Fig. 1: ASPSCR1::TFE3 expression is dispensable for cell maintenance in vitro but required for in vivo tumor development in ASPS.

a Schematic illustration of functional analysis in ASPS cells with or without ASPSCR1::TFE3 expression. b ASPSCR1::TFE3 expression in ASPS17 and ASPS25 was compared with their null counterparts at the transcriptional level (top) (n = 3 per group) and protein levels (bottom, two representative immunoblots from eight independent experiments). c Loss of the ASPSCR1::TFE3 protein in ASPS null cells exhibited by immunofluorescence using the anti-FLAG antibody. Scale bar: 20 µm. Experiments represent five biological replicates. d Cell proliferation of mouse ASPS17 and ASPS null cells (left, top), and human ASPS-KY cells with siRNA treatment (left, bottom) (n = 4 per group). ns: no significance. The efficiency of ASPSCR1::TFE3 knockdown is shown at transcriptional (n = 4 per group) and protein levels (right, representative immunoblots from five independent experiments). e Suppression of tumor development by loss of ASPSCR1::TFE3 expression. Average tumor volumes with SD are shown in the recipient transplanted with ASPS17 and ASPS null cells (n = 6 mice/12 independent tumors per group). The tumor volume was measured using 2 tumors per mouse. f Histology of transplanted area with ASPS17 and ASPS null cells 4 days after transplantation. Hematoxylin and eosin (HE) staining and immunohistochemistry with indicated antibodies. Scale bar: 50 µm. Experiments represent three biological replicates. g Gene set enrichment analysis (GSEA) showing enrichment of VEGF and exocytic vesicle pathways between ASPS17 and ASPS null cells. Normalized enrichment scores (NES), nominal p-values, and FDR q-values are indicated (left). The p-value is computed through the two-sided permutation test (n = 1000 randomizations) adjusted the Benjamini-Hochberg procedure. Quantitative RT-PCR (qRT-PCR) showing downregulation of Rab27a, Sytl2, Pdgfb, and Vwf in ASPS null cells while Myh9 expression was increased (n = 3 per group). h GSEA showing enrichment of VEGFA and pigment granule pathways by comparing human ASPS-KY cells with and without knockdown of ASPSCR1::TFE3 (left). Downregulation of RAB27A, SYTL2, PDGFB, and VWF is shown (n = 3 per group). Statistical analyses in (b, d, e, g, h) were performed by two-sided Student’s t-test and *marks adjusted p-value < 0.05, **marks adjusted p-value < 0.01 and ***marks adjusted p-value < 0.001. The data presented as mean ± SD. Source data are provided as a Source Data file.