjected to either immunoblot analysis of p62/SQSTM1 expression (upper panel) or FACS analysis of the loss of mitochondrial transmembrane potential by TMRM staining (lower panel). M represents the population of cells with low TMRM staining. ***P<0.001