Tag Archives: glutamine deprivation
ERN1 modifies the effect of glutamine deprivation on tumor growth related factors expression in U87 glioma cells
O. H. Minchenko, A. P. Kharkova, O. S. Hnatiuk, O. Y. Luzina, I. V. Kryvdiuk, A. Y. Kuznetsova
Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: ominchenko@yahoo.com
The expression of a subset of genes encoding important tumor growth related factors in U87 glioma cells with ERN1 (endoplasmic reticulum to nucleus signaling 1) loss of function as well as upon glutamine deprivation was studied. It was shown that glutamine deprivation down-regulated the expression level of ATF6 (activating transcription factor 6), EIF2AK3/PERK (eukaryotic translation initiation factor 2 alpha kinase 3), GLO1 (glyoxalase I), BIRC5 (baculoviral IAP repeat-containing 5), and RAB5C (RAB5C, a member of RAS oncogene family) mRNAs in control glioma cells. At the same time, the expression level of HSPB8 (heat shock 22kDa protein 8) and HSPA5/GRP78 (heat shock protein family A (Hsp70) member 5) mRNAs was resistant to glutamine withdrawal in these glioma cells. It was also shown that inhibition of ERN1, which controled cell proliferation and tumor growth, modified the effect of glutamine deprivation on the expression levels of most studied genes in U87 glioma cells: up-regulated the expression of ATF6 and HSPA5 genes and enhanced sensitivity of EIF2AK3 and BIRC5 genes to glutamine withdrawal. Furthermore, the expression of all studied genes, except EIF2AK3, was down-regulated in ERN1 knockdown glioma cells in the presence of glutamine. It was demonstrated that glutamine deprivation affected the expression of most studied genes in ERN1 dependent manner and that these changes possibly contributed to the suppression of glioma growth from cells without ERN1 signaling enzyme function.
Expression of ubiquitin specific peptidase and ATG7 genes in U87 glioma cells upon glutamine deprivation
O. V. Halkin1, D. O. Minchenko1,2, О. O. Riabovol1,
V. V. Telychko1, О. O. Ratushna1, O. H. Minchenko1
1Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: ominchenko@yahoo.com;
2Bohomolets National Medical University, Kyiv, Ukraine
We have studied the effect of glutamine deprivation on the expression of genes encoding for ubiquitin specific peptidases (USP) and ubiquitin activating enzyme E1-like protein/autophagy related 7 (GSA7/ATG7) in U87 glioma cells in relation to inhibition of inositol requiring enzyme-1 (IRE1). It was shown that exposure of control glioma cells (transfected by empty vector) upon glutamine deprivation led to suppression of USP1 and ATG7 mRNA expression and up-regulated USP25 mRNA. At the same time, glutamine deprivation did not significantly change USP4, USP10, USP14, and USP22 gene expressions in these cells. Inhibition of ІRE1 signaling enzyme function in U87 glioma cells increased effect of glutamine deprivation on the expression of USP1 gene and introduced sensitivity of USP4 and USP14 genes to this condition. Therefore, glutamine deprivation affected the expression level of most studied genes in gene specific manner in relation to the functional activity of IRE1 enzyme, a central mediator of endoplasmic reticulum stress, which controls cell proliferation and tumor growth.
Expression of IGFBP6, IGFBP7, NOV, CYR61, WISP1 and WISP2 genes in U87 glioma cells in glutamine deprivation condition
O. H. Minchenko1, A. P. Kharkova1, D. O. Minchenko1,2, L. L. Karbovskyi1
1Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: ominchenko@yahoo.com;
2Bohomolets National Medical University, Kyiv, Ukraine
We have studied gene expression of insulin-like growth factor binding proteins in U87 glioma cells upon glutamine deprivation depending on the inhibition of IRE1 (inositol requiring enzyme-1), a central mediator of endoplasmic reticulum stress. We have shown that exposure of control glioma cells upon glutamine deprivation leads to down-regulation of NOV/IGFBP9, WISP1 and WISP2 gene expressions and up-regulation of CYR61/IGFBP10 gene expression at the mRNA level. At the same time, the expression of IGFBP6 and IGFBP7 genes in control glioma cells was resistant to glutamine deprivation. It was also shown that the inhibition of IRE1 modifies the effect of glutamine deprivation on the expression of all studied genes. Thus, the inhibition of IRE1 signaling enzyme enhances the effect of glutamine deprivation on the expression of CYR61 and WISP1 genes and suppresses effect of the deprivation on WISP2 gene expression in glioma cells. Moreover, the inhibition of IRE1 introduces sensitivity of the expression of IGFBP6 and IGFBP7 genes to glutamine deprivation and removes this sensitivity to NOV gene. We have also demonstrated that the expression of all studied genes in glioma cells growing with glutamine is regulated by IRE1 signaling enzyme, because the inhibition of IRE1 significantly down-regulates IGFBP6 and NOV genes and up-regulates IGFBP7, CYR61, WISP1, and WISP2 genes as compared to control glioma cells. The present study demonstrates that glutamine deprivation condition affects most studied IGFBP and WISP gene expressions in relation to IRE1 signaling enzyme function and possibly contributes to slower glioma cell proliferation upon inhibition of IRE1.