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Osteosarcoma

Pathophysiology description

2026-01-31
Falcon MONDO:0009807 Model: Edison Scientific Literature 19 citations

Pathophysiology description Osteosarcoma (OS) is a high-grade primary malignant bone tumor characterized by profound genomic instability, dysregulated developmental and stress-response signaling, metabolic rewiring, and a uniquely immunosuppressive bone tumor microenvironment (TME) that collectively drive invasion, lung metastasis, and treatment resistance (nirala2023decipheringthesignaling pages 1-2). Genomic catastrophe is a defining feature: chromothripsis and kataegis co-occur with frequent loss of key tumor suppressors (TP53, RB1, ATRX) and gains of oncogenes (MYC, MDM2), with epigenetic dysregulation superimposed on widespread copy-number alterations (nirala2023decipheringthesignaling pages 1-2, pires2023analysisofthe pages 2-5, alansari2024unveilingtheprotective pages 6-8). Convergent activation of PI3K/AKT/mTOR, Wnt/β‑catenin, TGF‑β, JAK/STAT, NOTCH, Hedgehog/GLI, RANK/RANKL, and NF‑κB pathways promotes proliferation, survival, EMT-like migration, osteoclastogenic crosstalk, and metastasis (nirala2023decipheringthesignaling pages 2-4). Single-cell analyses reveal immune-evasion programs including downregulation of MHC-I/B2M and upregulation of PD‑L1 and the anti-phagocytic ligand CD24 on cancer cells, accompanied by expansion of immunoregulatory LAMP3+CCR7+CD83+ dendritic cells (mregDCs) and SPP1+ tumor-associated macrophages (TAMs) (liu2023characterizingthetumor pages 2-3). Neoadjuvant chemotherapy remodels this ecosystem toward stemness-enriched tumor cells, ECM‑remodeling CAFs, altered endothelium, and depletion of effector myeloid and T/NK compartments, contributing to resistance and relapse (zheng2024singlecelltranscriptomicinsights pages 1-2).

Key concepts and definitions (current understanding) - Chromothripsis: catastrophic one-off chromosome shattering and rejoining that accelerates karyotype evolution; prevalent in OS and linked to micronuclei and decatenation defects (quote: mechanisms include “micronuclear DNA damage”; RanGAP1 reduction increases chromothripsis risk) (nirala2023decipheringthesignaling pages 2-4). URL: https://doi.org/10.3390/ijms241411367 (Jul 2023). - Kataegis: localized hypermutation tracts; reported in roughly half of OS and often co‑occurs with chromothripsis (nirala2023decipheringthesignaling pages 2-4, pires2023analysisofthe pages 2-5, alansari2024unveilingtheprotective pages 6-8). URLs: https://doi.org/10.3390/ijms241411367 (Jul 2023); https://doi.org/10.3390/ijms241310463 (Jun 2023); https://doi.org/10.3390/biom14020145 (Jan 2024). - mregDCs: LAMP3+CCR7+CD83+ mature regulatory dendritic cells enriched in OS tumors; associated with Treg recruitment and poorer survival; increasing inhibitory ligands (PD‑L1, LAG3, LGALS9, SIRPA, TIGIT, PD‑L2) along DC maturation trajectories (liu2023characterizingthetumor pages 2-3). URL: https://doi.org/10.1038/s41413-022-00237-6 (Jan 2023). - SPP1+ TAMs: osteopontin-expressing macrophages linked to immune suppression and adverse prognosis in OS ecosystems (liu2023characterizingthetumor pages 2-3). URL: https://doi.org/10.1038/s41413-022-00237-6 (Jan 2023).

