SK-MEL-2 / SK-MEL-2-luc Orthotopic Mouse Model Service for Melanoma

The SK-MEL-2 / SK-MEL-2-luc orthotopic mouse model establishes an NRAS Q61R-mutant, BRAF wild-type human melanoma within the skin of immunodeficient mice — one of the original 127 human tumor lines proven to form malignant melanoma in nude mice, and a member of the NCI-60 panel whose public pharmacogenomic data spans four decades. Alfa Cytology delivers this MSK-heritage line with authenticated banking, intradermal orthotopic or subcutaneous implantation configurations, genotype-verified NRAS/TP53 status on every batch, and quantitative luciferase imaging in vivo, so your RAS-pathway, DNA-damage, and next-generation melanoma strategies are evaluated on the reference substrate for the NRAS-mutant subtype — the melanoma category that still lacks an approved targeted therapy.

Overview of SK-MEL-2 / SK-MEL-2-luc Orthotopic Mouse Model for Melanoma

SK-MEL-2 was established in 1972 at Memorial Sloan Kettering by Germain Trempe and Lloyd Old from a metastatic lesion on the thigh of a 60-year-old Caucasian man with malignant melanoma, and it entered history as one of the 127 cultured human tumor cell lines that Fogh and colleagues demonstrated to produce tumors in nude mice in their landmark 1977 Journal of the National Cancer Institute report — the foundational validation of the human tumor xenograft concept itself. The line is an adherent, polygonal epithelial cell with a 32-hour doubling time, a complex hypodiploid-to-hypertetraploid karyotype, and a genotype that defines one of melanoma's most treatment-resistant subtypes: homozygous NRAS Q61R mutation with wild-type BRAF and heterozygous TP53 p.Gly245Ser. As a member of the NCI-60 panel, every drug sensitivity comparison a program might want is anchored to public datasets generated over decades of screening — an unusual depth of reference for any single model.

Fig 1. Intracranial luciferase-tagged SK-MEL-2 xenograft (NRAS Q61R) in mice treated with vehicle, trametinib, avutometinib or NST-628, showing representative whole-head bioluminescence at D0/D7/D14 and quantified relative tumor growth curves where NST-628 (3 mg/kg q.d. or 1.5 mg/kg b.i.d.) drove tumor regressions while trametinib and avutometinib only modestly delayed intracranial SK-MEL-2 tumor growth. (Ryan, Meagan B., et al., 2024)

In vivo, SK-MEL-2 xenografts in nude mice form malignant melanoma, and the model has carried notable RAS-pathway pharmacology: the dual RAF/MEK inhibitor CH5126766 (RO5126766) blocked tumor growth in SK-MEL-2 xenografts, validating this RAS-mutant melanoma as a testbed for the pathway-clamp strategies that KRAS- and NRAS-driven tumors demand. NRAS-mutant melanoma remains a category with no approved targeted therapy — immunotherapy-dependent and historically chemotherapy-refractory — which makes validated NRAS lines like SK-MEL-2 strategically precious. Placed orthotopically by intradermal implantation, or subcutaneously as the benchmark configuration, SK-MEL-2-luc adds quantitative whole-body bioluminescence in vivo for imaging-guided staging and combination designs, while melanoma-marker histopathology (S100, tyrosinase, gp100) and metastasis screening at endpoint connect xenograft behavior to human disease biology.

Cell Line Information: SK-MEL-2 / SK-MEL-2-luc

SK-MEL-2 (ATCC HTB-68; RRID CVCL_0069) grows in vitro as an adherent polygonal monolayer in Eagle's MEM (or DMEM) with 10% fetal bovine serum, doubling every 32 hours, and it is annotated at biosafety level 1 with blood-type A, Rh-positive marker expression recorded in its characterization history. Its karyotype — hypodiploid to hypertetraploid with dicentrics, secondary constrictions, and large telocentric markers — reflects the cytogenetic chaos typical of advanced melanoma. The SK-MEL-2-luc derivative adds firefly luciferase for quantitative imaging in vivo, with monoclonal selection of high-signal clones in vitro recommended for uniform bioluminescence.

Our Services

NRAS-mutant melanoma is where generic melanoma panels fail most often: BRAF-centric models tell you nothing about the subtype that lacks approved targeted options. Alfa Cytology runs SK-MEL-2 programs with batch-level NRAS Q61R and TP53 G245S verification, both intradermal and subcutaneous configurations, monoclonal luciferase banks for quantitative imaging in vivo, and endpoint panels — S100, tyrosinase, gp100 immunohistochemistry and metastasis screening — that connect xenograft response to human melanoma biology, with NCI-60 public datasets available as an external reference frame for every comparison your program will face.

