Cell lines and culture conditions

JN-DSRCT-1, BER-DSRCT, and SK-DSRCT2 cell lines have been previously described and validated to harbor the defining EWSR1-WT1 fusion (Nishio et al., 2002; Markides et al., 2013; Smith et al., 2022). Adherent culture: cells were grown on tissue culture (treated) plates in DMEM/F12 media supplemented with 10% FBS (Gibco), 2 mM L-Glutamine, 100 U/ml penicillin and 100 μg/ml streptomycin (ThermoFisher, Waltham, MA). Sphere culture: 4 * 10⁶ cells were seeded on non-treated plates (Costar^® 6-well Clear Not Treated Multiple, Corning) in a 1:1 mixture of DMEM/F12 and Neurobasal Media supplemented with 2 mM L-Glutamine, 100 U/ml penicillin, and 100 μg/ml streptomycin (ThermoFisher, Waltham, MA). Media was changed every 2 days.