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Developmental and cancer models show Wnt/β-catenin-dependent signaling mediates diverse phenotypic outcomes in the pancreas that are dictated by context, duration and strength of activation. While generally assumed to be pro-tumorigenic, it is unclear to what extent dysregulation of Wnt/β-catenin signaling impacts tumor progression in pancreatic adenocarcinoma (PDAC). In the present study, Wnt/β-catenin activity was characterized across a spectrum of PDAC cell lines and primary tumors. Reporter and gene expression-based assays revealed wide heterogeneity in Wnt/β-catenin transcriptional activity across PDAC cell lines and patient tumors, as well as variable responsiveness to exogenous Wnt ligand stimulation. An experimentally generated, pancreas-specific gene expression signature of Wnt/β-catenin transcriptional activation was used to stratify pathway activation across a cohort of resected, early-stage PDAC tumors (N=41). In this cohort, higher Wnt/β-catenin activation was found to significantly correlate with lymphvascular invasion and worse disease-specific survival (median survival time 20.3 versus 43.9 months, log-rank P=0.03). Supporting the importance of Wnt ligand in mediating autocrine Wnt signaling, Wnt/β-catenin activity was significantly inhibited in PDAC cell lines by WLS gene silencing and the small-molecule inhibitor IWP-2, both of which functionally block Wnt ligand processing and secretion. Transcriptional profiling revealed elevated expression of WNT7B occurred in PDAC cell lines with high levels of cell autonomous Wnt/β-catenin activity. Gene-knockdown studies in AsPC-1 and HPAF-2 cell lines confirmed WNT7B-mediated cell autonomous Wnt/β-catenin activation, as well as an anchorage-independent growth phenotype. Our findings indicate WNT7B can serve as a primary determinant of differential Wnt/β-catenin activation in PDAC. Disrupting the interaction between Wnt ligands and their receptors may be a particularly suitable approach for therapeutic modulation of Wnt/β-catenin signaling in PDAC and other cancer contexts where Wnt activation is mediated by ligand expression rather than mutations in canonical pathway members.

Proteolysis of hydrophobic helices is required for complete breakdown of every transmembrane protein trafficked to the lysosome and sustains high rates of endocytosis. However, the lysosomal mechanisms for degrading hydrophobic domains remain unknown. Combining lysosomal proteomics with functional genomic data mining, we identify Lysosomal Leucine Aminopeptidase (LyLAP; formerly Phospholipase B Domain-Containing 1) as the hydrolase most tightly associated with elevated endocytic activity. Untargeted metabolomics and biochemical reconstitution demonstrate that LyLAP is not a phospholipase, but a processive monoaminopeptidase with strong preference for N-terminal leucine - an activity necessary and sufficient for breakdown of hydrophobic transmembrane domains. LyLAP is upregulated in pancreatic ductal adenocarcinoma (PDA), which relies on macropinocytosis for nutrient uptake, and its ablation led to buildup of undigested hydrophobic peptides, which compromised lysosomal membrane integrity and inhibited PDA cell growth. Thus, LyLAP enables lysosomal degradation of membrane proteins, and may represent a vulnerability in highly endocytic cancer cells., One Sentence Summary: LyLAP degrades transmembrane proteins to sustain high endocytosis and lysosomal membrane stability in pancreatic cancer.

Macropinocytosis has emerged as a scavenging pathway that cancer cells exploit to survive in a nutrient-deprived microenvironment. Tumor cells are especially reliant on glutamine for their survival, and in pancreatic ductal adenocarcinoma (PDAC) cells, glutamine deficiency can enhance the stimulation of macropinocytosis. Here, we identify the atypical protein kinase C (aPKC) enzymes, PKCζ and PKCι, as regulators of macropinocytosis. In normal epithelial cells, aPKCs associate with the scaffold proteins Par3 and Par6 to regulate cell polarity, affecting several targets, including the Par1 kinases and we find that each of these proteins is required for macropinocytosis. Mechanistically, aPKCs are regulated by EGFR signaling or by the transcription factor CREM to promote the Par3 relocation to microtubules, facilitating macropinocytosis in a dynein-dependent manner. Importantly, cell fitness impairment caused by aPKC depletion is rescued by the restoration of macropinocytosis and aPKCs support PDAC growth in vivo. Our findings enhance our understanding of the mechanistic underpinnings that control macropinocytic uptake in the context of metabolic stress., Competing Interests: Competing interests: C.C. is an inventor on a U.S. patent titled “Cancer diagnostics, therapeutics, and drug discovery associated with macropinocytosis,” Patent number: US-11209420-B2. The remaining authors declare no competing interests., (© 2024. The Author(s).)

Hypereosinophilic syndrome (HES) is characterized by blood and tissue hypereosinophilia leading to organ damage. Gastrointestinal involvement is the third most common manifestation. We present a patient with idiopathic HES with secondary eosinophilic esophagitis (EoE), gastritis, and enteritis, corticosteroids-dependent, azathioprine- and mepolizumab-refractory. The patient achieved clinical and histopathologic remission following dupilumab treatment. A 28 year-old female presented with chronic episodic nausea and emesis since childhood and initial diagnosis of primary eosinophilic gastrointestinal disease (EGID), improved with corticosteroids, refractory to azathioprine. She was found to have peripheral eosinophilia and multifactorial anemia, with iron, B12, and folate deficiencies. Esophageal, gastric, duodenal, and terminal ileum biopsies showed significant eosinophilic infiltrate. Bone marrow biopsy at age 31 confirmed HES diagnosis. By age 32, she became total parental nutrition (TPN)-dependent. She failed trials of benralizumab and mepolizumab [anti-interleukin (IL)-5 inhibitors], and cromolyn (mast-cell stabilizer). After developing new esophageal stricture, we initiated dupilumab (IL-4/13 inhibitor), recently FDA-approved for EoE. After 9 weeks, esophageal stricture, gut tissue eosinophilia, and prior intestinal ulcerations resolved. She ceased TPN and is tolerating a non-restricted diet, with complete symptom resolution. Our patient's complete remission with dupilumab shows promise for broadening its use in treating GI involvement in HES, along with primary EGIDs., (© 2024. Japanese Society of Gastroenterology.)

