DLD-1 Orthotopic Mouse Model Service for Colon Cancer

The DLD-1 orthotopic mouse model represents a well-characterized, KRAS-mutant human colorectal adenocarcinoma platform that recapitulates the chromosomal instability molecular subtype within a physiologically faithful colonic microenvironment, enabling robust evaluation of targeted therapies, combination regimens, and resistance mechanisms. Alfa Cytology constructs and manages this orthotopic xenograft system with authenticated DLD-1 cell stocks, standardized cecal wall implantation protocols in immunodeficient hosts, and comprehensive molecular endpoint analysis, delivering translationally relevant datasets for KRAS-driven, microsatellite-stable colorectal malignancies under in vivo conditions.

Overview of DLD-1 Orthotopic Mouse Model for Colon Cancer

The DLD-1 cell line is a human colorectal adenocarcinoma originally established by D.L. Dexter and associates during 1977–1979 from the epithelial tumor tissue of a 67-year-old male patient diagnosed with Dukes' type C colon cancer. Genetically, DLD-1 is classified within the chromosomal instability (CIN) molecular subtype and is microsatellite stable (MSS). The line harbors a heterozygous KRAS activating mutation (G13D, p.Gly13Asp) that drives constitutive MAPK/ERK signaling and confers intrinsic resistance to anti-EGFR therapies such as cetuximab and panitumumab. Additional pathogenic alterations include a truncated adenomatous polyposis coli (APC) protein (codon 1416 frameshift), TP53 missense mutations (S241F, R273H), and activating PIK3CA hotspot mutations (E545K, D549N)—collectively rendering DLD-1 a representative model for the most common molecular subtype of sporadic colorectal carcinoma. The pseudodiploid karyotype with a modal chromosome number of 46 reflects structurally altered but numerically near-diploid genomic architecture, a pattern frequently associated with chromosomal instability in cancer cells.

Fig 1. Immunohistochemical staining of colorectal cancer cell lines. PROK1 protein expression was detected in the cytoplasm of HCT116, HT29, and DLD-1. (Kono, Hiroko, et al., 2023)

Orthotopic implantation of DLD-1 cells into the cecal or colonic wall of immunodeficient mice (athymic nude or NOD-scid strains) reconstructs the native stromal architecture, vascularization, and organ-specific interactions of clinical colorectal cancer. Tumors establish with a documented 100% take rate and typically become palpable within 10–14 days post-implantation, progressing to endpoint volumes over 4–6 weeks. Notably, DLD-1 exhibits limited spontaneous distant metastatic potential in orthotopic settings, attributed to low expression of pro-metastatic factors such as Fascin1. This characteristic renders the model particularly well-suited for evaluating localized tumor growth, stromal interactions, and responses to locoregional and systemic therapies in KRAS-mutant, WNT-activated colorectal cancers, rather than metastasis-focused investigations. The model has been extensively employed to dissect feedback resistance mechanisms in kinase-targeted therapy, evaluate dual-pathway inhibition strategies involving AKT and WNT, and validate apoptotic responses to novel compounds.

Cell Line Information: DLD-1

DLD-1 is one of the most extensively characterized and widely utilized human colorectal adenocarcinoma cell lines in preclinical oncology, distinguished by its defined KRAS-mutant status, APC truncation, and CIN molecular subtype. The table below consolidates its essential biological, genetic, and culture parameters:

Our Services

Alfa Cytology offers a comprehensive DLD-1 orthotopic model service encompassing authenticated cell line banking, surgical cecal wall or colonic wall implantation in immunodeficient hosts, longitudinal tumor monitoring, therapeutic intervention, and multi-parameter endpoint analysis. Our platform is optimized for targeted therapy and combination regimen studies in KRAS-mutant, MSS colorectal cancer, delivering robust, mechanism-informed datasets that advance your preclinical pipeline with scientific rigor.

Workflow of DLD-1 Orthotopic Mouse Model Construction

Establishment of the DLD-1 orthotopic model requires meticulous surgical technique, authenticated human cell line stocks, and immunodeficient host management to achieve consistent engraftment and physiologically relevant tumor growth. The protocol proceeds through the following sequential stages:

