Targeting CXADR-mediated AKT signaling suppresses tumorigenesis and enhances chemotherapy efficacy in Ewing sarcoma

Abstract

Distant metastasis is the leading cause of mortality in Ewing sarcoma (EwS) - a malignant bone or soft-tissue cancer mainly affecting children, adolescents, and young adults. Despite continuous efforts in understanding its pathogenesis, the molecular mechanisms driving EwS metastasis remain poorly understood, thus limiting the potential for therapeutic progress. Here, we identify the tight junction component Coxsackievirus and Adenovirus receptor (CXADR) as a critical regulator of cancer progression and metastasis in EwS. Differential gene expression analysis of patient tumors from two independent cohorts revealed that elevated CXADR levels are associated with metastatic disease and poor overall survival. In functional experiments, conditional CXADR knockdown reduced the growth of EwS cell line models in vitro, and suppressed local tumorigenesis. Notably, CXADR knockdown completely abrogated metastasis formation in vivo. Integration of transcriptome profiling and mechanistic studies uncovered that CXADR promotes the activation of AKT signaling, likely through complex formation with PTEN. Consequently, pharmacological targeting of AKT using the FDA-approved pan-AKT inhibitor Capivasertib showed CXADR-dependent cytotoxicity, with enhanced efficacy if combined with the EwS standard-of-care chemotherapeutic agent Vincristine. Collectively, our findings establish CXADR as a prognostic and predictive biomarker in EwS, highlighting AKT inhibition combined with chemotherapy as a promising strategy for patients with high CXADR expression. Together, these findings support a precision medicine approach combining molecular stratification and targeted therapies to improve patient outcomes in metastatic EwS.