Modeling Principle

The Mouse 786‑O Model is an immunodeficient‑mouse xenograft tumor model constructed with human‑derived 786‑O clear‑cell renal‑cell‑carcinoma cells. The 786‑O cell line originates from human primary clear‑cell renal cell carcinoma and is characterized by functional loss of the VHL gene, which leads to constitutive activation of HIF‑1α/HIF‑2α pathways and high downstream VEGF expression, resulting in vigorous tumor angiogenesis. It recapitulates the molecular and phenotypic features of clinical VHL‑mutant human clear‑cell renal cell carcinoma. In‑vitro‑cultured 786‑O cells are inoculated into T‑cell‑deficient nude mice to avoid xenogeneic immune rejection and generate stable and reproducible solid xenograft tumors. This model preserves the intrinsic mutation spectrum of human tumor cells and is suitable for in‑vivo efficacy evaluation of human renal‑cancer proliferation, angiogenesis, anti‑angiogenic targeted agents and small‑molecule compounds. Distinct from the syngeneic Renca model, this mouse model lacks functional T‑lymphocytes and is not suitable for efficacy assessment of immune‑checkpoint‑inhibitor therapies requiring a full immune system. With stable tumorigenesis and controllable experimental timeline, it is widely applied in renal‑cell‑carcinoma mechanism research and pre‑clinical drug evaluation, and can be directly adopted for NSFC project applications, postgraduate research proposals and SCI manuscript methodology sections. Subcutaneous xenografts are routinely used for high‑throughput pharmacodynamic screening; renal‑capsule orthotopic xenografts can be established to mimic the growth and invasion of in‑situ human renal carcinoma.

Model Validation Criteria

Quantitative Criteria for Tumor Formation and Growth

1.Subcutaneous‑model tumor‑formation criteria: Tumor‑take rate ≥90% within 1‑2 weeks after inoculation; tumor volume＞50 mm³ is defined as successful engraftment. Tumors in vehicle‑control group grow progressively, reaching average volume 450‑900 mm³ at week 3 post‑inoculation without spontaneous regression.

2.Reproducibility criteria: Intra‑group coefficient of variation (CV) of tumor volume in vehicle‑control group ＜30%, indicating standardized operation and manageable individual variation.

3.Orthotopic‑model validation criteria: For luciferase‑labeled cells, specific bioluminescent signal at kidney region can be detected by in‑vivo imaging on day 7‑10 post‑inoculation; human‑origin tumor nodules are observed in kidney upon necropsy, confirming successful orthotopic engraftment.

4.Model‑responsiveness criteria: Positive‑control targeted treatment achieves TGI≥40% and significant tumor‑growth suppression versus vehicle group (P＜0.05), verifying reliable model response to anti‑angiogenic targeted agents.

Histopathological and Molecular Gold‑Standard Indexes

1.HE‑staining gold‑standard: Xenograft tumors display abundant human‑derived tumor cells with clear cytoplasm, obvious nuclear atypia and frequent mitotic figures, consistent with morphological features of human clear‑cell renal‑cell carcinoma. Orthotopic specimens show tumor‑cell infiltration into renal parenchyma.

2.IHC molecular phenotype: Tumor tissues show strong nuclear HIF‑2α positivity, high VEGF expression and abundant CD31‑positive microvessels, recapitulating downstream molecular phenotype caused by VHL‑deficiency in 786‑O cells; high Ki‑67 indicates robust proliferative activity.

3.Pharmacodynamic‑response criteria: Compared with vehicle control, treated groups show reduced Ki‑67 index, elevated Cleaved‑Caspase‑3, decreased CD31 microvessel density and down‑regulated HIF‑2α/VEGF, indicating inhibited proliferation, enhanced apoptosis and suppressed angiogenesis.

4.Evidence‑closure criteria: In‑vivo tissue molecular findings are consistent with in‑vitro 786‑O cell pathway results to form a complete mechanistic evidence chain.

Academic Evidence for Model Validity

Academic validity evidence for Mouse 786‑O Model: ① It uses human ccRCC tumor cells carrying VHL‑deficiency, a clinically frequent driver mutation, preserving human‑tumor molecular features; ② Subcutaneous xenograft protocol is well‑established with stable engraftment rate, suitable for pre‑clinical screening of human renal‑cancer targeted drugs; ③ Two systems are available: subcutaneous high‑throughput pharmacodynamic model and renal‑capsule orthotopic invasion model; ④ It exhibits stable and reproducible pharmacodynamic responses to anti‑angiogenic targeted agents; ⑤ Multi‑dimensional readouts include tumor growth, survival, angiogenesis, HIF‑pathway, innate immunity and molecular signaling. It is a classic xenograft model for pre‑clinical research of VHL‑mutant clear‑cell renal‑cell carcinoma, and its data are widely accepted by urologic‑oncology SCI journals. Limitations: Nude mice lack T‑cells so the model is not suitable for immune‑checkpoint‑inhibitor evaluation; full human tumor microenvironment is absent; clinical translation requires cross‑validation with PDX, organoids and clinical samples.

Model Advantages

The Mouse 786‑O Model represents the classic xenograft model for VHL‑deficient human clear‑cell renal‑cell‑carcinoma research. Core advantages: Cells carry clinically frequent driver mutation VHL‑loss with constitutive HIF‑VEGF‑pathway activation, recapitulating the angiogenic phenotype of human ccRCC. Human‑derived tumor cells retain human tumor molecular background and are suitable for in‑vivo efficacy assessment of anti‑angiogenic targeted agents and small‑molecule compounds. Subcutaneous modeling is technically straightforward with stable engraftment and controllable experimental timeline. Both high‑throughput subcutaneous screening and orthotopic renal‑capsule invasion models can be implemented. The cell line is well‑established and easily accessible. Experimental data are widely accepted by urologic‑oncology SCI journals. It fits NSFC projects, master/doctoral proposals, dissertations and SCI methodology writing. It can be complementary to the syngeneic Renca model for human‑target pharmacology versus full‑immune‑system studies respectively.

Research Applications

The Mouse 786‑O Model is mainly applied to pre‑clinical basic and translational research of VHL‑deficient human clear‑cell renal‑cell carcinoma. Core application scenarios: in‑vivo efficacy evaluation of anti‑angiogenic targeted agents (sunitinib, apatinib etc.); mechanistic investigation of HIF‑VEGF and PI3K‑AKT‑mTOR signaling pathways; in‑vivo activity screening of novel small‑molecule compounds and natural products against renal carcinoma; assessment of drug modulation on proliferation, apoptosis and angiogenesis of human renal‑cancer cells; comparative study of biological behaviors including growth and invasion between subcutaneous xenografts and renal‑capsule orthotopic xenografts. It supports basic urologic‑tumor research, pre‑clinical new‑drug development, national‑ and provincial‑level project applications, postgraduate proposals and dissertations, and SCI manuscript methodology construction. Combined with human organoids, PDX and syngeneic Renca model, it helps build multi‑level evidence chains for renal‑cell‑carcinoma research.

Mouse 786‑O model, human clear‑cell renal cell carcinoma, xenograft mouse model, in‑vivo ccRCC model, VHL‑deficient, renal‑cell‑carcinoma targeted drug screening, tumor proliferation and apoptosis, tumor angiogenesis, nude‑mouse subcutaneous tumor formation, pre‑clinical anti‑tumor pharmacodynamics