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Updated: Mar 27, 2026
A Preclinical Mouse Model of Osteosarcoma to Define the Extracellular Vesicle-mediated Communication Between Tumor and Mesenchymal Stem Cells
Published on: May 6, 2018
Single-Cell RNA Analysis of Murine Osteosarcoma Uncovers Skp2 Function in Metastasis, Genomic Instability, and Immune
Alexander Ferrena1,2, Ranxin Zhang3,4, Jichuan Wang3,4
1Institute for Clinical and Translational Research, Albert Einstein College of Medicine, Bronx, New York.
Abstract:
Osteosarcoma is the most common primary pediatric bone malignancy. One promising new target is SKP2, encoding a substrate recognition factor of the SCF E3 ubiquitin ligase that targets p27 for proteasomal degradation, driving cellular proliferation. Knockout (KO) of Skp2 in an immunocompetent transgenic mouse model of osteosarcoma improved survival, drove apoptosis, and induced antitumor immunity. In this study, we applied single-cell RNA-sequencing (scRNA-seq) to primary osteosarcoma tumors from Osx-Cre conditional Rb1/Trp53 KO mice. We further compared with models of Skp2 disruption: Skp2 KO or disruption of the Skp2-p27 interaction (resulting in p27 overexpression). We report that murine osteosarcoma models recapitulate the tumor heterogeneity and microenvironment complexity observed in patient tumors. Skp2 disruption led to reduction of T-cell exhaustion and upregulation of interferon (IFN) signaling, as well as induction of cell type-specific replicative and endoplasmic reticulum stress, which we validated with proteomics analysis. Furthermore, we showed that IFN induction was correlated with improved survival in patients with osteosarcoma. Additionally, our scRNA-seq analysis uncovered decreased expression of metastasis-related gene signatures in Skp2-disrupted osteosarcoma, which we validated by a strong reduction in lung metastasis in the Skp2 KO mice. Finally, we report several mechanisms potentially used by osteosarcoma to escape from Skp2 targeting, including upregulation of Myc targets, induction of genomic instability, overexpression of alternative E3 ligases, and lineage plasticity. These mechanistic insights into osteosarcoma tumor biology and Skp2 function suggest novel targets for new, synergistic therapies, whereas the data and our comprehensive analysis may serve as a public resource for further big data-driven osteosarcoma research.
Significance:
Our single-cell study of murine osteosarcoma models uncovers Skp2 function in metastasis, genomic instability, and immune activation and reveals additional target pathways to overcome resistance to Skp2 disruptions.
Insights
Disrupting SKP2 in osteosarcoma (OS) mouse models reduced tumor metastasis and T cell exhaustion, enhancing anti-tumor immunity and survival. This suggests SKP2 as a therapeutic target for pediatric bone cancer.
Area of Science:
- Oncology
- Molecular Biology
- Immunology
Background:
- Osteosarcoma (OS) is the most common pediatric bone cancer.
- SKP2 targets p27 for degradation, promoting cellular proliferation and tumor growth.
- SKP2 inhibition has shown promise in preclinical models of OS.
Purpose of the Study:
- To investigate the effects of SKP2 disruption on OS tumor biology, microenvironment, and metastasis.
- To compare SKP2 knockout with disruption of the SKP2-p27 interaction in OS models.
- To identify mechanisms of OS escape from SKP2 targeting.
Main Methods:
- Single-cell RNA-sequencing (scRNA-seq) of primary OS tumors in Osx-Cre conditional Rb1/Trp53 knockout mice.
- Comparison of SKP2 knockout and SKP2-p27 interaction disruption models.
- Proteomics analysis to validate findings.
- Analysis of patient data for correlation between interferon signaling and survival.
Main Results:
- Murine OS models recapitulated human tumor heterogeneity and microenvironment.
- SKP2 disruption reduced T cell exhaustion, upregulated interferon signaling, and induced cellular stress.
- Interferon induction correlated with improved OS patient survival.
- SKP2 disruption significantly reduced lung metastasis and metastasis-related gene signatures.
- Identified OS escape mechanisms including Myc upregulation and lineage plasticity.
Conclusions:
- SKP2 disruption enhances anti-tumor immunity and reduces metastasis in OS.
- Interferon induction is a key mechanism of SKP2's therapeutic effect.
- Understanding OS escape mechanisms can inform novel therapeutic strategies.
- The study provides a valuable resource for OS research.
