A375 Xenograft Rat Model Service for Melanoma

The A375 xenograft rat model recapitulates the aggressive, BRAF V600E–driven biology of metastatic cutaneous melanoma within an immunodeficient rat host, offering expanded tissue volumes for longitudinal bioluminescence tracking and serial pharmacokinetic sampling. Alfa Cytology constructs this model using authenticated ATCC CRL-1619 cell stocks and validated nude rat engraftment protocols, delivering reproducible tumor kinetics and integrated pharmacodynamic endpoints that advance your preclinical melanoma therapeutic pipeline with molecular precision.

Overview of A375 Xenograft Rat Model for Melanoma

The A375 cell line (ATCC CRL-1619) was originally established in 1973 from a metastatic skin lesion of a 54-year-old female patient diagnosed with malignant melanoma. Genetically, the line is defined by the hallmark BRAF V600E missense mutation—a thymine-to-adenine transversion at nucleotide 1799 that substitutes valine with glutamic acid at codon 600—resulting in constitutive activation of the MAPK/ERK signaling cascade and autonomous cellular proliferation. This mutation is present in approximately 50% of cutaneous melanomas and represents the primary oncogenic driver targeted by clinically approved agents such as vemurafenib and dabrafenib. In addition, A375 harbors a homozygous deletion in CDKN2A (p16INK4a), abolishing the G1/S cell-cycle checkpoint and accelerating tumorigenic progression. Histologically, the cells display epithelioid morphology with polygonal shapes, prominent nucleoli, and moderate melanin pigmentation, closely mirroring the appearance of human metastatic melanoma lesions.

Fig 1. 2155-14 and 18 are efficacious in the A375 CDX melanoma model. (Velayutham, Sadeeshkumar, et al., 2023)

In vivo, A375 exhibits exceptionally high tumorigenicity and rapid growth kinetics, with a doubling time of approximately 22–27 hours in culture and palpable tumor formation within 7–10 days following subcutaneous implantation into immunocompromised hosts. When engrafted into nude rats, the model capitalizes on the larger physiological scale of the host to enable repeated blood draws for pharmacokinetic profiling, expanded tumor tissue harvest for multiplex biomarker analysis, and prolonged dosing windows without the volume constraints typical of mouse models. The line is further amenable to luciferase transduction (A375-luc), permitting real-time, non-invasive bioluminescence imaging of tumor burden, regression, and relapse dynamics—an indispensable feature for evaluating BRAF inhibitor durability and acquired resistance mechanisms. These attributes have cemented A375 as the preclinical gold standard for melanoma drug development, spanning cytotoxic agents, targeted BRAF/MEK inhibitors, immunotherapeutics, and novel delivery platforms.

Cell Line Information: A375

The table below summarizes the authenticated characteristics of the A375 human malignant melanoma cell line, compiled from ATCC repository data, Cellosaurus records, and peer-reviewed literature.

Our Services

Alfa Cytology bridges the gap between in vitro A375 characterization and in vivo translational outcomes by managing every stage of xenograft construction—from authenticated cell banking and mycoplasma-free expansion through Matrigel-assisted subcutaneous implantation or tail-vein metastatic delivery into immunodeficient rats, longitudinal tumor monitoring via caliper and bioluminescence imaging, serial blood collection for pharmacokinetic analysis, and terminal histopathology with quantitative biomarker readouts. Each study is tailored to your compound's mechanism of action and conducted under accredited IACUC oversight with full GLP-aligned documentation.

Workflow of A375 Xenograft Rat Model Construction

Construction of the A375 xenograft rat model follows a standardized yet adaptable workflow designed to achieve high tumor take rates, consistent growth kinetics, and robust pharmacodynamic endpoints. The protocol supports both subcutaneous flank implantation for straightforward tumor volume monitoring and tail-vein delivery for metastatic dissemination modeling, selected according to the scientific objective.

