BTRC and nasopharyngeal carcinoma: To test if circPVT1 regulated the ubiquitination of c-Myc by β-TrCP, Co-IP was performed and the results showed that overexpression of circPVT1 reduced the interaction between β-TrCP and c-Myc, whereas knockdown of circPVT1 enhanced it in NPC cells (Fig. 5A).