RAGE expression in tumor-associated macrophages promotes angiogenesis in glioma

Area of Science:

• Oncology
• Immunology
• Molecular Biology

Background:

• Receptor for advanced glycation endproducts (RAGE) signaling promotes tumor progression, invasion, and angiogenesis.
• Blocking RAGE is a potential anticancer strategy, but its role in the tumor microenvironment (TME) is unclear.
• Gliomas are brain tumors with complex interactions within their TME.

Purpose of the Study:

• To investigate the effect of genetic RAGE depletion in the TME on glioma growth.
• To determine the mechanisms by which RAGE influences glioma progression and survival.
• To elucidate the role of RAGE in TME-mediated angiogenesis and inflammation.

Main Methods:

• Utilized genetically modified mice with RAGE knockout (Ager(-/-)) in the TME.
• Compared glioma growth, survival, and TME characteristics in Ager(-/-) and wild-type mice.
• Analyzed angiogenesis, vascularity, and expression of proangiogenic and inflammatory factors.
• Investigated the role of tumor-associated macrophages (TAM) by reconstituting Ager(-/-) TAM with wild-type cells.

Main Results:

• RAGE knockout in the TME prolonged animal survival in both invasive and noninvasive glioma models.
• Improved survival was linked to reduced tumor-associated inflammation, not altered tumor growth rate.
• RAGE ablation abrogated angiogenesis by downregulating proangiogenic factors, leading to leaky vasculature.
• VEGF and proinflammatory cytokine expression were lower in TAMs of Ager(-/-) mice, particularly in noninvasive gliomas.
• Reconstitution of RAGE-deficient TAMs with wild-type cells normalized tumor vascularity.

Conclusions:

• RAGE signaling in glioma-associated microglia and TAMs is a key driver of angiogenesis.
• Targeting RAGE in the TME represents a promising strategy for glioma treatment.
• RAGE plays a complex role in gliomagenesis, influencing both inflammation and vascularization.