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...

we explore a new cellular crosstalk between CAFs and tumor cells, based on extracellular vesicles (EVs), and investigate the inhibition of a related candidate therapeutic target as well as detecting it in serum as a diagnostic biomarker to discriminate PDA grade.

Abstract:Pancreatic ductal adenocarcinoma (PDAC) is characterized by extensive stroma and pathogenic modifications to the peripheral nervous system that elevate metastatic capacity. In this study, we show that the IL-6-related stem cell promoting factor LIF supports PDACassociated neural remodeling (PANR). LIF was overexpressed in tumor tissue compared to healthy pancreas, but its receptors LIFR and gp130 were expressed only in intratumoral Significance:This study suggests a target to limit neural remodeling in pancreatic cancer, which contributes to poorer quality of life and heightened metastatic progression in patients.

Advances made in pancreatic cancer therapy have been far from sufficient and have allowed only a slight improvement in global survival of patients with pancreatic ductal adenocarcinoma (PDA). Recent progresses in chemotherapy have offered some hope for an otherwise gloomy outlook, however, only a limited number of patients are eligible because of important cytotoxicity. In this context, enhancing our knowledge on PDA initiation and evolution is crucial to highlight certain weaknesses on which to specifically target therapy. We found that loss of transcriptionally active p73 (TAp73), a p53 family member, impacted PDA development. In two relevant and specific engineered pancreatic cancer mouse models, we observed that TAp73 deficiency reduced survival and enhanced epithelial-to-mesenchymal transition (EMT). Through proteomic analysis of conditioned media from TAp73 wild-type (WT) and deficient pancreatic tumor cells, we identified a secreted protein, biglycan (BGN), which is necessary and sufficient to mediate this pro-EMT effect. Interestingly, BGN is modulated by and modulates the transforming growth factor-β (TGF-β) pathway, a key regulator of the EMT process. We further examined this link and revealed that TAp73 impacts the TGF-β pathway by direct regulation of BGN expression and Sma and Mad-related proteins (SMADs) expression/ activity. Absence of TAp73 leads to activation of TGF-β signaling through a SMAD-independent pathway, favoring oncogenic TGF-β effects and EMT. Altogether, our data highlight the implication of TAp73 in the aggressiveness of pancreatic carcinogenesis through modulation of the TGF-β signaling. By suggesting TAp73 as a predictive marker for response to TGF-β inhibitors, our study could improve the classification of PDA patients with a view to offering combined therapy involving TGF-β inhibitors.

Pancreatic ductal adenocarcinoma (PDA) is a critical health issue in the field of cancer, with few therapeutic options. Evidence supports an implication of the intratumoral microenvironment (stroma) on PDA progression. However, its contribution to the role of neuroplastic changes within the pathophysiology and clinical course of PDA, through tumor recurrence and neuropathic pain, remains unknown, neglecting a putative, therapeutic window. Here, we report that the intratumoral microenvironment is a mediator of PDA-associated neural remodeling (PANR), and we highlight factors such as 'SLIT2' (an axon guidance molecule), which is expressed by cancer-associated fibroblasts (CAFs), that impact on neuroplastic changes in human PDA. We showed that 'CAF-secreted SLIT2' increases neurite outgrowth from dorsal root ganglia neurons as well as from Schwann cell migration/ proliferation by modulating N-cadherin/β-catenin signaling. Importantly, SLIT2/ROBO signaling inhibition disrupts this stromal/ neural connection. Finally, we revealed that SLIT2 expression and CAFs are correlated with neural remodeling within human and mouse PDA. All together, our data demonstrate the implication of CAFs, through the secretion of axon guidance molecule, in PANR. Furthermore, it provides rationale to investigate the disruption of the stromal/neural compartment connection with SLIT2/ROBO inhibitors for the treatment of pancreatic cancer recurrence and pain. Cell Death and Disease (2015) 6, e1592; doi:10.1038/cddis.2014.557; published online 15 January 2015Even after significant efforts from the scientific community in the past decade, pancreatic ductal adenocarcinoma (PDA) remains one of the most lethal cancers with worrying predictions.1 Median survival stagnates around 5 months, together with a 5-year survival at 5%. For 5-20% of patients treated surgically, the 5-year survival reaches 20%, with a median survival of 16 months. Metastasis onset and high prevalence of local tumor recurrence after potential curative resection influence patient's survival. A recent study revealed that the overall survival of patients with tumor recurrence was 9.3, versus 26.3 months for patients without early relapse. 2,3 Although several causes are attributed to local recurrence, reports highlight intrapancreatic nerve invasion as a predictor for recurrence 4 by playing the role of a specific niche for scattered tumoral cells. In light of such epidemiologic data, there is a crucial need to develop optimal therapeutic strategies, taking into account the tumoral cellular composition, over the next decade.

