Discovery and Validation of a Compound to Target Ewing's Sarcoma.

Ellie Esfandiari Nazzaro,Mohamad Nazari,Monika A Davare,Oleh Taratula,Katelyn S Nicholson,Olena Taratula,Mark Leid,Philip R Gafken,Walter K Vogel,Fahad Y Sabei

doi:10.3390/pharmaceutics13101553

Abstract

Ewing’s sarcoma, characterized by pathognomonic t (11; 22) (q24; q12) and related chromosomal ETS family translocations, is a rare aggressive cancer of bone and soft tissue. Current protocols that include cytotoxic chemotherapeutic agents effectively treat localized disease; however, these aggressive therapies may result in treatment-related morbidities including second-site cancers in survivors. Moreover, the five-year survival rate in patients with relapsed, recurrent, or metastatic disease is less than 30%, despite intensive therapy with these cytotoxic agents. By using high-throughput phenotypic screening of small molecule libraries, we identified a previously uncharacterized compound (ML111) that inhibited in vitro proliferation of six established Ewing’s sarcoma cell lines with nanomolar potency. Proteomic studies show that ML111 treatment induced prometaphase arrest followed by rapid caspase-dependent apoptotic cell death in Ewing’s sarcoma cell lines. ML111, delivered via methoxypoly(ethylene glycol)-polycaprolactone copolymer nanoparticles, induced dose-dependent inhibition of Ewing’s sarcoma tumor growth in a murine xenograft model and invoked prometaphase arrest in vivo, consistent with in vitro data. These results suggest that ML111 represents a promising new drug lead for further preclinical studies and is a potential clinical development for the treatment of Ewing’s sarcoma.

Highlights

Characterized Ewing’s sarcoma cell line harboring a type II EWS-Friend leukemia virus integration 1 (FLI1) oncofusion protein [24,25] and a chemical library composed of small molecules from the ChemBridge
Our analyses revealed that treatment of SK-N-MC cells with ML111 resulted in time-dependent stabilization of numerous cell cycle proteins, most of which are substrates for the anaphase-promoting complex/cyclosome (APC/C), an E3 ubiquitin ligase that targets mitotic factors for rapid proteasomal degradation (Figure 5A and Appendix A)
We postulated that a high-throughput phenotypic strategy would be advantageous in this case, given the challenges associated with identifying specific target proteins downstream of the complex, dysregulated transcriptional program driven by EWS-FLI1 or related fusion oncogenes

Summary

Introduction

Ewing’s sarcoma, a small and round blue-cell malignancy arising from bone or soft tissue, most commonly affects children and adolescent patients. Ewing’s sarcoma is a rare aggressive cancer, posing substantial clinical challenges, and while prognoses have improved for young patients or patients with localized disease, outcomes for metastatic or relapsed disease remain dire [1,2]. Standard treatment includes multimodal strategies with combinations of chemotherapy (vincristine, doxorubicin, cyclophosphamide, and ifosfamide), surgery, and radiation [3,4]. Targeted therapies for Ewing’s sarcoma have not 4.0/).

Results

Discussion

Conclusion