Osteosarcoma is a malignant bone tumor that predominantly affects children and adolescents, with strong invasiveness and high lung metastasis risk, severely affecting limb function and long-term survival. Alfa Cytology is a global leader in cancer research. With our extensive experience and advanced platforms, our talented scientists provide one-stop solutions for osteosarcoma animal model development, efficacy evaluation, bone orthotopic model validation, lung metastasis evaluation, postoperative relapse and minimal residual disease studies, tumor immunology testing, bone destruction testing, pathology testing, molecular mechanism testing, and PK/PD, based on client candidate drugs, target type, cell line characteristics, bone microenvironment, lung metastasis risk, immune system requirements, administration route, and R&D stages. We also provide zebrafish experimental services and cell-based experimental services, covering diverse research needs from in vitro to in vivo and from high-throughput screening to mechanism validation.
Osteosarcoma is the most common primary malignant bone tumor, with a particularly high incidence in children and adolescents. Its molecular landscape is dominated by large-scale structural variants, with TP53 (~80%) and RB1 (~40%) being the most frequently altered tumor suppressor genes, and chromothripsis detectable in over 70% of cases. The tumor immune microenvironment exhibits a characteristic "cold tumor" phenotype, marked by low T cell infiltration and enrichment of M2-polarized tumor-associated macrophages (TAMs), regulatory T cells (Tregs), and myeloid-derived suppressor cells (MDSCs). Osteosarcoma is highly aggressive, and the lung is the most common site of distant metastasis, which is also the primary cause of treatment failure. Before the advent of chemotherapy, approximately 74% of patients with localized osteosarcoma developed lung metastasis within one year of diagnosis. Currently, standard treatment for osteosarcoma combines perioperative chemotherapy based on the MAP regimen (high-dose methotrexate, doxorubicin, and cisplatin) with surgical resection. The 5-year survival rate for patients with localized disease has improved from 10% three decades ago to 60%–70%; however, the prognosis for recurrent or metastatic osteosarcoma remains poor, with the 5-year overall survival rate persistently below approximately 40%. In recent years, antibody-drug conjugates (ADCs) and CAR-T cell therapies targeting B7-H3 and GD2, as well as CD47-SIRPα axis-targeting strategies, have shown potential in preclinical and early-phase clinical trials, providing new therapeutic directions for relapsed/refractory osteosarcoma.
Fig. 1 Wnt/β-catenin signaling pathway and OS. (Bian J, et al.; 2023)
The core of osteosarcoma animal studies is to determine whether a candidate drug remains effective in the bone microenvironment, bone marrow cavity, cortical bone destruction, lung metastasis cascade, and postoperative adjuvant therapy settings. Alfa Cytology provides animal study services spanning subcutaneous xenograft models (CDX), long bone orthotopic models, experimental lung metastasis models, orthotopic spontaneous lung metastasis models, post-resection lung relapse models, K7M2 / LM8 / MOS-J syngeneic immunocompetent models, humanized immune models, and postoperative relapse and minimal residual disease models, offering end-to-end solutions. Our services include but are not limited to:
Osteosarcoma drug development requires model selection based on standard chemotherapy background, bone microenvironment, lung metastasis risk, target expression, and immune scenarios. Alfa Cytology provides integrated animal study solutions, from cell line selection to model validation, for small molecules, cytotoxic agents, MAP gain programs, DDR/PARP/ATR agents, ADCs, bispecifics, B7-H3, GD2, CAR-T/NK, immunotherapy, local delivery, and postoperative adjuvant therapy programs.
Osteosarcoma Mechanism Research
For osteosarcoma studies, experimental design typically needs to address bone microenvironment, bone destruction, lung metastasis, DDR, target expression, immune microenvironment, and relapse mechanisms simultaneously. Alfa Cytology provides model development, dosing intervention, pathology testing, immunology testing, protein testing, and RNA testing services, covering osteocalcin, ALP, TRAP, EMT, DDR, B7-H3, GD2, lung metastasis, postoperative relapse, and cell therapy.
