Pancreatic Ductal Adenocarcinoma Metabolism Research Articles

Abstract C01: Porcupine inhibition redirects mitochondrial metabolism in Wnt-dependent pancreatic cancer

Abstract Wnt/β-catenin signaling plays important roles in pancreatic ductal adenocarcinoma (PDA) tumor initiation and progression via broad-ranging effects on proliferation, differentiation, survival, and stemness. Although Wnt has been shown to promote glycolysis in colon cancer, its role in regulating metabolism in PDA has not been well explored. For this study, RNF43-mutant cell lines were selected as exemplars of ligand-dependent autocrine Wnt signaling in PDA. These cell lines harbor an inactivating mutation in RNF43 that confers Wnt growth-dependency and response to LGK974, a PORCN inhibitor that blocks Wnt ligand secretion and signaling. Global transcriptomic, proteomic, and metabolomic analysis revealed several metabolites and putative mediators of metabolism that are directly or indirectly linked to autocrine Wnt signaling. Pharmacologic inhibition of Wnt by LGK974 led to the accumulation of pyruvate and lactate, as well as reduced tricarboxylic acid cycle metabolites and decreased mitochondrial membrane potential as measured by tetramethylrhodamine and JC-1 assays. These metabolic changes were accompanied by cell cycle arrest and downregulation of transcriptional programs involved in cell cycle progression, DNA replication, and nucleotide metabolism. Importantly, LGK974 results were phenocopied by siRNA-mediated knockdown of WNT7B and rescued with WNT3A conditioned media. Thus, inhibition of mitochondrial oxidative phosphorylation by LGK974 in RNF43-mutant PDA appears linked to its inhibition of canonical Wnt signaling, an adaptation and potential metabolic vulnerability that could be leveraged to therapeutic advantage via combinatorial strategies. Altogether, these results suggest tissue context and mechanisms of Wnt pathway activation may profoundly influence its role in regulating cancer metabolism. Citation Format: Kristina Y. Aguilera, Rana Riahi, Edris A. Saadat, Anna R. Lay, Thuc Le, Timothy R. Donahue, Caius Radu, David W. Dawson. Porcupine inhibition redirects mitochondrial metabolism in Wnt-dependent pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2019 Sept 6-9; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2019;79(24 Suppl):Abstract nr C01.

Snail-Overexpression Induces Epithelial-mesenchymal Transition and Metabolic Reprogramming in Human Pancreatic Ductal Adenocarcinoma and Non-tumorigenic Ductal Cells.

The zinc finger transcription factor Snail is a known effector of epithelial-to-mesenchymal transition (EMT), a process that underlies the enhanced invasiveness and chemoresistance of common to cancerous cells. Induction of Snail-driven EMT has also been shown to drive a range of pro-survival metabolic adaptations in different cancers. In the present study, we sought to determine the specific role that Snail has in driving EMT and adaptive metabolic programming in pancreatic ductal adenocarcinoma (PDAC) by overexpressing Snail in a PDAC cell line, Panc1, and in immortalized, non-tumorigenic human pancreatic ductal epithelial (HPDE) cells. Snail overexpression was able to induce EMT in both pancreatic cell lines through suppression of epithelial markers and upregulation of mesenchymal markers alongside changes in cell morphology and enhanced migratory capacity. Snail-overexpressed pancreatic cells additionally displayed increased glucose uptake and lactate production with concomitant reduction in oxidative metabolism measurements. Snail overexpression reduced maximal respiration in both Panc1 and HPDE cells, with further reductions seen in ATP production, spare respiratory capacity and non-mitochondrial respiration in Snail overexpressing Panc1 cells. Accordingly, lower expression of mitochondrial electron transport chain proteins was observed with Snail overexpression, particularly within Panc1 cells. Modelling of 13C metabolite flux within both cell lines revealed decreased carbon flux from glucose in the TCA cycle in snai1-overexpressing Panc1 cells only. This work further highlights the role that Snail plays in EMT and demonstrates its specific effects on metabolic reprogramming of glucose metabolism in PDAC.

