P01.34.B MEMBRANE-BOUND EPICHAPEROME SUPPORTS MOLECULAR NETWORKS FACILITATING GLIOBLASTOMA CELL MIGRATION AND INVASION

Abstract BACKGROUND Heat shock proteins (HSP), in particular representatives of the HSP70 and HSP90 families, which are the folding centers of almost all cell proteins, have a wide range of interactions,which includes many molecules involved in cell migration and invasion pathways. Analyzing the interaction networks associated with chaperones (interactome) can provide data on the functional nodes for studying different aspects of tumor pathogenesis, and several studies have been already conducted for HSP90. Due to the molecular heterogenity of tumor cells, it’s necessary to gather HSP-related protein networks from primary samples of malignant neoplasms. The aim of the study was to identify functional patterns in the interactome of membrane-bound HSP70 tumors of the central nervous system. MATERIAL AND METHODS Magnetic nanoparticle conjugates (SPIONs) with monoclonal antibodies to HSP70 were tested as a platform for affinity-driven protein isolation. The HSP70 interactome samples were isolated from primary glioblastoma culture cells from patients (n=5) of the Polenov Research Institute of Neurosurgery and cell lines (C6, U251, T98G) (“Collection of Vertebrate Cell Cultures”, Russia). Similar isolates from mesenchymal stem cells were studied as a control. Interactome samples were analyzed using the method of mass spectrometry (SCIEX TOF 5800) with processing of the protein database in Cytoscape software. RESULTS During the analysis of interactome networks, it was observed that glioblastoma networks had greater heterogeneity and centralization in comparison with control. A set of proteins mediating migration and invasion (PLEC, EPPK, JUP) is a cluster represented for all analyzed tumor interactomes, and HSP70 chaperome proteins (P4HB, HSP90, HSPA8) mediate the cluster interface. These nodes of organization also have increased presence in tumor samples. Compared to stem cells, proteins mediating invasion (RAF1, DSP, DSG1) also are more abundant in glioblastoma. CONCLUSION The organization of HSP70 networks may determine the aggressive migration of neoplasms, and the elements of the chaperome are involved in functional cluster interplay, opening up targets for pathogenesis research.