Shift in Subcellular Expression and Increase in Immune Response Pathways After Radiation Suggests That HMGB2 is a Damage-Associated Molecular Pattern (DAMP) in Gliomas

Document Type

Conference Proceeding

Publication Date

11-2025

Publication Title

Neuro-Oncology

Abstract

While HMGB2 nuclear expression in gliomas is associated with enhanced cell proliferation, high HMGB2 expression in adult glioblastomas yielded better response to treatments with radiation+temozolomide and with viral vectors. Here we aimed to explore causes for this divergence and to generate a stable cell line with lentiviral-mediated HMGB2-GFP overexpression (HMGB2-GFP OE) for mechanistic studies on the role of HMGB2 in radiation response. METHODS AND RESULTS: 1) Mass spectrometry label-free proteomic analysis of THP-1 and U87 cells’ secretomes identified HMGB2 as one of the top proteins with decreased abundance in conditioned media from co-culture, compared to that from each cell line individually. 2) Subcellular immunoblotting indicated HMGB2 nucleus-to-cytoplasm translation 1h after 3Gy radiation of U87, SF188, and KNS42 cell lines compared to un-irradiated cells. 3) HMGB2 cytoplasmic expression was associated with up-regulation of immune response pathways at microarray transcriptomic analysis from SF188 cells, compared to clones with shRNA-mediated HMGB2-knockdown 1h and 4h after 3Gy radiation. 4) Lentiviral vectors containing GFP (eGFP and HMGB2-GFP) were successfully transduced in KNS42 cells and HMGB2 expression and subcellular location in both clones were assessed with immunoblot and direct fluorescence visualization. CONCLUSION: The differential secretion under mono- and co-culture suggested that HMGB2 may be an agent of intercellular communication between tumor (U87) and immune (THP-1) cells. HMGB2 nucleus-cytoplasmic translocation along with upregulation of immune pathways occurring after radiation in glioma cells in monoculture raises the hypothesis that HMGB2 is involved in immunogenic cell death and acts as a damage-associated molecular pattern (DAMP), like its paralog HMGB1, in pediatric and adult glioma cell lines. Our stable clones with HMGB2-GFP OE will allow us to explore the mechanistic aspects and the role of HMGB2 in glioma response to radiation, with improved direct visualization of the tumor-immune cells crosstalk in future in vitro and in vivo experiments.

Volume

27

Issue

Suppl 5

First Page

v392

Last Page

v392

Comments

World Federation of Neuro-Oncology Societies and Society for NeuroOncology Annual Meeting, November 19-23, 2025, Honolulu, HI

DOI

10.1093/neuonc/noaf201.1553

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