Inhibiting platelet-derived growth factor beta reduces Ewing's sarcoma growth and metastasis in a novel orthotopic human xenograft model.

BACKGROUND

Despite aggressive therapy, Ewing's sarcoma (ES) patients have a poor five-year overall survival of only 20-40%. Pulmonary metastasis is the most common form of demise in these patients. The pathogenesis of pulmonary metastasis is poorly understood and few orthotopic models exist that allow study of spontaneous pulmonary metastasis in ES.

MATERIALS AND METHODS

We have developed a novel orthotopic xenograft model in which spontaneous pulmonary metastases develop. While the underlying biology of ES is incompletely understood, in addition to the EWS-FLI-1 mutation, it is known that platelet-derived growth factor receptor beta (PDGFR-beta) is highly expressed in ES. Hypothesizing that PDGFR-beta expression is indicative of a specific role for this receptor protein in ES progression, the effect of PDGFR-beta inhibition on ES growth and metastasis was assessed in this novel orthotopic ES model.

RESULTS

Silencing PDGFR-beta reduced spontaneous growth and metastasis in ES.

CONCLUSION

Preclinical therapeutically relevant findings such as these may ultimately lead to new treatment initiatives in ES.