RNF20 Links Histone H2B Ubiquitylation with Inflammation and Inflammation-Associated Cancer

• RNF20 and H2Bub1 modulate the NF-kB response
• RNF20-deficient mice are prone to colonic inflammation and colorectal cancer
• Reduced H2Bub1 may create a pro-tumoral microenvironment
• Reduced H2Bub1 is associated with colitis and colorectal cancer in humans

SummaryFactors linking inflammation and cancer are of great interest. We now report that the chromatin-targeting E3 ubiquitin ligase RNF20/RNF40, driving histone H2B monoubiquitylation (H2Bub1), modulates inflammation and inflammation-associated cancer in mice and humans. Downregulation of RNF20 and H2Bub1 favors recruitment of p65-containing nuclear factor κB (NF-κB) dimers over repressive p50 homodimers and decreases the heterochromatin mark H3K9me3 on a subset of NF-κB target genes to augment their transcription. Concordantly, RNF20+/− mice are predisposed to acute and chronic colonic inflammation and inflammation-associated colorectal cancer, with excessive myeloid-derived suppressor cells (MDSCs) that may quench antitumoral T cell activity. Notably, colons of human ulcerative colitis patients, as well as colorectal tumors, reveal downregulation of RNF20/RNF40 and H2Bub1 in both epithelium and stroma, supporting the clinical relevance of our tissue culture and mouse model findings.

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