P01.29.A GLIOBLASTOMA CELL MOTILITY AND INVASION IS REGULATED BY MEMBRANE-ASSOCIATED HEAT SHOCK PROTEIN HSP70

Abstract BACKGROUND Glioblastoma multiforme (GBM) is the most aggressive primary brain tumor which characterized by a high ability to migrate and invade into surrounding brain tissue. The main problem in therapy is the tumor’s high invasiveness. The heat shock protein 70 (Hsp70) has a cytoplasmic localization in normal cells but specifically localized on the plasma membrane (mHsp70) of tumor cells which makes it a promising therapeutic target. We investigated the role of mHsp70 in motility of GBM cells. MATERIAL AND METHODS The study was performed using primary human glioblastoma cell cultures (n=4) isolated from biopsy material. The expression of mHsp70 was detected with confocal microscopy, flow cytometry, Western blot, and proteome analysis of lipid rafts. Сells were sorted into two subpopulations - high (mHsp70High) and low expressed mHsp70 (mHsp70Low). The motility characteristics were studied using automatic single-cell tracking and transwell analysis with Hsp70 inhibitors (PES, JG-98) blocking different domains. RESULTS The expression of mHsp70 was observed in 100% of cell populations. The highest content of mHsp70 revealed in lamellipodia and filopodia. Proteomic analysis of lipid rafts identified the interaction of mHsp70 with proteins involved in cytoskeletal remodeling and migration (tubulin-β, tubulin-α4a, myosin IX, filamin A, integrin β-1, α-enolase and the small GTPase RhoA) that may indicate the chaperone participation in the regulation of migration. The mHsp70High subpopulations had a mean speed of 1.5-2 times higher than mHsp70Low. The inhibitors of Hsp70 effectively decrease GBM cells speed. CONCLUSION This study expands our understanding of mHsp70 influence to the migration of GBM cells. The protein expression level correlates with motility. The Hsp70 inhibitors reduces the invasive potential of cells, which allows to use them as an adjuvant agents in the development of novel approaches to the treatment of malignant tumors. Research was funded by the Ministry of Science and Higher Education of Russia (agreement № 075-15-2022-301).