Development of a squamous cell carcinoma mouse model for immunotoxicity testing

Area of Science:

• Oncology
• Pharmacology
• Immunology

Background:

• Traditional cancer risk assessment for pharmaceuticals, like the 2-year rodent bioassay, is often unsuitable for biotherapeutics.
• Existing methods have limited predictive value for non-genotoxic immunosuppressive compounds.
• There is a critical need for alternative testing strategies in drug safety evaluation.

Purpose of the Study:

• To evaluate a novel 3-stage tumor model in syngeneic C3H/HeN mice for assessing immunosuppressive drug effects on tumor promotion and progression.
• To investigate the utility of this model for carcinogenicity risk assessment of immunosuppressive agents.

Main Methods:

• A syngeneic mouse model using a skin squamous cell carcinoma cell line (SCC VII) was developed.
• Evaluation of local invasion, tumor colonization (lung counts), and tumor progression (lesion area, angiogenesis, growth fraction).
• A validation set of immunosuppressive drugs (Cyclosporin, cyclophosphamide, azathioprine, etanercept, abatacept, prednisone) was tested.

Main Results:

• The model assessed local invasion via histology and fluorescence tracking to lymph nodes.
• Tumor colonization was quantified by lung colony counts after intravenous inoculation.
• Immunosuppressive drugs showed varied effects, with some demonstrating decreased tumor progression.

Conclusions:

• The developed in vivo syngeneic mouse tumor model provides valuable insights into the assessment of immunosuppressive drugs.
• This model offers a potential alternative for evaluating the carcinogenicity risk of immunosuppressive agents.
• The findings contribute to improving safety assessment strategies for new pharmaceuticals, particularly biotherapeutics.