CT26-luc Orthotopic Mouse Model Service for Colon Cancer

The CT26-luc orthotopic mouse model offers a fully immunocompetent, bioluminescent syngeneic platform for colorectal cancer, enabling longitudinal tumor monitoring within a physiologically authentic cecal microenvironment while preserving intact host immune surveillance. Alfa Cytology specializes in constructing this high-fidelity orthotopic allograft system, combining luciferase-reporter CT26.WT cells with precision surgical implantation into the murine cecum to deliver reproducible, quantifiable data on tumor growth kinetics, metastatic spread, and immuno-therapeutic response for your preclinical colon cancer pipeline.

Overview of CT26-luc Orthotopic Mouse Model for Colon Cancer

The CT26 cell line was originally established from an N-nitroso-N-methylurethane (NMU) induced undifferentiated colon adenocarcinoma arising in a BALB/c mouse. As a murine-derived syngeneic model, CT26 carries the H-2d MHC haplotype and is fully compatible with immunocompetent BALB/c hosts, distinguishing it fundamentally from human xenograft systems that require immunodeficient recipients. Molecularly, CT26 is characterized by homozygous Kras-G12D oncogenic mutation, homozygous deletion of Cdkn2a, wild-type Trp53 and Apc loci, and microsatellite stable (MSS) status—molecular features that align with the consensus molecular subtype 2 (CMS2) profile observed in approximately 85% of human colorectal cancers. When stably transfected with firefly luciferase, CT26-luc emits constitutive bioluminescent signals exceeding 100,000 photons per cell per second, permitting sensitive, non-invasive quantification of tumor burden in vivo via substrate-dependent IVIS imaging.

Fig 1. Integrated bioluminescence and micro-computed tomography imaging workflow for monitoring 5-fluorouracil therapeutic response in CT26 orthotopic colorectal cancer metastasis models, enabling simultaneous assessment of primary tumor regression and distant metastatic lesion detection. (Song, Wei-Jie, et al., 2023)

Orthotopic engraftment of CT26-luc into the cecal wall of syngeneic BALB/c mice replicates the anatomical site of origin, fostering tumor-stromal crosstalk, physiologic vascularization patterns, and organ-specific metastatic tropism that subcutaneous models cannot recapitulate. The model demonstrates robust engraftment exceeding 95%, with a bioluminescence-derived tumor doubling time of approximately 1.5 days and spontaneous dissemination to the liver, abdominal wall, and regional lymph nodes. Because the host immune system remains functionally intact, the CT26-luc orthotopic platform is uniquely suited for evaluating immune checkpoint inhibitors, adoptive cell therapies, oncolytic viruses, tumor vaccines, and combination regimens that modulate the tumor immune microenvironment—offering translational relevance that bridges murine immunology and human colorectal cancer biology.

Cell Line Information: CT26-luc

The CT26-luc reporter line is a luciferase-engineered derivative of the parental CT26.WT murine colon carcinoma cell line. The following table presents a comprehensive characterization of its biological origin, genetic architecture, and culture specifications:

Our Services

Alfa Cytology delivers comprehensive CT26-luc orthotopic model services tailored for immuno-oncology and targeted therapy programs in colorectal cancer. Our capabilities span luciferase-stable cell bank maintenance, cecal wall surgical implantation with validated engraftment protocols, weekly longitudinal bioluminescence imaging, and detailed terminal immunophenotyping—including flow cytometry of tumor-infiltrating lymphocytes, myeloid-derived suppressor cells, and dendritic cell subsets. We offer flexible study designs accommodating monotherapy, combination arms, and pharmacokinetic sampling, all executed under AAALAC-accredited animal care standards with rigorous data documentation.

Workflow of CT26-luc Orthotopic Mouse Model Construction

Building a reproducible CT26-luc orthotopic colon cancer model demands meticulous attention to cell culture integrity, sterile surgical technique, and calibrated bioluminescence acquisition. Our standardized workflow balances engraftment efficiency with animal welfare, yielding consistent tumor kinetics and metastatic patterns suitable for preclinical therapeutic assessment. The procedure unfolds as follows:

