MeWo / MeWo-luc Orthotopic Mouse Model Service for Melanoma

The MeWo / MeWo-luc orthotopic mouse model for melanoma engrafts a BRAF/NRAS double wild-type human melanoma into the skin—or via cardiac dissemination to the brain—of immunodeficient mice, providing the field’s standard wild-type comparator for targeted therapy studies. Serving only preclinical programs, Alfa Cytology provides this xenograft platform as a complete service: authenticated MeWo / MeWo-luc cell supply, route-matched orthotopic inoculation (intradermal or intracardiac brain-metastasis), scheduled in vivo imaging, and endpoint histopathological confirmation.

Overview of MeWo / MeWo-luc Orthotopic Mouse Model for Melanoma

MeWo is one of the oldest human melanoma lines in continuous use. Initiated in 1974 by Y. Kodera and M. Bean from a lymph node metastasis of a 78-year-old White male patient with malignant melanoma, and catalogued by ATCC as HTB-65, the line is a fibroblast-like, adherent melanoma with a deliberately unremarkable molecular genotype: it is wild-type for BRAF and wild-type for NRAS, the canonical “double wild-type” profile. That very plainness is MeWo’s experimental superpower—it serves as the standard BRAF-inhibitor-resistant comparator in virtually every melanoma drug program, the reference against which BRAF V600E lines like A375 and Malme-3M are judged. The cells are amelanotic, carry defined isoenzyme and antigen profiles (blood group A; HLA-A2, Aw30/A26, Bw16, B18), and grow steadily in Eagle’s MEM-based media with a defined STR fingerprint for authentication.

Fig 1. Spontaneous metastasis xenograft model in SCID mice showing that subcutaneously injected MeWo CEACAM1 knockdown cells (median OS 122 days) significantly prolonged survival compared with MeWo Luc controls (median OS 80 days), with CEACAM1 knockdown reducing lung metastatic foci (P=0.006) without altering primary tumor weight or circulating tumor cell counts, validated by CEACAM1 IHC of the MeWo xenografts. (Wicklein, Daniel, et al., 2018)

Orthotopically, MeWo forms xenografts in nude mice that are slow-growing and locally invasive, and the line has one format almost no other melanoma model can claim: intracardiac injection, in which MeWo cells injected into the left ventricle of female nude mice reproducibly colonize the brain, establishing an experimental brain metastasis model in which brain and bone marrow are the readout tissues—valuable for studying the deadliest complication of melanoma. Luciferase-tagged derivatives (MeWo-luc) bring quantitative whole-animal bioluminescence to both formats, tracking intradermal tumor growth or cerebral colonization after D-luciferin administration, while ex vivo imaging and H&E confirmation of resected brain and skin tumors anchor the endpoint. MeWo has served radiation and DNA-damage response studies, AMPK-pathway and metastasis mechanism research, toxicology programs, and as the indispensable wild-type control arm in targeted therapy evaluation. Figure 1 outlines how this orthotopic system is assembled and monitored.

Cell Line Information: MeWo / MeWo-luc

MeWo’s longevity has left it exhaustively documented, from isoenzyme charts to modern genomic surveys. The defining attributes are summarized below.

Our Services

A MeWo / MeWo-luc engagement with Alfa Cytology is run as one accountable program: verified cell banking, route-matched orthotopic inoculation (intradermal or intracardiac), calibrated IVIS imaging on long-timeline schedules, dosing per the client’s regimen, and a terminal package pairing photon-flux curves with skin- and brain-tumor histopathology.

Workflow of MeWo / MeWo-luc Orthotopic Mouse Model Construction

Constructing a MeWo or MeWo-luc orthotopic melanoma begins with a route decision that defines the study: intradermal implantation models the primary tumor in its tissue of origin, while intracardiac injection models cerebral metastasis. The workflow below reflects this dual-route execution.

1. Cell Bank Verification and Expansion: MeWo or MeWo-luc stocks are authenticated by STR profiling and mycoplasma testing, then expanded in EMEM-based medium, respecting the line’s slow, steady growth to reach the required scale.
2. Luciferase Calibration (MeWo-luc Only): Signal output per cell is verified in vitro; amelanotic biology keeps the signal-to-cell relationship clean, without pigment quenching.
3. Host Preparation and Route Selection: Female nude mice are acclimatized and randomized by body weight; the design selects intradermal implantation for primary-tumor questions or intracardiac injection for brain-metastasis questions.
4. Orthotopic Inoculation: For the skin format, 5 × 10⁶ cells in a minimal volume are injected intradermally at a depilated site; for the brain-metastasis format, a defined cell number is injected into the left ventricle under anesthesia with ultrasound guidance where available.
5. Engraftment Confirmation: Whole-animal bioluminescence after D-luciferin (150 mg/kg i.p.) confirms take, with per-animal baseline radiance recorded for quantitative comparison.
6. Extended Longitudinal Monitoring: Given MeWo’s slower kinetics, imaging and caliper sessions are scheduled at weekly intervals, tracking intradermal expansion or cerebral colonization over several weeks.
7. Treatment Administration: Test agents—targeted inhibitors, radiation regimens, AMPK-pathway modulators, or nanomedicines—are dosed per the client’s schedule once tumors or cerebral signals are established.
8. Endpoint Analysis: At endpoint, skin tumors or brains (with bone marrow) are resected for ex vivo imaging and weighing; tissues are processed for H&E and immunohistochemistry (S100, HMB45, Ki67, GFAP for brain lesions) to complete the dataset.

Fig 2. MeWo / MeWo-luc orthotopic mouse model construction workflow.

Case Study-MeWo / MeWo-luc Orthotopic Mouse Model Development

Alfa Cytology has executed preclinical programs on the MeWo / MeWo-luc orthotopic platform for clients benchmarking wild-type melanoma control arms, studying radiation and DNA-damage responses, and modeling cerebral metastasis, delivering extended-timeline bioluminescence records, brain- and skin-tumor histopathology, and endpoint packages configured around the client’s therapeutic question. Study outlines and representative datasets are available upon request.

Why Choose Alfa Cytology?

A wild-type comparator is only as credible as the CRO running it: slow kinetics, dual-route surgery, and long timelines all demand discipline. Alfa Cytology’s execution keeps MeWo / MeWo-luc studies reproducible from the first intradermal bleb to the final brain section.

• Authenticated MeWo / MeWo-luc banks with STR and mycoplasma verification before in vivo work.
• Dual-route expertise spanning intradermal primary tumors and intracardiac brain-metastasis models.
• Amelanotic imaging advantage: clean luciferase quantification without pigment quenching.
• Slow-kinetics-aware scheduling with weekly imaging calibrated to steady tumor growth.
• Endpoint histopathology with S100, HMB45, Ki67, and GFAP markers for skin and brain formats.
• A dedicated project team owning the study from route selection through final data delivery.

Contact Us

Whether your program needs a credible wild-type control arm or a cerebral metastasis model, Alfa Cytology can configure a MeWo / MeWo-luc orthotopic study to your specifications.

Contact us today to discuss route selection, study design, and scheduling, or reach out to our team for a customized quotation.

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