023 | Chaperone-associated macrophage polarization and extracellular matrix remodelling in human glioblastoma

Leila Noori^1|2, Rosario Barone¹, Giuseppe Vergilio^1|2, Maria Antonella Augello¹, Giuseppa D’Amico¹, Federica Scalia³, Pierlorenzo Veiceschi², Giovanni Tringali², Francesco Cappello¹, Celeste Caruso Bavisotto¹ | ¹Department of Biomedicine, Neuroscience and Advanced Diagnostics [BiND], University of Palermo, Italy; ²Department of Neurosurgery, National Relevance and High Specialization Hospital Trust ARNAS, Palermo, Italy; ³Department of Medicine and Surgery, Kore University of Enna, Italy.

Glioblastoma (GBM) is the most aggressive central nervous system tumor, with a poor prognosis and no effective treatment because of its high invasiveness, metabolic rate, and heterogeneity. The tumor microenvironment (TME) is characterized by massive cellular stress and contains many tumor-associated macrophages (TAMs), particularly M2-like macrophages, which play a critical role in tumor proliferation, invasion, metastasis, and angiogenesis and indirectly promote an immunosuppressive microenvironment [1]. Molecular chaperones are key regulators of cellular stress responses, cytoskeletal dynamics, and protein homeostasis, however, their involvement in macrophage polarization and ECM remodeling in GBM remains poorly defined [2]. In this preliminary study, human GBM biopsies and peri-tumoral tissues have been analyzed for macrophage markers (CD68, CD163), chaperones (hsp60, CCT5), cytoskeletal components (actin, tubulin), and ECM-remodeling enzyme MMP9 expression. Signal intensity and spatial co-localization were qualitatively assessed across tumoral and peri-tumoral regions. GBM tissues displayed strong CD68 immunoreactivity, accompanied by high hsp60 expression and marked co-localization, suggesting a stress-associated macrophage population within the tumor core. In peri-tumoral areas, CD163-positive cells were rare whereas multiple GBM biopsies showed robust CD163 expression, consistent with enrichment of M2-like macrophages in tumoral regions. Co-localization of CD163 with hsp60 was prominent in tumoral samples but markedly reduced in peri-tumoral tissue, indicating a potential association between chaperone expression and M2 polarization in GBM. In addition, a subset of GBM cases exhibited a pronounced colocalization between CD163-positive macrophages and MMP9, supporting a role for M2 macrophages in ECM remodeling and invasive niche formation. Whereas another subset showed high expression and co-localization of actin, tubulin, and the chaperonin CCT5, suggesting chaperone the involvement of chaperones in cytoskeletal reorganization and migratory capacity of tumor cells. These findings support a model in which molecular chaperones are enriched in GBM-associated macrophages and tumor cells, potentially linking cellular stress responses to M2 macrophage polarization, ECM remodeling, and invasive tumor behavior. Although limited by sample size, this study provides initial evidence that chaperone networks may contribute to the pro-tumoral microenvironment of GBM and warrant further investigation as potential therapeutic targets.