Malme-3M / Malme-3M-luc Orthotopic Mouse Model Service for Melanoma

The Malme-3M / Malme-3M-luc orthotopic mouse model for melanoma engrafts a slow-growing, MITF-dependent, BRAF V600E-mutant human melanoma into the skin of immunodeficient mice, where pigmented tumors can be tracked by bioluminescence for drug and immune studies. Serving clients only in the preclinical domain, Alfa Cytology provides this xenograft platform as a complete service, spanning authenticated Malme-3M / Malme-3M-luc cell supply, intradermal orthotopic inoculation, scheduled in vivo imaging with slow-growth-aware scheduling, and endpoint histopathological confirmation.

Overview of Malme-3M / Malme-3M-luc Orthotopic Mouse Model for Melanoma

Malme-3M belongs to the celebrated Fogh series of human tumor lines assembled at the Sloan Kettering Institute in the 1970s. Established in 1975 by Jörgen Fogh and Germaine Trempe from a lung metastasis of a 43-year-old Caucasian male with metastatic melanoma, and catalogued by ATCC as HTB-64, the line occupies a special niche in melanoma biology. It carries the BRAF V600E mutation—the single most druggable lesion in melanoma—with wild-type N-RAS, and its growth and survival depend on microphthalmia-associated transcription factor (MITF), the lineage master regulator. Notably, it retains wild-type p53. The cells display a fibroblast-like morphology and grow in a mixed adherent-suspension pattern, with a reported population doubling time near 43 hours—unusually slow for a cancer line—which demands patience and planning in study design. Malme-3M is also one of the NCI-60 panel lines used for national-scale drug screening, expresses HLA-A2 (of interest for antigen-specific immunotherapy work), and comes with a built-in experimental control: a normal skin fibroblast line, Malme-3, isolated from the same patient.

Fig 1. In vivo bioluminescence imaging of Malme-3M-luc-bearing mice comparing unarmed ATC controls (progressive tumor photon growth to ~5×10⁸ photons/sec by day 20) versus B7-H3Bi-ATCs (tumor signal dropped from day 1 and reached background by day 7–16), with longitudinal photon curves quantifying the eradication of Malme-3M-luc xenografts. (Ma, Juan, et al., 2019)

Orthotopically, Malme-3M forms pigmented malignant melanomas in nude mice, and luciferase-tagged derivatives (Malme-3M-luc) transform this slow-burn model into a quantitative imaging system: whole-animal bioluminescence after D-luciferin administration tracks intradermal tumor growth over several weeks, while ex vivo imaging of resected tumors and distant organs documents burden at endpoint. Because of the line’s extended doubling time, treatment windows are longer than in aggressive melanoma models such as A375 or B16—an advantage for agents whose efficacy depends on cytostatic rather than cytotoxic action, and for slow-release formulations. The platform has served BRAF/MEK inhibitor studies, MITF-pathway dependency research, HER2-directed cytotoxic T-cell work, radiobiology, and DNA-damage response programs. As with all pigmented melanoma models, endogenous melanin attenuates bioluminescent signal, so calibrated interpretation and corroborating caliper and histological readouts are essential. Figure 1 outlines how this orthotopic system is assembled and monitored.

Cell Line Information: Malme-3M / Malme-3M-luc

Malme-3M is one of the most intensively profiled human melanoma lines, from its NCI-60 drug-screening role to its MITF-dependency studies. The defining attributes are summarized below.

Our Services

A Malme-3M / Malme-3M-luc engagement with Alfa Cytology is engineered around the line’s unhurried biology: verified cell banking with passage discipline, intradermal inoculation sized to compensate for slow take rates, melanin-aware IVIS imaging scheduled for long timelines, dosing per the client’s regimen, and a terminal package combining pigmented-tumor histology with ex vivo organ mapping.

