Roscovitine is an effective inducer of apoptosis of Ewing's sarcoma family tumor cells in vitro and in vivo

The Ewing's sarcoma family of tumors (ESFT) comprises several well-characterized malignant neoplasms with particularly aggressive behavior. Despite recent progress in the use of multimodal therapeutic approaches and aggressive local control measures, a substantial proportion of patients die because of disease progression. Furthermore, this outcome has not changed significantly over the last 15 to 20 years. Consequently, new, more effective therapeutic options are sorely needed for the treatment of ESFT. Because ESFT cells overexpress several cyclin-dependent kinases (CDK), we explored the efficacy against ESFT of roscovitine, a CDK inhibitor shown to be surprisingly safe for humans in clinical trials of their anticancer activity. Results showed that ESFT cell lines are uniformly sensitive to roscovitine. In addition to exerting comparatively minor cell cycle effects, roscovitine treatment concomitantly caused the up-regulation of the expression of the proapoptotic protein BAX and the down-regulation of both survivin and XIAP, thus resulting in caspase-dependent apoptosis. Furthermore, in Vivo experiments showed that s.c. growth of ESFT xenografts was also significantly slowed by i.p. injection of roscovitine. These results strongly suggest that roscovitine may be an effective therapeutic agent against ESFT and recommend its evaluation against ESFT in clinical trials and its inclusion in future treatment protocols.