Fig. 3

TAK-981 induces proteasomal degradation of MYC. A, B Immunoblots of cells treated with or without 1 µM TAK-981 for the indicated periods. HCT116 and CT26 cells sensitive to TAK-981, and SW900 and KP-3 cells resistant to TAK-981 are shown. C Immunoblotting of ubiquitinated-MYC in HCT116 cells treated with or without 1 µM TAK-981 for 4 h. Ubiquitinated-MYC was assessed using the Signal-Seeker Ubiquitination Detection kit and MYC antibody. D Immunoblotting of HCT116 cells treated with or without TAK-243 1 µM for 4 h. E Immunoblotting of HCT 116 cells treated with DMSO, TAK-981 1 µM, or TAK-243 1 µM for 4 h. Samples of upper images were immunoprecipitated with MYC. The precipitated proteins were immunoblotted with the indicated antibodies. Simultaneously, whole-cell extracts were probed with the indicated antibodies. IP, immunoprecipitation; WCE, whole-cell extract. F Scheme of proteasomal degradation of MYC in the SUMOylation inhibition state. TAK-981 induces a polyubiquitinated state of MYC and promotes the binding of MYC and Fbxw7, an E3 ubiquitin ligase. 26S proteasome degrades the complex, resulting in MYC downregulation. S, SUMO; Ub, ubiquitin