Recent developments and latest research (2023–2024 priority) - Genomic landscape in new primary OS: 28-tumor cohort delineated 445 deleterious coding variants with recurrent TP53 (~60% considering SNV/indel/CNA), RB1, ATRX, and complex CNA patterns reminiscent of chromothripsis/chromoanasynthesis; pathway enrichment implicated immunity and bone development programs (pires2023analysisofthe pages 2-5). URL: https://doi.org/10.3390/ijms241310463 (Jun 2023). - Single-cell TME remodeling after chemotherapy: residual cells upregulate stemness; CAFs expand and increase ECM-remodeling capacity; endothelial cells increase with impaired differentiation; anti-tumor myeloid and T/NK subsets are depleted (zheng2024singlecelltranscriptomicinsights pages 1-2). URL: https://doi.org/10.1007/s00432-024-05787-2 (Jul 2024). - Single-cell immune evasion mechanisms: inferCNV-linked CNV‑high cancer cells downregulate interferon pathways and MHC-I/B2M; mregDCs correlate with Tregs; CD24 identified as a “don’t eat me” signal on OS cells (liu2023characterizingthetumor pages 2-3). URL: https://doi.org/10.1038/s41413-022-00237-6 (Jan 2023).

Current applications and real-world implementations - Molecular risk and target identification: Copy-number and expression assessment of TP53/RB1 loss, MDM2 gain, and MYC amplification inform prognosis and experimental targeting (e.g., MDM2–p53 axis) (pires2023analysisofthe pages 2-5, nirala2023decipheringthesignaling pages 1-2). URL: https://doi.org/10.3390/ijms241310463 (Jun 2023); https://doi.org/10.3390/ijms241411367 (Jul 2023). - Immune profiling for trial design: scRNA-seq-defined mregDC and SPP1+ TAM signatures, MHC-I/B2M loss, and PD‑L1 expression guide rational immunotherapy combinations (checkpoint blockade + myeloid/DC modulation) (liu2023characterizingthetumor pages 2-3). URL: https://doi.org/10.1038/s41413-022-00237-6 (Jan 2023). - Therapy sequencing considerations: Post-chemotherapy scRNA-seq suggests combining cytotoxic therapy with CAF/ECM-targeting or immune-restoring agents to mitigate stemness/ECM/immune escape (zheng2024singlecelltranscriptomicinsights pages 1-2). URL: https://doi.org/10.1007/s00432-024-05787-2 (Jul 2024).

Expert opinions and analysis (authoritative sources) - 2023 signaling review emphasizes the convergence of PI3K/AKT/mTOR, Wnt/β‑catenin, TGF‑β, JAK/STAT, NOTCH, Hedgehog, RANK/RANKL, and NF‑κB as drivers of proliferation, invasion, and lung metastasis; also highlights chromothripsis/kataegis as frequent, and immune–tumor crosstalk as clinically relevant (nirala2023decipheringthesignaling pages 2-4, nirala2023decipheringthesignaling pages 1-2). URL: https://doi.org/10.3390/ijms241411367 (Jul 2023). - 2023 mutational landscape study concludes “high genomic OS instability and heterogeneity,” identifying novel disrupted genes linked to poor outcomes and reinforcing TP53/RB1 centrality (pires2023analysisofthe pages 2-5). URL: https://doi.org/10.3390/ijms241310463 (Jun 2023). - 2023 single-cell atlas authors state that mregDCs “promote tumor immune tolerance through recruitment of Tregs” and that CNV‑high tumor cells exhibit “reduced interferon‑γ pathway activity and lower MHC‑I/B2M” (liu2023characterizingthetumor pages 2-3). URL: https://doi.org/10.1038/s41413-022-00237-6 (Jan 2023).

Relevant statistics and data (recent studies) - Genomic burden: 74,880 SNVs/indels across 28 primaries; filtered 445 coding non-synonymous candidates; TP53 alterations ~60% including SNV/indel/CNA; frequent gains 1q21, 6p21, 8q; losses 10q26, 13q14–21; complex CNA patterns (pires2023analysisofthe pages 2-5). URL: https://doi.org/10.3390/ijms241310463 (Jun 2023). - scRNA-seq TME composition (pre-therapy OS): myeloid ~35%, tumor ~27%, plus T/ILC, B cells, osteoclasts, endothelial, mesenchymal stromal cells (zheng2024singlecelltranscriptomicinsights pages 1-2). URL: https://doi.org/10.1007/s00432-024-05787-2 (Jul 2024).

