Oncogenic ETS fusions promote DNA damage and proinflammatory responses via pericentromeric RNAs in extracellular vesicles
Peter Ruzanov, … , Lincoln D. Stein, Poul H. Sorensen
Peter Ruzanov, … , Lincoln D. Stein, Poul H. Sorensen
Published March 26, 2024
Citation Information: J Clin Invest. 2024;134(9):e169470. https://doi.org/10.1172/JCI169470.
View: Text | PDF
Research Article Inflammation

Oncogenic ETS fusions promote DNA damage and proinflammatory responses via pericentromeric RNAs in extracellular vesicles

Abstract

Aberrant expression of the E26 transformation-specific (ETS) transcription factors characterizes numerous human malignancies. Many of these proteins, including EWS:FLI1 and EWS:ERG fusions in Ewing sarcoma (EwS) and TMPRSS2:ERG in prostate cancer (PCa), drive oncogenic programs via binding to GGAA repeats. We report here that both EWS:FLI1 and ERG bind and transcriptionally activate GGAA-rich pericentromeric heterochromatin. The respective pathogen-like HSAT2 and HSAT3 RNAs, together with LINE, SINE, ERV, and other repeat transcripts, are expressed in EwS and PCa tumors, secreted in extracellular vesicles (EVs), and are highly elevated in plasma of patients with EwS with metastatic disease. High human satellite 2 and 3 (HSAT2,3) levels in EWS:FLI1- or ERG-expressing cells and tumors were associated with induction of G2/M checkpoint, mitotic spindle, and DNA damage programs. These programs were also activated in EwS EV-treated fibroblasts, coincident with accumulation of HSAT2,3 RNAs, proinflammatory responses, mitotic defects, and senescence. Mechanistically, HSAT2,3-enriched cancer EVs induced cGAS-TBK1 innate immune signaling and formation of cytosolic granules positive for double-strand RNAs, RNA-DNA, and cGAS. Hence, aberrantly expressed ETS proteins derepress pericentromeric heterochromatin, yielding pathogenic RNAs that transmit genotoxic stress and inflammation to local and distant sites. Monitoring HSAT2,3 plasma levels and preventing their dissemination may thus improve therapeutic strategies and blood-based diagnostics.

Authors

Peter Ruzanov, Valentina Evdokimova, Manideep C. Pachva, Alon Minkovich, Zhenbo Zhang, Sofya Langman, Hendrik Gassmann, Uwe Thiel, Marija Orlic-Milacic, Syed H. Zaidi, Vanya Peltekova, Lawrence E. Heisler, Manju Sharma, Michael E. Cox, Trevor D. McKee, Mark Zaidi, Eve Lapouble, John D. McPherson, Olivier Delattre, Laszlo Radvanyi, Stefan E.G. Burdach, Lincoln D. Stein, Poul H. Sorensen

×

Figure 7

HSAT RNA-enriched EwS EVs activate innate immune and DNA damage pathways in the recipient cells.

Options: View larger image (or click on image) Download as PowerPoint
HSAT RNA-enriched EwS EVs activate innate immune and DNA damage pathway...
(A) ViewRNA-FISH with HSAT2 probes and (B and C) immunofluorescence imaging of MRC5 cells treated with TC32 or MRC5 EVs for 24 hours, counterstained with DAPI. Scale bars: 10 μm. (D) Experimental outline and chromosomal distribution of HSAT2,3 RNA-Seq reads from MRC5 cells treated with PBS (mock) or TC32 EVs. Gray color indicates no reads. (E) Volcano plot, log2 FC versus –log10 P value of differentially expressed genes in TC32 EV-treated MRC5 cells versus mock. Red dots, genes that passed P ≤ 0.05 thresholds and changed >2-fold. (F) Immunoblotting pathway analysis of MRC5 cells treated with mock (–), EwS, or MRC5 EVs, or with 5 ng/mL poly (I:C). (G) A proposed model of pericentromeric chromatin activation in EwS and PCa, and the effects on stromal cells. Dissemination of HSAT2,3 and other pathogen-like repeat RNAs in cancer EVs and their accumulation in stromal fibroblasts and immune cells induces DNA damage and cGAS-pTBK1 signaling. Prolonged activation of these pathways due to continuous exposure to cancer EVs, ongoing reverse transcription, or unresolved DNA damage may lead to local and systemic chronic inflammation, mitotic defects, and senescence.