In Vitro: BI8622 induces HUWE1 ectopically expresses to abolish ubiquitination of MCL1 with an IC50 value of 6.8 μM in HeLa cells. BI8622 suppresses colony formation of Ls174T cells with estimated IC50 value of 8.4 μM. BI8622 (10 μM; 1-4 days) treatment retards passage of Ls174T cells through all phases of the cell cycle, with the effect being strongest for G1. BI8622 (0-50 μM; 16 hours) retards the degradation of MCL1 in response to UV irradiation by inhibiting HUWE1 in HeLa cells. BI8622 inhibits MYC-dependent transactivation in colorectal cancer cells.