Our studies also demonstrated that combined treatment of thiostrepton and 5-FU decreased colony formation and migration ability in colon cancer cells, and also induced caspase 3/7 dependent apoptosis even in p53 mutant colon cancer cells, supporting previous studies that showed proteasome inhibitors like thiostrepton can induce p53-independent apoptosis in human cancer cells35–37. Here, CASP3 is linked to cancer.