PO-242 Myoferlin controls mitochondrial structure and metabolism in pancreatic ductal adenocarcinoma, and affects tumor aggressiveness

IntroductionPancreatic ductal adenocarcinoma (pdac) is the most common type of pancreatic cancer, and the third leading cause of cancer related death. therapeutic options remain very limited and are still based on classical chemotherapies. cell fraction can survive to the chemotherapy and is responsible for tumor relapse. it appears that these cells rely on oxydative phosphorylation (oxphos) for survival.Myoferlin, a membrane protein involved in cell fusion was recently shown by our laboratory to be overexpressed in pancreatic cancer.Material and methodsWe used pancreatic cancer cell lines depleted in myoferlin to assess mitochondrial function with an extracellular flux analyser. pancreas cancer samples from the institutional biobank with matched pet scan data were used to correlate myoferlin abundance and glycolysis.results and discussionsin the present study, we discovered that myoferlin was more expressed in cell lines undergoing (oxphos) than in glycolytic cell lines. in the former cell lines, we showed that myoferlin silencing reduced oxphos activity and forced cells to switch to glycolysis. the decrease in oxphos activity is associated with mitochondrial condensation and network disorganization. an increase of dynamin-related protein (drp)-1 phosphorylation in myoferlin-depleted cells led us to suggest mitochondrial fission, reducing cell proliferation, atp production and inducing autophagy and ros accumulation. electron microscopy observation revealed mitophagy, suggesting mitochondrial alterations.To confirm the clinical importance of myoferlin in pdac, we showed that low myoferlin expression was significantly correlated to high overall survival. myoferlin staining of pdac sections was negatively correlated with several 18fdg pet indices indicating that glycolytic lesions had less myoferlin. these observations are fully in accordance with our in vitro data.conclusionas the mitochondrial function was associated with cell chemoresistance, the metabolic switch induced by myoferlin silencing could open up a new perspective in the development of therapeutic strategies. among them, targeting functional domains (c2, dysf, …) of myoferlin should be a priority.

Myoferlin controls mitochondrial structure and activity in pancreatic ductal adenocarcinoma, and affects tumor aggressiveness

Pancreatic ductal adenocarcinoma (PDAC) is the third leading cause of cancer-related death. Therapeutic options remain very limited and are based on classical chemotherapies. Energy metabolism reprogramming appears as an emerging hallmark of cancer and is considered a therapeutic target with considerable potential. Myoferlin, a ferlin family member protein overexpressed in PDAC, is involved in plasma membrane biology and has a tumor-promoting function. In the continuity of our previous studies, we investigated the role of myoferlin in the context of energy metabolism in PDAC. We used selected PDAC tumor samples and PDAC cell lines together with small interfering RNA technology to study the role of myoferlin in energetic metabolism. In PDAC patients, we showed that myoferlin expression is negatively correlated with overall survival and with glycolytic activity evaluated by 18F-deoxyglucose positron emission tomography. We found out that myoferlin is more abundant in lipogenic pancreatic cancer cell lines and is required to maintain a branched mitochondrial structure and a high oxidative phosphorylation activity. The observed mitochondrial fission induced by myoferlin depletion led to a decrease of cell proliferation, ATP production, and autophagy induction, thus indicating an essential role of myoferlin for PDAC cell fitness. The metabolic phenotype switch generated by myoferlin silencing could open up a new perspective in the development of therapeutic strategies, especially in the context of energy metabolism.

The Interface of Pancreatic Cancer With Diabetes, Obesity, and Inflammation: Research Gaps and Opportunities: Summary of a National Institute of Diabetes and Digestive and Kidney Diseases Workshop.