Background: Pancreatic neuroendocrine tumors (pNETs) are genomically diverse tumors. The management of newly diagnosed well-differentiated pNETs is limited by a lack of sensitivity of existing biomarkers for prognostication. Our goal was to investigate the potential utility of genetic markers as a predictor of progression-free survival (PFS) and recurrence-free survival (RFS)., Methods: Whole-exome sequencing of resected well-differentiated, low and intermediate-grade (G1 and G2) pNETs and normal adjacent tissue from patients who underwent resection from 2005 to 2015 was performed. Genetic alterations were classified using pan-genomic and oncogenic pathway classifications. Additional samples with genetic and clinicopathologic data available were obtained from the publicly available International Cancer Genome Consortium (ICGC) database and included in the analysis. The prognostic relevance of these genomic signatures on PFS and RFS was analyzed., Results: Thirty-one patients who underwent resection for pNET were identified. Genomic analysis of mutational, copy number, cytogenetic, and complex phenomena revealed similar patterns to prior studies of pNETs with relatively few somatic gene mutations but numerous instances of copy number changes. Analysis of genomic and clinicopathologic outcomes using the combined data from our study as well as the ICGC pNET cohort (n = 124 patients) revealed that the recurrent pattern of whole chromosome loss (RPCL) and metastatic disease were independently associated with disease progression. When evaluating patients with local disease at the time of resection, RPCL and alterations in the TGFβ oncogenic pathway were independently associated with the risk of recurrence., Conclusions: Well-differentiated pNETs are genomically diverse tumors. Pathway signatures may be prognostic for predicting disease progression and recurrence., (© 2024 The Author(s). Journal of Surgical Oncology published by Wiley Periodicals LLC.)

The pleiotropic roles of nSMase2-generated ceramide include regulation of intracellular ceramide signaling and exosome biogenesis. We investigated the effects of eliminating nSMase2 on early and advanced PDA, including its influence on the microenvironment. Employing the KPC mouse model of pancreatic cancer, we demonstrate that pancreatic epithelial nSMase2 ablation reduces neoplasia and promotes a PDA subtype switch from aggressive basal-like to classical. nSMase2 elimination prolongs survival of KPC mice, hinders vasculature development, and fosters a robust immune response. nSMase2 loss leads to recruitment of cytotoxic T cells, N1-like neutrophils, and abundant infiltration of anti-tumorigenic macrophages in the pancreatic preneoplastic microenvironment. Mechanistically, we demonstrate that nSMase2-expressing PDA cell small extracellular vesicles (sEVs) reduce survival of KPC mice; PDA cell sEVs generated independently of nSMase2 prolong survival of KPC mice and reprogram macrophages to a proinflammatory phenotype. Collectively, our study highlights previously unappreciated opposing roles for exosomes, based on biogenesis pathway, during PDA progression.

Background and Aims: Decoding pancreatic ductal adenocarcinoma heterogeneity and the consequent therapeutic selection remains a challenge. We aimed to characterize epigenetically regulated pathways involved in pancreatic ductal adenocarcinoma progression., Methods: Global DNA methylation analysis in pancreatic cancer patient tissues and cell lines was performed to identify differentially methylated genes. Targeted bisulfite sequencing and in vitro methylation reporter assays were employed to investigate the direct link between site-specific methylation and transcriptional regulation. A series of in vitro loss-of-function and gain-of function studies and in vivo xenograft and the KPC ( LSL-Kras G12D/+ ; LSL-Trp53 R172H/+ ; Pdx1-Cre ) mouse models were used to assess pancreatic cancer cell properties. Gene and protein expression analyses were performed in 3 different cohorts of pancreatic cancer patients and correlated to clinicopathological parameters., Results: We identify Hepatocyte Nuclear Factor 4A (HNF4A) as a novel target of hypermethylation in pancreatic cancer and demonstrate that site-specific proximal promoter methylation drives HNF4A transcriptional repression. Expression analyses in patients indicate the methylation-associated suppression of HNF4A expression in pancreatic cancer tissues. In vitro and in vivo studies reveal that HNF4A is a novel tumor suppressor in pancreatic cancer, regulating cancer growth and aggressiveness. As evidenced in both the KPC mouse model and human pancreatic cancer tissues, HNF4A expression declines significantly in the early stages of the disease. Most importantly, HNF4 loss correlates with poor overall patient survival., Conclusion: HNF4A silencing, mediated by promoter DNA methylation, drives pancreatic cancer development and aggressiveness leading to poor patient survival., (© 2024 The Authors.)

