Cancer stem cells (CSCs) drive tumor relapse, which is a major clinical challenge in colon cancer. Targeting CSCs presents a great opportunity in eradicating cancer cells and thus treatment of patients with cancer. However, the epigenetic control of the CSC signature and key molecules involved in colon cancer remains undefined. In this study, we demonstrated that alpha-1,3-glucosyltransferase (ALG8) is upregulated in colon cancer tissues compared with normal tissues. Overexpression of the ALG8 gene predicted poor overall survival and disease-free survival in colon cancer patients. Silencing of the ALG8 gene repressed the stemness of colon tumor cells. Xenograft mice transplanted with ALG8-deficient tumor cells significantly alleviated tumor burden and prolonged survival in comparison with control mice. Further analysis showed that ALG8 gene promoted cancer stemness through inducing glycosylation of LRP6, which activates the WNT/beta-catenin signaling pathway. Importantly, attenuation of the glycosylation using tunicamycin abrogated the effect of ALG8 gene on cancer stemness. Taken together, our findings demonstrated that ALG8 enhances colon tumorigenesis by activating the WNT/beta-catenin signaling pathway. Therefore, ALG8 gene is a potential therapeutic target in colon cancer.
Keywords: ALG8; WNT; colon cancer; glycosylation; stemness.