Peer-reviewed article
IMMU-11. PRECLINICAL HIGH-RISK PEDIATRIC BRAIN TUMOR MODELS FOR IMMUNOTHERAPY: HURDLES AND THE WAY FORWARD
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Summary
Written by AI, not yet AICS's view · claude-haiku-4-5-20251001This paper discusses preclinical mouse models used to test immunotherapy approaches for high-risk pediatric brain tumors, focusing on technical challenges in translating laboratory findings to clinical treatment. The authors describe limitations they encountered when using syngeneic and humanized mouse models to test checkpoint inhibitors combined with epigenetic treatments. They highlight a key difference: MHC-I expression levels in patient tumors differed significantly from mouse models, requiring compensatory approaches. The paper emphasizes the importance of validating preclinical models before using them to develop immunotherapy strategies for children.
Key points
- High-risk pediatric brain tumors remain the leading cause of cancer-related deaths in children despite recent therapeutic advances
- Checkpoint inhibitors as monotherapy have failed in pediatric brain tumors partly due to 'immunologically cold' tumor environments
- Mouse DIPG tumors showed significantly lower MHC-I expression compared to patient tumors and matched normal tissue
- Addition of IFN-γ to epigenetic modulator treatment negatively affected animal survival compared to epigenetic modulator alone
- Current preclinical models have inadequate representation of human tumor immunology, limiting translation of successful immunotherapy strategies
Limitations
This is a technical paper about laboratory model systems rather than a study of child health outcomes or treatment efficacy in children. It does not evaluate whether immunotherapy interventions actually improve survival or quality of life in pediatric patients with brain tumors.
Abstract
Abstract Despite recent therapeutic advancements in the treatment of pediatric brain tumors, high-risk brain tumors (pHRBT) remain the leading cause of cancer-related deaths in children. In recent years, immunotherapy has become a viable treatment option for several cancers including brain tumors. However, several factors have limited the use of immunotherapy in the treatment of pHRBT. For example, an "immunologically cold" tumor environment has been predominantly implicated in the failure of checkpoint inhibitors (ICIs) as monotherapy in pHRBT. Nevertheless, priming the effects of ICIs with epigenetic modulators through a process called “viral mimicry” that induces the expression of human endogenous retroviruses has the potential to enhance immunotherapy by sparking a T-cell mediated immune response. However, the inadequate understanding of the limitations of the preclinical models has prevented the development of efficient immunotherapy strategies for pHRBT. Although several studies and reviews have compiled some limitations of the available models, a hands-on experience using preclinical models for ICIs testing has not been fully communicated. Here, we share our bedside to bench experience with syngeneic and humanized mouse models of DIPG, ATRT, and medulloblastoma using ICIs therapy in conjunction with an epigenetic alteration. We will present and discuss the limitations of mouse models for the development of immunotherapies for pHRBT. For instance, our results indicated that the baseline levels of MHC-I expression in patients’ DIPG tumors were comparable to matched normal tissue. However, these levels were significantly lower in mouse DIPG tumors. To compensate for this difference, we treated mice with IFN-γ in combination with an epigenetic modulator. Surprisingly, the addition of INF-γ had a negative effect on animal overall survival compared to the treatment with the epigenetic modulator alone. Together, our experience demonstrated the importance of suitability assessment of current models for developing and translating successful immunotherapy strategies to treat pHRBT.