Targeted Therapy of Ewing's Sarcoma

Area of Science:

• Pediatric Oncology
• Molecular Oncology
• Cancer Therapeutics

Background:

• Refractory and/or recurrent Ewing sarcoma (EWS) presents significant therapeutic challenges due to inherent resistance to conventional treatments like chemotherapy, radiation, and surgery.
• While insulin-like-growth-factor-1-receptor (IGF1R) antibodies demonstrate modest single-agent activity, further research into patient selection biomarkers and resistance mechanisms involving IGF1R and mTOR pathways is ongoing.

Purpose of the Study:

• To explore novel therapeutic strategies for refractory Ewing sarcoma (EWS) by targeting the unique EWS-FLI1 oncogenic fusion protein.
• To investigate the potential of inhibiting EWS-FLI1 at the transcriptional, translational, or protein function level for eradicating EWS stem cells.

Main Methods:

• Preclinical evaluation of a novel small molecule inhibitor designed to disrupt the EWS-FLI1 protein-protein interaction with RNA helicase A.
• Assessment of the inhibitor's efficacy in blocking EWS growth in relevant preclinical models.

Main Results:

• A small molecule inhibitor targeting the EWS-FLI1 interaction with RNA helicase A demonstrated significant inhibition of EWS growth in preclinical models.
• This targeted approach suggests a potential mechanism for eradicating EWS at the stem-cell level.

Conclusions:

• Targeting the EWS-FLI1 oncogenic fusion protein, particularly its interaction with RNA helicase A, represents a promising therapeutic avenue for refractory Ewing sarcoma.
• This first-in-class protein-protein inhibitor approach could serve as a model for developing treatments for other translocation-associated cancers.