Luzina O. Role of IRE1 on the expression of NAMPT and related proteins in U87 glioma cells.

The main research topic of the dissertation was to study molecular mechanisms of interactions at the level of gene expression in different types of tumors in order to improve and create new strategies to struggle against this disease. The current study aimed to investigate intergenic interactions in glioma cells by studying gene expression under conditions of silencing mRNA NAMPT and inhibition of the IRE1 signaling protein. For the first time it was shown that in U87 glioma cells with inhibited protein kinase and endoribonuclease activity or only endoribonuclease of IRE1, there is a decrease in the level of expression mRNA and protein of the pro-proliferative NAMPT in comparison with the control cells, indicating that these changes are mediated by endoribonuclease IRE1. Moreover, we found binding sites for miR-182 miRNAs on 3'-untranslated regions of NAMPT mRNA, and the level of this miR-182 increases under conditions 8 of IRE1 inhibition. Thus, IRE-dependent regulation expression of mRNA NAMPT can be performed at the post-transcriptional level by increasing miR-182 miRNA activity. It was shown that inhibition of the functional activity of IRE1 affects the expression of the most studied genes in U87 glioma cells, and silencing of NAMPT leads to opposite changes in mRNA expression. It has been shown that inhibition of IRE1 differentially modifies the effect of hypoxia, an important tumor growth factor, on the expression level of most studied genes. It was demonstrated that glutamine deprivation affected the expression of most studied genes in IRE1 dependent manner and that these changes possibly contributed to the suppression of glioma growth from cells without IRE1 signaling enzyme function. Dysregulation of most of the studied genes in glioma cells after silencing of NAMPT may be reflected by a complex of intergenic interactions in the conditions of metabolic changes in gliomas. This study provides unique insights into the molecular mechanisms of genome reprogramming in IRE1 and NAMPT knockdown glioma cells, are important for assessing and predicting the effects of targeted 9 therapy, and allow the identification of potential targets for further research and the creation of new approaches to combating the disease. Keywords: glioma, gene expression, IRE1 inhibition, silencing of NAMPT, endoplasmic reticulum stress, hypoxia, glutamine deprivation.