HCT-15 Orthotopic Mouse Model Service for Colon Cancer

The HCT-15 orthotopic mouse model captures a KRAS^G13D-driven, microsatellite-instability-high human colorectal adenocarcinoma within the murine cecal wall, offering a preclinical platform that preserves the anatomical site, stromal architecture, and metastatic potential of advanced-stage colon cancer for rigorous therapeutic evaluation. Alfa Cytology constructs this NCI-60 panel-derived orthotopic xenograft with authenticated cell line stewardship, precision surgical implantation into the cecal mesenteric triangle, and terminal multimodal histopathological analysis, enabling robust assessment of KRAS-targeted agents, PI3K pathway inhibitors, and combination regimens in a physiologically faithful tumor microenvironment.

Overview of HCT-15 Orthotopic Mouse Model for Colon Cancer

The HCT-15 cell line was originally established from a primary colorectal adenocarcinoma classified as Dukes type C, isolated from a 67-year-old male patient. It is a member of the prestigious NCI-60 cancer cell line panel, which has served as the cornerstone of the National Cancer Institute's anticancer drug screening program for decades. Genetically, HCT-15 is defined by a heterozygous KRAS^G13D activating mutation that drives constitutive MAPK signaling, coupled with heterozygous TP53 mutations (p.Ser241Phe and a splice acceptor variant) that abrogate p53 tumor suppressor function. Additionally, the line harbors heterozygous PIK3CA activating mutations (p.Glu545Lys and p.Asp549Asn) that converge with KRAS signaling to hyperactivate the PI3K/AKT/mTOR axis. Critically, HCT-15 is classified as microsatellite instability-high (MSI-H), a molecular phenotype associated with defective mismatch repair, elevated neoantigen burden, and distinct clinical behavior that sets it apart from microsatellite-stable counterparts. The near-diploid karyotype (46, XY) with characteristic translocations t(8;17)(p23;q21) and inv(11)(p15.3q13.1) further distinguishes its cytogenetic identity.

Fig 1. HCT15-based orthotopic colorectal cancer xenograft established by cecal implantation, demonstrating local tumor nodule formation and histopathological characteristics of the resulting intestinal tumors. (Zheng, Can‐Can, et al., 2022)

When established as an orthotopic xenograft within the cecal wall of immunodeficient mice, HCT-15 recapitulates the serosal-submucosal tumor invasion patterns and mesenteric lymphatic spread characteristic of human colorectal carcinoma progression. Implantation into the cecal mesenteric triangle—where the colonic wall lacks serosal covering and vasculature converges toward the portal venous system—promotes tumor angiogenesis, regional lymph node involvement, and hematogenous metastasis to the liver. Unlike subcutaneous models that grow in an ectopic stromal context, the orthotopic HCT-15 system preserves physiologic drug distribution, tumor-stromal crosstalk, and immune-depleted microenvironmental cues relevant to human disease. This makes the model particularly valuable for evaluating KRAS^G13D-directed therapeutics, PI3K/AKT pathway inhibitors, DNA damage response modulators, and combination strategies that exploit the MSI-H phenotype in a preclinical setting where anatomical fidelity directly informs translational relevance.

Cell Line Information: HCT-15

HCT-15 is a well-characterized human colorectal adenocarcinoma cell line with a distinctive molecular signature encompassing KRAS activation, TP53 loss, PI3K pathway dysregulation, and MSI-H status. The following table presents a comprehensive summary of its biological origin, genetic architecture, and culture specifications:

Our Services

Alfa Cytology provides end-to-end HCT-15 orthotopic model services spanning authenticated NCI-60 panel cell bank maintenance, cecal wall surgical implantation via validated direct injection or tumor fragment grafting techniques, longitudinal tumor monitoring by caliper or imaging modalities, and terminal comprehensive endpoint analysis. Our capabilities include KRAS^G13D allele-specific validation, PI3K pathway biomarker assessment, mismatch repair deficiency characterization, and MSI-H phenotyping to ensure molecular fidelity. We support single-agent efficacy studies, combination matrices with dose-escalation arms, and pharmacokinetic bridging investigations, all executed under AAALAC-accredited animal care standards with rigorous data documentation and GLP-compliant reporting upon request.

