Abstract

Both DCC/NEO1 and UNC5 homologues families have shown to behave as Dependence Receptors (RD), creating a cellular dependence state to its main ligands, the Netrin laminin-like proteins. Netrin-4 is an axon guidance factor implicated in tumor and vascular biology, including in invasive behaviors. Both Netrins and Neogenin-1 are highly expressed in NB, a very aggressive pediatric tumor, however, the functional role of these proteins in NB is not fully understood. We recently determined the exclusive presence of Netrin-4 and Neogenin-1 in SH-SY5Y cells. The latter gives us the advantage of having a simple cell model to study how Netrin-4 affects Neogenin-1 functionality. Our data reveal that stable in vitro knock-down of Netrin-4 (shNTN4) produces an increase in cell death, effect reversed when treating with recombinant Netrin-4. Overexpression of Neogenin-1 causes an increase of apoptotic cells; effect also blocked by exogenous Netrin-4. Migration is lower in shNTN4 and shNeogenin-1 cells as measured by transwell assay. Tumor growth and metastasis, analyzed by chick chorioallantoic membrane (CAM) dropping assay with shNetrin-4, shNeogenin-1 or shScramble cells followed by quantitative PCR, demonstrates that metastasis is reduced in knock-down cells compared to shScramble cells. Taken together, our results demonstrate that Netrin-4 acts as a novel dependence factor of its receptor Neogenin-1 in NB.