SF-268 xenograft model
According to the American Brain Tumor Association (ABTA), brain tumors are the most common pediatric malignancies and the primary cause of cancer fatalities in children. Approximately 80,000 new cases of brain tumors are detected annually among adults. Over one-third of them are malignant with 17,000 deaths per year. Many preclinical studies are carried out by using in vitro cellular models such as cancer cell lines that have proven to be essential model systems for exploring the fundamental properties of brain tumors. The SF-268 cell line (human brain; glioblastoma / astrocytoma) is used to create the CDX (Cell Line Derived Xenograft) SF-268 xenograft mouse model. The SF-268 xenograft model lends itself to pre-clinical therapeutic agents targeting ID4 due to the overexpression of ID4 leading to enhanced angiogenesis.
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Basic study design
- SF-268 cells used for injection are grown at exponential growth phase until collected for injection. Viable cell counts are determined with trypan blue, and cell counts are determined by hemocytometer. Total cell concentration is adjusted such that each mouse (athymic BALB/C or NOD/SCID, 10-12 w.o.) receives a single injection (subcutaneous) in the hind leg. One million SF-268 cells in 50% Matrigel solution used for 100 uL injection volume.
- All in-study animals are monitored and continuously palpated until tumor establishment is determined. In-life study initiation begins as mice are sorted (randomization) into treatment groups with average tumor sizes of 50-150 mm3.
- Administrations of all test material compounds are performed in conjunction with the treatment schedule.
- Tumor growth is monitored by daily measurements, along with whole body mouse weight documentation (3 times weekly).
- End of study commences when tumor size reaches 2,000 mm2 (or the client determined size limit).
- Necropsies and tissue collections are performed. Tumors are excised and weighed (tumor imaging is available). Tissues are resected into microtubes (snap frozen or immersed in RNAlater), prepared for histology or nucleic acids isolated.
Xenograft animal models are used to assess the effectiveness of experimental test compounds against specific types of cancer. Novel medicines are tested on staged tumor growths that have been engrafted via subcutaneous or orthotopic inoculation in an immunocompromised mouse or rat model (most common are NOD/SCID or Nude). 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 facilities are IACUC-regulated and meet GLP requirements. 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 SF-268 xenograft model:
- SF-268 Tumor Growth Delay (TGD; latency)
- SF-268 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)
- SF-268 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