GATA6 is a Novel Regulator of Gene Expression and 3D Genome in Colorectal Cancer (ATAC-Seq)

Colorectal cancer (CRC) is one of the most lethal and prevalent malignancies with elusive molecular causes. While the abnormal activity of transcription factors has been reported as a vital component of cancer progression, the mechanism through which they function remains unclear. Here, through the analysis of primary human CRC tissue data, we identified GATA6 as a CRC specific regulator, whose expression upregulation is potentially associated with promoter hypomethylation. In the human genome, GATA6 showed preferential binding at tumor specific active enhancers. Through both auxin-inducible degron (AID) and CRISPR knockout, we showed that GATA6 depletion severely impaired clonogenicity and proliferation. GATA6 depletion caused the loss of CRC specific open chromatin, suggesting a specific regulatory role of GATA6 in CRC pathogenesis. Interestingly, we also discovered the co-occupancy of GATA6 with CTCF and its direct involvement in promoter enhancer loops, suggesting the possibility that GATA6 mediate transcriptional regulation through 3D genome. The loss of GATA6 led to alterations in E-P chromatin interactions of a panel of oncogenes, accompanied by the oncogene downregulation. Finally, we showed that GATA6 loss is detrimental to the xenograft tumor growth and thereby rescued mice survival. Taken together, we unrevealed a novel mechanism by which GATA6 contributes to CRC.