Fig. 2

GLS1 sustains HNSCC cell growth and survival by upregulating glutamine metabolism. A The boxplot shows the pan-cancer expression profiling of GLS1 in human cancers. The row below refers to the standard abbreviations of tumors in TCGA cohorts. B Forest plot visualizing the HRs of GLS1 in human cancers. The first three columns display the cancer type, p-value, and HR, respectively. In the forest plot, risk factors are shown in red. (C) The knockdown effect of shGLS1 in HNSCC cells determined by Western blotting. shGFP: a negative control shRNA targeting the gene encoding GFP; shGLS1: shRNAs targeting the GLS1 gene. Numbers indicate different sequences of shGLS1. D Changes in secreted glutamate and glutamine consumption determined by Glutamine/Glutamate-Glo Assays in HNSCC cells with or without GLS1 knockdown. E The effect of GLS1 knockdown on HNSCC cell viability determined by MTT. F, G The effect of GLS1 knockdown on tumorsphere formation in HN6 and HN12 cells. Representative images and quantitative are shown in (F) and (G), respectively. Scale bar = 100 μm. H The effect of GLS1 knockdown on HN6-derived tongue tumor growth in NSG mice. Representative tongue tumors and quantitative data of tumor volume (n = 5/group) are shown in the upper and lower panels, respectively. I The effect of GLS1 knockdown on tumor cell proliferation determined by IHC with anti-Ki67 antibody. Representative IHC images and quantitative data (n = 5) are shown in left and right panels, respectively. Scale bar = 50 μm. *p < 0.05, **p < 0.01