A workshop on "The Interface of Pancreatic Cancer with Diabetes, Obesity, and Inflammation: Research Gaps and Opportunities" was held by the National Institute of Diabetes and Digestive and Kidney Diseases on October 12, 2017. The purpose of the workshop was to explore the relationship and possible mechanisms of the increased risk of pancreatic ductal adenocarcinoma (PDAC) related to diabetes, the role of altered intracellular energy metabolism in PDAC, the mechanisms and biomarkers of diabetes caused by PDAC, the mechanisms of the increased risk of PDAC associated with obesity, and the role of inflammatory events and mediators as contributing causes of the development of PDAC. Workshop faculty reviewed the state of the current knowledge in these areas and made recommendations for future research efforts. Further knowledge is needed to elucidate the basic mechanisms contributing to the role of hyperinsulinemia, hyperglycemia, adipokines, and acute and chronic inflammatory events on the development of PDAC.

An overview of polyamine metabolism in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest major cancers, with a five year survival rate of less than 8%. With current therapies only giving rise to modest life extension, new approaches are desperately needed. Even though targeting polyamine metabolism is a proven anticancer strategy, there are no reports, which thoroughly survey the literature describing the role of polyamine biosynthesis and transport in PDAC. This review seeks to fill this void by describing what is currently known about polyamine metabolism in PDAC and identifies new targets and opportunities to treat this disease. Due to the pleiotropic effects that polyamines play in cells, this review covers diverse areas ranging from polyamine metabolism (biosynthesis, catabolism and transport), as well as the potential role of polyamines in desmoplasia, autophagy and immune privilege. Understanding these diverse roles provides the opportunity to design new therapies to treat this deadly cancer via polyamine depletion.

Molecular Pathways Controlling Autophagy in Pancreatic Cancer.

Pancreatic ductal adenocarcinoma (PDAC) is one of the few cancer types where the 5-year survival rate shows no improvement.Despite conflicting evidence, the majority of data points to an essential role for autophagy in PDAC growth and survival, in particular constitutively activated autophagy, can provide crucial fuel to PDAC tumor cells in their nutrient-deprived environment.Autophagy, which is required for cell homeostasis, can both suppress and promote tumorigenesis and tumor survival in a context-dependent manner. Protein by protein, the mystery of how PDAC abuses the cell’s homeostasis system for its malignant growth has recently begun to be unraveled. In this review, we focus on how autophagy is responsible for growth and development of PDAC tumors and where autophagy and the mechanisms controlling it fit into PDAC metabolism. Understanding the range of pathways controlling autophagy and their interplay in PDAC could open the way for new therapeutic avenues.

The cornerstone K-RAS mutation in pancreatic adenocarcinoma: From cell signaling network, target genes, biological processes to therapeutic targeting.

RAS belongs to the super family of small G proteins and plays crucial roles in signal transduction from membrane receptors in the cell. Mutations of K-RAS oncogene lead to an accumulation of GTP-bound proteins that maintains an active conformation. In the pancreatic ductal adenocarcinoma (PDAC), one of the most deadly cancers in occidental countries, mutations of the K-RAS oncogene are nearly systematic (>90%). Moreover, K-RAS mutation is the earliest genetic alteration occurring during pancreatic carcinogenetic sequence. In this review, we discuss the central role of K-RAS mutations and their tremendous diversity of biological properties by the interconnected regulation of signaling pathways (MAPKs, NF-κB, PI3K, Ral…). In pancreatic ductal adenocarcinoma, transcriptome analysis and preclinical animal models showed that K-RAS mutation alters biological behavior of PDAC cells (promoting proliferation, migration and invasion, evading growth suppressors, regulating mucin pattern, and miRNA expression). K-RAS also impacts tumor microenvironment and PDAC metabolism reprogramming. Finally we discuss therapeutic targeting strategies of K-RAS that have been developed without significant clinical success so far. As K-RAS is considered as the undruggable target, targeting its multiple effectors and target genes should be considered as potential alternatives.

