Somatic stem cells contribute to normal tissue homeostasis, and their epigenomic features play an important role in regulating tissue identities or developing disease states. Enhancers are one of the key players controlling chromatin context-specific gene expression in a spatial and temporal manner while maintaining tissue homeostasis, and their dysregulation leads to tumorigenesis. Here, epigenomic and transcriptomic analyses reveal that forkhead box protein D2 (FOXD2) is a hub for the gene regulatory network exclusive to large intestinal stem cells, and its overexpression plays a significant role in colon cancer regression. FOXD2 is positioned at the closed chromatin and facilitates mixed-lineage leukemia protein-4 (MLL4/KMT2D) binding to deposit H3K4 monomethylation. De novo FOXD2-mediated chromatin interactions rewire the regulation of p53-responsive genes and induction of apoptosis. Taken together, our findings illustrate the novel mechanistic details of FOXD2 in suppressing colorectal cancer growth and suggest its function as a chromatin-tuning factor and a potential therapeutic target for colorectal cancer.

Inositol polyphosphate multikinase (IPMK), a key enzyme in the inositol polyphosphate (IP) metabolism, is a pleiotropic signaling factor involved in major biological events including transcriptional control. In yeasts, IPMK and its IP products were known to promote the activity of SWI/SNF chromatin remodeling complex, which plays a critical role in gene expression by regulating chromatin accessibility. However, the direct linkage between IPMK and chromatin remodelers remains unclear, raising a question on how IPMK contributes to the transcriptional regulation in mammals. By employing unbiased screenings and in vivo/in vitro immunoprecipitations, here we demonstrated that IPMK physically associates with native mammalian SWI/SNF complexes by directly binding to SMARCB1, BRG1, and SMARCC1. Furthermore, we identified the specific domains required for the IPMK-SMARCB1 binding. Notably, using CUT&RUN and ATAC-seq assays, we discovered that IPMK co-localizes with BRG1 and regulates BRG1 localization as well as BRG1-mediated chromatin accessibility in a genome-wide manner (including promoter-TSS) in mouse embryonic stem cells. Finally, our mRNA-seq analyses revealed that IPMK and SMARCB1 regulate common gene sets, validating a functional link between IPMK and SWI/SNF complex. Together, these findings establish an importance of IPMK in promoter targeting of the SWI/SNF complex, thereby contributing to SWI/SNF-meditated chromatin accessibility and transcription.