BR Syngeneic Model Service for Ovarian Cancer

The BR syngeneic model service for ovarian cancer is an immune-competent FVB/N platform built on genetically defined fallopian-tube-epithelial cells carrying the Brca1-null, p53-mutant, Myc-driven high-grade serous ovarian cancer genotype, recapitulating homologous-recombination-deficient human disease with 100% tumor penetrance and predictable latency. Alfa Cytology delivers this model as a complete preclinical capability — covering authenticated BR / BR-luciferase expansion and banking, orthotopic ovarian or intraperitoneal implantation, scheduled in vivo bioluminescence monitoring with HA-tag immunohistochemistry, and full serous histopathology with immune-microenvironment profiling — all configured around each sponsor’s PARP-inhibitor, platinum, checkpoint, or epigenetic-combination hypothesis.

Overview of BR Syngeneic Model for Ovarian Cancer

BR was engineered to answer a precise question: what does a BRCA1-deficient high-grade serous ovarian cancer look like when every driver lesion is defined? Sandra Orsulic’s laboratory transformed murine fallopian tube epithelial cells from FVB/N mice with a combination drawn straight from the human TCGA landscape — biallelic Brca1 loss, mutant Trp53 (R172H), and c-Myc overexpression, with Akt-driven derivatives such as BR5 extending the panel — to phenocopy the homologous-recombination-deficient (HRD) tumor spectrum (Xing & Orsulic, Cancer Research 66:8949–8953, 2006; refined and expanded by Iyer et al., Cancer Discovery 11:384–408, 2021). The result is a syngeneic model of unusual rigor: tumors form with 100% penetrance at predictable latency, display genuine serous histology, spread through the peritoneal cavity in the human pattern — with the omentum as the dominant metastatic site and ascites accumulating after intraperitoneal challenge — and, crucially, carry the HRD genotype as an experimentally manipulable variable, allowing Brca1-null and Brca1-wild-type tumors to be compared under identical conditions. Luciferase and HA tags engineered into the lines permit whole-animal bioluminescence quantification and unambiguous tumor-cell identification in paraffin sections against host stromal background.

Fig 1. Spatiotemporal analysis of patient-matched primary, metastatic and recurrent high-grade serous ovarian carcinomas, showing that INHBA(+) fibroblasts co-localize with Treg enrichment and correlate with poor survival—providing the clinical rationale for the BR syngeneic model study. (Hu, Ye, et al., 2024)

The model’s therapeutic record is where its value becomes vivid. Because the BR family is HR-deficient by design, it reproduces the platinum and PARP-inhibitor sensitivities of human BRCA1-mutant HGSC: carboplatin single-agent extended median survival from 56 to 116 days in the orthotopic setting, and — in the landmark combination result — olaparib plus anti-PD-L1 checkpoint blockade left 80% of Brca1-null tumor-bearing mice alive beyond 180 days with no evidence of disease, an effect absent in Brca1-wild-type counterparts, formally demonstrating that HRD is required for the PARP-inhibitor/checkpoint synergy. The immune biology has been mapped with equal care: PARP inhibition in the BR5 derivative upregulated CCL2 and CCL5, increased intratumoral CD8⁺ T cells and NK cells with interferon-γ production, and depleted MDSCs; CXCL12/CXCR4-axis blockade selectively reduced FoxP3⁺ regulatory T cells and amplified T-cell antitumor immunity; and the DNA-hypomethylating agent decitabine potentiated anti-CTLA-4 by driving naïve-to-effector T-cell differentiation. For sponsors, BR offers what few ovarian models can: a genetically legible HRD tumor in which platinum, PARP, checkpoint, and epigenetic combinations can be deconstructed, arm by arm, in a fully immunocompetent host.

Cell Line Information: BR

The table below consolidates the key genetic, biological, and modeling characteristics of the BR line family and its documented derivatives.

Our Services

A genetically defined HRD model rewards genotype-verified execution, and Alfa Cytology runs BR accordingly: PCR- and immunoblot-confirmed banking of the HRD and matched HRP lines, validated orthotopic and intraperitoneal formats with luciferase tracking from day 10, scheduled imaging with HA-tag immunohistochemistry, and endpoint pathology pairing serous morphology with CD8/FoxP3/MDSC immune profiling — all under one accountable preclinical operation.