1. Cell Line Resuscitation & Quality Control: Cryopreserved A375 stocks (ATCC CRL-1619) are thawed and expanded in DMEM supplemented with 10% FBS and 1% penicillin-streptomycin under antibiotic-free, low-passage conditions. Cell identity is confirmed by morphology, growth curve analysis, and STR profiling against the authenticated reference (RRID: CVCL_0132). Mycoplasma testing is performed prior to in vivo use. Harvest occurs at 70–80% confluence using 0.25% trypsin-EDTA; viability is assessed by trypan blue exclusion, with only suspensions exceeding 98% viability advanced to implantation. For subcutaneous studies, cells are resuspended in serum-free medium at 1 × 10⁷ cells/mL and mixed 1:1 with cold Matrigel (100 µL final volume per injection).
2. Host Selection & Acclimation: Immunodeficient nude rats (Crl:NIH-Foxn1rnu, 6–8 weeks old, 150–200 g) are ordered from accredited vendors and acclimated for 7–10 days under specific-pathogen-free conditions. Baseline body weights and complete blood counts are recorded. The larger body mass of rats relative to mice facilitates serial blood draws (up to 200–300 µL per collection) for pharmacokinetic profiling and expanded tissue availability for multi-omics analysis without compromising hemodynamic stability.
3. Tumor Cell Implantation: For subcutaneous models, 100 µL of the A375-Matrigel suspension (5 × 10⁶ cells) is injected into the right flank using a 25-gauge needle. For metastatic models, 200 µL of cell suspension (2 × 10⁶ A375-luc cells) is delivered via tail-vein injection to model hematogenous dissemination to lungs and distant organs. The subcutaneous route generates a localized, highly vascularized tumor mass amenable to caliper measurement and intratumoral dosing, while the metastatic route permits evaluation of organ-specific colonization and anti-metastatic therapeutic efficacy.
4. Post-Implantation Monitoring & Tumor Tracking: Animals are monitored daily for clinical signs including weight loss, reduced activity, and respiratory distress in metastatic models. Subcutaneous tumors are measured twice weekly with digital calipers (volume = L × W² / 2) from first palpable detection, typically 7–10 days post-implantation. For A375-luc variants, bioluminescence imaging is performed weekly following intraperitoneal D-luciferin injection (150 mg/kg), capturing total flux (photons/second) as a quantitative surrogate of viable tumor cell burden. This approach detects residual minimal lesions and early relapse with sensitivity superior to caliper measurement alone.
5. Therapeutic Intervention & Endpoint Harvest: Upon reaching the target tumor volume (typically 100–200 mm³ for subcutaneous) or defined bioluminescence signal in metastatic models, animals are randomized into treatment and vehicle control cohorts. Test articles are administered via the sponsor-specified route—intravenous, oral gavage, intraperitoneal, or intratumoral—according to the dosing regimen. Tumor measurements and body weights continue on schedule until the study endpoint. At termination, animals are humanely euthanized. Tumors, lungs, liver, spleen, and blood are harvested. Tumor weight is recorded, tissues are digitally imaged, and samples are processed for H&E histopathology, Ki-67 proliferation index, TUNEL apoptosis scoring, cleaved caspase-3 immunohistochemistry, and plasma drug-concentration profiling.

Fig 2. A375 Xenograft Rat Model construction workflow.

Case Study-A375 Xenograft Rat Model Development

In a recent preclinical engagement, Alfa Cytology utilized the A375 subcutaneous xenograft rat model to evaluate the antitumor efficacy of a novel BRAF/MEK dual-targeting small-molecule candidate in BRAF V600E–positive melanoma. Following authenticated A375 cell expansion and Matrigel-assisted implantation into nude rats, tumors were permitted to establish for 10 days prior to randomization into vehicle, benchmark (vemurafenib monotherapy), and combination cohorts. The candidate compound was administered via daily oral gavage for 28 days, with longitudinal tumor volume monitoring and interim body-weight assessments. Terminal analyses included H&E histopathology, Ki-67 and TUNEL dual staining to assess proliferation and apoptosis, p-ERK and p-MEK1/2 Western blotting to confirm target engagement, and plasma pharmacokinetic profiling. The dataset revealed dose-dependent tumor growth inhibition accompanied by sustained MAPK pathway suppression and reduced proliferative index, providing the sponsor with pharmacodynamic evidence to support downstream candidate selection and IND-enabling toxicology planning.

Why Choose Alfa Cytology?

Partnering with Alfa Cytology for your A375 melanoma program means accessing a specialized preclinical infrastructure built around authenticated melanoma cell biology, immunodeficient rat surgical expertise, and integrated pharmacodynamic analytics tailored to BRAF-driven disease.

• Authenticated A375 master and working cell banks are maintained under documented low-passage protocols with periodic STR verification and mycoplasma screening to ensure BRAF V600E and CDKN2A fidelity.
• Our surgical team is proficient in both subcutaneous flank and tail-vein metastatic implantation techniques in immunodeficient rats, achieving high tumor take rates with minimal perioperative mortality.
• The larger physiological scale of rats enables serial blood draws for pharmacokinetic profiling, expanded tumor tissue harvest for multiplex biomarker analysis, and prolonged dosing windows without mouse-specific volume constraints.
• Integrated bioluminescence imaging capabilities support real-time, longitudinal tracking of A375-luc tumor burden, regression, and relapse dynamics with sensitivity superior to caliper measurement alone.
• Study protocols are customized to your therapeutic modality—whether BRAF inhibitors, MEK inhibitors, combination targeted regimens, immunotherapeutics, or novel delivery platforms—with clear pharmacodynamic and efficacy decision criteria.
• All in vivo work is conducted under fully accredited IACUC oversight with real-time veterinary monitoring and GLP-aligned documentation, ensuring ethical integrity and generating audit-ready data packages for regulatory submissions.

Contact Us

If your melanoma therapeutic pipeline demands a preclinical model that faithfully recapitulates BRAF V600E–driven, metastatic cutaneous melanoma biology within an immunodeficient rat host, reach out to us to discuss how Alfa Cytology can architect an A375 study tailored to your development milestones. Our scientific team will review your target profile, propose a customized protocol with integrated pharmacokinetic and pharmacodynamic endpoints, and deliver a comprehensive proposal within two business days. Contact us today and accelerate your preclinical proof-of-concept with a CRO that understands the complexities of BRAF-mutant melanoma modeling.

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