A distinct mechanism of epigenetic reprogramming silences PAX2 and initiates endometrial carcinogenesis
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ABSTRACT: Functional inactivation of tumor suppressor genes drives cancer initiation, progression, and treatment responses. Most tumor suppressor genes are inactivated through one of two well-characterized mechanisms: DNA-level mutations such as point mutations or deletions, and promoter DNA hypermethylation. Here, we report a distinct third mechanism of tumor suppressor inactivation based on alterations to the histone rather than DNA code. We demonstrated that PAX2 is an endometrial tumor suppressor recurrently inactivated by a distinct epigenetic reprogramming event in >80% of human endometrial cancers. Integrative transcriptomic, epigenomic, 3D genomic, and machine learning analyses showed that PAX2 transcriptional downregulation is associated with replacement of open/active chromatin features (H3K27ac/H3K4me3) with inaccessible/repressive chromatin features (H3K27me3) in a framework dictated by 3D genome organization. The spread of the repressive H3K27me3 signal resembled a pearl necklace with its length modulated by cohesin loops, thereby preventing transcriptional dysregulation of neighboring genes. This mechanism, involving the loss of a promoter-proximal super-enhancer, underlied transcriptional silencing of PAX2 in human endometrial cancers. Mouse and human preclinical models established PAX2 as a potent endometrial tumor suppressor. Functionally, PAX2 loss promoted endometrial carcinogenesis by rewiring the transcriptional landscape via global enhancer reprogramming. The discovery that most endometrial cancers originate from a recurring epigenetic alteration carries profound implications for their diagnosis and treatment.
ORGANISM(S): Homo sapiens
PROVIDER: GSE275223 | GEO | 2025/06/06
REPOSITORIES: GEO
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