TMIC-51. THE RELEASE OF INFLAMMATORY CYTOKINES ARE REGULATED BY PYK2 SIGNALING IN GBM CELLS

Abstract

Abstract Glioblastoma (GBM) is a highly aggressive brain cancer that is typically fatal within a year of diagnosis. Previous research has shown a positive relationship between the activation of a protein called proline-rich non-receptor tyrosine kinase (Pyk2) in GBM cells in addition to the expression of cytokines by tumor-infiltrating myeloid (TIM cells). Leading to a sustained increase in the expression levels of monocyte chemoattractant protein 1 (CCL2), granulocyte-macrophage colony-stimulating factor (GM-CSF), IL10, IL12, and vascular endothelial growth factor (VEGF), as well as an increase in the CD86+/CD206+ TIM population. We hypothesize that Pyk2 signaling in GBM cells is involved in the regulation of the release of inflammatory cytokines, which in turn suppresses the immune response in the tumor microenvironment. We used CRISPR/Cas9 knockout Pyk2 (Pyk2KO) and wild type (Pyk2WT) GL261 mouse glioma cells in this study. Analysis of the cytokines present in the cell culture medium conditioned by Pyk2KO and Pyk2WT cells identified a decrease in the release of CCL2 and CCL5 in the Pyk2KO cells compared to the Pyk2WT cells. RT-PCR analysis of myeloid cell population, isolated from Pyk2WT and Pyk2KO tumors in the GL261-C57Bl/6 GBM model, identified a significant down-regulation of key pro-tumorigenic factors such as CCL2, CCL12, CCL5, tumor necrosis factor (TNF), VEGF and epidermal growth factor (EGF) in the Pyk2KO tumors compared to the Pyk2WT tumors. Additionally, flow cytometry analysis revealed a reduction in myeloid-derived suppressor cells (MDSCs), an increase in lymphoid dendritic cells (DC), and up-regulation in TNF/IFNg expressing and antigen-specific CD8+ T cells in Pyk2KO tumors. Furthermore, a significant decrease in pro-tumorigenic Ly6C+/CD206+ and an up-regulation of inflammatory Ly6C+/CD86+ myeloid cells were found in the Pyk2KO tumors. These findings suggest that Pyk2KO tumors display an immunocompetent microenvironment with enhanced phagocytic and cytotoxic function compared to Pyk2WT tumors. NIH Grant 1SC1GM122691 and PRSTRT2022 supported this study