Pancreatic stellate cells (PSCs) are crucial for metabolism and disease progression in pancreatic ductal adenocarcinoma (PDAC). However, detailed mechanisms of PSCs in glutamine (Gln) metabolism and tumor-stromal metabolic interactions have not been well clarified. Here we showed that tumor tissues displayed Gln deficiency in orthotopic PDAC models. Single-cell RNA sequencing analysis revealed metabolic heterogeneity in PDAC, with significantly higher expression of Gln catabolism pathway in stromal cells. Significantly higher glutamine synthetase (GS) protein expression was further validated in human tissues and cells. Elevated GS levels in tumor and stroma were independently prognostic of poorer prognosis in PDAC patients. Gln secreted by PSCs increased basal oxygen consumption rate in PCCs. Depletion of GS in PSCs significantly decreased PCCs proliferation in vitro and in vivo. Mechanistically, activation of Wnt signaling induced directly binding of β-catenin/TCF7 complex to GS promoter region and upregulated GS expression. Rescue experiments testified that GS overexpression recovered β-catenin knockdown-mediated function on Gln synthesis and tumor-promoting ability of PSCs. Overall, these findings identify the Wnt/β-catenin/TCF7/GS-mediated growth-promoting effect of PSCs and provide new insights into stromal Gln metabolism, which may offer novel therapeutic strategies for PDAC.
Keywords: Cancer-associated fibroblasts; Metabolic crosstalk; Stromal glutamine metabolism; Tumor proliferation; Wnt signaling.
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