P02.19.A ASSESSMENT OF HEAT SHOCK PROTEIN HSP70 EXPRESSION IN THE GLIOBLASTOMA STEM-LIKE CELLS

Abstract

Abstract BACKGROUND Glioblastoma multiforme (GBM) is a malignant brain tumor characterized by poor prognosis. The search of biomarkers for early diagnosis and as targets and for tumor theranostics due to the aggressiveness of the disease is urgently needed. One of the promising targets for therapy of brain tumors is 70 kDa heat shock protein (Hsp70), which has been found on the plasma membrane of various tumor cells (including GBM) but not on normal cells. GBM, like other types of tumors, has cellular heterogeneity. In particular, it contains tumor stem-like cells (TSLCs), which are considered analogues of healthy stem cells and are largely responsible for disease progression, recurrence and mediate resistance to ongoing therapy. In the present work, the histological sections of human GBM were analyzed to identify and quantify the colocalization of the heat shock protein Hsp70 with TSLC markers using the Opal Multiplex analysis system. MATERIAL AND METHODS Histological sections were prepared in accordance with the standard protocol using postoperative material from patients with newly diagnosed GBM (n=15). Zones of necrosis and living tissue were identified on tumor sections. Based on a phenotyping map using the Pathology Views™ fluorescence image analysis software, Hsp70 colocalization was quantified with Nestin and Sox2 in the areas of necrosis and viable tissue employing primary antibodies (anti-Hsp70, anti-Nestin and anti-Sox2). The preparations were stained using an Opal 3-Plex Manual Detection Kit according to the manufacturer's protocol. RESULTS The expression of Hsp70 and TSLC markers (Nestin and Sox2) was detected. The obtained quantitative data did not reveal significant differences in the distribution of cells expressing Hsp70 in the areas of necrosis and viable tissue (36 and 41%, respectively), which may indicate their uniform distribution in the tumor. Sufficiently high colocalization of Hsp70 with Nestin and Sox2 factors was detected mainly in the zone of viable tissue (57 and 30%, respectively). CONCLUSION Colocalization of Hsp70 with TSLC markers indicates the prospects for further studies of Hsp70, as well as its use for targeted therapy of malignant brain tumors.