Clinical Relevance Studies
When programs advance to bone microenvironment, bone destruction, bone pain, lung metastasis, perioperative, postoperative relapse, immunotherapy, or cell therapy stages, Alfa Cytology can further configure bone orthotopic, lung metastasis, syngeneic immunocompetent, humanized immune, or post-resection lung relapse models to help clients generate evidence more aligned with clinical scenarios.
In Vitro and In Vivo Layered Validation
Animal studies can address whether a candidate inhibits tumor growth, bone destruction, lung metastasis, or postoperative relapse; zebrafish platforms provide high-throughput in vivo screening covering tumor proliferation, metastatic invasion, angiogenesis, immune co-culture, and drug toxicity; cell-based experiments validate proliferation, apoptosis, migration and invasion, osteoblast/osteoclast interaction, DDR, target expression, drug internalization, and immune killing.
Candidate Screening
Early screening typically requires rapid assessment of whether a candidate demonstrates in vivo anti-tumor signals. Alfa Cytology conducts TGI, RTV, PK/PD, and target evaluations using subcutaneous CDX models, providing data to support dose selection, dosing frequency, and candidate prioritization.
Molecular Mechanism Studies
Depending on program needs, we offer IHC, IF, flow cytometry, ELISA, Western blot, qPCR, RNA-seq, target expression validation, DDR pathway testing, bone metabolism markers, immune profiling, PK/PD, and drug tissue distribution testing.
For clients with only a candidate drug, target direction, or preliminary mechanistic hypothesis, Alfa Cytology assists in structuring cell line selection, model pathways, group design, dosing regimens, detection endpoints, terminal sample collection, and data presentation，translating R&D questions into executable animal study protocols. Our capabilities support a broad spectrum of therapeutic modalities, including but not limited to:
| R&D Project | Cell Lines | Host System | Preferred Model | Key Endpoints |
| Early efficacy screening | SJSA-1, U2OS, SaOS-2, MG-63, 143B, HOS-MNNG | BALB/c nude, NSG | Subcutaneous CDX | TGI, RTV, terminal tumor weight, Ki67, cleaved caspase-3, PK/PD. |
| High-invasive / high-metastatic screening | 143B, 143B-luc, HOS-MNNG | BALB/c nude, NSG | High-metastatic CDX, escalation to orthotopic and lung metastasis | TGI, EMT, MMP-2/9, osteocalcin, γH2AX. |
| Bone growth and destruction | 143B-luc, HOS-MNNG, SJSA-1, U2OS, SaOS-2 | Nude, NSG | Long bone orthotopic model | Orthotopic tumor burden, limb swelling, micro-CT, X-ray, bone destruction score. |
| Bone pain and function | 143B-luc, K7M2-luc, LM8 | BALB/c, C3H/He | Orthotopic model + pain behavioral testing | von Frey, weight bearing, gait, bone destruction, TRAP. |
| Lung metastasis colonization | 143B-luc, K7M2-luc, LM8 | Nude, NSG, immunocompetent | Experimental lung metastasis model | BLI/IVIS, lung nodules, lung weight, pathology, survival. |
| Primary to lung metastasis cascade | 143B-luc, K7M2-luc, LM8 | Nude, NSG, immunocompetent | Orthotopic spontaneous lung metastasis model | Orthotopic burden, bone destruction, lung metastasis, survival. |
| Post-surgery recurrence / MRD | 143B-luc, K7M2-luc, LM8 | Nude, NSG, immunocompetent | Orthotopic model + resection/amputation follow-up | Post-surgery lung metastasis, recurrence time, survival. |
| MAP chemotherapy gain | SJSA-1, U2OS, MG-63, 143B, K7M2 | Nude, NSG, immunocompetent | Subcutaneous CDX + orthotopic validation | TGI, orthotopic burden, bone destruction, lung metastasis, survival. |
| DDR / PARP / ATR synthetic lethality | 143B, SJSA-1, U2OS | Nude, NSG | Stratified CDX, orthotopic or lung metastasis validation | γH2AX, RAD51, pCHK1, pATR, apoptosis, TGI. |