Structured knowledge base annotations - Genes/Proteins (HGNC): TP53, RB1, ATRX, MYC, MDM2, PIK3CA, AKT1, MTOR, CTNNB1, TGFBR2, JAK2, NOTCH1, SMO, NFKB1, SPP1, CD274 (PD‑L1), B2M, HLA‑A/B/E, CD24 (nirala2023decipheringthesignaling pages 2-4, pires2023analysisofthe pages 2-5, liu2023characterizingthetumor pages 2-3). - Biological processes (GO): DNA damage response; chromatin organization; mitotic cell cycle; signal transduction via PI3K/AKT/mTOR; Wnt signaling; TGF‑β signaling; JAK/STAT cascade; NOTCH signaling; Hedgehog signaling; NF‑κB signaling; osteoclast differentiation (RANK/RANKL); antigen processing and presentation via MHC class I; regulation of macrophage activation; extracellular matrix organization; glycolytic process; glutamine metabolic process; fatty acid metabolic process (nirala2023decipheringthesignaling pages 2-4, pires2023analysisofthe pages 2-5, liu2023characterizingthetumor pages 2-3, zheng2024singlecelltranscriptomicinsights pages 1-2). - Cellular components: micronuclei (chromothripsis mechanism); nucleus/chromatin; plasma membrane (PD‑L1, CD24); MHC-I complex; extracellular matrix; exocytic vesicles; endothelium; osteoclastic resorption lacunae (nirala2023decipheringthesignaling pages 2-4, liu2023characterizingthetumor pages 2-3, zheng2024singlecelltranscriptomicinsights pages 1-2). - Cell types (CL): osteoblast-like tumor cell; mesenchymal stromal cell; cancer-associated fibroblast; SPP1+ tumor-associated macrophage; mature regulatory dendritic cell (LAMP3+CCR7+CD83+); osteoclast; endothelial cell; T cell and NK cell (liu2023characterizingthetumor pages 2-3, zheng2024singlecelltranscriptomicinsights pages 1-2). - Anatomical locations (UBERON): bone (primary); lung (metastatic); bone marrow niche; perivascular/endosteal/hypoxic niches (nirala2023decipheringthesignaling pages 1-2, alansari2024unveilingtheprotective pages 6-8). - Chemical entities (ChEBI): lactate (glycolysis), glutamine, fatty acids; cisplatin context for chemosensitivity; growth factors such as TGF‑β; cytokines/chemokines influencing niches (zheng2024singlecelltranscriptomicinsights pages 1-2, nirala2023decipheringthesignaling pages 2-4, alansari2024unveilingtheprotective pages 6-8).

Evidence items with PMIDs/DOIs, key mechanistic quotes - Nirala 2023 (IJMS; Jul 2023): “Massive genomic rearrangement (chromothripsis) is highly prevalent in OS… loss/reduction of RanGAP1 increases chromothripsis risk… Alterations in PI3K/AKT/mTOR, JAK/STAT, Wnt/β‑catenin, NOTCH, Hedgehog/Gli, TGF‑β, RTKs, RANK/RANKL, and NF‑κB have been identified in OS development and metastasis.” DOI: 10.3390/ijms241411367. https://doi.org/10.3390/ijms241411367 (nirala2023decipheringthesignaling pages 2-4, nirala2023decipheringthesignaling pages 1-2). - Pires 2023 (IJMS; Jun 2023): “TP53 was the most recurrently mutated gene, with an overall rate of ~60%… Seven cases presented CNA patterns reminiscent of complex events (chromothripsis and chromoanasynthesis)… A protein–protein network enrichment highlighted biological pathways involved in immunity and bone development.” DOI: 10.3390/ijms241310463. https://doi.org/10.3390/ijms241310463 (pires2023analysisofthe pages 2-5). - Liu 2023 (Bone Research; Jan 2023): “mregDCs promote tumor immune tolerance through recruitment of Tregs… CNV-high cells exhibited reduced interferon‑gamma pathway activity and lower MHC‑I (HLA‑A, HLA‑B, HLA‑E) and B2M expression… CD24 was identified as a novel ‘don’t eat me’ signal that contributed to the immune evasion of OS cells.” DOI: 10.1038/s41413-022-00237-6. https://doi.org/10.1038/s41413-022-00237-6 (liu2023characterizingthetumor pages 2-3). - Zheng 2024 (J Cancer Res Clin Oncol; Jul 2024): “Chemotherapy caused the remaining OS cells to express higher levels of genes associated with stemness… enhances the presence of cancer-associated fibroblasts, increasing their ability to modify the extracellular matrix… reduced the immune cell population, including myeloid and T/NK cells, particularly subpopulations with tumor-fighting capabilities.” DOI: 10.1007/s00432-024-05787-2. https://doi.org/10.1007/s00432-024-05787-2 (zheng2024singlecelltranscriptomicinsights pages 1-2). - Al‑Ansari 2024 (Biomolecules; Jan 2024): summarizes ranges for chromothripsis (~20–89%) and kataegis (~50–85%) and high frequencies of TP53 (75–90%) and RB1 (50–78%) defects pooled from literature (context for variability across cohorts). DOI: 10.3390/biom14020145. https://doi.org/10.3390/biom14020145 (alansari2024unveilingtheprotective pages 6-8).

