Fig. 1: Glutamine deprivation induces IL-8 synthesis and secretion through the GCN2-ATF4 pathway. | Cell Death Discovery

Fig. 1: Glutamine deprivation induces IL-8 synthesis and secretion through the GCN2-ATF4 pathway.

From: Activation of the integrated stress response and loss of cFLIPL under glutamine limitation induce IL-8 gene expression and secretion in glutamine-dependent tumor cells

Fig. 1

A HCT116 cells were cultured in the presence or absence of glutamine for 16 and 24 h and IL-8 and CXCL1 mRNA levels were assessed via RT‒qPCR as described in the Materials and Methods section. Relative mRNA levels were determined by comparison to those observed under glutamine-supplemented conditions at each corresponding time point. B HCT116 cells were treated as described in A) and the resulting supernatants were analysed for IL-8 production by ELISA as described in the Materials and Methods. In C-E HCT116 cells were transfected with either a scrambled oligonucleotide or siRNAs targeting GCN2, ATF4 or CHOP. Forty-eight hours after transfection, the cells were incubated for 16 h in complete or glutamine-deprived medium, and the IL-8 (C) or TRAIL-R2/DR5 (D) mRNA levels were assessed by RT‒qPCR. Relative levels of IL-8 or TRAIL-R2/DR5 mRNA were quantified relative to those in scrambled siRNA-transfected cells under glutamine-supplemented conditions. ATF4, CHOP, TRAIL-R2/DR5 and GCN2 protein levels were assessed by western blotting after 16 h of treatment (E). α-Tubulin, Hsp70 and GAPDH were used as protein loading controls. Data are presented as mean ± SD from at least three independent experiments and were analyzed using two-way ANOVA. **P < 0.01; ***P < 0.001; ****P < 0.0001; ns not statistically significant.

Back to article page