| B7-H3 / GD2 / ADC / bispecific | 143B, SJSA-1, U2OS | Nude, NSG, humanized | Target-positive CDX, syngeneic or humanized | Target expression, TGI, drug distribution, immune infiltration. |
| Immunotherapy / TME | K7M2, K7M2-luc, LM8, MOS-J | BALB/c, C3H/He | Syngeneic immunocompetent model, orthotopic preferred | CD8/Treg, MDSC, macrophages, cytokines, orthotopic burden, survival. |
| Human immune-dependent therapy | 143B, SJSA-1, U2OS, SaOS-2 | huPBMC or huHSC | Humanized immune model | hCD45, hCD3, hCD8, hNK, T cell activation, cytokines. |
| Local delivery / intraosseous sustained-release system | 143B-luc, SJSA-1, K7M2-luc | Nude, NSG, immunocompetent | Bone orthotopic model | Intraosseous drug distribution, local tumor burden, bone destruction, local safety. |
We flexibly configure TGI, RTV, terminal tumor weight, BLI/IVIS, X-ray, micro-CT, MRI, survival, orthotopic bone tumor burden, limb swelling, bone destruction score, bone mineral density, cortical bone destruction, lung metastatic nodules, lung weight, osteocalcin, ALP, TRAP, RUNX2, γH2AX, RAD51, pCHK1, pATR, Ki67, cleaved caspase-3, TUNEL, B7-H3, GD2, CD8/Treg, myeloid cell profiling, cytokines, plasma drug concentration, tumor tissue concentration, and bone/lung tissue exposure, among other endpoints, according to project objectives, providing clients with comprehensive characterization spanning the bone microenvironment, bone destruction, lung metastasis cascade, TME immune phenotyping, and PK/PD bone tissue exposure.
Multimodal In Vivo Imaging and Bone Destruction Assessment
Pathology and IHC/IF Staining
Quantitative Pathology and Osteosarcoma Phenotyping
Alfa Cytology's osteosarcoma cell line panel covers general efficacy, high-invasion/high-metastasis, bone orthotopic microenvironment, DDR/PARP/ATR synthetic lethality, and immuno-oncology, enabling cell line selection and matching based on molecular background, metastatic potential, target expression, and immune system requirements.
General Efficacy and Mechanism Research Cell Lines
High-Invasion and High-Metastasis Cell Lines
DDR/PARP/ATR-Related Cell Lines
B7-H3, GD2, and Immune Target Cell Lines
Alfa Cytology provides end-to-end osteosarcoma animal model development services, spanning model design, cell line selection, model construction, dosing intervention, efficacy evaluation, pathology, immunology, molecular mechanism testing, and PK/PD analysis. The models below represent our core capabilities across bone orthotopic growth, cortical bone destruction, bone pain, lung metastasis, perioperative relapse, DDR/PARP/ATR synthetic lethality, B7-H3/GD2 immune targeting, and humanized cell therapy research. Each model can be customized to match your program's target type, cell line characteristics, bone microenvironment, lung metastasis risk, immune system requirements, and R&D stage, from early screening to clinical relevance validation.
Subcutaneous Xenograft Model (CDX)
Subcutaneous CDX models typically involve inoculating human osteosarcoma cells subcutaneously into immunodeficient mice, followed by randomization and dosing once tumors reach a predetermined volume. Commonly used hosts include BALB/c nude, NOD-SCID, and NSG mice. Commonly used cell lines include SJSA-1, U2OS, SaOS-2, MG-63, 143B, and HOS-MNNG.
Model characteristics
SJSA-1, U2OS, SaOS-2, and MG-63 are suitable for conventional osteosarcoma efficacy evaluation, dose exploration, and mechanism research. 143B, 143B-luc, and HOS-MNNG are suitable for high-invasion, high-metastasis, and anti-metastasis early efficacy screening. DDR, B7-H3, GD2, ADC, bispecific, and cell therapy programs can select appropriate models based on target expression for early validation. This model has high standardization, suitable for early screening and PK/PD research, but cannot address bone microenvironment, bone destruction, bone pain, local delivery, lung metastasis, and postoperative relapse.