Abstract: A 43-year-old man with a growing mass in the right groin, concerned for liposarcoma, underwent MRI and 68 Ga-fibroblast activation protein inhibitor (FAPI)-46 PET/CT before surgery. Fibroblast activation protein inhibitor PET/CT demonstrated increased uptake (SUV max , 3.2) predominantly in the solid portion, where MRI showed gadolinium enhancement. The patient subsequently underwent surgery and was diagnosed with hibernoma. The immunohistochemistry of the tumor revealed the fibroblast activation protein expression in the fibrovascular network and myofibroblastic cells of the tumor. This case suggests that the FAPI uptake can be affected by the vascular cells, and thus, a careful interpretation of the FAPI PET signal may be needed., Competing Interests: Conflicts of interest and sources of funding: J.C. is the recipient of grants from the ERF-SNMMI (2019–2021 Molecular Imaging Research Grant for Junior Academic Faculty), the Philippe Foundation Inc (New York), and the ARC Foundation (France) (International Mobility Award SAE20160604150). J.C. is a consultant for Blue Earth Diagnostics, Curium Pharma, GE Healthcare, Janssen Pharmaceuticals, Progenics Radiopharmaceuticals, Radiomedix, and Telix Pharmaceuticals, outside of the submitted work. The study was partially funded by the ERF- SNMMI (2019–2021 Molecular Imaging Research Grant for Junior Academic Faculty). All other coauthors have no conflict of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Objectives: Fibroblast activation protein alpha (FAP) is highly expressed by cancer-associated fibroblasts in multiple epithelial cancers. The aim of this study was to characterize FAP expression in sarcomas to explore its potential utility as a diagnostic and therapeutic target and prognostic biomarker in sarcomas., Methods: Available tissue samples from patients with bone or soft tissue tumors were identified at the University of California, Los Angeles. FAP expression was evaluated via immunohistochemistry (IHC) in tumor samples ( n  = 63), adjacent normal tissues ( n  = 30), and positive controls ( n  = 2) using semiquantitative systems for intensity (0 = negative; 1 = weak; 2 = moderate; and 3 = strong) and density (none, <25%, 25-75%; >75%) in stromal and tumor/nonstromal cells and using a qualitative overall score (not detected, low, medium, and high). Additionally, RNA sequencing data in publicly available databases were utilized to compare FAP expression in samples ( n  = 10,626) from various cancer types and evaluate the association between FAP expression and overall survival (OS) in sarcoma ( n  = 168)., Results: The majority of tumor samples had FAP IHC intensity scores ≥2 and density scores ≥25% for stromal cells (77.7%) and tumor cells (50.7%). All desmoid fibromatosis, myxofibrosarcoma, solitary fibrous tumor, and undifferentiated pleomorphic sarcoma samples had medium or high FAP overall scores. Sarcomas were among cancer types with the highest mean FAP expression by RNA sequencing. There was no significant difference in OS in patients with sarcoma with low versus high FAP expression., Conclusion: The majority of the sarcoma samples showed FAP expression by both stromal and tumor/nonstromal cells. Further investigation of FAP as a potential diagnostic and therapeutic target in sarcomas is warranted., Competing Interests: F.C.E. is on the Scientific Advisory Board of Certis Oncology. T.G.G. has consulting and equity agreements with Auron Therapeutics, Boundless Bio, Coherus BioSciences, and Trethera Corporation. The authors declare that they have no conflicts of interest., (Copyright © 2023 Jacquelyn N. Crane et al.)

Background: Pancreatic adenocarcinoma (PDAC) persists as a malignancy with high morbidity and mortality that can benefit from new means to characterize and detect these tumors, such as radiogenomics. In order to address this gap in the literature, constructed a transcriptomic-CT radiogenomic (RG) map for PDAC., Methods: In this Institutional Review Board approved study, a cohort of subjects (n = 50) with gene expression profile data paired with histopathologically confirmed resectable or borderline resectable PDAC were identified. Studies with pre-operative contrast-enhanced CT images were independently assessed for a set of 88 predefined imaging features. Microarray gene expression profiling was then carried out on the histopathologically confirmed pancreatic adenocarcinomas and gene networks were constructed using Weighted Gene Correlation Network Analysis (WCGNA) (n = 37). Data were analyzed with bioinformatics analyses, multivariate regression-based methods, and Kaplan-Meier survival analyses., Results: Survival analyses identified multiple features of interest that were significantly associated with overall survival, including Tumor Height (P = 0.014), Tumor Contour (P = 0.033), Tumor-stroma Interface (P = 0.014), and the Tumor Enhancement Ratio (P = 0.047). Gene networks for these imaging features were then constructed using WCGNA and further annotated according to the Gene Ontology (GO) annotation framework for a biologically coherent interpretation of the imaging trait-associated gene networks, ultimately resulting in a PDAC RG CT-transcriptome map composed of 3 stage-independent imaging traits enriched in metabolic processes, telomerase activity, and podosome assembly (P < 0.05)., Conclusions: A CT-transcriptomic RG map for PDAC composed of semantic and quantitative traits with associated biology processes predictive of overall survival, was constructed, that serves as a reference for further mechanistic studies for non-invasive phenotyping of pancreatic tumors., (© 2023. The Author(s).)

