The current study focuses on demonstrating the therapeutic efficacies of APG1244 against colorectal cancer and understanding the underlying mechanisms....High levels of Mcl-1 in these cell lines were significantly correlated to decreased sensitivity to APG1244. APG1244, when combined with a Mcl-1 inhibitor, synergistically decreased the survival and induced apoptosis of APG1244-insensitive cell lines with high levels of Mcl-1.