Netrin-1 induces medulloblastoma invasion and angiogenesis 1 Netrin-1 promotes medulloblastoma cell invasiveness and angiogenesis, and demonstrates elevated expression in tumor tissue and urine of pediatric medulloblastoma patients

There are no conflicts to disclose. Total number of figures: 6 main, 2 supplemental and 1 table Netrin-1 induces medulloblastoma invasion and angiogenesis 3 ABSTRACT Invasion and dissemination of medulloblastoma (MB) within the central nervous system is the principal factor predicting MB treatment failure and death. Netrin-1 is an axon guidance factor implicated in tumor and vascular biology, including in invasive behaviors. We found that exogenous netrin-1 stimulated invasion of human MB cells and endothelial cells (EC) in contrast to VEGF-A, which promoted invasion of EC but not MB cells. Further, MB cells expressed endogenous netrin-1 along with its receptors, neogenin and UNC5B. Blockades in endogenous netrin-1, neogenin or UNC5B reduced MB invasiveness. Neogenin blockade inhibited netrin-1-induced EC tube formation and recruitment of EC into Matrigel plugs, two hallmarks of angiogenesis. In pediatric MB patients, netrin-1 mRNA levels were increased 1.7-fold in MB tumor specimens compared to control specimens from the same patient. Immunohistochemical analyses showed that netrin-1 was elevated in MB tumors versus cerebellum controls. Notably, urinary levels of netrin-1 were 9-fold higher in MB patients compared to control individuals. Moreover, urinary netrin-1 levels were higher in patients with invasive MB compared to patients with non-invasive MB. Lastly, we noted that urinary netrin-1 levels diminished after MB resection in patients. Our results suggest netrin-1 as a candidate biomarker capable of detecting an invasive, disseminated phenotype in MB patients and predicting their disease status. Netrin-1 induces medulloblastoma invasion and angiogenesis 4 INTRODUCTION