Genome binding/occupancy profiling by high throughput sequencing
Summary
The H3K4 demethylase KDM5B is overexpressed in multiple cancer types, but the underlying mechanistic contribution of dysregulated H3K4 demethylation in cancer is poorly understood. Here, we show that depletion of KDM5B in multiple types of cancer cells leads to increased proliferation, decreased heterogeneity, and phenotype changes consistent with a de-differentiated or stem cell-like phenotype. Our results also support a role for KDM5B in regulating epigenetic plasticity, where loss of KDM5B in cancer cell lines with elevated KDM5B expression leads to permissive or repressive chromatin states, which facilitate activation or repression of alternative transcriptional programs. KDM5B depleted cancer cells exhibited altered epigenetic and transcriptional profiles resembling a more primitive cellular state. Genome-wide maps of H3K4me3 across a compendium of KDM5B-depleted cancer cell lines revealed altered distributions of canonical and broad H3K4me3 domains at promoters of tumor suppressors. Genes with altered H3K4me3 in KDM5B-depleted cancer cells were enriched with tumor suppressors and housekeeping genes. While high expression of KDM5B is associated with poor clinical outcomes, findings from this study suggest that targeted inhibition of KDM5B as a therapeutic strategy may not be sufficient to inhibit growth of cancer cells as KDM5B regulates H3K4 methylation at a wide range of genes, but does so in a context-dependent manner. This study also provides a resource for evaluating associations between alterations in epigenetic patterning of H3K4 methylation and transcriptome profiles in a diverse set of cancer cells.
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