MKN-45 / MKN-45-luc Orthotopic Mouse Model Service for Gastric Cancer

The MKN-45 / MKN-45-luc orthotopic mouse model implants a c-MET-amplified, diffuse-type human gastric carcinoma into the stomach wall, where it recreates not only local tumor growth but also the peritoneal dissemination that is the dominant route of spread in advanced gastric cancer. Alfa Cytology develops this model with a tunable design — implantation cell number can be adjusted to dial metastatic burden up or down — and supports it with luciferase-based monitoring in vivo, peritoneal cavity assessment, and full histopathological characterization, delivering preclinical datasets built around the questions that matter most to your program.

Overview of MKN-45 / MKN-45-luc Orthotopic Mouse Model for Gastric Cancer

MKN-45 is a classic diffuse-type gastric cancer line established in 1981 from the liver metastasis of a 62-year-old Japanese female patient with poorly differentiated adenocarcinoma. When placed orthotopically into the sub-serosal layer of the stomach in immunodeficient mice, MKN-45 cells develop primary gastric tumors with predictable, dose-dependent kinetics: studies inoculating 5 × 10⁴, 5 × 10⁵, or 5 × 10⁶ cells have shown that both tumor growth and the incidence of metastasis scale with the number of implanted cells, with dissemination occurring predominantly in the peritoneal and pelvic cavities and lung lesions emerging in the higher-dose cohorts by the fourth week. This controllability is a distinctive practical advantage — the same cell line can be configured as a primary-tumor-focused model or as an aggressive peritoneal carcinomatosis model, simply by adjusting the inoculum.

Fig 1. Establishment of MKN-45 orthotopic xenograft model by transplanting subcutaneous tumor fragments from donor mice. (Wang, Chao, et al., 2024)

In longitudinal studies, luciferase-tagged MKN-45 (MKN-45-luc) has demonstrated moderate metastatic potential with minimal invasion through the stomach wall during the first two weeks, followed by progressive invasion and dissemination — a time course that leaves a clear window for evaluating anti-invasive and anti-metastatic interventions before extensive spread occurs. Orthotopic MKN-45 xenografts in NSG mice develop stomach tumors with lung metastases in 100% of recipients and liver and peritoneal metastases in 50–80% of animals, and the model has been used to demonstrate the anti-dissemination activity of PI3K-pathway inhibition. With firefly luciferase enabling repeated, non-invasive quantification in vivo, and straightforward expansion in vitro supporting either cell-suspension injection or tumor fragment implantation, the MKN-45 / MKN-45-luc orthotopic system is a flexible workhorse for evaluating cytotoxic agents, c-MET and PI3K-pathway inhibitors, biologics, and anti-peritoneal-dissemination strategies in gastric cancer.

Cell Line Information: MKN-45 / MKN-45-luc

MKN-45 was established by Motoyama and colleagues in Japan in 1981 from the liver metastasis of a female patient with poorly differentiated gastric adenocarcinoma of the diffuse histological type. It is one of the most molecularly annotated gastric cancer lines available: c-MET is amplified, TP53 remains wild-type, and CDH1 (E-cadherin) function is defective, while homozygous deletions of CDKN2A (p16^INK4a) and CDKN2B (p15^INK4b) mirror events seen in patient tumors. Genomically, the line is microsatellite-stable, EBV-negative, and classifies within the chromosomal instability (CIN) subtype of The Cancer Genome Atlas gastric cancer classification. A high-potential peritoneal dissemination derivative, MKN-45P, secretes elevated levels of IL-6, IL-8, VEGF, and MMP-2 and adheres more strongly to fibronectin, making the MKN-45 family uniquely suited to dissemination research. MKN-45-luc adds constitutive firefly luciferase expression for sensitive, quantitative bioluminescence imaging in vivo.

Our Services

Because the MKN-45 system rewards careful titration — of cell number, implantation route, and observation schedule — Alfa Cytology approaches each study as a design exercise rather than a routine procedure. Our scientists help you select the inoculum and host strain that match your therapeutic question, then execute implantation, imaging, dosing, and peritoneal endpoint analysis as one integrated plan, so the model performs exactly as your program needs it to.

Workflow of MKN-45 / MKN-45-luc Orthotopic Mouse Model Construction

MKN-45 orthotopic models can be built by direct injection of a cell suspension or by implantation of donor-derived tumor fragments, and each route has been described in detail in the literature. The workflow below covers the standard construction and study-execution process, with the flexibility to adjust inoculum size to the desired metastatic intensity.