Modeling and dosing timelines
Subcutaneous inoculation typically reaches enrollment volume within 1–4 weeks, with randomization commonly performed at tumor volumes of approximately 80–150 mm3. The conventional treatment period is 2–4 weeks. For resistance, withdrawal rechallenge, sustained pathway inhibition, ADC interval dosing, or synthetic lethality studies, this can be extended to 4–8 weeks. Small molecules can be dosed daily or every other day; doxorubicin and cisplatin can be dosed cyclically or at intervals; ADCs, antibodies, and cell therapy should be designed based on pharmacokinetics, target expression, and toxicity window.
Detection endpoints
Recommended positive controls
Doxorubicin at 2–5 mg/kg IV or IP, once weekly or cyclically; cisplatin at 2–5 mg/kg IP or IV, once weekly or at intervals. Cabozantinib at 10–60 mg/kg oral. Olaparib combined with ceralasertib as a PARP/ATR direction research reference. B7-H3 direction can reference HS-20093-class ADC development; GD2 direction can reference GD2 CAR-T or C7R-GD2.CAR strategies.
Bone Orthotopic Model
Bone orthotopic models typically involve injecting 143B-luc, HOS-MNNG, SJSA-1, U2OS, or SaOS-2 cells into the proximal tibia, distal tibia, or distal femoral bone marrow cavity. BLI/IVIS, X-ray, or micro-CT can be used for baseline confirmation and dynamic monitoring. K7M2-luc, LM8, or MOS-J can establish syngeneic bone orthotopic models in matched strains.
Model characteristics
143B-luc and HOS-MNNG are suitable for high-invasion, bone destruction, and lung metastasis research. K7M2-luc is suitable for high lung metastasis research in BALB/c background; LM8 is suitable for primary lesion to lung metastasis full-cascade research in C3H/He background. Bone injection site, cell number, injection speed, postoperative care, and imaging confirmation significantly affect model consistency. This model is closer to the true site of osteosarcoma, suitable for bone microenvironment, bone destruction, local invasion, bone pain, local delivery, and perioperative research, but has complex procedures, low throughput, and significant individual variability.
Modeling and dosing timelines
Bone orthotopic models typically show orthotopic burden or imaging changes 1–3 weeks after inoculation. The conventional treatment period is 2–6 weeks. If studying bone destruction, lung metastasis, postoperative relapse, or sustained local delivery effects, observation should be appropriately extended. Treatment can begin after BLI positivity, visible limb swelling, or micro-CT evidence of bone changes.
Detection endpoints
Recommended positive controls
Doxorubicin combined with cisplatin as a basic osteosarcoma chemotherapy reference. Cabozantinib or multi-target TKIs as mechanism references for anti-metastasis, bone microenvironment, and lung metastasis inhibition. Local delivery programs can set systemic dosing controls, blank vehicle controls, and local dosing groups. Syngeneic bone orthotopic models can set anti-PD-1, cytokine, or STING-related references.
Experimental Lung Metastasis Model
Experimental lung metastasis models typically involve tail vein injection of 143B-luc, K7M2-luc, or LM8 cells, focusing on lung colonization after circulation and intrapulmonary expansion. Xenograft models commonly use nude or NSG mice; syngeneic models require matched immunocompetent mice.
Model characteristics
Suitable for anti-lung colonization, anti-metastasis, perioperative systemic therapy, and distant dissemination latter-half research. This model has relatively high reproducibility and short cycles, but mainly reflects the lung colonization step and does not fully represent the complete natural metastasis cascade.
Modeling and dosing timelines
The treatment period is typically 2–6 weeks. High-colonization models can show lung BLI signal or nodule formation earlier.
Detection endpoints
BLI/IVIS, lung nodule count, lung weight, lung tissue HE, metastatic area, Ki67, apoptosis, MMP, VEGF, and survival.
Recommended positive controls
MAP chemotherapy simplified regimen as a basic reference; cabozantinib or multi-target TKIs as anti-metastasis mechanism references; DDR programs can add PARP/ATR combination references based on mechanism.
Orthotopic Spontaneous Lung Metastasis Model
Orthotopic spontaneous lung metastasis models are based on 143B-luc, K7M2-luc, or LM8 long bone orthotopic models, observing primary lesion growth, local invasion, hematogenous dissemination, and lung metastasis formation.
