HEY1-NCOA2 expression modulates chondrogenic differentiation and induces mesenchymal chondrosarcoma in mice
Miwa Tanaka, Mizuki Homme, Yasuyo Teramura, Kohei Kumegawa, Yukari Yamazaki, Kyoko Yamashita, Motomi Osato, Reo Maruyama, Takuro Nakamura
Miwa Tanaka, Mizuki Homme, Yasuyo Teramura, Kohei Kumegawa, Yukari Yamazaki, Kyoko Yamashita, Motomi Osato, Reo Maruyama, Takuro Nakamura
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Research Article Cell biology Oncology

HEY1-NCOA2 expression modulates chondrogenic differentiation and induces mesenchymal chondrosarcoma in mice

Abstract

Mesenchymal chondrosarcoma affects adolescents and young adults, and most cases usually have the HEY1::NCOA2 fusion gene. However, the functional role of HEY1-NCOA2 in the development and progression of mesenchymal chondrosarcoma remains largely unknown. This study aimed to clarify the functional role of HEY1-NCOA2 in transformation of the cell of origin and induction of typical biphasic morphology of mesenchymal chondrosarcoma. We generated a mouse model for mesenchymal chondrosarcoma by introducing HEY1-NCOA2 into mouse embryonic superficial zone (eSZ) followed by subcutaneous transplantation into nude mice. HEY1-NCOA2 expression in eSZ cells successfully induced subcutaneous tumors in 68.9% of recipients, showing biphasic morphologies and expression of Sox9, a master regulator of chondrogenic differentiation. ChIP sequencing analyses indicated frequent interaction between HEY1-NCOA2 binding peaks and active enhancers. Runx2, which is important for differentiation and proliferation of the chondrocytic lineage, is invariably expressed in mouse mesenchymal chondrosarcoma, and interaction between HEY1-NCOA2 and Runx2 is observed using NCOA2 C-terminal domains. Although Runx2 knockout resulted in significant delay in tumor onset, it also induced aggressive growth of immature small round cells. Runx3, which is also expressed in mesenchymal chondrosarcoma and interacts with HEY1-NCOA2, replaced the DNA-binding property of Runx2 only in part. Treatment with the HDAC inhibitor panobinostat suppressed tumor growth both in vitro and in vivo, abrogating expression of genes downstream of HEY1-NCOA2 and Runx2. In conclusion, HEY1::NCOA2 expression modulates the transcriptional program in chondrogenic differentiation, affecting cartilage-specific transcription factor functions.

Authors

Miwa Tanaka, Mizuki Homme, Yasuyo Teramura, Kohei Kumegawa, Yukari Yamazaki, Kyoko Yamashita, Motomi Osato, Reo Maruyama, Takuro Nakamura

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Figure 3

Gene expression network during chondrogenic differentiation of mesenchymal chondrosarcoma revealed by single-cell RNA sequencing and immunostaining.

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Gene expression network during chondrogenic differentiation of mesenchym...
(A) scRNA-Seq followed by PCA-guided uniform manifold and projection (UMAP) identifies neoplastic and nonneoplastic cellular fractions. Clusters are divided into 0–10 as indicated on the right. (B) Heatmap revealing 120 differentially expressed genes for each cluster defined in A. (C) Dot plot analysis using 19 chondrogenesis-related genes that represent each tumor cluster. (D) Differential expression of Cytl1, Igfbp5, Vcan, S100a6, Sdc4, and Anxa1 was further demonstrated by ridge plot. (E) Pseudotime trajectory analysis showing a differentiation pathway from progenitor/proliferation cluster (see 4) to more differentiation stages via fibrocartilage (see 5) and prehypertrophic cartilage (see 2). (F) Immunohistochemical analysis demonstrates distinct expression patterns with partial overlapping of Sox9, Runx2, endogenous Hey1, and Ki67 in mouse mesenchymal chondrosarcoma. Scale bar: 100 μm.