Ewing’s sarcoma precursors are highly enriched in embryonic osteochondrogenic progenitors
Miwa Tanaka, … , Jun Kanno, Takuro Nakamura
Miwa Tanaka, … , Jun Kanno, Takuro Nakamura
Published June 9, 2014
Citation Information: J Clin Invest. 2014;124(7):3061-3074. https://doi.org/10.1172/JCI72399.
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Research Article Oncology

Ewing’s sarcoma precursors are highly enriched in embryonic osteochondrogenic progenitors

Abstract

Ewing’s sarcoma is a highly malignant bone tumor found in children and adolescents, and the origin of this malignancy is not well understood. Here, we introduced a Ewing’s sarcoma–associated genetic fusion of the genes encoding the RNA-binding protein EWS and the transcription factor ETS (EWS-ETS) into a fraction of cells enriched for osteochondrogenic progenitors derived from the embryonic superficial zone (eSZ) of long bones collected from late gestational murine embryos. EWS-ETS fusions efficiently induced Ewing’s sarcoma–like small round cell sarcoma formation by these cells. Analysis of the eSZ revealed a fraction of a precursor cells that express growth/differentiation factor 5 (Gdf5), the transcription factor Erg, and parathyroid hormone-like hormone (Pthlh), and selection of the Pthlh-positive fraction alone further enhanced EWS-ETS–dependent tumor induction. Genes downstream of the EWS-ETS fusion protein were quite transcriptionally active in eSZ cells, especially in regions in which the chromatin structure of the ETS-responsive locus was open. Inhibition of β-catenin, poly (ADP-ribose) polymerase 1 (PARP1), or enhancer of zeste homolog 2 (EZH2) suppressed cell growth in a murine model of Ewing’s sarcoma, suggesting the utility of the current system as a preclinical model. These results indicate that eSZ cells are highly enriched in precursors to Ewing’s sarcoma and provide clues to the histogenesis of Ewing’s sarcoma in bone.

Authors

Miwa Tanaka, Yukari Yamazaki, Yohei Kanno, Katsuhide Igarashi, Ken-ichi Aisaki, Jun Kanno, Takuro Nakamura

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Figure 7

Effects of small molecule inhibitors on Ewing’s sarcoma.

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Effects of small molecule inhibitors on Ewing’s sarcoma. (A) In vitro gr...
(A) In vitro growth inhibition of mouse and human Ewing’s sarcoma, human clear cell sarcoma, and human osteosarcoma cell lines by iCRT14, PNU74654, DZNeP, and olaparib. Cells were treated with each reagent at the indicated concentration for 48 hours. The experiment was performed in triplicate, and average suppression rates with standard errors are indicated. (B) Cell cycle analyses of mES #1 cells treated with 1 μM of each reagent (i.e., DMSO, iCRT14, PNU74854, DZNep, or Olaparib) for 48 hours. Frequencies (percentages) of G1 and G2/M are indicated. (C) Growth inhibitory effects of small molecules for mouse Ewing’s sarcoma in vivo. mES #1 cells were transplanted subcutaneously into nude mice, and tumor volume was measured every other day. Mean tumor volumes ± SD for 5 mice of each group are plotted. *P < 0.01; **P < 0.03.