Cancer cells with stem cell properties have been acknowledged to be responsible for cancer initiation and progression. Wnt/β-catenin signalling is a major signal pathway promoting the stemness of cancer cells. Anterior gradient 3 (AGR3), a member of the protein disulfide isomerase (PDI) family, was found to be overexpressed in several cancers. However, the roles and mechanisms of AGR3 in colorectal cancer (CRC) have not been previously described. In our study, we find that AGR3 is highly expressed in CRC and associated with poor prognosis. Functional studies show that AGR3 promotes the stemness of CRC cells. Mechanically, AGR3 activates Wnt/β-catenin signalling and promotes the nuclear translocation of β-catenin to upregulate stemness related genes. Wnt/β-catenin signalling inhibition counteracts the promoting effect of AGR3 on cancer stemness. Moreover, the effect of AGR3 on Wnt/β-catenin signalling and cancer stemness depends on the presence of frizzled 4 (FZD4). Thus, our study first uncovers the stemness-promoting role and the oncogenic mechanism of AGR3 in CRC, which might provide a novel target for designing anti-CRC strategies.
Keywords: AGR3; Cancer stemness; Colorectal cancer; Wnt; β-catenin.
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