1. Master Cell Bank Revival and Quality Control: CT26-luc cells are recovered from cryopreserved master stocks and expanded under antibiotic-free RPMI 1640 medium. Each production batch is validated for mycoplasma negativity by PCR, mouse STR identity confirmation, and in vitro luciferase functional assay to ensure reporter fidelity before implantation.
2. Pre-Surgical Cell or Tumor Fragment Preparation: Two validated approaches are employed: (A) direct cell injection—log-phase CT26-luc cells are harvested, washed in sterile HBSS, and concentrated to 1–2 x 10⁸ cells/mL for a 10–20 μL cecal wall inoculum; or (B) tumor fragment grafting—subcutaneous CT26-luc tumors are grown in donor mice, excised at ~100 mm³, and aseptically sectioned into 1 mm³ fragments for serosal implantation.
3. Recipient Mouse Preparation and Anesthesia: Syngeneic female BALB/c mice (6–8 weeks, 18–22 g) are acclimatized for 7 days under SPF conditions. On the day of surgery, general anesthesia is induced with 2–3% isoflurane inhalation in oxygen. Mice are positioned in dorsal recumbency, the lower abdomen is shaved and sterilized with povidone-iodine and 70% ethanol, and a sterile surgical drape is applied.
4. Cecal Wall Orthotopic Implantation: A 3–5 mm midline abdominal incision exposes the cecum. For cell injection, a 33-gauge Hamilton micro-syringe delivers the suspension into the subserosal muscularis layer of the cecal wall; for fragment grafting, a 1 mm³ tumor piece is sutured onto the serosal surface with 8-0 absorbable sutures. The cecum is gently returned to the peritoneal cavity, and the abdominal wall and skin are closed with 5-0 absorbable sutures or surgical staples.
5. Post-Operative Recovery and Clinical Monitoring: Mice recover on a heated pad until ambulatory. Post-operative analgesia (buprenorphine 0.05–0.1 mg/kg, s.c.) is administered per IACUC guidelines. Animals are monitored daily for wound dehiscence, body weight, food intake, and abdominal distension for 7–10 days. Mice showing signs of severe distress, wound infection, or >20% body weight loss are humanely euthanized per predetermined criteria.
6. Baseline Bioluminescence Imaging and Randomization: Beginning 3–5 days post-implantation, mice receive intraperitoneal D-luciferin (150 mg/kg) and are imaged under isoflurane anesthesia using an IVIS Spectrum system. Mice with confirmed bioluminescent signal are enrolled, and baseline total flux (photons/sec) is recorded. Cohorts are randomized once mean tumor burden reaches 1–5 x 10⁶ photons/sec or when palpable abdominal masses become evident.
7. Therapeutic Dosing and Longitudinal Monitoring: Test articles are administered according to the study protocol—common routes include intraperitoneal, intravenous, oral gavage, or subcutaneous injection. Tumor burden is monitored via bioluminescence imaging twice weekly; body weights and clinical observations are recorded three times weekly. Blood samples may be collected via submandibular or retro-orbital bleed at defined intervals for pharmacokinetic or cytokine analysis.
8. Necropsy, Tumor Harvest, and Multimodal Endpoint Analysis: At study termination, mice are euthanized humanely. The primary cecal tumor is excised, weighed, photographed, and dimensions recorded. Metastatic organs (liver, lung, mesenteric lymph nodes, peritoneum) are inspected macroscopically and harvested. Tissues are fixed in 10% neutral buffered formalin for H&E histology, or snap-frozen for molecular analysis. Immunohistochemistry for Ki-67, CD31, F4/80, CD8, and PD-L1, plus flow cytometry of dissociated tumor infiltrates, provides mechanistic insight into treatment effects on proliferation, angiogenesis, and immune modulation.

Fig 2. CT26-luc Orthotopic Mouse Model construction workflow.

Case Study-CT26-luc Orthotopic Mouse Model Development

In a recent preclinical program, the CT26-luc orthotopic model was deployed to evaluate the efficacy of a novel bispecific antibody engaging both PD-1 and VEGF pathways in combination with FOLFOX chemotherapy. CT26-luc cells were injected into the cecal wall of BALB/c mice, with tumor engraftment confirmed by bioluminescence within 5–7 days. Following randomization at a standardized photon flux threshold, mice received weekly intraperitoneal dosing over a 3-week treatment window. The bispecific combination arm exhibited marked suppression of bioluminescent signal relative to vehicle and FOLFOX monotherapy groups, accompanied by reduced primary tumor mass at necropsy and diminished hepatic metastatic nodules. Flow cytometric analysis of dissociated tumor tissue revealed elevated CD8+ cytotoxic T lymphocyte infiltration and reduced myeloid-derived suppressor cell frequency in the combination cohort, corroborating the imaging data with mechanistic immune correlates. These observations underscore how the CT26-luc orthotopic platform integrates real-time tumor burden quantification with deep immune profiling to deconvolute combination therapy activity in a single in vivo study.

Why Choose Alfa Cytology?

Preclinical success in colorectal cancer immuno-oncology hinges on model fidelity, immune contexture preservation, and analytical depth. Alfa Cytology structures its CT26-luc orthotopic service around these pillars, offering distinct advantages that accelerate your program from concept to IND-enabling package:

• We operate authenticated, low-passage CT26-luc master and working cell banks with routine mouse STR verification and mycoplasma surveillance, ensuring genetic stability and reporter consistency across every study cohort.
• Our surgical team achieves >95% orthotopic engraftment rates through optimized cecal wall injection and tumor fragment grafting techniques, with rigorous perioperative care that minimizes mortality and morbidity.
• Bioluminescence imaging is performed on calibrated IVIS platforms with locked D-luciferin dosing protocols and automated ROI quantification, delivering photon flux data with inter-study coefficient of variation below 15%.
• The immunocompetent BALB/c host environment is preserved throughout, enabling robust assessment of checkpoint inhibitors, cytokine therapies, cellular immunotherapies, and stromal-targeting agents in a fully functional immune landscape.
• We offer integrated immune profiling as a standard deliverable, including multiparameter flow cytometry of tumor, spleen, and draining lymph node samples, plus multiplex cytokine analysis of serum and tumor homogenates.
• Study protocols are modular and scalable—we support single-agent screens, complex combination matrices with dose-escalation arms, and pharmacokinetic bridging studies, with GLP-compliant documentation available upon request.

Contact Us

If your colorectal cancer research program demands an immunocompetent orthotopic model with real-time bioluminescent readouts and deep immune phenotyping capabilities, we invite you to reach out to us for a confidential consultation. The scientists at Alfa Cytology are ready to architect a CT26-luc orthotopic study that aligns with your immuno-oncology hypotheses, compound characteristics, and regulatory milestones. Contact us now to obtain a customized proposal, feasibility assessment, and projected timeline—let us translate your therapeutic vision into rigorous, publication-quality preclinical data.

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