Tumor cells boost IL-6–driven glutamine synthesis in fibroblasts by activating Syk/NF-κB pathway. (A) Kinome assay of NFs treated with or without TCM for 3 h (n = 4 for each group). Median final score is plotted against mean kinase statistic, which represents normalized kinase statistics (>0 indicates higher activity in TCM group). (B and C) NFs were treated with TCM in the presence of Syk inhibitor R406 for 24 h. qPCR analysis of relative mRNA expression levels of GS (B) and Il6 (C). (D and E) NFs were pretreated with NF-κB inhibitor PDTC for 30 min and then were treated with TCM for 24 h. qPCR analysis of relative mRNA expression levels of GS (D) and Il6 (E). (F and G) qPCR analysis of relative mRNA expression levels of glutamine synthesis pathway genes (F) or Il6 (G) in NFs with Syk or NFkB p65 knockdown treated with TCM for 24 h. Data in A were analyzed using paired t test with a false discovery rate (FDR) correction applied for multiple comparisons at a threshold of 0.1. Data are representative of at least two independent experiments with similar results (B–E and G) or cumulative results from at least two independent experiments (F and G). All data are shown as mean ± SEM and were analyzed by two-way ANOVA with Sidak’s multiple comparison test (B–G). ****P < 0.0001; ***P < 0.001; **P < 0.01; *P < 0.05; P > 0.05 not significant (ns).