(Pro)renin receptor promotes colorectal cancer through the Wnt/beta-catenin signalling pathway despite constitutive pathway component mutations

BACKGROUND: Although constitutive activating mutations in the Wnt/β-catenin signalling pathway are important for colorectal cancer development, canonical signalling through Wnt ligands is essential for β-catenin activation. Here, we investigated the role of (pro)renin receptor ((P)RR), a component of the Wnt receptor complex, in the pathogenesis of colorectal cancer. METHODS: (P)RR silencing was performed in human colorectal cancer cells containing constitutive activating mutations in the Wnt/β-catenin pathway. (P)RR overexpression was induced in normal colon epithelial cells. Protein and mRNA levels of pathway components were detected, and Wnt signalling activity was measured using a β-catenin reporter. Cell proliferative activity and apoptosis were evaluated using WST-1 assay and flow cytometry. Xenografts were induced in nude mice. RESULTS: (P)RR expression was greater in colorectal cancer tissues and cells than in normal colorectal samples. Patients with strong (P)RR expression took more proportion in groups with poorly-differentiated, advanced and rapidly-progressing cancers. (P)RR silencing attenuated the pathway in colorectal cancer cells, impaired their proliferation in vitro and vivo. (P)RR overexpression enhanced the pathway and proliferation of normal colon epithelial cells. CONCLUSIONS: Aberrant (P)RR expression promotes colorectal cancer through the Wnt/β-catenin signalling pathway despite constitutive pathway-activating mutations. (P)RR is a potential diagnostic and therapeutic target for colorectal cancer.