Objectives: Extracellular vesicles (EVs) are lipid bound vesicles secreted by cells into the extracellular environment. Studies have implicated EVs in cell proliferation, epithelial-mesenchymal transition, metastasis, angiogenesis, and mediating the interaction of tumor cells and microenvironment. A systematic characterization of EVs from pancreatic cancer cells and cancer-associated fibroblasts (CAFs) would be valuable for studying the roles of EV proteins in pancreatic tumorigenesis., Methods: Proteomic and functional analyses were applied to characterize the proteomes of EVs released from 5 pancreatic cancer lines, 2 CAF cell lines, and a normal pancreatic epithelial cell line (HPDE)., Results: More than 1400 nonredundant proteins were identified in each EV derived from the cell lines. The majority of the proteins identified in the EVs from the cancer cells, CAFs, and HPDE were detected in all 3 groups, highly enriched in the biological processes of vesicle-mediated transport and exocytosis. Protein networks relevant to pancreatic tumorigenesis, including epithelial-mesenchymal transition, complement, and coagulation components, were significantly enriched in the EVs from cancer cells or CAFs., Conclusions: These findings support the roles of EVs as a potential mediator in transmitting epithelial-mesenchymal transition signals and complement response in the tumor microenvironment and possibly contributing to coagulation defects related to cancer development., Competing Interests: The authors declare no conflict of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Fibroblast activation protein (FAP)-expressing cancer-associated fibroblasts confer treatment resistance and promote metastasis and immunosuppression. Because FAP is overexpressed in many cancers, radiolabeled molecules targeting FAP are studied for their use as pancancer theranostic agents. This study aimed to establish the spectrum of FAP expression across various cancers by immunohistochemistry and to explore whether 68 Ga FAP inhibitor (FAPi)-46 PET biodistribution faithfully reflects FAP expression from resected cancer and non-cancer specimens. Methods: We conducted a FAP expression screening using immunohistochemistry on a pancancer human tissue microarray (141 patients, 14 different types of cancer) and an interim analysis of a prospective exploratory imaging trial in cancer patients. Volunteer patients underwent 1 whole-body 68 Ga-FAPi-46 PET/CT scan and, subsequently, surgical resection of their primary tumor or metastasis. 68 Ga-FAPi-46 PET SUV max and SUV mean was correlated with FAP immunohistochemistry score in cancer and tumor-adjacent non-cancer tissues for each patient. Results: FAP was expressed across all 14 cancer types on tissue microarray with variable intensity and frequency, ranging from 25% to 100% (mean, 76.6% ± 25.3%). Strong FAP expression was observed in 50%-100% of cancers of the bile duct, bladder, colon, esophagus, stomach, lung, oropharynx, ovary, and pancreas. Fifteen patients with various cancer types (colorectal [ n  = 4], head and neck [ n  = 3], pancreas [ n  = 2], breast [ n  = 2], stomach [ n  = 1], esophagus [ n  = 2], and uterus [ n  = 1]) underwent surgery after their 68 Ga-FAPi-46 PET/CT scan within a mean interval of 16.1 ± 14.4 d. 68 Ga-FAPi-46 SUVs and immunohistochemistry scores were higher in cancer than in tumor-adjacent non-cancer tissue: mean SUV max 7.7 versus 1.6 ( P  < 0.001), mean SUV mean 6.2 versus 1.0 ( P  < 0.001), and mean FAP immunohistochemistry score 2.8 versus 0.9 ( P  < 0.001). FAP immunohistochemistry scores strongly correlated with 68 Ga-FAPi 46 SUV max and SUV mean : r  = 0.781 (95% CI, 0.376-0.936; P  < 0.001) and r  = 0.783 (95% CI, 0.379-0.936; P  < 0.001), respectively. Conclusion: In this interim analysis of a prospective exploratory imaging trial, 68 Ga-FAPi-46 PET biodistribution across multiple cancers strongly correlated with FAP tissue expression. These findings support further exploration of FAPi PET as a pancancer imaging biomarker for FAP expression and as a stratification tool for FAP-targeted therapies., (© 2022 by the Society of Nuclear Medicine and Molecular Imaging.)

Pancreatic ductal adenocarcinoma (PDAC) is correlated with poor outcomes because of limited therapeutic options. Laminin-5 gamma-2 (LAMC2) plays a critical role in key biological processes. However, the detailed molecular mechanism and potential roles of LAMC2 in PDAC stay unexplored. The present study examines the essential role and molecular mechanisms of LAMC2 in the tumorigenesis of PDAC. Here, we identified that LAMC2 is significantly upregulated in microarray cohorts and TCGA RNA sequencing data of PDAC patients compared to non-cancerous/normal tissues. Patients with higher transcript levels of LAMC2 were correlated with clinical stages; dismal overall, as well as, disease-free survival. Additionally, we confirmed significant upregulation of LAMC2 in a panel of PDAC cell lines and PDAC tumor specimens in contrast to normal pancreatic tissues and cells. Inhibition of LAMC2 significantly decreased cell growth, clonogenic ability, migration and invasion of PDAC cells, and tumor growth in the PDAC xenograft model. Mechanistically, silencing of LAMC2 suppressed expression of ZEB1, SNAIL, N-cadherin (CDH2), vimentin (VIM), and induced E-cadherin (CDH1) expression leading to a reversal of mesenchymal to an epithelial phenotype. Interestingly, co-immunoprecipitation experiments demonstrated LAMC2 interaction with epidermal growth factor receptor (EGFR). Further, stable knockdown of LAMC2 inhibited phosphorylation of EGFR, ERK1/2, AKT, mTOR, and P70S6 kinase signaling cascade in PDAC cells. Altogether, our findings suggest that silencing of LAMC2 inhibited PDAC tumorigenesis and metastasis through repression of epithelial-mesenchymal transition and modulation of EGFR/ERK1/2/AKT/mTOR axis and could be a potential diagnostic, prognostic, and therapeutic target for PDAC., (© 2022. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

