Dual inhibition of REV-ERB? and autophagy as a novel pharmacological approach to induce cytotoxicity in cancer cells.

ABSTRACT: REV-ERB? and REV-ERB? nuclear receptors regulate several physiological processes, including circadian rhythm and metabolism. A previous study reported the REV-ERB? gene to be co-overexpressed with ERBB2 in breast cancer cell lines. Surprisingly, we found that several tumor types, including a number of breast cancer cell lines, predominantly express the REV-ERB? variant. This pattern was independent of ERBB2 and ER status, and opposite to that of non-cancer mammary epithelial HMEC cells, in which REV-ERB? was the major variant. Consistent with this molecular profile, REV-ERB target genes in both circadian and metabolic pathways were derepressed upon silencing of REV-ERB?, but not REV-ERB?. Strikingly, we found that REV-ERB? is a determinant of sensitivity to chloroquine, a clinically relevant lysosomotropic agent that suppresses autophagy. The cytoprotective function of REV-ERB? appears to operate downstream of autophagy blockade. Through compound screening, we identified ARN5187, a novel lysosomotropic REV-ERB? ligand with a dual inhibitory activity toward REV-ERB-mediated transcriptional regulation and autophagy. Remarkably, although ARN5187 and chloroquine share similar lysosomotropic potency and have a similar effect on autophagy inhibition, ARN5187 is significantly more cytotoxic. Collectively, our results reveal that dual inhibition of REV-ERB? and autophagy is an effective strategy for eliciting cytotoxicity in cancer cells. Furthermore, our discovery of a novel inhibitor compound of both REV-ERB and autophagy may provide a scaffold for the discovery of new multifunctional anticancer agents.

SUBMITTER: De Mei C 

PROVIDER: S-EPMC4761647 | biostudies-literature | 2015 May

REPOSITORIES: biostudies-literature