Bestrophin-4 relays Hes4 and interacts with Twist1 to suppress epithelial-to-mesenchymal transition in colorectal cancer cells

Bestrophin isoform 4 (BEST4) is a newly identified subtype of the calcium-activated chloride channel family. Analysis of colonic epithelial cell diversity by single cell RNA-sequencing has revealed the existence of a cluster ofBEST4+ mature colonocytes in humans. However, if the role ofBEST4is involved in regulating tumour progression remains largely unknown. In this study, we demonstrate thatBEST4overexpression attenuates cell proliferation, colony formation, and mobility in colorectal cancer (CRC)in vitro, and impedes the tumor growth and the liver metastasisin vivo.BEST4is coexpressed with hairy/enhancer of split 4 (Hes4) in the nucleus of cells, andHes4signalsBEST4by interacting with the upstream region of theBEST4promoter.BEST4is epistatic toHes4and downregulates Twist1, thereby inhibiting epithelial-to-mesenchymal transition (EMT) in CRC. Conversely, knockout of BEST4 using CRISPR/Cas9 in CRC cells revitalises tumor growth and induces EMT. Furthermore, the low level of theBEST4mRNA is correlated with advanced and the worse prognosis, suggesting its potential role in regulating CRC progression.