WNT signaling promotes pancreatic ductal adenocarcinoma (PDAC) through diverse effects on proliferation, differentiation, survival, and stemness. A subset of PDAC with inactivating mutations in ring finger protein 43 (RNF43) show growth dependency on autocrine WNT ligand signaling and are susceptible to agents that block WNT ligand acylation by Porcupine O-acyltransferase, which is required for proper WNT ligand processing and secretion. For this study, global transcriptomic, proteomic, and metabolomic analyses were performed to explore the therapeutic response of RNF43-mutant PDAC to the Porcupine inhibitor (PORCNi) LGK974. LGK974 disrupted cellular bioenergetics and mitochondrial function through actions that included rapid mitochondrial depolarization, reduced mitochondrial content, and inhibition of oxidative phosphorylation and tricarboxylic acid cycle. LGK974 also broadly altered transcriptional activity, downregulating genes involved in cell cycle, nucleotide metabolism, and ribosomal biogenesis and upregulating genes involved in epithelial-mesenchymal transition, hypoxia, endocytosis, and lysosomes. Autophagy and lysosomal activity were augmented in response to LGK974, which synergistically inhibited tumor cell viability in combination with chloroquine. Autocrine WNT ligand signaling dictates metabolic dependencies in RNF43-mutant PDAC through a combination of transcription dependent and independent effects linked to mitochondrial health and function. Metabolic adaptations to mitochondrial damage and bioenergetic stress represent potential targetable liabilities in combination with PORCNi for the treatment of WNT ligand-addicted PDAC., (©2022 American Association for Cancer Research.)

Cancer-associated fibroblast (CAF) heterogeneity is increasingly appreciated, but the origins and functions of distinct CAF subtypes remain poorly understood. The abundant and transcriptionally diverse CAF population in pancreatic ductal adenocarcinoma (PDAC) is thought to arise from a common cell of origin, pancreatic stellate cells (PSC), with diversification resulting from cytokine and growth factor gradients within the tumor microenvironment. Here we analyzed the differentiation and function of PSCs during tumor progression in vivo . Contrary to expectations, we found that PSCs give rise to a numerically minor subset of PDAC CAFs. Targeted ablation of PSC-derived CAFs within their host tissue revealed nonredundant functions for this defined CAF population in shaping the PDAC microenvironment, including production of specific extracellular matrix components and tissue stiffness regulation. Together, these findings link stromal evolution from distinct cells of origin to transcriptional heterogeneity among PDAC CAFs and demonstrate unique functions for CAFs of a defined cellular origin. SIGNIFICANCE: By tracking and ablating a specific CAF population, we find that a numerically minor CAF subtype from a defined cell of origin plays unique roles in establishing the pancreatic tumor microenvironment. Together with prior studies, this work suggests that mesenchymal lineage heterogeneity and signaling gradients diversify PDAC CAFs. See related commentary by Cukierman, p. 296 . This article is highlighted in the In This Issue feature, p. 275 ., (©2021 The Authors; Published by the American Association for Cancer Research.)

We determine that type I interferon (IFN) response biomarkers are enriched in a subset of pancreatic ductal adenocarcinoma (PDAC) tumors; however, actionable vulnerabilities associated with IFN signaling have not been systematically defined. Integration of a phosphoproteomic analysis and a chemical genomics synergy screen reveals that IFN activates the replication stress response kinase ataxia telangiectasia and Rad3-related protein (ATR) in PDAC cells and sensitizes them to ATR inhibitors. IFN triggers cell-cycle arrest in S-phase, which is accompanied by nucleotide pool insufficiency and nucleoside efflux. In combination with IFN, ATR inhibitors induce lethal DNA damage and downregulate nucleotide biosynthesis. ATR inhibition limits the growth of PDAC tumors in which IFN signaling is driven by stimulator of interferon genes (STING). These results identify a cross talk between IFN, DNA replication stress response networks, and nucleotide metabolism while providing the rationale for targeted therapeutic interventions that leverage IFN signaling in tumors., Competing Interests: Declaration of interests C.G.R. and J. Czernin are co-founders of Sofie Biosciences and Trethera Corporation. They and the University of California (UC) hold equity in Sofie Biosciences and Trethera Corporation. T.R.D. is an executive board member and holds equity in Trethera Corporation. The intellectual property developed by C.G.R. and J. Czernin and licensed by UC to Sofie Biosciences and Trethera Corporation was not used in this study., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Immune checkpoint blockade using PD-1 inhibition is an effective approach for treating a wide variety of cancer subtypes. While lower gastrointestinal (GI) side effects are more common, upper gastrointestinal adverse events are rarely reported. Here, we present a case of nivolumab-associated autoimmune gastritis. To elucidate the immunology underlying this condition, we leverage multiplexed ion beam imaging by time-of-flight (MIBI-TOF) to identify the presence and proportion of infiltrating immune cells from a single section of biopsy specimen. Using MIBI-TOF, we analyze formalin-fixed, paraffin-embedded human gastric tissue with 28 labels simultaneously. Our analyses reveal a gastritis characterized by severe mucosal injury, interferon gamma (IFN-γ)-producing gastric epithelial cells, and mixed inflammation that includes CD8 and CD4 T cell infiltrates with reduced expression of granzyme B and FOXP3, respectively. Here, we provide a comprehensive multiplexed histopathological mapping of gastric tissue, which identifies IFN-γ-producing epithelial cells as possible contributors to the nivolumab-associated gastritis., Competing Interests: S.F. was a paid speaker for an IonPath webinar. M.A. and S.C.B. have patents relating to MIBI technology and are paid consultants and shareholders at IonPath. E.F.M. has previously consulted for IonPath., (© 2021 The Author(s).)

