Abstract: Objective To analyze the expression of DKK3 in colorectal cancer tissues and its effect on the prognosis of patients. To explore the effect of DKK3 on proliferation, migration and invasion ability of colorectal cancer cells, and indicate the mechanism. Methods The expression of DKK3 in colorectal cancer tissues and its effect on the prognosis of patients were analyzed by online database. The expression of DKK3 was down-regulated using shRNA. Cell proliferation was detected by MTT assay. In addition, transwell assay was performed to determine cell migration and invasion. Meanwhile, the expression levels of MMP2, MMP7, MMP9 were detected by RT-qPCR assays and western blot assays. Results The expression of DKK3 in colorectal cancer tissue was higher than that in normal colorectal tissue, and negatively correlated with patient prognosis (P<0.05). Cell proliferation was reduced in DKK3 knocked down group (P<0.05). Compared with negative group, the ability of migration and invasion was weaker (P<0.01). The expression of MMP2, MMP7 and MMP9 were positively correlated with the expression of DKK3 (P<0.001). In addition, the expression levels of MMP2, MMP7, MMP9 and p-ERK were decreased significantly in DKK3 down-regulation group (P<0.01). Conclusions DKK3 is up-regulated in colorectal cancer and negatively correlated with patient prognosis, and it may promote the proliferation and migration of cells through MAPK/ERK signaling pathway.

Key words: Key words：DKK3、colorectal cancer、proliferation、migration and invasion