FOXC2‐induced circCASK aggravates colorectal cancer progression by upregulating SIX1 expression

Abstract

AbstractColorectal cancer (CRC) ranks as the most common gastrointestinal solid carcinoma globally. Substantial evidence has established a pivotal role for circular RNAs (circRNAs) in CRC progression. In this study, differentially expressed circRNAs were analyzed based on a public dataset (GSE126094) and elevated expression of circCASK (hsa_circ_0001917) was validated in CRC. Moreover, increased circCASK was also confirmed in CRC patients. Functionally, circCASK knockdown led to a significant decrease in CRC cell growth and attenuated cell migration and invasion. Similarly, circCASK knockdown markedly attenuated tumor growth in vivo. Mechanistically, circCASK sponged miR‐1271‐5p and enhanced sine oculis homeobox homolog 1 (SIX1) expression. More importantly, both SIX1 overexpression and miR‐1271‐5p knockdown could reverse the cellular behavior inhibition induced by circCASK knockdown. Furthermore, SIX1 was most strongly and positively linked with Wnt/β‐catenin signaling pathways, circCASK triggered Wnt/β‐catenin signaling through the miR‐1271‐5p/SIX1 axis, and FOXC2 transcriptionally induced circCASK expression. In conclusion, circCASK induced by FOXC2 accelerated CRC progression through the miR‐1271‐5p/SIX1 axis, thus providing an interesting insight into CRC tumorigenesis.