Disordered lysosomal/autophagy pathways initiate and drive pancreatitis, but the underlying mechanisms and links to disease pathology are poorly understood. Here, we show that the mannose-6-phosphate (M6P) pathway of hydrolase delivery to lysosomes critically regulates pancreatic acinar cell cholesterol metabolism. Ablation of the Gnptab gene encoding a key enzyme in the M6P pathway disrupted acinar cell cholesterol turnover, causing accumulation of nonesterified cholesterol in lysosomes/autolysosomes, its depletion in the plasma membrane, and upregulation of cholesterol synthesis and uptake. We found similar dysregulation of acinar cell cholesterol, and a decrease in GNPTAB levels, in both WT experimental pancreatitis and human disease. The mechanisms mediating pancreatic cholesterol dyshomeostasis in Gnptab-/- and experimental models involve a disordered endolysosomal system, resulting in impaired cholesterol transport through lysosomes and blockage of autophagic flux. By contrast, in Gnptab-/- liver the endolysosomal system and cholesterol homeostasis were largely unaffected. Gnptab-/- mice developed spontaneous pancreatitis. Normalization of cholesterol metabolism by pharmacologic means alleviated responses of experimental pancreatitis, particularly trypsinogen activation, the disease hallmark. The results reveal the essential role of the M6P pathway in maintaining exocrine pancreas homeostasis and function, and implicate cholesterol disordering in the pathogenesis of pancreatitis.

Mucormycosis is a rare fungal infection that typically affects severely immunocompromised individuals, often resulting in significant morbidity and mortality. Although early and aggressive intervention is necessary to prevent poor outcomes, diagnosis of this infection remains difficult. We report the first case, to our knowledge, of invasive gastrointestinal mucormycosis initially identified by next-generation sequencing of cfDNA from the blood, and discuss the various benefits and challenges which come with new molecular diagnostic techniques., (© 2021 Wiley Periodicals LLC.)

WNT signaling promotes the initiation and progression of pancreatic ductal adenocarcinoma (PDAC) through wide-ranging effects on cellular proliferation, survival, differentiation, stemness, and tumor microenvironment. Of therapeutic interest is a genetically defined subset of PDAC known to have increased WNT/β-catenin transcriptional activity, growth dependency on WNT ligand signaling, and response to pharmacologic inhibitors of the WNT pathway. Here we review mechanisms underlying WNT ligand addiction in pancreatic tumorigenesis, as well as the potential utility of therapeutic approaches that functionally antagonize WNT ligand secretion or frizzled receptor binding., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Aguilera and Dawson.)

Lysosomes must maintain the integrity of their limiting membrane to ensure efficient fusion with incoming organelles and degradation of substrates within their lumen. Pancreatic cancer cells upregulate lysosomal biogenesis to enhance nutrient recycling and stress resistance, but it is unknown whether dedicated programmes for maintaining the integrity of the lysosome membrane facilitate pancreatic cancer growth. Using proteomic-based organelle profiling, we identify the Ferlin family plasma membrane repair factor Myoferlin as selectively and highly enriched on the membrane of pancreatic cancer lysosomes. Mechanistically, lysosomal localization of Myoferlin is necessary and sufficient for the maintenance of lysosome health and provides an early acting protective system against membrane damage that is independent of the endosomal sorting complex required for transport (ESCRT)-mediated repair network. Myoferlin is upregulated in human pancreatic cancer, predicts poor survival and its ablation severely impairs lysosome function and tumour growth in vivo. Thus, retargeting of plasma membrane repair factors enhances the pro-oncogenic activities of the lysosome.

Emerging evidence suggests that intratumoral interferon (IFN) signaling can trigger targetable vulnerabilities. A hallmark of pancreatic ductal adenocarcinoma (PDAC) is its extensively reprogrammed metabolic network, in which nicotinamide adenine dinucleotide (NAD) and its reduced form, NADH, are critical cofactors. Here, we show that IFN signaling, present in a subset of PDAC tumors, substantially lowers NAD(H) levels through up-regulating the expression of NAD-consuming enzymes PARP9, PARP10, and PARP14. Their individual contributions to this mechanism in PDAC have not been previously delineated. Nicotinamide phosphoribosyltransferase (NAMPT) is the rate-limiting enzyme in the NAD salvage pathway, a dominant source of NAD in cancer cells. We found that IFN-induced NAD consumption increased dependence upon NAMPT for its role in recycling NAM to salvage NAD pools, thus sensitizing PDAC cells to pharmacologic NAMPT inhibition. Their combination decreased PDAC cell proliferation and invasion in vitro and suppressed orthotopic tumor growth and liver metastases in vivo., Competing Interests: Competing interest statement: C.G.R. is a cofounder of Sofie Biosciences and Trethera Corporation. He and the University of California (UC) hold equity in Sofie Biosciences and Trethera Corporation. The intellectual property developed by C.G.R. and licensed by UC to Sofie Biosciences and Trethera Corporation was not used in this study.

