Abstract: ObjectiveTo investigate the effects of CD137L on biological behaviors of Colo 205 and the possible mechanisms by which CD137L promotes colorectal cancer development. MethodsColo 205 was cultured in 3 different conditions, ie. immobilized CD137/Fc IgG1 Fc or blank control. The cell proliferation was detected by CCK-8 at 24, 48 and 72 h. The secretion of IL-8 was analyzed by ELISA and the cell invasive activity was detected by transwell at 48 h. ResultsThe cell proliferation of CD137/Fc group was significantly increased compared with IgG1 Fc group and blank control group at 24, 48 and 72 h. The difference between IgG1 Fc group and blank control group has no statistical significance. The IL-8 concentration of culture supernatant in CD137/Fc group was (195.3±24.3) ng/ml, and significantly higher than that in IgG1 Fc group or blank control group (P=0.000, 0.000). The IL-8 concentration in IgG1 Fc group was (52.7±11.4) ng/ml, and the same as blank control group is (54.7±12.5) ng/ml(P=0.891). The invasion assay showed that the migrated cell number of CD137/Fc group was (105±10) per field, and significantly higher than that of IgG1 Fc group or blank control group (P=0.000, 0.000). The migrated cell number of IgG1 Fc group was similar to that of blank control group (57±3) per field vs. (60±6) per field (P=0.602). ConclusionCD137L can significantly enhance the cell proliferation, IL-8 secretion and invasive ability of Colo 205. CD137L may be an important molecule involved in the tumor genesis, progression and metastasis of colorectal cancer.