Model characteristics
Suitable for anti-metastasis agents, perioperative therapy, long-term maintenance therapy, and lung metastasis cascade research. This model is closer to clinical course but has longer cycles and greater variability, with high requirements for primary lesion burden control.
Modeling and dosing timelines
The overall cycle is typically 4–10 weeks, depending on primary lesion growth rate, lung metastasis formation time, and whether local intervention is performed.
Detection endpoints
Orthotopic bone tumor burden, bone destruction, lung BLI signal, lung nodule count, lung tissue pathology, survival, and metastasis-related molecular markers.
Recommended positive controls
MAP chemotherapy simplified regimen as a basic reference; cabozantinib or multi-target TKIs as anti-metastasis mechanism references; immunotherapy or cell therapy programs can set combination references based on mechanism.
Post-Resection Lung Relapse Model
Post-resection lung relapse models typically involve local resection, amputation, or debulking after 143B-luc, K7M2-luc, or LM8 bone orthotopic model formation, followed by observation of lung micrometastasis expansion and relapse.
Model characteristics
Suitable for postoperative adjuvant therapy, perioperative therapy, minimal residual disease clearance, postoperative lung relapse, and long-term maintenance therapy research. This model has strong clinical mapping but is technically complex, has longer cycles, and requires high postoperative care; it is not suitable for early large-scale screening.
Modeling and dosing timelines
This model includes primary lesion growth phase, local resection phase, and postoperative relapse observation phase; the total cycle is typically longer than tail vein lung metastasis models.
Detection endpoints
Postoperative lung metastasis burden, BLI/IVIS, lung nodule count, lung pathology, time to relapse, survival, residual disease-related markers, and treatment tolerance.
Recommended positive controls
Doxorubicin combined with cisplatin as a basic perioperative reference; cabozantinib or multi-target TKIs as anti-metastasis and postoperative lung relapse mechanism references; GD2 CAR-T, B7-H3-related immune strategies, anti-PD-1, or cytokine strategies can be set based on model system and program mechanism.
Syngeneic Immunocompetent Model
Syngeneic immunocompetent models typically use K7M2, LM8, or MOS-J in matched strains to establish syngeneic subcutaneous or bone orthotopic models, retaining an intact immune system.
Model characteristics
Syngeneic subcutaneous models are suitable for immune checkpoint, STING, cytokines, combination therapy, and preliminary PK/PD research. Syngeneic bone orthotopic models are suitable for immunotherapy, local therapy, bone TME, radiotherapy combination, lung metastasis, and perioperative research. For osteosarcoma immunotherapy programs, syngeneic bone orthotopic models are typically closer to real disease course than syngeneic subcutaneous models. Murine models differ from human osteosarcoma in target expression and biological background; human target drugs, TCE, CAR-T/NK, and human immune-dependent drugs still require CDX or humanized model supplementary validation.
Modeling and dosing timelines
Enrollment occurs when tumor volume reaches approximately 50–100 mm3, with a treatment period of typically 10–21 days. Due to faster syngeneic tumor growth, immunotherapy typically needs to start earlier. Syngeneic bone orthotopic models should be followed with BLI/IVIS, X-ray, or micro-CT.
Detection endpoints
Recommended positive controls
MAP chemotherapy simplified regimen as a basic reference; immunotherapy combination programs can set anti-PD-1, anti-PD-L1, STING, cytokines, multi-target TKIs, or radiotherapy combination references. Antibody doses can start at 100–200 μg/mouse IP, twice weekly or once every 3 days.
Humanized Immune Osteosarcoma Model
Humanized immune osteosarcoma models reconstruct the human immune environment by infusing human immune cells or human hematopoietic stem cells into immunodeficient mice, suitable for TCE, CAR-T/NK, human cytokines, and ADCs or bispecifics highly dependent on human immune effects. Optional models include 143B, SJSA-1, U2OS, SaOS-2, or other target-positive models.