In pancreatic ductal adenocarcinoma (PDAC), signaling from stromal cells is implicated in metastatic progression. Tumor-stroma cross-talk is often mediated through extracellular vesicles (EVs). We previously reported that EVs derived from cancer-associated stromal fibroblasts (CAFs) that are abundant in annexin A6 (ANXA6 + EVs) support tumor cell aggressiveness in PDAC. Here, we found that the cell surface glycoprotein and tetraspanin CD9 is a key component of CAF-derived ANXA6 + EVs for mediating this cross-talk. CD9 was abundant on the surface of ANXA6 + CAFs isolated from patient PDAC samples and from various mouse models of PDAC. CD9 colocalized with CAF markers in the tumor stroma, and CD9 abundance correlated with tumor stage. Blocking CD9 impaired the uptake of ANXA6 + EVs into cultured PDAC cells. Signaling pathway arrays and further analyses revealed that the uptake of CD9 + ANXA6 + EVs induced mitogen-activated protein kinase (MAPK) pathway activity, cell migration, and epithelial-to-mesenchymal transition (EMT). Blocking either CD9 or p38 MAPK signaling impaired CD9 + ANXA6 + EV–induced cell migration and EMT in PDAC cells. Analysis of bioinformatic datasets indicated that CD9 abundance was an independent marker of poor prognosis in patients with PDAC. Our findings suggest that CD9-mediated stromal cell signaling promotes PDAC progression.

Pancreatic ductal adenocarcinoma (PDA) tumor cells are deprived of oxygen and nutrients and therefore must adapt their metabolism to ensure proliferation. In some physiological states, cells rely on ketone bodies to satisfy their metabolic needs, especially during nutrient stress. Here, we show that PDA cells can activate ketone body metabolism and that b-hydroxybutyrate (bOHB) is an alternative cell-intrinsic or systemic fuel that can promote PDA growth and progression. PDA cells activate enzymes required for ketogenesis, utilizing various nutrients as carbon sources for ketone body formation. By assessing metabolic gene expression from spontaneously arising PDA tumors in mice, we find HMG-CoA lyase (HMGCL), involved in ketogenesis, to be among the most deregulated metabolic enzymes in PDA compared to normal pancreas. In vitro depletion of HMGCL impedes migration, tumor cell invasiveness, and anchorage-independent tumor sphere compaction. Moreover, disrupting HMGCL drastically decreases PDA tumor growth in vivo, while bOHB stimulates metastatic dissemination to the liver. These findings suggest that bOHB increases PDA aggressiveness and identify HMGCL and ketogenesis as metabolic targets for limiting PDA progression.

Isocitrate dehydrogenase (IDH) mutations are common genetic alterations in myeloid disorders, including acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). Epigenetic changes, including abnormal histone and DNA methylation, have been implicated in the pathogenic build-up of hematopoietic progenitors, but it is still unclear whether and how IDH mutations themselves affect hematopoiesis. Here, we show that IDH1-mutant mice develop myeloid dysplasia in that these animals exhibit anemia, ineffective erythropoiesis, increased immature progenitor and erythroblast. In erythroid cells of these mice, D-2-hydroxyglutarate (D-2HG), an aberrant metabolite produced by the mutant IDH1 enzyme, inhibits oxoglutarate dehydrogenase (OGDH) activity and diminishes succinyl-CoA production. This succinyl-CoA deficiency attenuates heme biosynthesis in IDH1-mutant hematopoietic cells, thus blocking erythroid differentiation at the late erythroblast stage and the erythroid commitment of hematopoietic stem cells (HSC), while the exogenous succinyl-CoA or 5-ALA rescues erythropoiesis in IDH1-mutant erythroid cells. Heme deficiency also impairs heme oxygenase-1 (HO-1) expression, which reduces levels of important heme catabolites such as biliverdin and bilirubin. These deficits result in accumulation of excessive reactive oxygen species (ROS) that induce the cell death of IDH1-mutant erythroid cells. Our results clearly demonstrate the essential role of IDH1 in normal erythropoiesis and show how its mutation leads to myeloid disorders. Our data thus have important implications for the devising of new treatments for IDH-mutant tumors.