Figure 4.

YM155 concurrently promotes p62/SQSTM1 protein degradation and induces p62/SQSTM1 gene transcription in breast cancer cells. (A) MCF7 cells were treated with DMSO (-ve control), chloroquine, bafilomycin A1, rapamycin, YM155 or YM155 combined with chloroquine for 24 h and subsequently co-treated with the de novo protein synthesis inhibitor, CHX. The rate of p62/SQSTM1 protein degradation in MCF7 cells was examined by Western blotting. Actin was used as an internal control. The numbers under each blot are intensity of the blot relative to that of the control (0 h post-CHX treatment). (B) MCF7 cells were treated either with DMSO (-ve control) or 2×IC₅₀ YM155. Expression of p62/SQSTM1 was examined by RT-PCR. Equal sample loading was verified by actin. The numbers under each band are intensity of the band relative to that of the control (-ve control). (C) MCF7 cells were treated either with DMSO (-ve control) or 2×IC₅₀ YM155. Expression of p62/SQSTM1 was examined by quantitative real-time PCR.