Mesenchymal tumor organoid models recapitulate rhabdomyosarcoma subtypes

Abstract

Rhabdomyosarcomas (RMS) are mesenchyme-derived tumors and the most common childhood soft tissue sarcomas. Treatment is intense, with a nevertheless poor prognosis for high-risk patients. Discovery of new therapies would benefit from additional preclinical models. Here, we describe the generation of a collection of 19 pediatric RMS tumor organoid (tumoroid) models (success rate of 41%) comprising all major subtypes. For aggressive tumors, tumoroid models can often be established within 4-8 weeks, indicating the feasibility of personalized drug screening. Molecular, genetic, and histological characterization show that the models closely resemble the original tumors, with genetic stability over extended culture periods of up to 6 months. Importantly, drug screening reflects established sensitivities and the models can be modified by CRISPR/Cas9 with TP53 knockout in an embryonal RMS model resulting in replicative stress drug sensitivity. Tumors of mesenchymal origin can therefore be used to generate organoid models, relevant for a variety of preclinical and clinical research questions.

Implementation of paediatric precision oncology into clinical practice: The Individualized Therapies for Children with cancer program ‘iTHER’

“…tropomyosin receptor kinase (TRK) inhibitor). As another example, a pulmonary metastatic lesion of an embryonal rhabdomyosarcoma harboured a novel PAX3-WWTR1 fusion transcript, which was, in retrospect, also detected in the primary tumour from the shoulder [ 26 ]. Diagnosis was revised in another patient, where the histopathological diagnosis initially favoured malignant rhabdoid tumour.…”

Fusion-negative Rhabdomyosarcoma 3D-organoids as an innovative model to predict resistance to cell death inducers

“…Although new models were recently successfully derived from RMS patients’ biopsies or patient-derived xenografts 36,37 , such 3D-tumor-derived organoid models, characterized as reproducing the features of their original tumors and expandable over the long term to fit with the criteria of the organoid technology, have not been developed for FNRMS yet. By adjusting culture conditions according to the existing literature, but also by deciphering active signaling cascades that could support tumor cell growth thanks to transcriptome datasets (Extended Data Fig.…”

“…Here, we show that it is feasible to derive 3D-tumoroids from mesenchymal FNRMS tumors, which meet the definition of organoids since they accurately and precisely reproduce the histology and molecular characteristics of their tumor-of-origin. Although other protocols have been proposed 36,37 , our derivation pipeline is to date the only one that allows the accurate reproduction of FNRMS tumor features especially in their three-dimensional component, and the expansion of tumoroids over a long period of time. Preservation of this 3D structure is definitely a key issue to reproduce cell-cell contacts, as well as physical and mechanical constraints existing in malignancies, and thus to mimic tumor behavior 56 .…”

“…According to the initial definition 35 , these 3D cellular structures derived from tumor stem/progenitor-like cells, preserve the histological and molecular characteristics of their original tumor even after long-term expansion in culture, making them accurate and powerful tools for basic, translational and clinical research 35 . Although new models were recently successfully derived from RMS patients' biopsies or patient-derived xenografts 36,37 , such 3D-tumor-derived organoid models, characterized as reproducing the features of their original tumors and expandable over the long term to fit with the criteria of the organoid technology, have not been developed for FNRMS yet. By adjusting culture conditions according to the existing literature, but also by deciphering active signaling cascades that could support tumor cell growth thanks to transcriptome datasets (Extended Data Fig.…”

Organoids: A New Chapter in Sarcoma Diagnosis and Treatment

“…Moreover, with 5/7 tested lines reaching passage 40, the models remain genetically and transcriptionally stable after culture over time, while rhabdomyosarcoma organoid drug screening reflects established drug sensitivities. Of note, the study group succeeded in genetically editing the organoid models using CRISPR/Cas9 and described that p53-deficient embryonal rhabdomyosarcoma tumoroid cells show a more sensitive response to the checkpoint kinase inhibitor prexasertib [ 26 ].…”