STUB1 and cancer: To find suitable models for testing the involvement of CHIP in Snail‐mediated EMT, we sought cell lines in which the Snail protein undergoes proteasomal degradation and found that in several cancer cell lines we tested, the expression levels of CHIP correlated negatively with the Snail expression levels (Fig. S3A), and MG132 treatment increased Snail protein levels in SW480, SW620, SKOV3, and OVCAR3 cells (Fig. S3B).