Cell culture

RH30 human aRMS cells (kindly provided by Associate Professor Judith Davie, Southern Illinois University), AX-OH-1 human aRMS and FL-OH-1 human eRMS cells (kindly provided by Professor Stefan Bath, University of Cape Town) were cultured in Roswell Park Memorial Institute Medium (RPMI)-1640 (Sigma Aldrich, Missouri, USA). RD human eRMS cells (ATCC^® CCL-136™), FG0 and DMB human skin fibroblasts (kindly provided by Associate Professor Denver Hendricks, University of Cape Town), mouse myoblast cells (ATCC^® CRL-1772™), human mesenchymal stem cells A10021501 (kindly provided by Professor Michael Pepper, University of Pretoria and confirmed to meet the criteria to be defined as mesenchymal stem cells as set out by the Mesenchymal and Tissue Stem Cell Committee of the International Society for Cellular Therapy⁵⁷), HT1080 human fibrosarcoma cells (ATCC^® CCL-120™), SW1353 human chondrosarcoma cells (ATCC^® HTB-94™), SW982 human synovial sarcoma cells (ATCC^® HTB-93™), SW872 human liposarcoma (ATCC^® HTB-92™) and MG-63 human osteosarcoma cells (kindly provided by Associate Professor Philippa Hulley, University of Oxford) were cultured in Dulbecco’s modified Eagle’s medium (Sigma Aldrich). All culture medium was supplemented with 10% heat-inactivated foetal bovine serum, 100 U/mL penicillin and 100 μg/mL streptomycin. Cells were maintained at 37 °C in a 95% air and 5% CO₂ humidified incubator. Medium was replaced every 2 to 3 days and cells were routinely subjected to mycoplasma tests. Only mycoplasma free cells were used in experiments. Cell morphology was monitored using an Olympus CKX41 inverted microscope (MSAC Ltd, UK) and imaged with an EVOS™ XL AMEX1000 Core Imaging System (Thermo Fisher Scientific, Massachusetts, USA).