Kaposi's Sarcoma-Associated Herpesvirus G-protein Coupled Receptor Activates the Canonical Wnt/β-catenin Signaling Pathway.
National Institutes of Health
P20GM103424, R01HD51998, R21HD076283
Department of Biology
Abstract Background: KSHV is a tumorigenic γ-herpesvirus that has been identified as the etiologic agent of Kaposi's sarcoma (KS), a multifocal highly vascularized neoplasm that is the most common malignancy associated with acquired immunodeficiency syndrome (AIDS). The virus encodes a constitutively active chemokine receptor homologue, vGPCR that possesses potent angiogenic and tumorigenic properties, and is critical for KSHV pathobiology. To date, a number of signaling pathways have been identified as key in mediating vGPCR oncogenic potential. Findings: In this study, we identify a novel pathway, the Wnt/β-catenin pathway, which is dysregulated by vGPCR expression in endothelial cells. Expression of vGPCR in endothelial cells enhances the nuclear accumulation of β-catenin, that correlates with an increase in β-catenin transcriptional activity. Activation of β-catenin signaling by vGPCR is dependent on the PI3K/Akt pathway, as treatment of vGPCR-expressing cells with a pharmacological inhibitor of PI3K, leads to a decreased activation of a β-catenin-driven reporter, a significant decrease in expression of β-catenin target genes, and reduced endothelial tube formation. Conclusions: Given the critical role of Wnt/β-catenin signaling in angiogenesis and tumorigenesis, the findings from this study suggest a novel mechanism in KSHV-induced malignancies.
Angelova, M.; McFerrin, M.; Swan, K. F.; McFerrin, H.; Pridjian, G.; Morris, C. A.; and Sullivan, D. E., "Kaposi's Sarcoma-Associated Herpesvirus G-protein Coupled Receptor Activates the Canonical Wnt/β-catenin Signaling Pathway." (2014). Faculty and Staff Publications. 232.