High-content drug screening in zebrafish xenografts reveals high efficacy of dual MCL-1/BCL-XL inhibition against Ewing sarcoma

• Published in: Cancer letters 2023-02, Vol.554, p.216028-216028, Article 216028
• Main Authors: Grissenberger, Sarah, Sturtzel, Caterina, Wenninger-Weinzierl, Andrea, Radic-Sarikas, Branka, Scheuringer, Eva, Bierbaumer, Lisa, Etienne, Vesnie, Némati, Fariba, Pascoal, Susana, Tötzl, Marcus, Tomazou, Eleni M., Metzelder, Martin, Putz, Eva M., Decaudin, Didier, Delattre, Olivier, Surdez, Didier, Kovar, Heinrich, Halbritter, Florian, Distel, Martin
• Format: Article
• Language: English
• Subjects: Anti-apoptotic protein inhibitors; Ewing sarcoma; High-content imaging; Phenotypic drug screening; Zebrafish xenografts
• ISSN: 0304-3835; 1872-7980
• DOI: 10.1016/j.canlet.2022.216028

Ewing sarcoma is a pediatric bone and soft tissue cancer with an urgent need for new therapies to improve disease outcome. To identify effective drugs, phenotypic drug screening has proven to be a powerful method, but achievable throughput in mouse xenografts, the preclinical Ewing sarcoma standard model, is limited. Here, we explored the use of xenografts in zebrafish for high-throughput drug screening to discover new combination therapies for Ewing sarcoma. We subjected xenografts in zebrafish larvae to high-content imaging and subsequent automated tumor size analysis to screen single agents and compound combinations. We identified three drug combinations effective against Ewing sarcoma cells: Irinotecan combined with either an MCL-1 or an BCL-XL inhibitor and in particular dual inhibition of the anti-apoptotic proteins MCL-1 and BCL-XL, which efficiently eradicated tumor cells in zebrafish xenografts. We confirmed enhanced efficacy of dual MCL-1/BCL-XL inhibition compared to single agents in a mouse PDX model. In conclusion, high-content screening of small compounds on Ewing sarcoma zebrafish xenografts identified dual MCL-1/BCL-XL targeting as a specific vulnerability and promising therapeutic strategy for Ewing sarcoma, which warrants further investigation towards clinical application. •High-content drug screening in zebrafish xenografts discovers compound combinations effective against Ewing sarcoma.•Combining topoisomerase I inhibitors with anti-apoptotic protein inhibitors enhances single agent efficacy.•Ewing sarcoma cells are highly sensitive to dual targeting of anti-apoptotic proteins MCL-1 and BCL-XL.•MCL-1 and BCL-XL represent therapeutic targets across Ewing sarcomas.