DHD/K12/TRb (PROb) Xenograft Rat Model Service for Colon Cancer

The DHD/K12/TRb (PROb) Xenograft Rat Model Service for Colon Cancer furnishes a transplantable, immunocompetent platform that recapitulates the local invasion and metastatic dissemination patterns of colorectal adenocarcinoma. Alfa Cytology orchestrates the entire preclinical continuum—from cell authentication and surgical implantation to longitudinal tumor monitoring and necropsy—ensuring each study arm is powered by reproducible tumor kinetics and compliant data packages that de-risk your downstream development decisions.

Overview of DHD/K12/TRb (PROb) Xenograft Rat Model for Colon Cancer

The DHD/K12/TRb cell line—frequently abbreviated as PROb—was cloned from a 1,2-dimethylhydrazine (DMH)-induced colonic adenocarcinoma arising in the inbred BD-IX rat strain. Following establishment at the Brain Tumor Research Center, University of California, San Francisco, the line was deposited with the European Collection of Cell Cultures (ECACC) and has since served as a cornerstone syngeneic model for colorectal cancer research. Histologically, PROb tumors exhibit a well-differentiated glandular architecture with desmoplastic stromal reaction, closely mirroring the adenomatous-to-carcinomatous progression observed in human disease. Their predictable tropism for regional mesenteric lymph nodes and the peritoneal cavity—depending on implantation site—makes the model uniquely suited for investigating metastatic cascade, tumor-microenvironment crosstalk, and locoregional therapeutic delivery.

Fig 1. Rodent models available to study human colorectal cancer. (Nascimento-Goncalves, Elisabete, et al., 2021)

A defining feature of the DHD/K12/TRb system is its site-dependent pattern of dissemination. When cells are injected into the mesenteric (M) aspect of the cecal wall, tumors tend to grow locally and spread to regional mesenteric lymph nodes, whereas antimesenteric (AM) implantation favors diffuse peritoneal carcinomatosis with minimal nodal involvement. This dichotomy allows investigators to tailor the model to specific translational questions—whether testing intraperitoneal chemotherapy regimens, evaluating hyperthermic intraperitoneal perfusion protocols, or profiling the angiogenic switch during peritoneal metastasis. The line is also strongly immunogenic, rendering it an excellent substrate for immunotherapy and vaccine studies in fully immunocompetent hosts.

Cell Line Information: DHD/K12/TRb (PROb)

The DHD/K12/TRb (PROb) rat colonic adenocarcinoma cell line is one of the most extensively documented chemically induced colon tumor lines in preclinical oncology. Established through DMH carcinogenesis and subsequently cloned for stable propagation, PROb retains a reproducible metastatic phenotype that supports both heterotopic and orthotopic tumor development in syngeneic BD-IX rats. The table below enumerates the salient characteristics of this line.

Our Services

Alfa Cytology brings deep expertise in colon cancer model construction to every DHD/K12/TRb engagement, offering flexible implantation routes—subcutaneous, intraperitoneal, and orthotopic cecal wall—that align with your mechanistic or translational objectives. Our integrated platform spans cell banking, surgical oncology, in vivo imaging, and GLP-grade histopathology, delivering tumor-bearing cohorts and data packages that meet the stringent reproducibility standards required for IND-enabling studies.

Workflow of DHD/K12/TRb (PROb) Xenograft Rat Model Construction

Establishment of a DHD/K12/TRb colon cancer model requires rigorous cell quality control, aseptic surgical technique, and standardized post-operative surveillance to ensure consistent tumor take rates and biologically relevant endpoints. The workflow below details the sequence used to generate reliable tumor-bearing BD-IX rat cohorts for preclinical evaluation.