Pancreatic stellate cells support tumour metabolism through autophagic alanine secretion.

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive disease characterized by an intense fibrotic stromal response and deregulated metabolism. The role of the stroma in PDAC biology is complex and it has been shown to play critical roles that differ depending on the biological context. The stromal reaction also impairs the vasculature, leading to a highly hypoxic, nutrient-poor environment. As such, these tumours must alter how they capture and use nutrients to support their metabolic needs. Here we show that stroma-associated pancreatic stellate cells (PSCs) are critical for PDAC metabolism through the secretion of non-essential amino acids (NEAA). Specifically, we uncover a previously undescribed role for alanine, which outcompetes glucose and glutamine-derived carbon in PDAC to fuel the tricarboxylic acid (TCA) cycle, and thus NEAA and lipid biosynthesis. This shift in fuel source decreases the tumour’s dependence on glucose and serum-derived nutrients, which are limited in the pancreatic tumour microenvironment. Moreover, we demonstrate that alanine secretion by PSCs is dependent on PSC autophagy, a process that is stimulated by cancer cells. Thus, our results demonstrate a novel metabolic interaction between PSCs and cancer cells, in which PSC-derived alanine acts as an alternative carbon source. This finding highlights a previously unappreciated metabolic network within pancreatic tumours in which diverse fuel sources are used to promote growth in an austere tumour microenvironment.

Metabolic Reprogramming of Pancreatic Cancer Mediated by CDK4/6 Inhibition Elicits Unique Vulnerabilities.

Due to loss of p16ink4a in pancreatic ductal adenocarcinoma (PDA), pharmacological suppression of CDK4/6 could represent a potent target for treatment. In PDA models, CDK4/6 inhibition had a variable effect on cell cycle but yielded accumulation of ATP and mitochondria. Pharmacological CDK4/6 inhibitors induce cyclin D1 protein levels; however, RB activation was required and sufficient for mitochondrial accumulation. CDK4/6 inhibition stimulated glycolytic and oxidative metabolism and was associated with an increase in mTORC1 activity. MTOR and MEK inhibitors potently cooperate with CDK4/6 inhibition in eliciting cell-cycle exit. However, MTOR inhibition fully suppressed metabolism and yielded apoptosis and suppression of tumor growth in xenograft models. The metabolic state mediated by CDK4/6 inhibition increases mitochondrial number and reactive oxygen species (ROS). Concordantly, the suppression of ROS scavenging or BCL2 antagonists cooperated with CDK4/6 inhibition. Together, these data define the impact of therapeutics on PDA metabolism and provide strategies for converting cytostatic response to tumor cell killing.

Abstract B44: The histone deacetylase SIRT6 regulates metabolism in pancreatic ductal adenocarcinoma

Abstract Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer death and one of the most aggressive and deadly malignancies, with limited therapeutic options. Sirtuin 6 (SIRT6) is a nicotinamide adenine dinucleotide (NAD+)-dependent histone deacetylase that functions as a novel tumor suppressor, which regulates aerobic glycolysis in cancer cells. Whether glycolysis plays a role in pancreatic cancer development remains a topic of intense study. Importantly, we found SIRT6 to be downregulated in human PDAC and most pancreatic cancer cell lines, resulting in increased expression of glycolytic genes. To determine the role of SIRT6 in pancreatic cancer we utilized human PDAC cell lines that demonstrated low expression of SIRT6 compared to a human pancreatic ductal epithelial (HPDE) control cell line. Restoration of SIRT6 expression decreased the levels of glycolytic gene expression, reduced glucose uptake, and inhibited cell growth. Conversely, knockdown of SIRT6 in HPDE cells increased glycolytic gene expression, glucose uptake and enhanced cell growth. To further explore the role of SIRT6 in a genetically defined PDAC model, we used an autochthonous mouse model with conditional alleles for KRASG12D, p53, and SIRT6, together with a p48-Cre allele to delete SIRT6 and p53 while expressing oncogenic Ras exclusively in the pancreas. SIRT6null, KRASG12D, p53+/- p48 tumor cells also exhibited increased expression of glycolytic genes and had enhanced glucose uptake compared to SIRT6+/+, KRASG12D, p53+/- p48 tumor cells, a phenotype which is reversed by restoration of wild-type but not catalytically inactive SIRT6 expression. Understanding how SIRT6 regulates PDAC metabolism through the modulation of chromatin dynamics will hopefully lead to new therapies to tackle aberrant metabolism in this devastating disease. Citation Format: Sita Kugel, Carlos Sebastián, Rushika M. Perera, Nabeel Bardeesy, Raul Mostoslavsky. The histone deacetylase SIRT6 regulates metabolism in pancreatic ductal adenocarcinoma. [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Innovations in Research and Treatment; May 18-21, 2014; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2015;75(13 Suppl):Abstract nr B44.

