Characterization of the glial profile and glutamatergic cytotoxicity in the tumor microenvironment and surroundings of a new model of pontine diffuse glioma: a preclinical analysis

• Grant number: 24/02441-9
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): May 01, 2024
• Effective date (End): December 31, 2024
• Field of knowledge: Biological Sciences - Physiology - Physiology of Organs and Systems
• Principal Investigator: Danielle Varin de Assis
• Grantee: Leandro Kaoru Shoji
• Host Institution: Hospital Sírio-Libanês. Sociedade Beneficente de Senhoras (SBSHSL). São Paulo , SP, Brazil

Abstract

Diffuse intrinsic pontine glioma (DIPG) is undeniably one of the greatest challenges in modern neuro-oncology. It is a lethal pediatric brain tumor with an average survival of approximately 12 months, deemed untreatable due to its infiltrative nature, complex anatomical location, and well-preserved blood-brain barrier (BBB). This presents a significant challenge for neurosurgeons and researchers in the 21st century. DIPG cells coexist and can recruit, manipulate, and utilize other non-neoplastic normal cells, including endothelial, astrocytic, and immune cells, creating a complex and dynamic tumor microenvironment (TME) recognized as a crucial factor in DIPG progression. Astrocytes from different regions of the Central Nervous System (CNS) exhibit highly distinct morphological, molecular, and functional properties, suggesting the existence of heterogeneous subpopulations.Therefore, deciphering the mechanisms by which astrocytes interact with other TME cells to influence DIPG progression could be crucial for the development of new therapies. Decades of complete ignorance regarding the molecular biology, mechanisms, and microenvironment of DIPG have hindered significant progress in treatment without impacting patient quality of life and survival. Our project aims to gain a better understanding of the tumor microenvironment and adjacent areas by characterizing glial cells and glutamatergic cytotoxicity in an experimental model of DIPG. Additionally, we aim to explore: (i) cytological events (and their dynamics) between tumor cells, neurons, vascular compartments, and immune cells; (ii) regional tumor heterogeneity; and (iii) the role of autophagy in tumorigenesis through immunohistochemistry and immunofluorescence assays. To achieve this, we will evaluate the staining pattern of astrocytes (GFAP) and microglia/macrophages (Iba-1, CD68, and CD163), the glutamatergic receptors NMDAR1 and EAAT2, as well as EGF and VEGF for tumor proliferation, and LC3B and Beclin-1 related to autophagic dysregulation in the proposed model. We hope that our findings may contribute to a better understanding of the tumor microenvironment, aiding in the development of future multi-target therapeutic strategies.