Workflow of Malme-3M / Malme-3M-luc Orthotopic Mouse Model Construction

Building a Malme-3M or Malme-3M-luc orthotopic melanoma rewards planners: the slow doubling time lengthens every phase of the study, from cell expansion to engraftment to treatment windows. The workflow below reflects this extended, calibration-rich execution.

1. Cell Bank Verification and Expansion: Malme-3M or Malme-3M-luc stocks are authenticated by STR profiling and mycoplasma testing, then expanded patiently in IMDM- or DMEM-based medium, respecting the ~43-hour doubling time to reach sufficient scale.
2. Luciferase Calibration with Pigment Awareness (Malme-3M-luc Only): Signal per cell is verified, and a pigment-versus-signal relationship is established to govern interpretation of in vivo photon flux from pigmented tumors.
3. Mouse Preparation and Randomization: Six- to eight-week-old nude mice are acclimatized and randomized by body weight; skin sites are shaved and depilated under approved animal protocols.
4. Orthotopic Intradermal Inoculation: A single-cell suspension (commonly 5 × 10⁶ cells in a minimal volume) is injected strictly intradermally; correct plane placement is confirmed by a visible bleb, and engraftment is given extended time given the slow growth.
5. Extended Primary Tumor Monitoring: Because tumors emerge slowly, monitoring combines weekly caliper measurements with whole-animal bioluminescence after D-luciferin, scheduled on longer intervals than for fast melanoma models.
6. Treatment Administration: Test agents—BRAF/MEK inhibitors, MITF-pathway modulators, DNA-damaging agents, or immunotherapeutics—are dosed once tumors reach the pre-defined size threshold, with regimens sized to the extended treatment window.
7. Optional Comparative Controls: Where the study design calls for it, the paired normal Malme-3 fibroblast line serves as a matched comparator for selectivity or biodistribution questions.
8. Endpoint Analysis and Ex Vivo Mapping: At endpoint, pigmented tumors are resected, photographed, and weighed; draining lymph nodes and major organs are collected for ex vivo bioluminescence, H&E confirmation, and immunohistochemistry (MITF, S100, HMB45, Ki67).

Fig 2. Malme-3M / Malme-3M-luc orthotopic mouse model construction workflow.

Case Study-Malme-3M / Malme-3M-luc Orthotopic Mouse Model Development

Alfa Cytology has executed preclinical programs on the Malme-3M / Malme-3M-luc orthotopic platform for clients evaluating BRAF/MEK pathway inhibitors, probing MITF dependency, benchmarking DNA-damaging agents, and validating antigen-specific T-cell concepts, delivering extended-timeline bioluminescence records, pigmented-tumor histopathology, and MITF/lineage-marker-supported endpoint packages. As each engagement is configured around the client’s own therapeutic concept and the line’s slow kinetics, study outlines and representative datasets are available upon request.

Why Choose Alfa Cytology?

Slow-growing models separate disciplined CROs from rushed ones: timelines, inocula, and imaging cadences must all be re-scaled around a 43-hour doubling time, and pigmented tumors add a second interpretive layer. Alfa Cytology’s slow-kinetics expertise keeps Malme-3M / Malme-3M-luc studies efficient without cutting corners.

• Authenticated Malme-3M / Malme-3M-luc banks with STR and mycoplasma verification and passage discipline.
• Slow-growth-aware study designs with extended engraftment and treatment windows.
• Precise intradermal orthotopic inoculation sized to compensate for slow take rates.
• Melanin-aware IVIS imaging calibrated for quantitative long-timeline tracking.
• Paired-normal-line comparator options using the matched Malme-3 fibroblasts.
• Endpoint histopathology with MITF, S100, HMB45, and Ki67 lineage markers.

Contact Us

If your program calls for a patient-relevant, MITF-dependent, BRAF V600E-mutant melanoma model with patient-matched controls, Alfa Cytology can configure a Malme-3M / Malme-3M-luc orthotopic study to your specifications. Contact us today to discuss study design and long-timeline scheduling, or reach out to our team for a customized quotation.

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