CNTNAP4 signaling regulates osteosarcoma disease progression

Abstract

AbstractImproved treatment strategies for sarcoma rely on clarification of the molecular mediators of disease progression. Recently, we reported that the secreted glycoprotein NELL-1 modulates osteosarcoma (OS) disease progression in part via altering the sarcomatous extracellular matrix (ECM) and cell-ECM interactions. Of known NELL-1 interactor proteins, Contactin-associated protein-like 4 (Cntnap4) encodes a member of the neurexin superfamily of transmembrane molecules best known for its presynaptic functions in the central nervous system. Here, CRISPR/Cas9 gene deletion ofCNTNAP4reduced OS tumor growth, sarcoma-associated angiogenesis, and pulmonary metastases.CNTNAP4knockout (KO) in OS tumor cells largely phenocopied the effects ofNELL-1KO, including reductions in sarcoma cell attachment, migration, and invasion. Further,CNTNAP4KO cells were found to be unresponsive to the effects of NELL-1 treatment. Transcriptomic analysis combined with protein phospho-array demonstrated notable reductions in the MAPK/ERK signaling cascade withCNTNAP4deletion, and the ERK1/2 agonist isoproterenol restored cell functions amongCNTNAP4KO tumor cells. Finally, human primary cells and tissues in combination with sequencing datasets confirmed the significance ofCNTNAP4signaling in human sarcomas. In summary, our findings demonstrate the biological importance of NELL-1/CNTNAP4 signaling axis in disease progression of human sarcomas and suggest that targeting the NELL-1/CNTNAP4 signaling pathway represents a strategy with potential therapeutic benefit in sarcoma patients.