Wnt-5a–Receptor Tyrosine Kinase-Like Orphan Receptor 2 Signaling Provokes Metastatic Colonization and Angiogenesis in Renal Cell Carcinoma, and Prunetin Supresses the Axis Activation

Wnt-5a is a protein encoded by the WNT5A gene and is a ligand for the receptor tyrosine kinase-like orphan receptor 2 (ROR2). However, its biological impact on clear cell renal cell carcinoma (ccRCC) remains unclear. In this study, the prognostic significance of concurrent WNT5A and ROR2 expression levels was observed to predict unfavorable overall survival and disease-specific survival. High Wnt-5a expression was detected in a ccRCC cell line panel but not in HK-2 cells, a normal proximal tubular cell line. Inhibition of DNA methyltransferase by 5-azacytidine in 786-O and Caki-2 cells resulted in Wnt-5a up-regulation, indicating potential epigenetic modification. Furthermore, there was a repression of cell movement in vitro and metastatic colonization in vivo on WNT5A and ROR2 knockdown. Suppressions of angiogenesis in vivo and tubular-like structure formation in endothelial cells in vitro were also observed after silencing WNT5A and ROR2 expression. In addition, alteration in the downstream gene signature of the Wnt-5a–ROR2 signaling was similar to that in metastasis-associated gene 1–β-catenin axis. Moreover, prunetin treatment reversed the gene signature derived from Wnt-5a–ROR2 signaling activation and to abolish ccRCC cell migration and proliferation. Overall, this study demonstrates the clinical and functional significance of the Wnt-5a–ROR2 axis and identifies prunetin as a potential precision medicine for patients with ccRCC harboring aberrant Wnt-5a–ROR2 signaling pathways.