Workflow of HCT-15 Orthotopic Mouse Model Construction

Construction of the HCT-15 orthotopic colon cancer model demands meticulous coordination between cell culture quality assurance, sterile surgical technique, and standardized endpoint harvesting. Our protocol is calibrated for consistent engraftment, minimal perioperative mortality, and robust metastatic readouts that support KRAS-directed and MSI-H-focused therapeutic assessment. The workflow proceeds as follows:

1. Cell Line Authentication and Master Bank Expansion: HCT-15 master stocks are revived and expanded in antibiotic-free RPMI 1640 medium under standardized conditions. Each production batch undergoes STR profiling against the ATCC reference database, mycoplasma PCR screening, and in vitro KRAS^G13D allele-specific validation to confirm oncogenic driver expression prior to surgical use.
2. Pre-Implantation Cell or Tumor Fragment Preparation: Two validated engraftment routes are prepared. Route A (direct cell injection): logarithmic-phase HCT-15 cells are harvested with 0.05% trypsin-EDTA, washed twice in sterile PBS, and resuspended at 1–2 x 10⁷ cells/mL in ice-cold PBS or PBS/Matrigel (1:1 v/v) for a 30 μL cecal wall inoculum. Route B (tumor fragment grafting): subcutaneous donor tumors are grown in nude mice, excised at ~100–150 mm³, necrotic tissue is trimmed, and fragments are sectioned to 0.15 mg pieces with weight verified on a precision microbalance (±0.05 mg deviation).
3. Recipient Mouse Preparation and Anesthesia: Female athymic nude mice (BALB/c nu/nu, 6–8 weeks, 18–22 g) are acclimated for 7 days under SPF barrier conditions. On the procedure day, general anesthesia is induced with 1–2% isoflurane in medical oxygen via nose cone. The ventral abdomen is shaved, cleansed sequentially with povidone-iodine and 70% ethanol, and draped sterilely.
4. Cecal Mesenteric Triangle Orthotopic Implantation: A 3–5 mm lower midline laparotomy exposes the cecum. For Route A, a 30-gauge Hamilton micro-syringe delivers 1 x 10⁶ cells in 30 μL PBS/Matrigel into the subserosal muscularis of the cecal mesenteric triangle, where the colonic wall lacks serosal covering and vascular ingress facilitates engraftment. For Route B, a 0.15 mg tumor fragment is positioned on the cecal serosa and secured with 8-0 absorbable sutures or a biocompatible tissue adhesive (~10 μL, drying 10–15 s). The cecum is 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 Surveillance: Mice recover on a heated pad until fully ambulatory. Post-operative analgesia (buprenorphine 0.05–0.1 mg/kg, s.c.) is administered per IACUC guidelines. Daily monitoring for 7–10 days assesses wound integrity, body weight, food intake, and abdominal distension. Humane endpoints include >20% body weight loss, wound dehiscence, or signs of severe distress.
6. Tumor Establishment Monitoring and Cohort Randomization: Tumor engraftment is confirmed by palpable abdominal mass beginning 7–10 days post-implantation. Tumor dimensions are measured twice weekly by digital caliper (length x width² x 0.5 = mm³). Mice with confirmed tumors are enrolled and randomized into treatment cohorts once mean tumor burden reaches a predefined threshold (e.g., palpable mass ~75–125 mm³, typically Day 13–18).
7. Therapeutic Intervention and In-Life Assessment: Test articles are administered per protocol via oral gavage, intravenous, intraperitoneal, or subcutaneous routes. Tumor dimensions and body weights are recorded twice weekly; clinical observations are documented three times weekly. Blood samples may be collected via submandibular bleed for pharmacokinetic analysis, CEA biomarker quantification, or circulating tumor DNA assessment at designated intervals.
8. Necropsy, Tumor Harvest, and Multimodal Endpoint Analysis: At study termination, mice are humanely euthanized. The primary cecal tumor is excised, weighed, photographed, and dimensions recorded. The abdominal cavity is inspected macroscopically for peritoneal carcinomatosis. Metastatic target organs (liver, lung, spleen, mesenteric lymph nodes, diaphragm) are harvested. Tissues are fixed in 10% neutral buffered formalin for H&E histology, or snap-frozen in liquid nitrogen for molecular analysis. Immunohistochemistry for Ki-67, cleaved caspase-3, CD31, KRASG13D, phospho-ERK1/2, phospho-AKT, and MLH1/MSH2 provides mechanistic insight into proliferation, apoptosis, angiogenesis, MAPK/PI3K pathway suppression, and mismatch repair status.