Workflow of BR Syngeneic Model Construction

Construction follows the Orsulic-laboratory methodology: BR or BR-Luc cells are expanded under authenticated, genotype-reconfirmed conditions, implanted orthotopically into the ovary or intraperitoneally into FVB/N mice, tracked by bioluminescence, treated after standardization, and analyzed with HRD-specific efficacy and immune endpoints. The workflow comprises the following stages.

1. Cell authentication and banking: BR or derivative lines are identity-verified, confirmed mycoplasma-negative with a murine pathogen panel, and re-confirmed for the defined genotype (Brca1 loss, Trp53 R172H, Myc status) by PCR-based analysis and immunoblotting at banking.
2. Cell harvest and formulation: Healthy cultures are trypsinized, washed, counted and viability-checked, then resuspended at approximately 5 × 10⁶ cells in 200 μL of PBS per mouse for intraperitoneal dissemination, or per validated orthotopic dosing for ovarian implantation.
3. Anesthesia and implantation: FVB/N mice are anesthetized with isoflurane; cells are injected into the ovarian bursa for orthotopic arms through a dorsal approach, or into the peritoneal cavity for dissemination arms, with luciferase-arm animals assigned before surgery.
4. Establishment verification and randomization: Luciferase signal is confirmed from approximately day 10 post-implantation; animals are randomized by imaging burden or study day once tumors are standardized, balancing HRD and matched HRP cohorts.
5. Treatment administration: Experimental arms — PARP inhibitors (olaparib-class), platinum agents, CHK1 inhibitors, checkpoint inhibitors, CXCR4 antagonists, decitabine, and combinations — proceed per study design with documented dosing schedules (e.g., checkpoint antibodies twice weekly for four weeks) and toxicity monitoring.
6. Imaging and immune monitoring: Scheduled bioluminescence sessions quantify whole-body and peritoneal kinetics; mid-point omental tumors are profiled for CD4⁺/CD8⁺ T cells, B cells, NK cells, Tregs, tumor-associated macrophages, and MDSCs by flow cytometry; bulk RNA-seq arms characterize genotype-driven immune signatures.
7. Endpoint and histopathological analysis: Endpoints integrate survival, imaging burden, and ascites volume with histopathology (H&E confirming serous morphology, plus HA-tag tumor-cell identification with Ki67, CD8, FoxP3, and PD-L1 immunohistochemistry) and rechallenge-based immune-memory assessment where specified.

Fig 2. BR Syngeneic Model construction workflow.

Case Study-BR Syngeneic Model Development

Alfa Cytology has conducted preclinical programs on the BR platform spanning PARP-inhibitor and platinum benchmarking with paired HRD/HRP arms, PARP-plus-checkpoint combination discovery, and Treg- and MDSC-targeting regimen evaluation in defined-genotype serous ovarian cancer. In these studies, implanted BR tumors were longitudinally quantified by in vivo bioluminescence, treated per randomized regimens, and characterized at endpoint by histopathology with HA-tag tumor-cell identification and immune-microenvironment profiling. Study-level datasets are available upon request.

Why Choose Alfa Cytology?

Alfa Cytology pairs defined-genotype model governance with HRD-specific combination-therapy expertise, so every BR study is executed with verified Brca1/Trp53/Myc status, paired HRP controls, and immune endpoints that connect PARP biology to checkpoint response.

• Focused experience with the Orsulic FTE-engineered platform, including HRD and matched HRP lines under PCR/immunoblot genotype re-confirmation.
• A single coordinated team managing cell banking, orthotopic and intraperitoneal surgery, in vivo imaging, HA-tag pathology, and flow-cytometric immune profiling under one quality framework.
• Design fluency with PARP, platinum, CHK1, checkpoint, CXCR4, and decitabine formats, including anti-CD8 depletion arms for effector-dependence claims.
• Imaging-plus-IHC dual verification via luciferase and HA tags enabling tumor-versus-stroma-resolved pharmacodynamics.
• Transparent milestone reporting and rapid scientific feedback throughout the engagement.

Contact Us

If your ovarian cancer program targets the HR-deficient high-grade serous genotype — with PARP, platinum, checkpoint, or epigenetic combinations to test — Alfa Cytology is ready to build the study around your hypothesis. Reach out to us with your regimen and endpoint requirements, or contact us today for a customized proposal and quotation for the BR syngeneic model service.

For research use only. Not intended for any clinical use.