ZEB2 and colorectal carcinoma: Furthermore, when hsa_circ_0004771 was knocked down in 5-FU-resistant CRC cells, it caused a corresponding decline in ZEB2 expression, and a combination of down-regulation of hsa_circ_0004771 with up-regulation of miR-653 in 5-FU-resistant CRC cells resulted in a lower expression on ZEB2 in the cells (Fig. 6C).