Fig 2. HCT-15 Orthotopic Mouse Model construction workflow.

Case Study-HCT-15 Orthotopic Mouse Model Development

In a recent preclinical program, the HCT-15 orthotopic model was employed to evaluate the efficacy of a dual PI3K/mTOR inhibitor in combination with a MEK1/2 antagonist against KRAS^G13D-driven colorectal cancer. HCT-15 cells were implanted into the cecal wall of athymic nude mice via subserosal injection, with tumor establishment confirmed by palpation within 10–14 days. Upon reaching a mean tumor volume of approximately 100 mm^3, mice were randomized to receive vehicle, PI3K/mTOR inhibitor monotherapy, MEK inhibitor monotherapy, or the combination for 3 weeks. The combination arm demonstrated marked suppression of primary cecal tumor growth compared to both monotherapy and vehicle controls, as evidenced by reduced tumor weight at necropsy and diminished tumor dimensions. Immunohistochemical analysis revealed decreased phospho-ERK1/2 and phospho-AKT staining intensity in the combination cohort, indicating concurrent MAPK and PI3K pathway blockade. Notably, liver metastatic burden—assessed by macroscopic nodule count and H&E histology—was substantially lower in the combination group relative to vehicle, suggesting that dual pathway inhibition not only restrains local tumor expansion but also attenuates portal venous dissemination. These findings illustrate the utility of the HCT-15 orthotopic platform for dissecting combination therapy activity in a KRAS-mutant, MSI-H molecular context with both local and metastatic endpoint readouts.

Why Choose Alfa Cytology?

Preclinical evaluation of KRAS-mutant, MSI-high colorectal cancer demands a model that preserves molecular driver fidelity, anatomical relevance, and metastatic behavior. Alfa Cytology structures its HCT-15 orthotopic service around these imperatives, delivering capabilities that distinguish our offering:

• We maintain authenticated, low-passage HCT-15 master and working cell banks with documented STR profiles, routine mycoplasma surveillance, and KRAS^G13D allele-specific qPCR validation—ensuring that every study batch retains the oncogenic driver signature essential for translational relevance.
• Our surgical team achieves consistent engraftment via both direct cecal wall injection and tumor fragment grafting techniques, with particular expertise in targeting the cecal mesenteric triangle to maximize portal venous metastasis modeling and minimize inter-animal variability.
• Endpoint analysis extends beyond standard caliper measurements to include quantitative IHC for MAPK and PI3K pathway biomarkers (phospho-ERK1/2, phospho-AKT), mismatch repair protein assessment (MLH1, MSH2, MSH6, PMS2), and CEA biomarker quantification—yielding mechanistic data that informs clinical biomarker development.
• Study designs are architected around your compound class—whether KRAS^G13D-directed small molecules, PI3K/AKT pathway inhibitors, DNA damage response modulators, or combination regimens—with flexible dosing schedules, pharmacokinetic integration, and biomarker-driven adaptive randomization.
• We provide digital whole-slide pathology with remote access, enabling real-time peer review, AI-assisted image quantification, and seamless integration with your internal data management and regulatory submission workflows.
• Comprehensive study deliverables include raw data packages, statistical analysis plans, and GLP-compliant documentation upon request, supporting efficient transition from preclinical efficacy studies to IND-enabling toxicology and regulatory filing packages.

Contact Us

If your colorectal cancer research program targets the KRAS-mutant, MSI-high population and requires an orthotopic model with validated hepatic metastasis and deep molecular endpoint characterization, we invite you to reach out to us for a confidential project consultation. The scientific team at Alfa Cytology is prepared to design a customized HCT-15 orthotopic study aligned with your therapeutic hypothesis, compound mechanism, and regulatory milestones. Contact us today to receive a detailed proposal, feasibility assessment, and projected timeline—let us advance your KRAS-directed pipeline with rigorous, publication-quality preclinical data.

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