1. Cell Expansion and Quality Control: MKN-45 or MKN-45-luc cells are cultured in vitro to the logarithmic phase; each preparation is confirmed mycoplasma-negative, authenticated, and assessed for viability, with luciferase expression verified for tagged cells before release.
2. Donor Tumor Generation (Fragment Route): For fragment implantation, 5 × 10⁶ MKN-45-luc cells are injected subcutaneously into donor nude mice; two to three weeks later, tumors of approximately 1 cm³ are harvested and the viable peripheral tissue — excluding the necrotic core — is minced into ~1 mm³ fragments.
3. Host Preparation and Anesthesia: Five- to six-week-old female BALB/c nude or NSG mice are acclimatized and health-screened; anesthesia is induced intraperitoneally with ketamine (100 mg/kg, with xylazine as indicated), and the left abdomen is disinfected before a 5–10 mm incision opens the skin and peritoneum.
4. Sub-serosal Implantation: The stomach is exteriorized, a 1–2 mm serosal incision is made at the gastric corpus (or at the corpus–antrum junction for cell suspensions), and a sub-serosal pocket is widened with microsurgical scissors; one tumor fragment is placed in the pocket — or a suspension of 5 × 10⁴ to 5 × 10⁶ cells in 20 µL PBS is injected through a 30 G needle — and the entry is sealed with a gelatin sponge and tissue adhesive.
5. Closure and Recovery: The stomach is returned to the abdominal cavity and the abdominal wall and skin are closed with 4–0 absorbable sutures; animals recover on a warming platform with postoperative analgesia and are monitored daily until fully ambulatory.
6. Longitudinal Bioluminescence Monitoring: Tumor growth and early dissemination are tracked by weekly or twice-weekly bioluminescence imaging in vivo after D-luciferin injection, capturing the invasion window of the first two weeks and the subsequent metastatic phase without serial sacrifice.
7. Treatment and Randomization: Once tumors reach the predefined bioluminescence threshold, animals are randomized into vehicle and treatment arms, and test agents — administered on client-specified schedules — are dosed with body weight and health status recorded throughout the study.
8. Endpoint Analysis and Reporting: At termination, the primary gastric tumor is excised, measured, and weighed; the peritoneal and pelvic cavities are inspected for carcinomatosis and ascites, and the lung, liver, and spleen are imaged ex vivo and sectioned for H&E and human-specific marker staining (e.g., HLA) to confirm metastatic origin; all imaging and pathology data are compiled into the final report.

Fig 2. MKN-45 / MKN-45-luc orthotopic mouse model construction workflow.

Case Study-MKN-45 / MKN-45-luc Orthotopic Mouse Model Development

MKN-45-based orthotopic xenografts have been applied across a wide range of preclinical questions, from benchmarking kinase inhibitors to modeling peritoneal carcinomatosis and testing anti-dissemination strategies. Alfa Cytology has supported client programs using this platform for cytotoxic compounds, targeted agents against amplified c-MET and PI3K signaling, and biologic therapies, with study readouts that pair longitudinal bioluminescence imaging in vivo with detailed mapping of peritoneal and distant metastases at endpoint. Representative, anonymized case summaries can be shared on request to illustrate typical timelines and deliverable formats.

Why Choose Alfa Cytology?

The value of the MKN-45 system lies in its flexibility, and capturing that flexibility requires a CRO that treats model parameters as design variables rather than fixed defaults. Alfa Cytology brings precisely that mindset, backed by hands-on experience with both cell-suspension and fragment implantation routes.

• Tunable metastatic intensity through controlled adjustment of implantation cell number, from localized primary tumors to full peritoneal carcinomatosis.
• Two validated implantation routes — direct sub-serosal injection and donor-derived fragment placement — selectable to match study goals and timelines.
• Longitudinal bioluminescence imaging in vivo that captures the early invasion window and follows dissemination without serial sacrifice.
• A genetically annotated, c-MET-amplified diffuse-type tumor aligned with the TCGA chromosomal instability subtype for biomarker-driven studies.
• Dedicated peritoneal endpoint expertise, including carcinomatosis scoring, ascites assessment, and ex vivo organ imaging.
• Histopathology workflows using human-specific markers (e.g., HLA) to rigorously confirm the human origin of metastatic lesions.
• IACUC-compliant surgery, husbandry, and perioperative care throughout every study.

Contact Us

Whether your goal is primary tumor efficacy or a faithful peritoneal dissemination model, Alfa Cytology can configure the MKN-45 / MKN-45-luc orthotopic platform to fit. Reach out to us to discuss your study design, request a feasibility assessment and quotation, or arrange a consultation — we are ready to help you generate the evidence your next decision requires.

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