1. Cell Expansion and Authentication: DLD-1 cells are propagated in RPMI 1640 with 10% FBS, harvested during logarithmic growth, and authenticated via STR profiling against the human reference. Mycoplasma negativity is confirmed by PCR. Cells are washed, counted by automated hemocytometer, and resuspended in ice-cold PBS at a concentration of 1 × 10⁷ cells/mL for in vitro preparation.
2. Recipient Mouse Preparation: Female athymic nude (BALB/c nu/nu) or NOD-scid mice (6–8 weeks old) are quarantined and acclimated for a minimum of 72 hours. Health status is assessed daily, and any mice displaying abnormal behavior or weight loss are excluded prior to cell implantation.
3. Matrigel Suspension Preparation: The cell suspension is mixed 1:1 by volume with ice-cold Matrigel Basement Membrane Matrix immediately prior to injection. Matrigel provides an extracellular scaffold that supports initial tumor colonization within the cecal wall and enhances engraftment consistency.
4. Surgical Cecal Wall Implantation: Under general anesthesia, a midline laparotomy (~10 mm) is performed, and the cecum is exteriorized onto sterile gauze moistened with PBS. A small cecotomy is made at the cecal tip, and 100 µL of the Matrigel-cell suspension (1 × 10⁶ cells) is injected submucosally into the cecal wall from the luminal side using a 27-gauge needle. The cecotomy is closed with interrupted 5-0 silk sutures in Lembert fashion, the cecum is returned to the abdominal cavity, and the abdominal wall is closed in two layers.
5. Postoperative Care and Monitoring: Mice receive sustained-release buprenorphine for analgesia and are monitored closely during the 48-hour perioperative period for signs of pain, dehydration, or intestinal obstruction. Body weights are recorded daily for the first week and twice weekly thereafter.
6. Tumor Monitoring and Cohort Randomization: Tumor establishment is assessed by palpation of the abdominal cavity beginning on day 7–10 post-surgery. Once tumors reach 50–100 mm³, mice are randomized into treatment cohorts based on tumor volume to ensure balanced baseline distributions across all experimental arms.
7. Therapeutic Intervention and Longitudinal Assessment: Test compounds are administered according to the predefined regimen (dose, route, frequency, and duration). Tumor dimensions are measured twice weekly with digital calipers, and body weights are recorded concurrently to monitor treatment tolerability. Optional high-frequency ultrasound imaging can be incorporated for non-invasive volumetric assessment.
8. Endpoint Necropsy and Comprehensive Analysis: Upon reaching study endpoints (tumor volume ~2,000 mm³, humane moribund criteria, or scheduled termination), mice are euthanized. The primary cecal tumor is excised, weighed, and photographed. The liver, lungs, and mesenteric lymph nodes are harvested for metastasis assessment. Tumor tissues are fixed for H&E and immunohistochemistry (CD31, Ki-67, cleaved caspase-3, phospho-ERK, phospho-AKT), or snap-frozen for Western blot, qPCR, and RNA-seq.

Fig 2. DLD-1 Orthotopic Mouse Model construction workflow.

Case Study-DLD-1 Orthotopic Mouse Model Development

In a preclinical program investigating feedback resistance mechanisms in KRAS-mutant colorectal cancer, the DLD-1 orthotopic model was employed to evaluate the efficacy of a dual-pathway inhibition strategy combining a next-generation mTOR kinase inhibitor with an EGFR tyrosine kinase inhibitor. Following surgical cecal wall implantation and postoperative recovery, tumor-bearing mice were randomized into treatment arms receiving the mTOR inhibitor alone, the EGFR inhibitor alone, the combination regimen, or vehicle control. Longitudinal tumor monitoring revealed that the mTOR monotherapy produced only transient growth inhibition, with tumor volumes rebounding after initial suppression—consistent with documented EGFR-mediated feedback reactivation of mTORC2 signaling. In contrast, the combination cohort exhibited sustained and significantly greater tumor growth suppression throughout the study duration. Endpoint histopathological analysis demonstrated reduced phospho-S6 and phospho-AKT staining in the combination-treated tumors, alongside increased cleaved caspase-3 and PARP fragmentation indicative of enhanced apoptosis. These findings illustrate the model's utility in dissecting kinase inhibitor resistance mechanisms, validating dual-targeting hypotheses, and informing combination regimen optimization for KRAS-mutant, EGFR-expressing colorectal cancers in the preclinical space.

Why Choose Alfa Cytology?

Partnering with Alfa Cytology for your DLD-1 orthotopic colon cancer study ensures access to a scientifically rigorous, quality-focused CRO platform with deep expertise in human xenograft model construction and targeted therapy evaluation. Our core differentiators include:

• Authenticated DLD-1 cell banking with documented STR profiling, mycoplasma clearance, and low-passage expansion to preserve genetic stability and KRAS/APC/PIK3CA mutation fidelity across study cohorts.
• Skilled surgical team experienced in cecal wall orthotopic implantation with documented 100% take rates and low perioperative mortality, ensuring robust statistical power and reproducible tumor growth kinetics.
• In-house histopathology and molecular profiling capabilities featuring validated antibody panels for phospho-ERK, phospho-AKT, phospho-S6, Ki-67, cleaved caspase-3, and CD31 vascular markers.
• Flexible combination study designs supporting MEK, PI3K, mTOR, EGFR, and WNT pathway inhibitors with customizable dosing schedules, sequential treatment arms, and pharmacodynamic sampling timepoints.
• Integrated resistance mechanism assessment encompassing longitudinal tumor growth curve analysis, rebound detection, and molecular validation of feedback loop reactivation via Western blot and RT-qPCR.
• Dedicated project scientists providing weekly progress updates, interim data reviews, and collaborative interpretation of pharmacodynamic and efficacy endpoints to align preclinical outcomes with your clinical development strategy.

Contact Us

If your preclinical pipeline demands a KRAS-mutant, MSS colorectal cancer model that faithfully recapitulates the in vivo tumor microenvironment of the most common molecular subtype, we invite you to reach out to us to discuss how Alfa Cytology can design and execute a tailored DLD-1 orthotopic study aligned with your therapeutic hypotheses. From surgical implantation and targeted therapy dosing through resistance mechanism analysis and comprehensive endpoint profiling, our team is committed to delivering translationally relevant data that advance your colorectal cancer drug development program. Contact us today to initiate your project and leverage our specialized expertise in KRAS-mutant colorectal cancer preclinical research.

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