1. Cell Line Resuscitation & Quality Control. Cryopreserved DHD/K12/TRb cells are thawed and expanded in DMEM/Ham's F-10 medium supplemented with 10% FBS and gentamycin. Identity is confirmed via STR profiling, and mycoplasma negativity is verified by PCR. Viability exceeds 95% by trypan blue exclusion before any in vivo use.
2. Recipient Animal Acclimation & Randomization. Syngeneic BD-IX rats are quarantined and acclimatized for a minimum of 7 days under controlled environmental conditions. Baseline body weights are recorded, and animals are randomized into treatment cohorts using stratified randomization to minimize inter-group variance prior to tumor cell injection.
3. Tumor Cell Preparation & Inoculum Standardization. Log-phase PROb cells are harvested with 0.125% EDTA-trypsin, washed in sterile PBS, and resuspended at the designated concentration—typically 1 × 10⁶ cells in 100–200 µL for subcutaneous or intraperitoneal delivery, or 1 × 10⁶ cells in 50 µL for intramural cecal wall implantation. Cell suspensions are kept on ice and used within 30 minutes of preparation.
4. Surgical Implantation (Route-Specific). For subcutaneous models, cells are injected into the right flank using a 25-gauge needle. For intraperitoneal dissemination studies, cells are delivered via midline laparotomy or sterile percutaneous injection. For orthotopic cecal wall models, a mini-laparotomy exposes the cecum; a 30-gauge Hamilton syringe injects the cell suspension into the submucosal layer of either the mesenteric or antimesenteric border, followed by a 10-second dwell to prevent leakage.
5. Post-Operative Monitoring & Analgesia. Animals receive buprenorphine (0.05–0.1 mg/kg subcutaneously every 8–12 hours for 48 hours) and are housed in warmed recovery cages. Surgical sites are inspected daily for dehiscence, infection, or herniation. Body weights and clinical scores are recorded every 48 hours during the immediate post-operative period.
6. Longitudinal Tumor Assessment. Subcutaneous tumors are measured with digital calipers twice weekly, and volumes are calculated using the modified ellipsoid formula (length × width² × 0.5). For intraperitoneal and orthotopic models, tumor burden is monitored via abdominal girth, body condition scoring, and small-animal ultrasound or MRI every 5–7 days. Ascites volume is quantified when present.
7. Necropsy, Tissue Harvest & Histopathological Validation. At study endpoint, animals are humanely euthanized under deep anesthesia. Primary tumors, regional lymph nodes, peritoneal nodules, liver, lung, and spleen are excised, weighed, and fixed in 10% neutral-buffered formalin. Paraffin sections (5 µm) undergo H&E staining and immunohistochemistry for cytokeratin, Ki-67, CD31, and F4/80 to confirm tumor histology, proliferation index, vascular density, and immune infiltrate composition.

Fig 2. DHD/K12/TRb (PROb) Xenograft Rat Model construction workflow.

Case Study-DHD/K12/TRb (PROb) Xenograft Rat Model Development

In a recent preclinical program, Alfa Cytology established an intraperitoneal DHD/K12/TRb dissemination model to evaluate the anti-tumor activity of a novel platinum-based metallointercalator combined with mild hyperthermia. Following intraperitoneal inoculation of 2 × 10⁶ viable PROb cells, tumor-bearing BD-IX rats were randomized into treatment and control arms once peritoneal nodules became detectable by ultrasound. Animals in the treatment group received intraperitoneal drug infusion followed by controlled hyperthermic exposure, while controls received vehicle alone. Endpoint analysis at 35 days demonstrated a significant reduction in peritoneal carcinomatosis score, decreased ascites volume, and diminished mesenteric angiogenesis in the treated cohort relative to controls. Histopathological review confirmed lower Ki-67 indices and increased caspase-3 positivity in treated tumors, providing the sponsor with preclinical pharmacodynamic evidence to advance the regimen toward formal toxicology assessment.

Why Choose Alfa Cytology?

Partnering with Alfa Cytology for your DHD/K12/TRb colon cancer model means gaining access to a team that understands the nuances of gastrointestinal tumor biology and the regulatory landscape surrounding preclinical oncology. Our service is differentiated by the following attributes:

• Veterinary surgical team proficient in mini-laparotomy, cecal wall micro-injection, and intraperitoneal catheter placement, ensuring high tumor take rates and anatomically precise tumor seeding.
• Multiple implantation configurations—subcutaneous flank, intraperitoneal dissemination, and orthotopic cecal wall (mesenteric or antimesenteric)—allowing direct alignment with your metastatic or locoregional study objectives.
• Real-time tumor monitoring via small-animal ultrasound and MRI, supplemented by automated caliper tracking and body condition scoring, to capture treatment response kinetics with temporal resolution.
• Full-spectrum histopathology and immune profiling encompassing H&E, IHC, multiplex immunofluorescence, and digital image analysis for quantifying tumor burden, proliferation, apoptosis, angiogenesis, and immune cell infiltration.
• IACUC-approved, GLP-capable study conduct with complete chain-of-custody documentation, enabling seamless integration of preclinical data into regulatory submission packages.
• Responsive project leadership with weekly data dashboards, milestone-driven reporting, and direct access to study directors for real-time protocol optimization and troubleshooting.

Contact Us

If your colorectal oncology program demands a rigorously controlled, immunocompetent rat model with documented metastatic behavior, Alfa Cytology is prepared to deliver. Contact us today to explore how our DHD/K12/TRb (PROb) xenograft service can generate the preclinical evidence you need to advance your therapeutic candidate with clarity and confidence.

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