MDA-MB-361 Orthotopic Mouse Model Service for Breast Cancer

The MDA-MB-361 orthotopic mouse model represents a refined preclinical platform for investigating luminal B breast cancer progression, therapeutic response, and resistance mechanisms within a physiologically relevant mammary microenvironment. Alfa Cytology delivers end-to-end construction and management of this specialized model, leveraging authenticated cell assets, standardized orthotopic protocols, and longitudinal monitoring capabilities to generate robust, publication-ready datasets for your oncology research programs.

Overview of MDA-MB-361 Orthotopic Mouse Model for Breast Cancer

The MDA-MB-361 cell line was originally established from a brain metastasis specimen obtained from a 40-year-old female patient diagnosed with breast adenocarcinoma. Genetically, this line is classified within the luminal B molecular subtype, characterized by concurrent estrogen receptor positivity (ER+) and HER2 gene amplification (HER2+), with partial progesterone receptor expression (PR±). The model harbors wild-type BRCA1/2 status alongside TP53 and PIK3CA mutations, presenting a moderate proliferation rate with an approximate doubling time of 48 hours. When established orthotopically within the murine mammary fat pad, MDA-MB-361 cells recapitulate the histoarchitectural features and dual-receptor expression patterns observed in clinical metastatic breast cancer, forming solid tumors that maintain epithelial morphology and hormone-responsive growth characteristics.

Fig 1. Actein mediated MDA-MB-361 cell arrest in G1 phase through the modulation of p21-cyclin E1/CDK2-pRb pathway. (Wu, Xiao-Xiao, et al., 2025)

Orthotopic implantation into the mammary fat pad offers distinct advantages over subcutaneous approaches by preserving the native stromal compartment, vascular architecture, and immune contexture specific to breast tissue. This configuration enables spontaneous dissemination to regional lymph nodes and distant organs, including lung and liver, thereby supporting investigations into metastatic cascade mechanisms. The dual ER+/HER2+ phenotype makes this model particularly suited for evaluating cross-talk between steroid hormone and growth factor receptor signaling axes, studying endocrine resistance emergence under HER2-targeted pressure, and benchmarking next-generation antibody-drug conjugates, CDK4/6 inhibitors, and selective estrogen receptor degraders in a translationally relevant setting.

Cell Line Information: MDA-MB-361

The following table summarizes the essential biological and technical characteristics of the MDA-MB-361 cell line, providing a comprehensive reference for researchers designing preclinical studies involving this model.

Our Services

Alfa Cytology provides a comprehensive, turnkey MDA-MB-361 orthotopic mouse model service designed to accelerate your preclinical breast cancer research pipeline. From authenticated cell line procurement and mycoplasma screening through orthotopic surgical implantation, estradiol supplementation, and longitudinal tumor monitoring, our technical team manages every critical milestone with precision. We tailor study parameters—including tumor volume stratification windows, dosing schedules, and multi-parametric endpoint analyses—to align with your specific compound profile and research objectives, delivering reproducible data packages that meet the standards of peer-reviewed publication and regulatory submission.

Workflow of MDA-MB-361 Orthotopic Mouse Model Construction

Construction of the MDA-MB-361 orthotopic model follows a rigorously standardized protocol that balances surgical precision with animal welfare considerations. Each phase is executed under controlled facility conditions to ensure reproducible engraftment, consistent tumor growth kinetics, and reliable therapeutic readouts. The complete workflow encompasses the following sequential stages:

