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Isolation and Flow Cytometric Analysis of Glioma-infiltrating Peripheral Blood Mononuclear Cells
Published on: November 28, 2015
RAGE ablation attenuates glioma progression and enhances tumor immune responses by suppressing galectin-3 expression
Ian Y Zhang1, Shunan Liu2, Leying Zhang1
1Division of Neurosurgery, City of Hope Beckman Research Institute, Duarte, California, USA.
Background:
Malignant gliomas consist of heterogeneous cellular components that have adopted multiple overlapping escape mechanisms that overcome both targeted and immune-based therapies. The receptor for advanced glycation end products (RAGE) is a member of the immunoglobulin superfamily that is activated by diverse proinflammatory ligands present in the tumor microenvironment. Activation of RAGE by its ligands stimulates multiple signaling pathways that are important in tumor growth and invasion. However, treatment strategies that only target the interaction of RAGE with its ligands are ineffective as cancer therapies due to the abundance and diversity of exogenous RAGE ligands in gliomas.
Methods:
As an alternative approach to RAGE ligand inhibition, we evaluated the genetic ablation of RAGE on the tumorigenicity of 2 syngeneic murine glioma models. RAGE expression was inhibited in the GL261 and K-Luc gliomas by shRNA and CRSPR/Cas9 techniques prior to intracranial implantation. Tumor growth, invasion, and inflammatory responses were examined by histology, survival, Nanostring, and flow cytometry.
Results:
Intracellular RAGE ablation abrogated glioma growth and invasion by suppressing AKT and ERK1/2 activities and by downregulating MMP9 expression. Interestingly, RAGE inhibition in both glioma models enhanced tumor inflammatory responses by downregulating the expression of galectin-3 and potentiated immunotherapy responses to immune checkpoint blockade.
Conclusions:
We demonstrated that intracellular RAGE ablation suppresses multiple cellular pathways that are important in glioma progression, invasion, and immune escape. These findings strongly support the development of RAGE ablation as a treatment strategy for malignant gliomas.
Insights
Genetic ablation of the receptor for advanced glycation end products (RAGE) suppressed glioma growth and invasion. RAGE inhibition also enhanced anti-tumor immune responses, supporting its development as a novel glioma treatment.
Area of Science:
- Neuro-oncology
- Cancer immunology
- Molecular oncology
Background:
- Malignant gliomas exhibit complex cellular heterogeneity and multiple immune escape mechanisms, challenging current therapies.
- The receptor for advanced glycation end products (RAGE) is activated by tumor microenvironment ligands, promoting glioma growth and invasion.
- Targeting RAGE-ligand interactions alone is insufficient due to the abundance and diversity of RAGE ligands in gliomas.
Purpose of the Study:
- To investigate the efficacy of genetically ablating RAGE in suppressing glioma tumorigenicity.
- To evaluate the impact of RAGE ablation on glioma growth, invasion, and inflammatory responses.
- To assess the potential of RAGE inhibition in enhancing immunotherapy responses.
Main Methods:
- Utilized shRNA and CRISPR/Cas9 techniques to genetically inhibit RAGE expression in syngeneic murine glioma models (GL261 and K-Luc).
- Performed intracranial implantation of RAGE-ablated gliomas.
- Assessed tumor growth, invasion, inflammatory responses, and survival using histology, Nanostring, and flow cytometry.
Main Results:
- Intracellular RAGE ablation significantly abrogated glioma growth and invasion by suppressing AKT and ERK1/2 signaling pathways.
- RAGE inhibition led to downregulation of matrix metalloproteinase 9 (MMP9) expression, a key factor in invasion.
- RAGE ablation enhanced anti-tumor inflammatory responses by downregulating galectin-3 and potentiated responses to immune checkpoint blockade.
Conclusions:
- Intracellular RAGE ablation effectively suppresses critical cellular pathways driving glioma progression, invasion, and immune evasion.
- RAGE inhibition represents a promising therapeutic strategy for malignant gliomas by targeting multiple tumor-promoting mechanisms.
- This approach holds potential for combination with immunotherapy to overcome treatment resistance in gliomas.
