Comprehensive single cell transcriptomics analysis of murine osteosarcoma uncovers Skp2 function in metastasis, genomic instability and immune activation and reveals additional target pathways

ABSTRACT: Osteosarcoma (OS) is the most common primary pediatric bone malignancy. One promising new therapeutic target is SKP2, encoding a substrate recognition factor of the SCF E3 ubiquitin ligase responsible for ubiquitination and proteasome degradation of substrate p27, thus driving cellular proliferation. We have shown previously that knockout of Skp2 in an immunocompetent transgenic mouse model of OS improved survival, drove apoptosis, and induced anti-tumor immunity. Here, we applied single-cell RNA-sequencing (scRNA-seq) to study primary OS tumors derived from Osx-Cre driven conditional knockout of Rb1 and Trp53 in mice. We further compared this model with OS models with functional disruption of Skp2: one with Skp2 knockout and the other with the Skp2-p27 interaction disrupted (resulting in p27 overexpression). We report that murine OS 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 signaling, as well as induction of cell-type specific replicative and endoplasmic reticulum stress, which we corroborated via mass spectrometry proteomics. Further, we observed that interferon induction was correlated with improved survival in OS patients. Additionally, our scRNA-seq analysis uncovered decreased expression of metastasis-related gene signatures in Skp2-disrupted OS, which we validated by observation of a strong reduction in lung metastasis in the Skp2 knockout mice. Finally, we report several potential mechanisms of escape from targeting Skp2 in OS, including upregulation of Myc targets, induction of genomic instability, overexpression of alternative E3 ligases, and lineage plasticity. These mechanistic insights into OS tumor biology and Skp2 function suggest novel targets for new, synergistic therapies, while the data and our comprehensive analysis may serve as a public resource for further big data-driven OS research.

INSTRUMENT(S):

ORGANISM(S): Mus Musculus (mouse)

SUBMITTER: Simone Sidoli  

LAB HEAD: Simone Sidoli

PROVIDER: PXD059605 | Pride | 2026-03-12

REPOSITORIES: Pride