ARID1A terminates gastric regeneration to prevent cancer.

Exposed constantly to environmental challenges, the stomach undergoes highly reversible cycles of regeneration and recovery. Although abnormal activation of regeneration is known to be associated with cancer, the mechanisms underlying tissue restoration remain unclear. Our single-cell gene expression and chromatin analysis defined cell state dynamics during regeneration and recovery, identifying the Brahma-related gene 1(BRG1)/BRM-associated factor (BAF) chromatin remodeling complex during recovery. Strikingly, deletion of AT-rich interaction domain 1A (Arid1a), a subunit of the BAF complex and the second most frequently mutated gene in gastric cancer, impaired recovery across multiple murine injury models, resulting in a persistent regenerative state. Integrative analyses combining single-cell multiome and chromatin immunoprecipitation sequencing (ChIP-seq) demonstrated that the BAF complex recruits lineage-specific transcription factors such as MIST1 and estrogen related receptor gamma (ERRγ) to regulate enhancers of recovery genes. Notably, deletion of Trp53 in the unresolved regenerative state caused by Arid1a loss is sufficient to drive cancer development and invasion, revealing the epigenetic mechanisms bridging gastric regeneration, recovery, and cancer.