Modeling Principle

The Mouse 22RV-1 Model is a world-class gold-standard in vivo model for research on AR-V7-positive castration-resistant prostate cancer (CRPC), androgen receptor splice variant-mediated drug resistance, and enzalutamide/abiraterone resistance and recurrence mechanisms. Derived from recurrent drug-resistant lesions of human prostate cancer xenografts after castration treatment, 22RV-1 cells are a classic transitional cell line connecting early androgen-dependent prostate cancer and advanced completely hormone-independent prostate cancer. It stably expresses full-length androgen receptor (AR), mutant AR, and core drug-resistant splice variant AR-V7 at high levels, and continuously secretes prostate-specific antigen (PSA). Different from DU145 (AR-negative, pure hormone-independent, highly metastatic) and LNCaP (pure hormone-dependent, drug-sensitive), 22RV-1 presents characteristic pathological phenotypes of weak androgen dependence, autonomous proliferation after castration, primary resistance to anti-androgen drugs and easy recurrence in vivo, which accurately recapitulates the real pathological process of clinical prostate cancer recurrence and progression to CRPC after endocrine therapy. With stable in vitro characteristics, negligible batch variation, excellent in vivo tumor homogeneity and non-drifting drug-resistant phenotypes, 22RV-1 is currently the most matched and widely recognized exclusive model for studies on AR-V7 resistance, endocrine therapy failure and staged malignant progression of prostate cancer. Logarithmic-phase low-passage 22RV-1 cells are subcutaneously inoculated into BALB/c-nu nude mice to establish a standardized CRPC xenograft model with stable tumorigenesis, typical drug-resistant phenotypes and robust data reproducibility, fully meeting the standardized methodological writing requirements of NSFC urological tumor projects, postgraduate proposals, dissertations and high-score SCI mechanism papers.

Model Validation Criteria

Quantitative Criteria for Tumor Formation and Growth

1. Positive modeling criteria: Clear macroscopic tumor nodules appear 5–7 days after 22RV-1 cell subcutaneous inoculation. The tumor formation rate is ≥95% within 12 days, and tumor volume ＞50 mm³ is defined as successful modeling. Tumors in the vehicle control group proliferate autonomously and continuously without spontaneous regression, perfectly reproducing the malignant characteristics of non-hormone-dependent continuous recurrent proliferation of clinical CRPC after castration.

2. Model reproducibility criteria: The intra-group coefficient of variation (CV) of tumor volume in the vehicle control group is ＜30%, indicating high standardized modeling operation, minimal individual differences and excellent batch stability, fully meeting the quality control requirements of SCI experimental data.

3. Pharmacodynamic response criteria: After intervention with CRPC first-line positive drugs, the tumor growth inhibition rate (TGI) is ≥35%, and tumor volume and tumor weight are significantly reduced compared with the vehicle control group (P＜0.05). The model has stable and sensitive pharmacodynamic responses to AR-V7 pathway inhibitors, endocrine resistance reversal drugs and targeted sensitizers, suitable for drug screening and resistance reversal mechanism verification of drug-resistant prostate cancer.

Histopathological and Molecular Gold-Standard Indexes

1. HE staining gold standard: Tumor tissues contain a large number of atypical prostate epithelial cancer cells with dense and disordered cell arrangement, large deeply stained nuclei, obvious nucleoli, visible mitotic figures and definite cell atypia, which conform to the typical histological morphological characteristics of clinical castration-resistant prostate cancer.

2. Molecular phenotypic criteria: Tumor tissues stably overexpress AR, AR-V7 and PSA with continuously elevated Ki-67 proliferation index, confirming the core phenotype of AR splice variant-mediated autonomous proliferation and endocrine resistance; accompanied by mild EMT activation, low-to-moderate expression of Vimentin/MMP2/MMP9 and partial down-regulation of E-cadherin, it recapitulates the pathological characteristics of slow invasion, indolent progression and high recurrence tendency of mid-stage clinical CRPC.

3. Pharmacodynamic response criteria: Compared with the vehicle control group, the treatment group shows significantly down-regulated AR/AR-V7/PSA expression, decreased Ki-67 proliferation index, increased Cleaved-Caspase-3 apoptosis level and declined expression of EMT invasion markers, confirming that drugs can target and inhibit AR-V7 drug-resistant pathways, reverse endocrine resistance, and block tumor recurrent proliferation and malignant invasion.

