SKOV3 xenograft model
Ovarian cancer is the deadliest gynecological malignancy that is often asymptomatic at early stages. The vast majority of the patients are already at the advanced stages of the disease at the time of diagnosis. The SK-OV-3 tumorigenic epithelial cell line was isolated in 1973 from the ovarian tissue of a 64-year-old Caucasian female patient with adenocarcinoma. SK-OV-3 is resistant to tumor necrosis and several other cytotoxic drugs, including Adriamycin, cis-platinum, and diphtheria toxin. SK-OV-3 is hypodiploid and a suitable transfection host for ovarian cancer research. Integrin-associated protein (IAP) CD47 is a membrane protein of the immunoglobulin superfamily that is a proven ovarian cancer marker. CD47 is overexpressed in ovarian cancer cells and indicates a poor prognosis. A 2017 study by Liu et al. published in Oncotarget, reported that CD47 knockdown in the SK-OV-3 ovarian cancer cell line promoted phagocytosis by macrophages in vitro. Also, it blocks tumor growth in vivo in the SK-OV-3 xenograft model. These findings indicate that CD47 inhibition could be a potential strategy for the treatment of ovarian cancer patients. The SK-OV-3 cell line (human ovarian) is used to create the CDX (Cell Line Derived Xenograft) SKOV-3 xenograft mouse model. The SK-OV-3 xenograft model exhibits the following features:
- Clinical efficacy of taxol is well documented and allows for combination therapies of novel compounds
- High HER2-positive expression leads to antitumor activity of HER2 targeted therapies (e.g. trastuzumab-DM1, T-DM1)
- Utilized for the study of epothilone analogues, which are natural product-based antitumor drugs (e.g. iso-dehydelone)
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Basic study design
- Athymic nu/nu mice (10 to 12 weeks) are inoculated with a subcutaneous injection of 1 x 10^6 cells plus matrigel in the hind leg (injection volume = 100 uL).
- Tumors are calipered (digital calipers) and grouped into treatment cohorts with an average size of 50-150 mm3. Administration of test compounds is performed according to client supplied treatment schedule.
- Whole body mouse weights are logged up to 3 times a week. Tumor sizes are measured per client instructions (typically daily).
- The in-life portion of the study is completed as tumor size reaches the client supplied tumor size limit (or a maximum of 2,000 mm2). Tissue collection proceeds according to the termination of experiment agreement.
- All remaining tumors are excised from the mice and weighed. Standard gross necropsies alloq for the collection of tissue requested by the client (options include snap frozen, histology preparation in 10% NBF or stabilized in RNAlater).
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 SK-OV-3 xenograft model:
- SK-OV-3 Tumor Growth Delay (TGD; latency)
- SK-OV-3 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)
- SK-OV-3 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