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Stereotactic Adoptive Transfer of Cytotoxic Immune Cells in Murine Models of Orthotopic Human Glioblastoma Multiforme Xenografts
Published on: September 1, 2018
TCR-engineered adoptive cell therapy effectively treats intracranial murine glioblastoma
Maximilian O Schaettler1, Rupen Desai1, Anthony Z Wang1
1Department of Neurological Surgery, Washington University School of Medicine, St. Louis, Missouri, USA.
Background:
Adoptive cellular therapies with chimeric antigen receptor T cells have revolutionized the treatment of some malignancies but have shown limited efficacy in solid tumors such as glioblastoma and face a scarcity of safe therapeutic targets. As an alternative, T cell receptor (TCR)-engineered cellular therapy against tumor-specific neoantigens has generated significant excitement, but there exist no preclinical systems to rigorously model this approach in glioblastoma.
Methods:
We employed single-cell PCR to isolate a TCR specific for the Imp3D81N neoantigen (mImp3) previously identified within the murine glioblastoma model GL261. This TCR was used to generate the Mutant Imp3-Specific TCR TransgenIC (MISTIC) mouse in which all CD8 T cells are specific for mImp3. The therapeutic efficacy of neoantigen-specific T cells was assessed through a model of cellular therapy consisting of the transfer of activated MISTIC T cells and interleukin 2 into lymphodepleted tumor-bearing mice. We employed flow cytometry, single-cell RNA sequencing, and whole-exome and RNA sequencing to examine the factors underlying treatment response.
Results:
We isolated and characterized the 3×1.1C TCR that displayed a high affinity for mImp3 but no wild-type cross-reactivity. To provide a source of mImp3-specific T cells, we generated the MISTIC mouse. In a model of adoptive cellular therapy, the infusion of activated MISTIC T cells resulted in rapid intratumoral infiltration and profound antitumor effects with long-term cures in a majority of GL261-bearing mice. The subset of mice that did not respond to the adoptive cell therapy showed evidence of retained neoantigen expression but intratumoral MISTIC T cell dysfunction. The efficacy of MISTIC T cell therapy was lost in mice bearing a tumor with heterogeneous mImp3 expression, showcasing the barriers to targeted therapy in polyclonal human tumors.
Conclusions:
We generated and characterized the first TCR transgenic against an endogenous neoantigen within a preclinical glioma model and demonstrated the therapeutic potential of adoptively transferred neoantigen-specific T cells. The MISTIC mouse provides a powerful novel platform for basic and translational studies of antitumor T-cell responses in glioblastoma.
Insights
We developed a novel preclinical model, the MISTIC mouse, to test T cell receptor (TCR)-engineered cellular therapy against glioblastoma neoantigens. This approach demonstrated significant antitumor effects and long-term cures in mice, highlighting its therapeutic potential.
Area of Science:
- Immunology
- Oncology
- Genetics
Background:
- Chimeric antigen receptor (CAR) T cell therapy shows promise in malignancies but has limited efficacy in solid tumors like glioblastoma.
- Existing therapeutic targets for glioblastoma are scarce, prompting exploration of alternative strategies.
- T cell receptor (TCR)-engineered cellular therapy targeting tumor-specific neoantigens is a promising alternative, but lacks robust preclinical models for glioblastoma.
Purpose of the Study:
- To develop and characterize a novel preclinical model for studying TCR-engineered cellular therapy against glioblastoma neoantigens.
- To assess the therapeutic efficacy of neoantigen-specific T cells in a murine glioblastoma model.
- To investigate the mechanisms underlying treatment response and resistance in adoptive cellular therapy for glioblastoma.
Main Methods:
- Isolation and characterization of a TCR specific for the Imp3D81N neoantigen (mImp3) using single-cell PCR.
- Generation of the Mutant Imp3-Specific TCR TransgenIC (MISTIC) mouse, where all CD8 T cells are specific for mImp3.
- Assessment of therapeutic efficacy via adoptive transfer of activated MISTIC T cells and IL-2 into tumor-bearing mice, followed by analysis using flow cytometry and multi-omics sequencing.
Main Results:
- A high-affinity TCR (3×1.1C) specific for mImp3 without wild-type cross-reactivity was isolated.
- Adoptive transfer of MISTIC T cells led to rapid tumor infiltration, significant antitumor effects, and long-term cures in a majority of treated mice.
- Non-responding mice exhibited intratumoral T cell dysfunction despite retained neoantigen expression, and therapy failed in tumors with heterogeneous neoantigen expression, indicating barriers to treatment.
Conclusions:
- The study generated and characterized the first TCR transgenic model targeting an endogenous neoantigen in a preclinical glioma model.
- Neoantigen-specific T cells demonstrated significant therapeutic potential in adoptive cellular therapy for glioblastoma.
- The MISTIC mouse serves as a valuable platform for fundamental and translational research into antitumor T cell responses in glioblastoma.
