Document Type
Article
Publication Date
10-2026
Identifier
DOI: 10.1242/bio.062763; PMCID: PMC13730126
Abstract
Microtubule-destabilizing agents (MDAs) and microtubule-stabilizing agents (MSAs) are commonly used chemotherapeutic agents due to their ability to induce cell death by compromising the dynamics of spindles during mitosis. Ewing sarcoma, the second most common pediatric bone cancer, is known to selectively respond to MDAs as a first-line treatment, but not to MSAs. Ewing sarcoma cells carry an aberrant EWSR1-FLI1 fusion gene and only one wild-type EWSR1 allele. To investigate the origin of this MDA sensitivity, we used an isogenic cell line carrying a (AID-EWSR1/wt;EWSR1-FLI1-mCherry/wt) genotype that enables conditional induction of EWSR1-FLI1 expression (Tet-On system) and EWSR1 knockdown derived from one EWSR1 allele (auxin-degron system). A combination of EWSR1-FLI1 expression and EWSR1 knockdown enhances apoptosis upon nocodazole treatment, a type of MDA. Our study revealed that the mitotic spindles of Ewing sarcoma cells (A673, RD-ES and SK-ES1) contain elevated levels of tubulin damage, visualized with GTP-tubulin, compared to mesenchymal stem cells. Consistently, the combination of EWSR1-FLI1 expression and EWSR1 knockdown in the isogenic (AID-EWSR1/wt;EWSR1-FLI1-mCherry/wt) cell line also leads to an increased incidence of damage in mitotic spindles. Together, we propose that the sensitivity of Ewing sarcoma cells is potentially derived from the increased levels of damage to mitotic spindles caused by EWSR1-FLI1 expression and EWSR1 knockdown.
Journal Title
Biol Open
Volume
15
Issue
10
MeSH Keywords
Humans; RNA-Binding Protein EWS; Spindle Apparatus; Cell Line, Tumor; Oncogene Proteins, Fusion; Nocodazole; Sarcoma, Ewing; Proto-Oncogene Protein c-fli-1; Gene Knockdown Techniques; Alleles; Gene Expression Regulation, Neoplastic; Apoptosis; Mitosis
PubMed ID
42924892
Keywords
Mitosis; Sarcoma; Tubulin
Recommended Citation
Schulz ET, Parrales A, Iwakuma T, Azuma M. EWSR1-FLI1 expression combined with monoallelic EWSR1 depletion is associated with mitotic spindle damage and nocodazole sensitivity. Biol Open. 2026;15(10):bio062763. doi:10.1242/bio.062763
Comments
Grants and funding
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution and reproduction in any medium provided that the original work is properly attributed.
Publisher's Link: https://journals.biologists.com/bio/article/15/10/bio062763/373253/EWSR1-FLI1-expression-combined-with-monoallelic