Agrin promotes the proliferation, invasion and migration of rectal cancer cells via the WNT signaling pathway to contribute to rectal cancer progression

Rectal cancer is the most common malignant tumor in the digestive system with rapidly metastasis and highly recurrence. Agrin (AGRN) is a proteoglycan involving in a large number of human cancers. However, how AGRN regulates the progression of rectal cancer remains largely unknown. We aimed to determine the biological role of AGRN and its mechanism in rectal cancer. AGRN expression in rectal cancer tissues was detected based on TCGA. The survival curve was plotted using the Kaplan-Meier method. qRT-PCR and western blot were utilized to examine the expression level of AGRN in cells. Cell proliferation, clonogenic ability, invasion, and migration of rectal cancer cells were analyzed by CCK-8, colony formation and transwell experiments. GSEA was employed for the analysis of the potential pathways-related with AGRN in rectal cancer. The activity of WNT pathway was determined by western blot. AGRN expression was dramatically increased in rectal cancer, and its up-regulation was associated with poorer prognosis of rectal cancer patients. AGRN expression was an independent factor for the prognosis of rectal cancer. AGRN inhibition suppressed rectal cancer cell growth, invasion, and migration, whereas AGRN overexpression facilitated these behaviors of rectal cancer cells in vitro. Mechanistically, WNT signaling pathway was enriched in high AGRN-expressing patients with rectal cancer. AGRN elevated the activity of WNT pathway through increasing Cyclin D1, C-Myc, p-GSK-3β, and p-β-catenin expression. Our present study indicated that AGRN might function as an oncogenic indicator in rectal cancer via activating the WNT pathway, which would help develop optimized therapeutic therapies for rectal cancer.