Model characteristics
The huPBMC model is suitable for short-cycle human immune effector validation, while the huHSC model is suitable for longer-cycle immune reconstitution, T cell exhaustion, and combination strategy research. This model has long cycles, high cost, significant donor variability, and carries xGvHD or cytokine release risk; it is not recommended as a large-scale early screening model.
Detection endpoints
hCD45, hCD3, hCD4, hCD8, hNK, T cell activation, tumor infiltration, IFN-γ, TNF-α, IL-6, Granzyme B, tumor burden, body weight, CRS, and xGvHD risk markers. huHSC models should also detect human immune reconstitution ratio, T/B/NK/myeloid cell spectrum, and major organ pathology.
Recommended positive controls
GD2 CAR-T or C7R-GD2.CAR-related strategies as cell therapy direction research references. B7-H3 ADC or bispecific programs can set target-positive models and corresponding mechanism references. Cell therapy doses can start at 106–107 cells/mouse.
Postoperative Relapse and Minimal Residual Disease Model
Postoperative relapse and MRD models typically use 143B-luc, K7M2-luc, or LM8 bone orthotopic models as the base. First, monitorable orthotopic tumor burden is established, followed by local resection, amputation, debulking, or short-course therapy, then lung metastasis expansion and relapse are observed.
Model characteristics
Suitable for postoperative adjuvant therapy, perioperative therapy, minimal residual disease clearance, postoperative lung relapse, and long-term maintenance therapy research. This model has strong clinical mapping but is technically complex, has longer cycles, and requires high postoperative care; it is not suitable for early large-scale screening.
Modeling and dosing timelines
First establish bone orthotopic tumors and confirm burden by BLI, X-ray, micro-CT, or limb changes. Local resection, amputation, or debulking is performed according to the program; postoperative observation continues for 2–6 weeks or longer, recording lung metastasis burden, survival, time to relapse, and lung tissue pathology.
Detection endpoints
Recommended positive controls
Doxorubicin combined with cisplatin as a basic perioperative reference; cabozantinib or multi-target TKIs as anti-metastasis and postoperative lung relapse mechanism references; GD2 CAR-T, B7-H3-related immune strategies, anti-PD-1, or cytokine strategies can be set based on model system and program mechanism.
By Development Stage
By Drug Type
By Research Objective
By Route of Administration
By Development Pathway
Genomic Instability & Osteogenic Lineage Modeling
Osteosarcoma is characterized by high structural genomic complexity, osteoid matrix deposition, and frequent mutations in TP53 and RB1. Alfa Cytology designs tailored evaluation pathways based on differentiation status and genomic instability, avoiding oversimplified modeling that misses bone-forming microenvironment mechanics.
Stratified Cell Line & PDX Directory
Model selection directly impacts therapeutic sensitivity readouts for chemotherapy, targeted agents, and immunotherapies. Alfa Cytology helps clients match optimal systems, such as 143B, U2OS, Saos-2, MG-63, and patient-derived xenograft (PDX) models, based on bone-forming potential, metastatic velocity, and baseline chemo-resistance profiles.
Orthotopic Tibial & Pulmonary Metastasis Models
Subcutaneous models cannot replicate the intramedullary bone microenvironment, cortical destruction, or early hematogenous spread. Alfa Cytology helps clients generate clinical-correlative evidence through orthotopic intra-tibial inoculation and spontaneous/experimental pulmonary metastasis models.
Target Validation & Integrated PK/PD Workflows
Programs targeting Receptor Tyrosine Kinases (RTKs), RANKL/RANK, GD2, or immune checkpoints require rigorous mineralization and microenvironment evaluation. Alfa Cytology configures Micro-CT imaging, bone histomorphometry, and integrated PK/PD workflows to track primary bone destruction and metastatic nodule clearance.
Alfa Cytology is a global leader in osteosarcoma translational research, delivering integrated animal model solutions that span the bone microenvironment, cortical bone destruction, bone pain and function, lung metastasis cascade, perioperative and postoperative relapse/MRD settings, DDR/PARP/ATR synthetic lethality, B7-H3/GD2-targeted therapies, and humanized immune evaluation. If you are interested in our services, please do not hesitate to contact us to learn how we can accelerate your osteosarcoma drug development
Reference
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