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We have studied the glucose and glutamine deprivation effect on the expression of nuclear genes encoding mitochondrial proteins in U87 glioma cells in relation to inhibition of inositol requiring enzyme-1 (IRE1). It was shown that glutamine deprivation down-regulated the expression of mitochondrial (NADP+)-dependent isocitrate dehydrogenase 2 (IDH2), malic enzyme 2 (ME2), mitochondrial aspartate aminotransferase (GOT2), and subunit B of succinate dehydrogenase (SDHB) genes in control glioma cells in gene specific manner. At the same time, the expression level of malate dehydrogenase 2 (MDH2) and subunit D of succinate dehydrogenase (SDHD) genes in these cells was not changed upon glutamine deprivation. It was also shown that inhibition of ІRE1 signaling enzyme function in U87 glioma cells modified the glutamine deprivation effect on the expression of all studied genes. Furthermore, the expression of the majority of studied genes was resistant to glucose deprivation, except IDH2 and SDHB genes, which expression levels were slightly down-regulated. Inhibition of IRE1 modified the effect of glucose deprivation on ME2, SDHB, SDHD, and GOT2 genes expression. Therefore, glucose and glutamine deprivation affected the expression level of the majority of nuclear genes encoding mitochondrial proteins in relation to the functional activity of IRE1 enzyme, which is a central mediator of endoplasmic reticulum stress and controls cell proliferation and tumor growth. [ABSTRACT FROM AUTHOR]

We have studied the expression of genes encoding proliferation related factors and enzymes such as IL13RA2, KRT18, CD24, ING1, ING2, MYL9, BET1, TRAPPC3, ENDOG, POLG, TSFM , and MTIF2 in U87 glioma cells upon glucose and glutamine deprivation in relation to inhibition of inositol requiring enzyme 1, a central mediator of endoplasmic reticulum stress. It was shown that glutamine deprivation leads to up-regulation of the expression of BET1, MYL9 , and MTIF2 genes and down-regulation of CD24, ING2, ENDOG, POLG , and TSFM genes in control (with native IRE1) glioma cells. At the same time, glucose deprivation enhances the expression of MYL9 gene only and decreases - ING1, ING2, and MTIF2 genes in control glioma cells. Thus, effect of glucose and glutamine deprivation on gene expressions in glioma cells is gene-specific. Inhibition of inositol requiring enzyme 1 by dnIREI significantly modifies the effect of both glutamine and glucose deprivation on the expression of most studied genes with different direction and magnitude, especially for ING2, CD2 4, and MTIF2 genes. Present study demonstrates that IRE1 knockdown modifies glucose and glutamine deprivation effects on the expression of proliferation related genes and possibly contributes to slower tumor growth of these glioma cells after inhibition of IRE1 signaling enzyme. [ABSTRACT FROM AUTHOR]