1. Cell Line Authentication and Expansion: MDA-MB-361 cells are revived from cryopreserved stocks and expanded under optimized culture conditions. Prior to inoculation, cells undergo mandatory STR profiling for identity confirmation, mycoplasma PCR screening for contamination exclusion, and viability assessment via trypan blue exclusion to ensure a suspension of >95% live cells.
2. Host Selection and Acclimation: Immunocompromised female mice—typically athymic nude (nu/nu) or NOD/SCID gamma (NSG) strains aged 4–6 weeks—are selected based on study design requirements. Animals are acclimated for a minimum of five days under controlled temperature (22 ± 2°C), humidity (50 ± 10%), and 12-hour light/dark cycle conditions with ad libitum access to sterilized chow and water.
3. Estradiol Priming: Given the estrogen-dependent growth characteristics of MDA-MB-361, controlled-release 17β-estradiol pellets (0.36–0.72 mg, 60-day release) are implanted subcutaneously in the dorsal interscapular region 1–2 days prior to tumor cell inoculation. This hormonal supplementation is essential for achieving robust and consistent tumor take rates in immunodeficient hosts.
4. Preoperative Preparation: Twenty-four hours before surgery, the inguinal region encompassing the fourth abdominal mammary gland is shaved and depilated to expose the nipple landmarks. On the day of operation, mice are anesthetized with 2% isoflurane inhalation, confirmed by absence of toe-pinch withdrawal reflex, and administered ophthalmic ointment to prevent corneal desiccation.
5. Orthotopic Cell Inoculation: A single-cell suspension of 5 × 10⁴ to 2 × 10⁶ viable MDA-MB-361 cells, resuspended in 25–50 µL of PBS or serum-free medium mixed 1:1 with Matrigel matrix, is loaded into a sterile 1 mL syringe fitted with a 27 G needle. Using forceps to tent the skin adjacent to the fourth nipple, the needle is advanced subcutaneously along the mammary ductal plane until the bevel rests beneath the nipple base, and the cell suspension is delivered slowly into the mammary fat pad.
6. Postoperative Monitoring and Tumor Tracking: Following injection, mice are maintained under anesthesia for an additional 60–90 seconds to minimize cell leakage, then transferred to a warmed recovery chamber. Tumor development is monitored twice weekly via digital caliper measurements, with volumes calculated using the modified ellipsoid formula V = (L × W²) / 2. Body weights and clinical scores are recorded concurrently to assess overall health status.
7. Randomization and Treatment Initiation: Once tumors reach a predetermined volume range—typically 100–200 mm³—mice are randomized into treatment cohorts using stratified randomization based on tumor volume and body weight. Dosing protocols are initiated according to the investigational compound schedule, with administration routes including intraperitoneal, intravenous, oral gavage, or subcutaneous delivery as study design dictates.
8. Endpoint Analysis and Tissue Harvest: At study termination, mice are humanely euthanized under deep anesthesia. Primary tumors are excised, weighed, and processed for histopathological examination (H&E staining, IHC for ER/HER2/Ki-67), molecular profiling (qPCR, Western blot), and pharmacokinetic/pharmacodynamic analyses. Metastatic burden in draining lymph nodes, lung, liver, and brain is assessed via ex vivo bioluminescence imaging and histological sectioning.

Fig 2. MDA-MB-361 Orthotopic Mouse Model construction workflow.

Case Study-MDA-MB-361 Orthotopic Mouse Model Development

In a representative preclinical engagement, the MDA-MB-361 orthotopic model was employed to evaluate the anti-tumor efficacy of a dual-targeting therapeutic strategy combining a next-generation HER2-directed antibody-drug conjugate with a selective estrogen receptor degrader. Under optimized estradiol-supported conditions, investigators achieved consistent tumor engraftment with uniform growth trajectories across all experimental arms. Longitudinal monitoring revealed dose-dependent tumor growth inhibition following combination treatment, with corresponding reductions in Ki-67 proliferation index and phospho-AKT signaling intensity observed in post-treatment tumor sections. Metastatic dissemination to regional lymph nodes was attenuated in treated cohorts compared to vehicle controls, as confirmed by histopathological examination. These findings underscore the translational value of the MDA-MB-361 orthotopic platform for benchmarking multi-modal therapeutic regimens in the HER2+/ER+ breast cancer setting.

Why Choose Alfa Cytology?

Partnering with Alfa Cytology for your MDA-MB-361 orthotopic model requirements means gaining access to a technically specialized service infrastructure built around reproducibility, scientific rigor, and operational transparency. Our distinguishing strengths include:

• Authenticated cell line assets with verified STR profiles and documented mycoplasma-negative status, ensuring phenotypic fidelity from culture through in vivo engraftment.
• Optimized estradiol-supplementation protocols tailored to the hormone-dependent growth requirements of MDA-MB-361, maximizing tumor take rates and minimizing inter-animal variability.
• Surgical teams experienced in orthotopic mammary fat pad implantation, delivering precise cell placement with minimal procedural morbidity and rapid postoperative recovery.
• Customizable study designs spanning monotherapy, combination therapy, and resistance-emergence paradigms, with flexible endpoint selection aligned to your compound mechanism.
• Integrated multi-parametric readouts encompassing tumor kinetics, receptor expression analysis (ER/HER2 IHC), pharmacokinetic sampling, and metastatic burden quantification.
• Dedicated project management with transparent milestone reporting, enabling real-time oversight of study progress and adaptive protocol adjustments as scientific needs evolve.

Contact Us

Ready to advance your preclinical breast cancer research with a rigorously validated MDA-MB-361 orthotopic mouse model? The scientific team at Alfa Cytology is prepared to design a customized study framework that aligns with your therapeutic development goals and generates the high-quality data your program demands. Reach out to us today to discuss your project requirements, request a detailed quotation, or schedule a consultation with one of our oncology model specialists.

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