Synthetic essentiality of chromatin remodelling factor CHD1 in PTEN-deficient cancer
Menée sur des lignées cellulaires cancéreuses présentant un déficit d'expression du gène suppresseur de tumeurs PTEN, ainsi qu'à l'aide de données issues du projet "The Cancer Genome Atlas", cette étude met en évidence des mécanismes par lesquels un facteur de remodelage de la chromatine, CHD1, favorise la tumorigenèse
Synthetic lethality and collateral lethality are two well-validated conceptual strategies for identifying therapeutic targets in cancers with tumour-suppressor gene deletions. Here, we explore an approach to identify potential synthetic-lethal interactions by screening mutually exclusive deletion patterns in cancer genomes. We sought to identify ‘synthetic-essential’ genes: those that are occasionally deleted in some cancers but are almost always retained in the context of a specific tumour-suppressor deficiency. We also posited that such synthetic-essential genes would be therapeutic targets in cancers that harbour specific tumour-suppressor deficiencies. In addition to known synthetic-lethal interactions, this approach uncovered the chromatin helicase DNA-binding factor CHD1 as a putative synthetic-essential gene in PTEN-deficient cancers. In PTEN-deficient prostate and breast cancers, CHD1 depletion profoundly and specifically suppressed cell proliferation, cell survival and tumorigenic potential. Mechanistically, functional PTEN stimulates the GSK3
β-mediated phosphorylation of CHD1 degron domains, which promotes CHD1 degradation via the β-TrCP-mediated ubiquitination
–proteasome pathway. Conversely, PTEN deficiency results in stabilization of CHD1, which in turn engages the trimethyl lysine-4 histone H3 modification to activate transcription of the pro-tumorigenic TNF–NF-
κB gene network. This study identifies a novel PTEN pathway in cancer and provides a framework for the discovery of
‘trackable’ targets in cancers that harbour specific tumour-suppressor deficiencies.