Modified DNA aptamers incorporated with amino-acid like side chains or drug-like ligands can offer unique advantages and enhance specificity as affinity ligands. Thy-1 membrane glycoprotein (THY1 or CD90) was previously identified as a biomarker candidate of neovasculature in pancreatic ductal adenocarcinoma (PDAC). The current study developed and evaluated modified DNA X-aptamers targeting THY1 in PDAC. The expression and glycosylation of THY1 in PDAC tumor tissues were assessed using immunohistochemistry and quantitative proteomics. Bead-based X-aptamer library that contains 10 8 different sequences was used to screen for high affinity THY1 X-aptamers. The sequences of the X-aptamers were analyzed with the next-generation sequencing. The affinities of the selected X-aptamers to THY1 were quantitatively evaluated with flow cytometry. Three high affinity THY1 X-aptamers, including XA-B217, XA-B216 and XA-A9, were selected after library screening and affinity binding evaluation. These three X-aptamers demonstrated a high binding affinity and specificity to THY1 protein and the THY1 expressing cell lines, using THY1 antibody as a comparison. The development of these X-aptamers provides highly specific and non-immunogenic affinity ligands for THY1 binding in the context of biomarker development and clinical applications. They could be further exploited to assist molecular imaging of PDAC targeting THY1., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.)

Purpose: Prostate-specific membrane antigen (PSMA) targeting radioligands deliver radiation to PSMA-expressing cells. However, the relationship between PSMA levels and intralesion heterogeneity of PSMA expression, and cytotoxic radiation by radioligand therapy (RLT) is unknown. Here we investigate RLT efficacy as function of PSMA levels/cell, and the fraction of PSMA + cells in a tumor., Experimental Design: RM1 cells expressing different levels of PSMA (PSMA - , PSMA + , PSMA ++ , PSMA +++ ; study 1) or a mix of PSMA + and PSMA - RM1 (study 2, 4) or PC-3/PC-3-PIP (study 3) cells at various ratios were injected into mice. Mice received 177 Lu- (studies 1-3) or 225 Ac- (study 4) PSMA617. Tumor growth was monitored. Two days post-RLT, tumors were resected in a subset of mice. Radioligand uptake and DNA damage were quantified., Results: 177 Lu-PSMA617 efficacy increased with increasing PSMA levels (study 1) and fractions of PSMA positive cells (studies 2, 3) in both, the RM1 and PC-3-PIP models. In tumors resected 2 days post-RLT, PSMA expression correlated with 177 Lu-PSMA617 uptake and the degree of DNA damage. Compared with 177 Lu-PSMA617, 225 Ac-PSMA617 improved overall antitumor effectiveness and tended to enhance the differences in therapeutic efficacy between experimental groups., Conclusions: In the current models, both the degree of PSMA expression and the fraction of PSMA + cells correlate with 177 Lu-/ 225 Ac-PSMA617 tumor uptake and DNA damage, and thus, RLT efficacy. Low or heterogeneous PSMA expression represents a resistance mechanism to RLT. See related commentary by Ravi Kumar and Hofman, p. 2774 ., (©2020 American Association for Cancer Research.)

Arginine (Arg) deprivation is a promising therapeutic approach for tumors with low argininosuccinate synthetase 1 (ASS1) expression. However, its efficacy as a single agent therapy needs to be improved as resistance is frequently observed. Methods: A tissue microarray was performed to assess ASS1 expression in surgical specimens of pancreatic ductal adenocarcinoma (PDAC) and its correlation with disease prognosis. An RNA-Seq analysis examined the role of ASS1 in regulating the global gene transcriptome. A high throughput screen of FDA-approved oncology drugs identified synthetic lethality between histone deacetylase (HDAC) inhibitors and Arg deprivation in PDAC cells with low ASS1 expression. We examined HDAC inhibitor panobinostat (PAN) and Arg deprivation in a panel of human PDAC cell lines, in ASS1-high and -knockdown/knockout isogenic models, in both anchorage-dependent and -independent cultures, and in multicellular complex cultures that model the PDAC tumor microenvironment. We examined the effects of combined Arg deprivation and PAN on DNA damage and the protein levels of key DNA repair enzymes. We also evaluated the efficacy of PAN and ADI-PEG20 (an Arg-degrading agent currently in Phase 2 clinical trials) in xenograft models with ASS1-low and -high PDAC tumors. Results: Low ASS1 protein level is a negative prognostic indicator in PDAC. Arg deprivation in ASS1-deficient PDAC cells upregulated asparagine synthetase (ASNS) which redirected aspartate (Asp) from being used for de novo nucleotide biosynthesis, thus causing nucleotide insufficiency and impairing cell cycle S-phase progression. Comprehensively validated, HDAC inhibitors and Arg deprivation showed synthetic lethality in ASS1-low PDAC cells. Mechanistically, combined Arg deprivation and HDAC inhibition triggered degradation of a key DNA repair enzyme C-terminal-binding protein interacting protein (CtIP), resulting in DNA damage and apoptosis. In addition, S-phase-retained ASS1-low PDAC cells (due to Arg deprivation) were also sensitized to DNA damage, thus yielding effective cell death. Compared to single agents, the combination of PAN and ADI-PEG20 showed better efficacy in suppressing ASS1-low PDAC tumor growth in mouse xenograft models. Conclusion: The combination of PAN and ADI-PEG20 is a rational translational therapeutic strategy for treating ASS1-low PDAC tumors through synergistic induction of DNA damage., Competing Interests: Competing Interests: The authors have declared that no competing interest exists., (© The author(s).)

