Fig. 1

Myxoid liposarcoma scaffolds as an in vivo-like growth model system to study the effect of fusion oncogene FUS::DDIT3. A The tumor tissue was cut into pieces (~ 6 × 6 × 6 mm) and then decellularized using two rounds of detergent washing and cut into smaller pieces (~ 2 × 2 × 2 mm). Cell-free scaffolds were repopulated by adding sarcoma cells of interest followed by 3 weeks of growth before downstream analysis. B Hematoxylin and eosin staining of myxoid liposarcoma (MLS) scaffolds repopulated with HT1080 wild-type (WT) cells cultured for 1, 3 and 7 weeks. Images below are representative magnifications. C, D Comparison of HT1080 WT cells after 1, 3 and 7 weeks of culture in scaffolds and quantification of C cellularized fraction of the scaffold area, calculated as the area covered by cells divided by the total area, and D maximum thickness of surface cell layer. Mean ± SEM is shown, n = 3–7. *p ≤ 0.05, **p ≤ 0.01, one-way ANOVA with Tukey’s multiple comparison test. E–H Comparison of HT1080 cells with and without ectopic FUS::DDIT3-eGFP expression cultured in scaffolds for 3 weeks and quantification of E cellularized fraction of the scaffold area, F maximum thickness of surface cell layer, G the number of single cells migrating into the matrix, where the single cells inside the scaffold area was calculated (0 = 0 cells, 1 = 1–20 cells, 2 = 20–50 cells, 3 ≥ 51 cells), and H number of quadrants with single cells, where the scaffold area was divided into four quadrants and the number of quadrants containing at least 5 single cells were calculated. Mean ± SEM is shown, n = 5–7. *p < 0.05, Student’s t-test. I Hematoxylin and eosin staining of scaffolds repopulated with HT1080 cells with ectopic FUS::DDIT3-eGFP expression and MLS cell line 1765-92 cells both cultured for 3 weeks. Images below are representative magnifications