Thrombospondin-targeting TAX2 peptide impairs tumor growth in preclinical mouse models of childhood neuroblastoma

Background: We have previously identified TAX2 peptide as an orthosteric antagonist for thrombospondin-1 (TSP-1) interaction with the cell-surface receptor CD47. TAX2 displays exciting antiangiogenic, antitumor, and antimetastatic properties in both allograft and xenograft models of melanoma as well as pancreatic carcinoma. Here, TAX2 therapeutic potential was investigated in two distinct preclinical mouse models of neuroblastoma. Methods: SK-N-BE(2) ( MYCN -amplified) and SK-N-SH ( MYCN -negative) human neuroblastoma cells have been implanted in outbred NMRI nude mice prior to systemic administrations of TAX2, and then tumor growth as well as intratumoral blood flow were longitudinally monitored. At study termination, subcutaneous xenografts were macroscopically and histopathologically examined. Results: In both models, TAX2 induced a significant inhibition of tumor burden in mice engrafted with large pre-established neuroblastoma tumors. Indeed, TAX2 administered at biologically relevant doses sharply alters xenograft vascularization as well as multiple features of tumor progression. Conclusion: Altogether, our results present TAX2 peptide specifically targeting TSP-1:CD47 interaction as a new putative therapeutic approach for treating neuroblastoma, whether utilized alone or in combination with existing chemotherapy drugs.