Strengthened glycolysis under hypoxia supports tumor symbiosis and hexosamine biosynthesis in pancreatic adenocarcinoma

Abstract

Pancreatic ductal adenocarcinoma is one of the most intractable and fatal cancer. The decreased blood vessel density displayed by this tumor not only favors its resistance to chemotherapy but also participates in its aggressiveness due to the consequent high degree of hypoxia. It is indeed clear that hypoxia promotes selective pressure on malignant cells that must develop adaptive metabolic responses to reach their energetic and biosynthetic demands. Here, using a well-defined mouse model of pancreatic cancer, we report that hypoxic areas from pancreatic ductal adenocarcinoma are mainly composed of epithelial cells harboring epithelial-mesenchymal transition features and expressing glycolytic markers, two characteristics associated with tumor aggressiveness. We also show that hypoxia increases the "glycolytic" switch of pancreatic cancer cells from oxydative phosphorylation to lactate production and we demonstrate that increased lactate efflux from hypoxic cancer cells favors the growth of normoxic cancer cells. In addition, we show that glutamine metabolization by hypoxic pancreatic tumor cells is necessary for their survival. Metabolized glucose and glutamine converge toward a common pathway, termed hexosamine biosynthetic pathway, which allows O-linked N-acetylglucosamine modifications of proteins. Here, we report that hypoxia increases transcription of hexosamine biosynthetic pathway genes as well as levels of O-glycosylated proteins and that O-linked N-acetylglucosaminylation of proteins is a process required for hypoxic pancreatic cancer cell survival. Our results demonstrate that hypoxia-driven metabolic adaptive processes, such as high glycolytic rate and hexosamine biosynthetic pathway activation, favor hypoxic and normoxic cancer cell survival and correlate with pancreatic ductal adenocarcinoma aggressiveness.pancreas | malignancy | metabolism | glutamate N inety-five percent of patients with pancreatic cancer harbor tumors classified as pancreatic ductal adenocarcinoma (PDAC). Commonly described as a silent killer regarding its late diagnosis, PDAC is noted for its aggressiveness and its intrinsic resistance to standard chemotherapy. This specificity is probably due to a low vascular density and a prominent nontumoral cell compartment (stroma), which impact on intratumoral perfusion, therapeutic delivery, and patient outcome (1). Indeed, PDAC is characterized by numerous and severe hypoxic regions (2), a feature that has been proven to be correlated with tumor aggressiveness and poor prognosis compared with well-oxygenated tumors (3). Moreover, combined with hypoxia, the subsequent nutrient-devoid environment provides physiological selective pressure promoting expansion of the most aggressive malignant cells, particularly those acquiring mutations in genes encoding tumor suppressor protein p53 (TP53) and v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog protein (KRAS) (4, 5), two of the main mutations present in PDAC patients. Regarding such statements, it appears relevant to deeply explore consequ...

TAp73 loss favors Smad-independent TGF-β signaling that drives EMT in pancreatic ductal adenocarcinoma

“…Cell lines were developed from tumors of TAp73 WT and TAp73 knockout mice as previously described. 59 Cells were cultured in DMEM/F-12 (Life Technologies, Saint-Aubin, France), 1.22 mg/ml nicotinamide (Sigma-Aldrich, Lille-Lezennes, France), 5 mg/ml glucose (Sigma-Aldrich), 5% ITS+ (BD Biosciences, Le pont de Claix, France), 100 μg/ml gentamicin (Life Technologies), 1x fungizone (Life Technologies), 5% Nu-serum IV (BD Biosciences), 25 μg/ml BPE (Life Technologies), 20 ng/ml EGF (BD Biosciences), 50 nM 3,3′,5-triiodo-Lthyronine (Sigma-Aldrich), 1 μg dexamethasone (Sigma-Aldrich), and 100 ng/ml cholera toxin (Sigma-Aldrich). After 10 passages, cell culture medium was replaced by DMEM (Life Technologies) supplemented with 10% FBS (Sigma-Aldrich).…”

Differential protein analysis of chicken skin infected with Marek΄s disease virus

“…Therefore, glycolytic genes are often overexpressed in tumor cells (Daskalow et al, 2009;Wolf et al, 2011;Zhou et al, 2011). High rates of glycolysis and the activation of the hexosamine biosynthetic pathway may favor cancer cell survival and aggressiveness (Guillaumond et al, 2013). In the current study, TPI1, PGK1 and beta-enolase enzymes, which are all components of the glycolytic pathway, were up-regulated in MDV-infected chickens.…”

LDL Receptor: An open route to feed pancreatic tumor cells

“…The ensuing increase in lactate released by hypoxic cells serves as an energy source for the neighboring oxygenated cells. 4 This illustrates that these 2 tumor cell populations function symbiotically. Under hypoxic stress, pancreatic cancer cells also show an intense appetite for glutamine, and the resulting enhanced glutaminolysis, coupled with increased glycolytic flux, promotes overactivation of the hexosamine biosynthetic pathway (HBP).…”

“…In this GEMM, faithfully reproducing the evolution and malignancy of human disease (Pdx1-Cre; LSL-Kras G12D ; Ink4a/Arf fl/fl mice), we have shown that a fifth of the total tumor area is composed of hypoxic cancer cells. 4 The presence of these hypoxic areas creates a glycolytic gradient within the tumor mass, with hypoxic tumor cells exhibiting a higher glycolytic rate than normoxic cells. The ensuing increase in lactate released by hypoxic cells serves as an energy source for the neighboring oxygenated cells.…”

“…Under hypoxic stress, pancreatic cancer cells also show an intense appetite for glutamine, and the resulting enhanced glutaminolysis, coupled with increased glycolytic flux, promotes overactivation of the hexosamine biosynthetic pathway (HBP). 4 In response to hypoxia, the HBP strongly contributes to tumor aggressiveness because it drives post-translational modifications, such as OGlcNAcylation, that stabilize hypoxia-inducible factor 1, glucose transporter 1, and the glycolytic enzyme phosphofructokinase 1. 5,6 Glucose and glutamine are commonly described as the main substrates for tumor growth.…”