Disease progression (sequence of events) 1) Initiation: developmental osteoblast/MSC lineage acquires catastrophic structural lesions (chromothripsis/kataegis), with early loss of TP53/RB1/ATRX and focal oncogene gains (MYC/MDM2) (nirala2023decipheringthesignaling pages 1-2, pires2023analysisofthe pages 2-5). 2) Clonal selection: dysregulated PI3K/AKT/mTOR, Wnt/β‑catenin, TGF‑β, NOTCH, Hedgehog, JAK/STAT and NF‑κB drive proliferation, survival, osteoid production, invasion (nirala2023decipheringthesignaling pages 2-4). 3) Microenvironmental conditioning: RANK/RANKL promotes osteoclastogenesis; TAMs (SPP1+) and mregDCs accumulate; cancer cells reduce MHC‑I/B2M and elevate PD‑L1/CD24 to evade immunity (liu2023characterizingthetumor pages 2-3). 4) Metastatic dissemination: EMT-like programs, ECM remodeling, and chemotactic axes enable intravasation and lung colonization; AKT1/FGFR signaling contribute to invasive/metastatic phenotypes (nirala2023decipheringthesignaling pages 2-4, chen2025harnessingmultiomicsto pages 4-5). 5) Treatment remodeling: chemotherapy enriches stem-like tumor cells and CAF-driven ECM programs while depleting effectors, fostering resistance and recurrence (zheng2024singlecelltranscriptomicinsights pages 1-2).

Phenotypic manifestations (link to mechanisms) - Clinical: destructive metaphyseal bone lesions with periosteal reaction; osteoid production by malignant cells; high propensity for lung metastases. Mechanistic correlates: osteoblast-lineage origin with RANKL–osteoclast crosstalk; ECM remodeling and immune evasion supporting dissemination (nirala2023decipheringthesignaling pages 2-4, liu2023characterizingthetumor pages 2-3).

Citations and metadata (URLs and dates) - Nirala BK et al., Int J Mol Sci, Jul 2023, https://doi.org/10.3390/ijms241411367 (nirala2023decipheringthesignaling pages 2-4, nirala2023decipheringthesignaling pages 1-2). - Pires SF et al., Int J Mol Sci, Jun 2023, https://doi.org/10.3390/ijms241310463 (pires2023analysisofthe pages 2-5). - Liu W et al., Bone Research, Jan 2023, https://doi.org/10.1038/s41413-022-00237-6 (liu2023characterizingthetumor pages 2-3). - Zheng X et al., J Cancer Res Clin Oncol, Jul 2024, https://doi.org/10.1007/s00432-024-05787-2 (zheng2024singlecelltranscriptomicinsights pages 1-2). - Al‑Ansari N et al., Biomolecules, Jan 2024, https://doi.org/10.3390/biom14020145 (alansari2024unveilingtheprotective pages 6-8). - Chen X et al., Int J Mol Med, Apr 2025, https://doi.org/10.3892/ijmm.2025.5533 (chen2025harnessingmultiomicsto pages 4-5).

Notes on evidence scope - Where possible, we prioritized 2023–2024 primary and integrative studies; one 2025 precision‑medicine review is included to connect AKT/FGFR signaling to metastasis and resistance. Future updates should incorporate emerging 2024–2026 genomics (e.g., chromothripsis dynamics) as they are peer‑reviewed.

References

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