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PAX9 determines epigenetic state transition and cell fate in small cell lung cancer

ABSTRACT: Small cell lung cancer (SCLC) is a more aggressive and deadlier form of lung cancer with limited effective therapies currently available. By utilizing a genome-wide CRISPR-Cas9 dropout screen, we have identified the Paired box protein 9 (PAX9) as an essential factor for the cell viability of SCLC-A type, which accounts for approximately 70% of all SCLC. PAX9 is transcriptionally driven by the BAP1/ASXL3/BRD4 epigenetic axis and is overexpressed in human malignant SCLC tumor samples. Genome-wide studies have revealed that PAX9 occupies distal enhancer elements and represses gene expression by restricting enhancer activity. Genetic depletion of PAX9 leads to a dramatic induction of a primed-active enhancer transition, resulting in an increased expression of a large number of neural differentiation and tumor-suppressive genes in multiple SCLC cell lines. Mechanistically, PAX9 interacts and co-functions with the Nucleosome Remodeling and Deacetylase (NuRD) complex at enhancers and they repress the nearby gene expression, which could be rescued by pharmacological HDAC inhibition. Overall, this study provides mechanistic insight into the oncogenic function of the PAX9/NuRD complex epigenetic axis in human SCLC and suggests that re-activation of the primed enhancers may have therapeutic efficacy in treating SCLC-A type cancers expressing high levels of PAX9.

ORGANISM(S): Homo sapiens

PROVIDER: GSE164247 | GEO | 2021/08/03

REPOSITORIES: GEO

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