SNB-75 xenograft model
The SNB-75 cell line (human brain; astrocytoma) is used to create the CDX (Cell Line Derived Xenograft) SNB-75 xenograft mouse model. The SNB-75 xenograft model is a functional animal model used to develop novel monotherapies along with combinatorial studies to determine pre-clinical antitumor synergism with temozolomide (e.g. BCNU).
Basic study design
- 10 to 12 w.o. athymic BALB/C or NOD/SCID receive single injections into the flank of the hind leg. Each injection contains one million cells of the matrigel plus SNB-75 cell suspension (in a vol of 100 uL).
- The injection sites are watched and palpated until tumors are deemed established. Tumors are assessed (digital calipers) until they reach average sizes in the range of 50-150 mm3. Treatment groups are established by randomization. The compound of interest is injected according to customer supplied dosing schedule.
- In-life tumor measurements are taken daily, with whole body weights tracked 3 times weekly.
- Maximum permitted tumor size determines the end of the study, at which time necropsies and tissue collections are performed.
- Tumor samples are excised and weighed. Tumor samples can also be documented by digital imaging. All tissues collected are stored according to customer indication (snap frozen, immersed in 10% NBF, etc).
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 SNB-75 xenograft model:
- SNB-75 Tumor Growth Delay (TGD; latency)
- SNB-75 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)
- SNB-75 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