IRE1 KNOCKDOWN MODIFIES THE EFFECT OF GLUTAMINE DEPRIVATION ON THE EXPRESSION OF A SUBSET OF PROTEASES IN U87 GLIOMA CELLS

The aim of this research was to study the effect of glutamine deprivation on the expression of genes encoding for HTRA1/PRSS11, LONP1/PRSS15, and some cathepsins in U87 glioma cells in relation to inhibition of IRE1 (inositol requiring enzyme-1). It was shown that in control glioma cells (transfected by empty vector) glutamine deprivation up-regulated the expression of LONP1, CTSD, CTSF, CTSO, and CTSS genes, down-regulated HTRA1, CTSC, and CTSK gene expressions, and did not significantly change the expression of CTSA, CTSB, and CTSL genes. Inhibition of ІRE1 signaling enzyme function in U87 glioma cells modified the effect of glutamine deprivation on the expression of HTRA1, LONP1, CTSD, CTSL, CTSO, and CTSS genes: removed the effect of glutamine deprivation on HTRA1 and CTSO genes, introduces on CTSL gene, reduced — on CTSD gene, and enhanced — on LONP1 and CTSS genes. Therefore, glutamine deprivation affect the expression level of most studied genes in relation to the functional activity of IRE1 enzyme, a central mediator of endoplasmic reticulum stress, which responsible for control of cell proliferation and tumor growth.