4. Evidence closed-loop criteria: In vivo histopathological and molecular protein detection results are highly consistent with the in vitro 22RV-1 cell experimental mechanism trend, forming a complete and credible academic evidence closed-loop.

Academic Evidence for Model Validity

The Mouse 22RV-1 Model is the exclusive transitional gold-standard in vivo model for international research on AR-V7-positive castration-resistant prostate cancer, endocrine therapy resistance and tumor recurrent progression mechanisms. Core academic validity evidence: ① Derived from clinical recurrent drug-resistant lesions after castration, 22RV-1 cells retain both full-length AR and drug-resistant splice variant AR-V7, accurately simulating the key pathological stage of clinical prostate cancer progression from hormone dependence to hormone independence, anti-androgen drug failure and recurrent progression; ② It presents stable in vivo tumorigenesis, constant AR-V7 drug-resistant phenotypes, mild and typical proliferation and invasion characteristics without batch phenotypic drift, with excellent data reproducibility; ③ It is primarily resistant to first-line endocrine drugs such as enzalutamide and abiraterone, and has clear response gradients to targeted sensitization and combined drug resistance reversal regimens, serving as an exclusive core model for CRPC drug resistance mechanism analysis and new drug research and development; ④ It exclusively covers the characteristic research dimensions of staged drug-resistant progression and AR splice variant-driven recurrence of prostate cancer, perfectly filling the research gaps of LNCaP (hormone-sensitive) and DU145 (AR-free, highly metastatic) models; ⑤ Widely accepted by top SCI journals in the field of urological oncology for a long time, it is a benchmark model for prostate cancer endocrine resistance, translational medicine and precise targeted therapy research, improving the complete urological tumor research system.

Model Advantages

The Mouse 22RV-1 Model is an exclusive SCI gold-standard transitional model for research on clinical AR-V7-positive castration-resistant prostate cancer, endocrine-resistant recurrence and staged malignant progression. Core advantages: It accurately corresponds to AR-V7-mediated drug-resistant CRPC with the highest clinical incidence and the most difficult clinical intervention, perfectly simulating the core pathological mechanism of prostate cancer endocrine therapy failure, drug-resistant recurrence and indolent progression. Retaining both full-length AR and drug-resistant splice variant AR-V7, it is the only current in vivo model that can truly restore the entire transformation process of prostate cancer from hormone sensitivity to hormone resistance. With extremely stable drug-resistant phenotypes, high tumorigenesis homogeneity and excellent data signal-to-noise ratio, it is suitable for in-depth exploration of high-score SCI drug resistance mechanisms and innovative design of NSFC urological tumor projects. It can exclusively carry out characteristic mechanism research on AR splice variant resistance, endocrine reversal and recurrent proliferation blockade, filling the translational research gaps that cannot be covered by traditional prostate cancer models. Complementary with the DU145 model, it fully covers the two major phenotypes of advanced prostate cancer (metastatic and drug-resistant) and constructs a complete standardized model research system for advanced prostate cancer.

Research Applications

The Mouse 22RV-1 Model is mainly applied to preclinical translational research on endocrine resistance, hormone pathway remodeling, recurrent proliferation, low-grade invasion and targeted drug resistance reversal of AR-V7-positive castration-resistant prostate cancer. Core application scenarios: molecular mechanism analysis of AR splice variant AR-V7 abnormal activation-mediated endocrine therapy failure and recurrence of prostate cancer; exploration of core pathways of autonomous tumor proliferation and indolent progression after anti-androgen drug resistance; in vivo efficacy evaluation of innovative small molecules, natural products and nano-formulations used alone or in combination to reverse AR-V7 resistance, sensitize endocrine therapy and inhibit tumor recurrent proliferation. It exclusively compensates for the characteristic research shortcomings of prostate cancer hormone-resistant progression, and forms a **complete standardized model system for advanced prostate cancer** when combined with the DU145 high-metastatic model. It fully supports innovative drug resistance mechanism exploration for NSFC projects, postgraduate proposals, dissertations and high-score SCI papers in urological tumor research.

22RV-1 cell, human prostate cancer, castration-resistant prostate cancer, CRPC, androgen receptor splice variant AR-V7, enzalutamide resistance, PSA positive, weak androgen dependence, tumor recurrence, targeted drug resistance, nude mouse subcutaneous xenograft model, prostate cancer endocrine resistance, preclinical efficacy evaluation