Author Correction: Cytotoxic unsaturated electrophilic compounds commonly target the ubiquitin proteasome system.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Proteasome inhibitor b-AP15 induces enhanced proteotoxicity by inhibiting cytoprotective aggresome formation.

Proteasome inhibitors have been shown to induce cell death in cancer cells by triggering an acute proteotoxic stress response characterized by accumulation of poly-ubiquitinated proteins, ER stress and the production of reactive oxygen species. The aggresome pathway has been described as an escape mechanism from proteotoxicity by sequestering toxic cellular aggregates. Here we show that b-AP15, a small-molecule inhibitor of proteasomal deubiquitinase activity, induces poly-ubiquitin accumulation in absence of aggresome formation.

The deubiquitinase inhibitor b-AP15 induces strong proteotoxic stress and mitochondrial damage.

Human cancers are characterized by intrinsic or acquired resistance to apoptosis and evasion of apoptosis has been proposed to contribute to treatment resistance. Bis-benzylidine piperidone compounds, containing α,β-unsaturated carbonyl functionalities, have been extensively documented as being effective in killing apoptosis-resistant cells and to display promising antineoplastic activities in a number of tumor models. We here explored the phenotypic response of colon cancer cells to b-AP15, a bis-benzylidine piperidone previously shown to inhibit the proteasome deubiquitinases (DUBs) USP14 and UCHL5.