SW480 xenograft model
Colon cancer often affects people in their late 60s-early 70s, per the Colon Cancer Alliance (CCA). Metastasis is typically the most common cause of treatment failure in colorectal cancer patients. Murine xenograft models could facilitate cancer diagnosis and treatment by closely resembling human tumors. The SW480 epithelial cell line is isolated from a colon tumor of a 50-year-old Caucasian male patient with colorectal adenocarcinoma. The SW480 cell line is susceptible to human immunodeficiency virus 1 and expresses elevated levels of p53 protein. Also, SW480 cells positively express c-myc, K-ras, H-ras, N-ras, myb, sis and fos oncogenes. The SW480 cell line is tumorigenic in nude mice and produces carcinoembryonic antigen (CEA) as well as keratin. SW480 is used to create the CDX (Cell Line Derived Xenograft) SW480 xenograft mouse model. The SW480 xenograft model is a pre-clinical model utilized in studies examining therapeutics targeting the β-catenin pathway (e.g. silibinin). The SW480 model also lends itself to studies addressing the link between human epidermal growth factor receptor (EGFR) expression levels and anti-tumor growth therapies (e.g. cetuximab).
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Basic study design
- Trypan blue exclusion is utilized to determine cell viability and cell count. After cell suspensions are diluted to the appropriate cell density for injection (10,000 cells/uL; injection volume = 100uL containing matrigel), each immunocompromised mouse (10-12 w.o.) receives a single injection in the flank of the hind leg.
- Tumors are continually calipered (digital) tumor size averages are 50-150 mm3. Treatment cohorts are formed (randomization) the in-life study begins. All drug administration is performed according to the dosing schedule.
- Throughout the study tumors receive daily measurements, along with tri-weekly mouse weights recordings. As the predetermined tumor size is reached, animals are euthanized.
- Collected tissues are stored for downstream analysis (snap frozen, RNAlater, 10% NBF or nucleic acid isolations). Tumor are weights and documented and digital images captured.
Xenograft animal models are used to assess the effectiveness of drugs against specific types of cancer. New medicines are tested on staged tumor growths that have been engrafted via subcutaneous or orthotopic inoculation in an immunocompromised mouse or rat model. All clinically approved anti-cancer agents have been evaluated with conventional preclinical in vivo models. Xenograft studies can be highly complex, starting with the selection of the appropriate animal model, choice of tumorigenic cell line, administration method, dosing, analysis of tumor growth rates and tumor analysis (histology, mRNA and protein expression levels).
Altogen Labs provides an array of laboratory services using over 30 standard Cell Line Derived Xenograft (CDX) models and over 20 PDX models. Researchers investigating the role of specific proteins or gene products in regulating tumor growth can benefit from development of protein overexpression (genetically engineered to ectopically express proteins, tumor suppressors, or oncogenes) and RNAi cell lines with long term gene silencing. Altogen Labs provides quantitative gene expression analysis of mRNA expression (RT-PCR) and protein expression analysis using the WES system (ProteinSimple).
The dosing of the experimental compound of interest is initiated, for a staged study, when the mean tumor size reaches a specified volume (typically 50-100 mm3). In an unstaged study, the dosing of the compound of interest is initiated immediately after xenografting. Mice are dosed once or twice a day for 28 days (or other desired study duration) via the chosen route of administration. Tumor volume (mm3) is calculated via the “(W x W x L) / 2” formula, where W is tumor width and L is tumor length.
Animal handling and maintenance at the Altogen Labs facility is IACUC-regulated and GLP-compliant. Following acclimation to the vivarium environment, mice are sorted according to body mass. The animals are examined daily for tumor appearance and clinical signs. We provide detailed experimental procedures, health reports and data (all-inclusive report is provided to the client that includes methods, results, discussion and raw data along with statistical analysis). Additional services available include collection of tissue, histology, isolation of total protein or RNA and analysis of gene expression. Our animal facilities have the flexibility to use specialized food or water systems for inducible gene expression systems.
Following options are available for the SW480 xenograft model:
- SW480 Tumor Growth Delay (TGD; latency)
- SW480 Tumor Growth Inhibition (TGI)
- Dosing frequency and duration of dose administration
- Dosing route (intravenous, intratracheal, continuous infusion, intraperitoneal, intratumoral, oral gavage, topical, intramuscular, subcutaneous, intranasal, using cutting-edge micro-injection techniques and pump-controlled IV injection)
- SW480 tumor immunohistochemistry
- Alternative cell engraftment sites (orthotopic transplantation, tail vein injection and left ventricular injection for metastasis studies, injection into the mammary fat pad, intraperitoneal injection)
- Blood chemistry analysis
- Toxicity and survival (optional: performing a broad health observation program)
- Gross necropsies and histopathology
- Positive control group employing cyclophosphamide, at a dosage of 50 mg/kg administered by intramuscular injection to the control group daily for the study duration
- Lipid distribution and metabolic assays
- Imaging studies: Fluorescence-based whole body imaging, MRI