Figure 1

Glutamine metabolism is critical for overall survival and proliferation of NSCLC. (a) As was the case with the clinical information dataset from TCGA, higher levels of expression of GLS and TYMS were associated with reduced overall survival. Log-rank P-values of the genes were 0.0043 and 0.0135, respectively. Cases with higher expression levels of GLS and TYMS are coloured red, and cases without higher expression levels of these genes are coloured black. (b) Immunohistochemical staining of GLS1. The expression level of GLS1 in NSCLC tumour tissues was significantly higher than that in penumocytes from normal lung tissues (N=57).The expression score was obtained from immuno-staining intensity and the percentage of positive cells in tissue microarray core as in Materials and Methods. The expression score was significantly higher in NSCLC tumor cells than in normal lung pneumocytes (P<0.0001 by Mann-Whitney U test). (c) NSCLC cells were treated with glutamine-free medium for 48 h, and cell proliferation was tested by the SRB assay. (d) NSCLC cells were treated with GLS1 inhibitor, bis-2-(5-phenylacetamido-1,3,4-thiadiazol-2-yl)ethyl sulfide (BPTES, 100 μM), for 48 h, and cell proliferation was tested by the SRB assay. (e) The expression level of GLS1 in NSCLC cells and the primary small airway epithelial cells IMR90 was analysed by immunoblotting. SRB, sulforhodamine B