In vivo orthotopic glioblastoma model

Based on the intracranial implantation of tumors thus closely mimicking human glioblastoma (GBM) with respect to tumor progression and clinical response to tumor growth, our syngeneic glioma tumor-bearing model is a very suitable tool for assessing both in vivo efficacy and MOA of novel therapeutic strategies for brain cancer. Interestingly, this model is run with stable Luc2-expressing GL261 tumor cells which has the advantage to monitor tumor growth and disease progression in vivo by bioluminescence imaging (BLI) along the study.
Apart from the advantage of the tumor cells (stably expressing the 2nd generation firefly luciferase) which are intracranially implanted by stereotactic surgery, our syngeneic GBM model mimics the major human disease features including immune cell activation and infiltration, and astrogliosis, among other characteristics.
Moreover, our GBM model was set up and validated to assess novel combination regimens with chemotherapy or immunotherapy. Robust treatment protocols combined with validated gold standard chemotherapeutics and immune checkpoint inhibitors have been optimized and allowed to characterize and validate GL261 glioma as responsive to Temozolomide (TMZ) and to anti-CTLA-4 treatment.

In vivo efficacy and anti-tumor immune response profiling

  • Standard efficacy package: Tumor growth and progression are monitored and quantitatively measured by BLI along the study. Tumor growth, body weight and survival are assessed weekly in experimental groups of standardly 10 mice, to test a drug candidate alone and in combination with a chemo- or immunotherapeutic reference.
  • Upon study initiation, the model is quickly set up. Weekly reports are provided to follow the progressively achieved efficacy profile of treatments in conjunction with the Sponsor, which allows, if needed, to adjust the experimental design.
  • As for our satellite immune response profiling studies for MOA deconvolution, satellite mice (N=4) can be added to each group to study the impact of a treatment on immune response modulation at the tumor level and/or peripheral compartments. Immune function can be studied using appropriate methodologies and platforms, e.g. flow cytometry, RT-qPCR, immunohistology-based imaging.

Illustrative data

Orthotopic GL261 tumor model is responsive to CTLA4 and PD1 immunotherapies, and to temozolomide chemotherapy
Delayed GL261 tumor growth upon temozolomide (TMZ), anti-PD1 and anti-CTLA4 antibody treatment.

Mice are intracranially inoculated with GL261-Luc2 glioblastoma tumor cells, and then challenged with either TMZ, anti-PD1 or anti-CTLA4 antibodies. Tumor growth is then followed overtime and determined by in vivo bioluminescence imaging. 

Delayed GL261 tumor growth upon temozolomide (TMZ), anti-PD1 and anti-CTLA4 antibody treatment. ...

Characterization of tumor immune cell infiltration in orthotopic GL261 tumor model
Orthotopic glioma tumor-bearing model is characterized by tumor-infiltrating immune cells.

Hematoxylin-associated immunohistochemistry staining of brain sections of GL261 glioma-bearing mouse (left image) shows the presence of F4/80+ macrophages (a) and of CD8+ cytotoxic lymphocytes infiltrating the tumor (b). Presence of tumor-infiltrating PD1-expressing immune cells is highlighted in (c).

Orthotopic glioma tumor-bearing model is characterized by tumor-infiltrating immune cells. ...

Our added-value

  • Longitudinal mice bleeding: blood samples can be collected every week, allowing the evaluation of peripheral markers overtime or at given analysis time-points.
  • A strong expertise in syngeneic tumor models of immune checkpoint inhibition: Explicyte offers a range of in vivo tumor models including orthotopic and subcutaneous models for anti-CTLA-4 and/or anti-PD-1/PD-L1 therapy.