ETV4 and ETV5 drive synovial sarcoma through cell cycle and DUX4 embryonic pathway control
Joanna DeSalvo, … , Jonathan C. Trent, Josiane E. Eid
Joanna DeSalvo, … , Jonathan C. Trent, Josiane E. Eid
Published May 13, 2021
Citation Information: J Clin Invest. 2021;131(13):e141908. https://doi.org/10.1172/JCI141908.
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Research Article Oncology

ETV4 and ETV5 drive synovial sarcoma through cell cycle and DUX4 embryonic pathway control

Abstract

Synovial sarcoma is an aggressive malignancy with no effective treatments for patients with metastasis. The synovial sarcoma fusion SS18-SSX, which recruits the SWI/SNF-BAF chromatin remodeling and polycomb repressive complexes, results in epigenetic activation of FGF receptor (FGFR) signaling. In genetic FGFR-knockout models, culture, and xenograft synovial sarcoma models treated with the FGFR inhibitor BGJ398, we show that FGFR1, FGFR2, and FGFR3 were crucial for tumor growth. Transcriptome analyses of BGJ398-treated cells and histological and expression analyses of mouse and human synovial sarcoma tumors revealed prevalent expression of two ETS factors and FGFR targets, ETV4 and ETV5. We further demonstrate that ETV4 and ETV5 acted as drivers of synovial sarcoma growth, most likely through control of the cell cycle. Upon ETV4 and ETV5 knockdown, we observed a striking upregulation of DUX4 and its transcriptional targets that activate the zygotic genome and drive the atrophy program in facioscapulohumeral dystrophy patients. In addition to demonstrating the importance of inhibiting all three FGFRs, the current findings reveal potential nodes of attack for the cancer with the discovery of ETV4 and ETV5 as appropriate biomarkers and molecular targets, and activation of the embryonic DUX4 pathway as a promising approach to block synovial sarcoma tumors.

Authors

Joanna DeSalvo, Yuguang Ban, Luyuan Li, Xiaodian Sun, Zhijie Jiang, Darcy A. Kerr, Mahsa Khanlari, Maria Boulina, Mario R. Capecchi, Juha M. Partanen, Lin Chen, Tadashi Kondo, David M. Ornitz, Jonathan C. Trent, Josiane E. Eid

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Figure 3

BGJ398 inhibits ETV4 and ETV5 expression in SS cells.

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BGJ398 inhibits ETV4 and ETV5 expression in SS cells. (A and B) Immunobl...
(A and B) Immunoblots show the effect of 50 nM and 500 nM BGJ398 on phospho-ERK1/2 and phospho-AKT levels in SYO-1 (A) and HS-SY-II (B) cells at the indicated times. V, vehicle (DMSO). n = 2. (C) Functional categorization of the SYO-1 transcriptome following a 24-hour BGJ398 treatment. (D) Heatmap illustrates the downregulation of FGFR pathway–related targets by BGJ398 in SYO-1 cells; -1 and -2 represent duplicate samples. (E) RT-PCR of the indicated genes in SYO-1 (left panel) and HS-SY-II (right panel) cells treated with BGJ398 or vehicle. GAPDH served as input control. The PCR primers are described in Methods. (F) Immunoblot shows ETV4 and ETV5 levels in SYO-1 and HS-SY-II cells treated with BGJ398 or vehicle. Actin served as loading control. n = 2. (G) Immunoblots show ETV4 and ETV5 expression in 50 μg of SYO-1, HS-SY-II, CDS-S2, and CDS-X1 lysates. Two exposures of the ETV4 immunoblot are included. (H) Dot plot shows ETV4 and ETV5 mRNA levels in SS (SYO-1, HS-SY-II) relative to CDS-X1 cells. Dots represent independent values normalized against GAPDH and plotted as fold change. Data are derived from 2 RT-qPCR experiments performed in triplicate. Crossbars indicate the mean. Error bars indicate SEM. P values (*P < 0.00001) compare ΔCt averages in CDS-X1, SYO-1, and HS-SY-II cells. (I and J) Bar graphs show CIC binding to ETV4 and ETV5 promoters in SYO-1 (I) and CDS-X1 (J) cells. Dots represent independent values from 2 ChIP-qPCR experiments each conducted in triplicate. IgG served as background control. IgG binding and CIC binding were quantified as percentage of input chromatin. Error bars indicate SEM. P values (*P ≤ 0.0003 in SYO-1; *P < 0.00001 in CDS-X1) compare ΔCt averages of CIC antibody versus IgG.