E3 ubiquitin ligase BTBD3 inhibits tumorigenesis of colorectal cancer by regulating the TYRO3/Wnt/β-catenin signaling axis

Clinical trials and studies have implicated that E3 ubiquitin ligase BTBD3 (BTB Domain Containing 3) is a cancer-associated gene. However, the role and underlying mechanism of BTBD3 in colorectal cancer (CRC) is not fully understood yet. Herein, our study demonstrated that the mRNA and protein levels of BTBD3 were decreased in CRC tissues and associated with TYPO3 and Wnt/β-catenin pathway. Our results showed that circRAE1 knockdown and TYRO3 overexpression activated Wnt/β-catenin signaling pathway and the EMT process-associated markers, indicating that circRAE1/miR-388-3p/TYRO3 axis exacerbated tumorigenesis of CRC by activating Wnt/β-catenin signaling pathway. In addition, overexpression of BTBD3 reduced CRC cell migration and invasion in vitro and inhibited tumor growth in vivo. Our data demonstrated that BTBD3 suppressed CRC progression through negative regulation of the circRAE1/miR-388-3p/TYRO3 axis and the Wnt/β-catenin pathway. Our data further confirmed that BTBD3 bound and ubiquitinated β-catenin and led to β-catenin degradation, therefore blocked the Wnt/β-catenin pathway and suppressed the CRC tumorigenesis. This study explored the mechanism of BTBD3 involved in CRC tumorigenesis and provided a new theoretical basis for the prevention and treatment of CRC.