Modeling Principle

The Mouse Renca Model is the most widely recognized syngeneic renal cell carcinoma (RCC) model established by inoculating murine spontaneous clear-cell renal carcinoma Renca cells into immunocompetent BALB/c mice. Renca cells recapitulate core malignant characteristics of clinical clear cell renal cell carcinoma (ccRCC), including rapid proliferation, vigorous angiogenesis, typical immunosuppressive tumor microenvironment, and high sensitivity to anti-angiogenic targeted agents and immune checkpoint inhibitors. Different from immunodeficient xenograft models, this syngeneic model possesses an intact endogenous immune system, faithfully preserving tumor immune microenvironment components such as tumor-infiltrating lymphocytes, myeloid-derived suppressor cells, tumor-associated macrophages and angiogenesis networks. It serves as the SCI gold-standard in vivo model for evaluating renal cancer immunotherapy, anti-angiogenic targeted therapy and combination regimens. Both subcutaneous solid tumor models for high-throughput drug screening and orthotopic renal capsule models simulating clinical in-situ tumor invasion are available. With stable tumorigenicity and excellent data reproducibility, this model is widely applied in exploring the proliferation, apoptosis, angiogenesis and immune escape mechanisms of renal cell carcinoma, and can be directly used for NSFC project application, postgraduate research proposals and standardized SCI manuscript methodology writing.

Model Validation Criteria

Quantitative Criteria for Tumor Formation and Growth

1. Subcutaneous model tumor formation criteria: The tumor formation rate is ≥95% within 1–2 weeks after inoculation, and local tumor volume ＞50 mm³ is defined as successful tumor formation. Tumors in the vehicle control group grow stably and continuously, with the average tumor volume reaching 500–1000 mm³ at the 3rd week after inoculation without spontaneous regression.

2. Model reproducibility criteria: The intra-group coefficient of variation (CV) of tumor volume in the vehicle control group is ＜30%, verifying standardized inoculation operation, minimal individual differences and excellent model reproducibility.

3. Orthotopic model validation criteria: In vivo imaging detects in-situ fluorescent signals in the kidney 1 week after surgery; mice show slowed body weight growth and slightly decreased mental status, and in-situ tumor nodules are observed in the kidney after dissection, which confirms successful modeling.

4. System effectiveness criteria: The tumor growth inhibition rate (TGI) of the positive control group (sunitinib/immunosuppressant) is ≥45% after intervention, or the median survival time is significantly prolonged compared with the blank model group (P＜0.05), proving that the model is highly sensitive to targeted and immune drug intervention, and the pharmacodynamic evaluation system is reliable and effective.

Histopathological and Molecular Gold-Standard Indexes

1. HE staining gold standard: A large number of atypical renal carcinoma cells with transparent cytoplasm, enlarged hyperchromatic nuclei and abundant mitotic figures are observed in tumor tissues, consistent with the typical pathological characteristics of clear cell renal cell carcinoma; the orthotopic model shows that normal renal tissues are invaded and destroyed by tumor cells.

2. Immunohistochemical phenotypic criteria: Tumor tissues present high Ki-67 proliferation expression, high CD31/VEGF expression indicating vigorous angiogenesis, and positive PD-L1 expression, perfectly recapitulating the core phenotype of high angiogenesis and high immunosuppression in clinical ccRCC.

3. Pharmacodynamic response criteria: Compared with the vehicle control group, the treatment group shows significantly down-regulated Ki-67 proliferation index, up-regulated Cleaved-Caspase-3 apoptotic protein, down-regulated VEGF/CD31 angiogenesis indicators and reduced PD-L1 expression, indicating inhibited tumor proliferation, activated apoptosis, blocked angiogenesis and improved immune microenvironment.

4. Mechanism cross-validation criteria: In vivo histopathological, molecular and immune detection results are highly consistent with the pathway regulation rules of in vitro cell experiments, forming a complete academic evidence closed loop.

Academic Evidence for Model Validity

Core academic validity evidence of the Renca model: ① The BALB/c syngeneic immunocompetent system has no immune rejection, with a tumor formation rate close to 100% and extremely high model stability; ② It perfectly recapitulates the core characteristics of clinical clear cell renal carcinoma, including high angiogenesis, immunosuppressive microenvironment and sensitivity to targeted and immune drugs; ③ It supports dual systems of subcutaneous high-throughput pharmacodynamic screening and in-situ disease simulation to adapt to different experimental requirements; ④ It presents stable and repeatable pharmacodynamic responses to anti-angiogenic targeted drugs, immune checkpoint inhibitors and chemotherapeutic drugs; ⑤ It has a complete multi-dimensional indicator system covering tumor growth, survival analysis, angiogenesis, immune microenvironment and molecular pathways. The data are widely recognized by global SCI journals in the field of renal cancer, serving as an authoritative gold-standard model for basic research and preclinical transformation of renal cell carcinoma.

Model Advantages

The Renca murine renal cancer model is currently the most recognized and widely used syngeneic immune-intact model in the field of ccRCC research with prominent core advantages: syngeneic genetic background avoids immune rejection and ensures extremely stable tumorigenicity; it possesses a complete functional mouse immune system, which can truly simulate the immunosuppressive microenvironment of renal cancer and serves as the only gold-standard in vivo model suitable for renal cancer immune checkpoint inhibitors and immune combined targeted therapy; it supports both subcutaneous high-throughput drug screening and orthotopic renal cancer disease simulation with short experimental cycle, strong repeatability and robust data; the cell culture system is mature with simple operation and controllable modeling cost; experimental data are universally recognized by all oncology and urology SCI journals; it is perfectly compatible with NSFC projects, doctoral and master’s research proposals, graduation theses and SCI methodology writing, and highly complementary with the research group’s lymphoma and glioma model systems.

Research Applications

The Mouse Renca Model is mainly used for preclinical basic and translational research of clear cell renal cell carcinoma. Core application scenarios include: in vivo efficacy evaluation of renal cancer anti-angiogenic targeted drugs (sunitinib, apatinib, etc.); verification of anti-tumor mechanisms and efficacy of immune checkpoint inhibitor monotherapy and combination therapy; analysis of renal cancer immune escape, immune microenvironment remodeling and angiogenesis regulation mechanisms; high-throughput screening of novel anti-renal cancer small-molecule compounds, natural drugs and combined administration regimens; comparative study on the differences in growth, invasion and metastasis between subcutaneous solid tumors and orthotopic renal tumors. It fully supports basic research of urinary system tumors, preclinical new drug development, national and provincial project application, postgraduate proposal and dissertation writing, and SCI journal methodology construction, serving as an irreplaceable SCI gold-standard model for targeted therapy, immunotherapy and combination therapy research of renal cell carcinoma.

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