Investigating the Role of Tumor-Associated Neutrophils (TANs) in the Suppression of T cell Function in Glioblastoma

Abstract

Glioblastoma (GBM) is known as a highly aggressive and malignant form of brain cancer. Despite advances in understanding the genetic and molecular basis of glioblastoma, it has a poor prognosis with a median survival rate of 9 months. The complex interplay between malignant cells and the surrounding tumor microenvironment (TME) plays a pivotal role in tumor progression and treatment response. However, not all of the non-malignant cells have been extensively studied in terms of their contribution towards the TME such as tumor associated neutrophils and its relation with T-cells. We investigated the association and role of TANs in T-cell function suppression to pave the way for novel combinatorial therapeutic strategies for glioblastoma multiforme by co-culturing cells followed by qRT-PCR to observe the changes in gene expression levels and IF staining to understand T-cell activation during the co-culture. It was found that when neutrophils are co-cultured individually with A172 cells, they suppress the aggressive MES-like GBM subtype by downregulating PDGFRA expression. Conversely, co-culturing Jurkat T-cells individually with A172 cells reduces the expression of genes associated with GBM aggressiveness and enhances NF1, a tumor-suppressor gene. However, co-culturing all three cell types together abolishes T-cell-mediated suppression of pro-tumor genes, resulting in immunosuppression. This is evidenced by increased expression of CDK4, PDGFRA, and EGFR, decreased NF1 expression, and reduced fluorescence intensity through immunofluorescence staining. Further experiments can be conducted including cytokine profiling and RNA sequencing analysis to understand the pathways involved in the co-culture process.