LDL Receptor: An open route to feed pancreatic tumor cells

ABSTRACTThe role of altered lipid metabolism in pancreatic ductal adenocarcinoma (PDAC) is poorly appreciated. We recently identified the lipid signature of PDAC and revealed low-density lipoprotein receptor (Ldlr) as a metabolic driver of this disease. Here, we comment our findings that disruption of Ldlr leads to intratumoral cholesterol imbalance and improves chemotherapy efficiency.

Role of abnormal lipid metabolism in development, progression, diagnosis and therapy of pancreatic cancer.

There is growing evidence that metabolic alterations play an important role in cancer development and progression. The metabolism of cancer cells is reprogrammed in order to support their rapid proliferation. Elevated fatty acid synthesis is one of the most important aberrations of cancer cell metabolism. An enhancement of fatty acids synthesis is required both for carcinogenesis and cancer cell survival, as inhibition of key lipogenic enzymes slows down the growth of tumor cells and impairs their survival. Based on the data that serum fatty acid synthase (FASN), also known as oncoantigen 519, is elevated in patients with certain types of cancer, its serum level was proposed as a marker of neoplasia. This review aims to demonstrate the changes in lipid metabolism and other metabolic processes associated with lipid metabolism in pancreatic ductal adenocarcinoma (PDAC), the most common pancreatic neoplasm, characterized by high mortality. We also addressed the influence of some oncogenic factors and tumor suppressors on pancreatic cancer cell metabolism. Additionally the review discusses the potential role of elevated lipid synthesis in diagnosis and treatment of pancreatic cancer. In particular, FASN is a viable candidate for indicator of pathologic state, marker of neoplasia, as well as, pharmacological treatment target in pancreatic cancer. Recent research showed that, in addition to lipogenesis, certain cancer cells can use fatty acids from circulation, derived from diet (chylomicrons), synthesized in liver, or released from adipose tissue for their growth. Thus, the interactions between de novo lipogenesis and uptake of fatty acids from circulation by PDAC cells require further investigation.

Novel pathway identified for glutamine metabolism in PDAC

A new study published in Nature reports that pancreatic ductal adenocarcinoma (PDAC) cells utilise a novel glutamine metabolism pathway that is essential for tumour growth.

Proteomic Analysis of Pancreatic Ductal Adenocarcinoma Cells Reveals Metabolic Alterations

In this present work, we characterized the proteomes of pancreatic ductal adenocarcinoma (PDAC) cells and normal pancreatic duct cells by mass spectrometry using LTQ-Orbitrap, and identified more than 1200 proteins from each sample. On the basis of spectra count label-free quantification approach, we identified a large number of differentially expressed metabolic enzymes and proteins involved in cytoskeleton, cell adhesion, transport, transcription, translation, and cell proliferation as well. The data demonstrated that metabolic pathways were altered in PDAC, consistent with Warburg effect. Our analysis provides a potentially comprehensive picture of metabolism in PDAC, which may serve as the basis of new diagnostic and treatment of PDAC.