Hsa_Circ_0000826 inhibits the proliferation of colorectal cancer by targeting AUF1.

Many circular RNAs (circRNAs) are reported to be abnormally expressed during the progression of various tumors, and these circRNAs can be used as anti-tumor targets. Therefore, it is important to identify circRNAs that can be used effectively for the clinical diagnosis and treatment of colorectal cancer (CRC). Here, we report that hsa_Circ_0000826 (Circ_0000826), a circRNA with significantly reduced expression level in CRC tissues, is associated with a poor prognosis in patients. The silencing of Circ_0000826 promotes the proliferation of CRC cells. Conversely, the overexpression of Circ_0000826 restricted CRC cell proliferation both in vitro and in vivo. Furthermore, Circ_0000826 could target AU-rich element RNA-binding protein 1 (AUF1). AUF1, known as heterogeneous nuclear ribonucleoprotein D (hnRNP D), could bind to the c-MYC 3'-UTR and promote c-MYC expression. When Circ_0000826 binds to AUF1, it competitively inhibits the binding of AUF1 to the c-MYC 3'-UTR, which inhibits the c-MYC expression and cell proliferation. These results provide novel insights into the functional mechanism of Circ_0000826 action in CRC progression and indicate its potential use as a therapeutic target in CRC.