Advisor(s)
Christohper Willey
Committee Member(s)
C Miller
J Rose
Peter King
William Placzek
School
School of Health Professions
Document Type
Dissertation
Department (new version)
Health Professions
Date of Award
9-11-2025
Abstract
Glioblastoma (GBM) remains one of the most treatment-refractory cancers, with few therapeutic advances translating into survival benefit. With a median survival of just 15-18 months, the need for effective therapies is urgent. A key obstacle is the underutilization of tumor-associated macrophages (TAMs) in preclinical models. TAMs account for a sizable proportion of GBM by mass and drive malignant behaviors such as angiogenesis, invasion, and resistance to chemoradiotherapy, making them attractive therapeutic targets. Unfortunately, most in vitro GBM-TAM models are inadequate, as they fail to capture the cellular heterogeneity and microenvironmental interactions that drive tumor progression, therapeutic resistance, and immune evasion. To address this gap, we developed and rigorously characterized a fully serum-free triculture platform of GBM patient-derived xenograft (PDX) cell lines, astrocytes, and macrophages. This system preserves the stem-like properties of PDX cells while supporting canonical astrocyte and macrophage functions. When cultured together, GBM PDX cells upregulate markers of hypoxia and stemness, underscoring the importance of including non-neoplastic stromal cells to recreate a physiologically relevant model system in vitro. Furthermore, we demonstrated that these GBM PDX cells polarize our macrophages to a unique TAM-like state that diverges from the classical M1/M2 polarization states that are frequently used to model TAM interactions. We also demonstrated that macrophages polarized by RT-selected GBM PDX cells exhibit a phenotype characterized by elevated interferon signatures, which we validated using spatial transcriptomics on 10 matched primary and recurrent GBM samples. Our model offers a scalable in vitro system faithfully recapitulates GBM-TAM crosstalk, thereby allowing us to study the effects of genetically distinct GBMs on TAM polarization. Preliminary spatial analysis of human GBM samples revealed niche-specific enrichment of macrophage subtypes. Lipid-catabolic macrophage signatures were enriched in the invasive edge, the region responsible for post-resection recurrence, while inflammatory and phagocytic macrophage signatures were enriched in the hypoxic core. Confirming these spatial patterns in situ will benchmark further refinement of our triculture model system. Altogether, this dissertation presents a high-throughput, physiologically faithful in vitro model of GBM-TAM interactions that is poised to accelerate immunomodulatory drug discovery and deepen our understanding of tumor-immune crosstalk in GBM.
ProQuest ID
Recommended Citation
Alrefai, Hasan, "Moving Beyond M1/M2: Xenoline-Polarized Macrophages As A Physiologically Relevant Model Of Tumor-Associated Macrophages In Glioblastoma" (2025). All ETDs from UAB. 7351.
https://digitalcommons.library.uab.edu/etd-collection/7351