Workflow of SK-MEL-2 / SK-MEL-2-luc Orthotopic Mouse Model Construction

SK-MEL-2 model construction follows standard human melanoma xenograft practice, strengthened by genotype verification and imaging options. The workflow below covers construction from authenticated cell preparation through melanoma-marker endpoints.

1. Cell Expansion and Genotype Verification: SK-MEL-2 or SK-MEL-2-luc cells are expanded in vitro in EMEM or DMEM + 10% FBS to the logarithmic phase; batches are confirmed mycoplasma-negative, STR-authenticated, and verified for NRAS Q61R, BRAF wild-type, and TP53 G245S status, with monoclonal luciferase populations confirmed for tagged lines.
2. Host Selection and Acclimatization: BALB/c nude or NSG mice, typically 5–7 weeks of age, are acclimatized for approximately one week under SPF conditions and health-screened before assignment to study cohorts.
3. Inoculum Preparation: Cells are detached, washed in PBS, and resuspended at the working concentration; standard challenges are 3–10 × 10⁶ cells in ~100 µL for subcutaneous implantation or 25–50 µL for intradermal delivery.
4. Subcutaneous or Intradermal Implantation: For the benchmark configuration, cells are implanted subcutaneously into the flank; for the orthotopic configuration, the inoculum is injected intradermally into shaved dorsal skin using a fine needle to form a dermal depot — both sites recorded for kinetics.
5. Monitoring: Tumors are measured by caliper two to three times weekly; SK-MEL-2-luc cohorts are imaged weekly by bioluminescence in vivo after D-luciferin administration, and body weight is recorded throughout.
6. Randomization and Treatment: Animals are randomized once tumors reach predefined volumes (commonly 100–200 mm³); test agents are dosed on study-defined schedules — RAS-pathway clamps, DNA-damage agents, or immunotherapy combinations — with body weight and clinical condition monitored as tolerability readouts.
7. Survival Follow-Up: Animals are followed to standard tumor-burden euthanasia criteria with Kaplan–Meier analysis, and combination designs extend observation for durability assessment.
8. Endpoint Analysis and Reporting: At termination, tumors are excised and weighed; lungs, lymph nodes, and liver are screened for metastatic spread; tissues are processed for H&E and melanoma-marker immunohistochemistry (S100, tyrosinase, gp100), phospho-ERK and phospho-AKT pathway staining where RAS-pathway engagement is a study endpoint, ex vivo bioluminescence maps signal distribution in luciferase studies, and tumor-growth, imaging, and pathology data are compiled into the final report.

Fig 2. SK-MEL-2 / SK-MEL-2-luc orthotopic mouse model construction workflow.

Case Study-SK-MEL-2 / SK-MEL-2-luc Orthotopic Mouse Model Development

SK-MEL-2 xenografts carry one of the longest documented pedigrees in human melanoma research — from the 1977 nude-mouse validation cohort to modern RAS-pathway inhibitor studies — and the platform has supported a broad range of Alfa Cytology client programs targeting the NRAS-mutant subtype. Across these programs, readouts have combined caliper or bioluminescence kinetics in vivo, pathway-engagement immunohistochemistry, and metastasis screening at necropsy. Anonymized case summaries and representative deliverable formats are available on request.

Why Choose Alfa Cytology?

SK-MEL-2's value lies in scarcity: validated NRAS-mutant melanoma substrates are few, and decades of NCI-60 reference data raise the bar for how carefully they must be run. Alfa Cytology meets that bar.

• A homozygous NRAS Q61R, BRAF wild-type genotype — the subtype with no approved targeted therapy — verified by sequencing on every study batch.
• Foundational xenograft pedigree: one of the original 127 human tumor lines validated in nude mice (Fogh, JNCI 1977).
• NCI-60 panel membership with four decades of public drug-sensitivity data anchoring every comparison.
• A published in vivo benchmark — dual RAF/MEK inhibition blocking tumor growth (CH5126766) — available as a reference arm.
• Batch-level TP53 G245S verification for DNA-damage and p53-pathway study integrity.
• Flexible configurations spanning subcutaneous benchmarking and intradermal orthotopic implantation within one protocol.
• Melanoma-marker endpoint panels (S100, tyrosinase, gp100) with phospho-ERK/AKT pathway staining options.

Contact Us

If your program targets NRAS-mutant melanoma — the subtype still waiting for its first approved targeted therapy — the SK-MEL-2 / SK-MEL-2-luc orthotopic model offers the reference genotype, the NCI-60 data pedigree, and the in vivo benchmarks to build on. Alfa Cytology is ready to configure your study. Reach out to us to review implantation options, genotype verification, and pathway endpoint panels, and receive a customized study quotation today.

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