BCL2L1 and cancer: Both ER and mitochondrial apoptosis signaling pathways lead to Bax and Bak activation and apoptosis, although there are differences between the two apoptosis signaling pathways.22, 43 Therefore, pro-apoptotic proteins, such as Bax, Bad, and Bak, were increased, whereas the anti-apoptotic proteins, such as Bcl-2 and Bcl-xL, were decreased on I-Trp treatment in these CCT-β overexpressed cancer cells.