Robust in vivo models of anti-CTLA-4 blockade

CTLA-4 blockade is known to install a long-lasting anti-tumor immunity in only a small fraction of patients. To test new drugs capable of improving the benefit of CTLA-4 modulators, Explicyte has validated and optimized preclinical in vivo tumor models treated with an anti-CTLA-4 monoclonal antibody. Our in vivo efficacy studies can be consolidated with immunological data, to investigate the mechanism of action of test compounds.
 
  • A validated treatment protocol in line with data described in the literature.
  • Syngeneic tumor models: tumor cells are implanted into immunocompetent mice, to evaluate drug effects on the anti-tumor immune response.
  • Anti-CTLA-4 responding & non-responding tumor models, including glioblastoma, colon and breast cancer models.
CTLA-4 blockade enhances survival of CT26 (colorectal), GL261 (glioma) but not 4T1 (breast)
CTLA-4 blockade enhances survival of CT26 (colorectal), GL261 (glioma) but not 4T1 (breast). Mice were challenged with either CT26, GL261 or 4T1 tumor cells, and exposed to anti-CTLA4 antibody. Survival (and tumor growth) was followed. CTLA4 blockade enhances survival in CT26 and GL261 responding models but not in 4T1 non-responding model.

In Vivo Efficacy And Profiling Of Anti-Tumor Response

  • Standard package: Tumor growth, body weight and survival  are monitored 3 times per week in 4 experimental groups (N=10), including vehicle, anti-CTLA4 antibody treatment, test compound, and anti-CTLA4 combination therapy.
  • Immune profiling package: Satellite mice (N=4) can be added to each group to study the tumour-host immune interactions at the tumor site & in peripheral compartments.
  • Multiplex and quantitative immunological analysis: validated immune markers (eg. CD4, CD8, FoxP3, CD11b, Gr1, …) can be analyzed by FACS and/or RT-qPCR to delineate the in vivo mechanism of action of the drug candidate.
Analysis of key immune markers encoding genesáby RT-qPCR
Analysis of key immune markers encoding genes by RT-qPCR. TDLN (Tumor Draining Lymph Nodes) and CD11c + dendritic cells from CT26 tumor bearing mice exposed to anti-CTLA4 antibody or only exposed to vehicle were analyzed by RT-qPCR for specific immune markers. Results show that anti-CTLA4 exposure induces an up-regulation of Il6 and Il17 in TDLN while an icrease in Ifng and Pdl2 is observed in dendritic cells.

Our added value

  • Weekly progress reports: the first report is sent within 10 days after study initation. Weekly reports enable to adjust the study design according to the results.
  • Longitudinal mice bleeding: blood samples can be collected every week, allowing the monitoring of peripheral markers over time in responding and non-responding animals.
  • A unique anti-CTLA-4 glioblastoma model, in which brain tumor progression is monitored in live animals by bioluminescence imaging.
 

References