Bio-Available Selective Iap Inhibitor Dual-Activated Trail-Induced Apoptosis Via Caspase-Mediated Pathway In Human Colorectal Cancer

TRAIL is a new orientation of anti-tumor research ligand due to its tumor selectivity and its non-toxicity to normal cells. Nevertheless, the potential of TRAIL as a chemotherapeutic agent is limited, because of the emergence of TRAIL resistance. So, this research aimed to explore the ability of representative XIAP inhibitor to overcome TRAIL resistance by increasing apoptosis in colorectal cancer models, as well as to investigate the potential mechanisms of regulating inflammatory cytokines TNF-alpha, IL-1 beta by TRAIL-induced cascade pathway. Cell viability was assessed by MTT assay for incubating 24 h and 48 h, with the expression level of apoptotic and anti-apoptotic proteins was measured by Western-blot and analyzed by ImageJ software. The mRNA expression level of inflammatory markers, TNF-alpha, IL-1 beta, was determined by qRT-PCR method. The results shown combined treatment with AT406 and TRAIL augmented the activation of caspase-dependent manner as compared with treating them alone. Moreover, the data indicated that after TRAIL treatments, the expression level of inflammation-related genes (TNF-alpha, IL-1 beta) was higher up-regulation (P< 0.05) as compared with placebo. Therefore, we demonstrated here for the first time that co-treatment in vitro with TRAIL and AT-406 in two human colorectal cancer models resulted in significantly greater tumor growth inhibition compared to single treatments, and the combination effects were synergistic and significantly enhanced apoptosis in colorectal cancer cells, but have no cytotoxicity to normal cell. Additionally, combination therapy on targeting TRAIL-induced apoptosis not only play significant for cell death through cancer apoptosis signaling, but could be shed light on the future research directions.