Objective: Despite advances in the identification of epigenetic alterations in pancreatic cancer, their biological roles in the pathobiology of this dismal neoplasm remain elusive. Here, we aimed to characterise the functional significance of histone lysine methyltransferases (KMTs) and demethylases (KDMs) in pancreatic tumourigenesis., Design: DNA methylation sequencing and gene expression microarrays were employed to investigate CpG methylation and expression patterns of KMTs and KDMs in pancreatic cancer tissues versus normal tissues. Gene expression was assessed in five cohorts of patients by reverse transcription quantitative-PCR. Molecular analysis and functional assays were conducted in genetically modified cell lines. Cellular metabolic rates were measured using an XF24-3 Analyzer, while quantitative evaluation of lipids was performed by liquid chromatography-mass spectrometry (LC-MS) analysis. Subcutaneous xenograft mouse models were used to evaluate pancreatic tumour growth in vivo., Results: We define a new antitumorous function of the histone lysine (K)-specific methyltransferase 2D (KMT2D) in pancreatic cancer. KMT2D is transcriptionally repressed in human pancreatic tumours through DNA methylation. Clinically, lower levels of this methyltransferase associate with poor prognosis and significant weight alterations. RNAi-based genetic inactivation of KMT2D promotes tumour growth and results in loss of H3K4me3 mark. In addition, KMT2D inhibition increases aerobic glycolysis and alters the lipidomic profiles of pancreatic cancer cells. Further analysis of this phenomenon identified the glucose transporter SLC2A3 as a mediator of KMT2D-induced changes in cellular, metabolic and proliferative rates., Conclusion: Together our findings define a new tumour suppressor function of KMT2D through the regulation of glucose/fatty acid metabolism in pancreatic cancer., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Patients with early-stage pancreatic neuroendocrine tumors (PNETs) may develop metastatic recurrences despite undergoing potentially curative pancreas resections. We sought to identify factors predictive of metastatic recurrences and develop a prognostication strategy to predict recurrence-free survival (RFS) in resected PNETs., Methods: Patients with localized PNETs undergoing surgical resection between 1989 and 2015 were identified. Univariate and multivariate analysis were used to identify potential predictors of post-resection metastasis. A score-based prognostication system was devised using the identified factors. The bootstrap model validation methodology was utilized to estimate the external validity of the proposed prognostication strategy., Results: Of the 140 patients with completely resected early-stage PNETs, overall 5- and 10-year RFS were 84.6% and 67.1%, respectively. The median follow-up was 56 months. Multivariate analysis identified tumor size > 5 cm, Ki-67 index 8-20%, lymph node involvement, and high histologic grade (G3, or Ki-67 > 20%) as independent predictors of post-resection metastatic recurrence. A scoring system based on these factors stratified patients into three prognostic categories with distinct 5-year RFS: 96.9%, 54.8%, and 33.3% (P < 0.0001). The bootstrap model validation methodology projected our proposed prognostication strategy to retain a high predictive accuracy even when applied in an external dataset (validated c-index of 0.81)., Conclusions: The combination of tumor size, LN status, grade, and Ki-67 was identified as the most highly predictive indicators of metastatic recurrences in resected PNETs. The proposed prognostication strategy may help stratify patients for adjuvant therapies, enhanced surveillance protocols and future clinical trials.

Although survival has improved in recent years, the prognosis of patients with advanced pancreatic ductal adenocarcinoma (PDAC) remains poor. Despite substantial differences in anatomy, physiology, genetics, and metabolism, the overwhelming majority of preclinical testing relies on transgenic mice. Hence, while mice have allowed for tremendous advances in cancer biology, they have been a poor predictor of drug performance/toxicity in the clinic. Given the greater similarity of sus scrofa pigs to humans, we engineered transgenic sus scrofa expressing a LSL-KRAS G12D -TP53 R167H cassette. By applying Adeno-Cre to pancreatic duct cells in vitro, cells self-immortalized and established tumors in immunocompromised mice. When Adeno-Cre was administered to the main pancreatic duct in vivo, pigs developed extensive PDAC at the injection site hallmarked by excessive proliferation and desmoplastic stroma. This serves as the first large animal model of pancreatic carcinogenesis, and may allow for insight into new avenues of translational research not before possible in rodents.

Pancreatic ductal adenocarcinoma (PDAC) is a particularly deadly disease. Chronic conditions, including obesity and type-2 diabetes are risk factors, thus making PDAC amenable to preventive strategies. We aimed to characterize the chemo-preventive effects of metformin, a widely used anti-diabetic drug, on PDAC development using the Kras G12D mouse model subjected to a diet high in fats and calories (HFCD). LSL-Kras G12D/+ ;p48-Cre (KC) mice were given control diet (CD), HFCD, or HFCD with 5 mg/ml metformin in drinking water for 3 or 9 months. After 3 months, metformin prevented HFCD-induced weight gain, hepatic steatosis, depletion of intact acini, formation of advanced PanIN lesions, and stimulation of ERK and mTORC1 in pancreas. In addition to reversing hepatic and pancreatic histopathology, metformin normalized HFCD-induced hyperinsulinemia and hyperleptinemia among the 9-month cohort. Importantly, the HFCD-increased PDAC incidence was completely abrogated by metformin (p < 0.01). The obesogenic diet also induced a marked increase in the expression of TAZ in pancreas, an effect abrogated by metformin. In conclusion, administration of metformin improved the metabolic profile and eliminated the promoting effects of diet-induced obesity on PDAC formation in KC mice. Given the established safety profile of metformin, our findings have a strong translational potential for novel chemo-preventive strategies for PDAC.

Peroxiredoxin-1 (Prdx1), a member of the thioredoxin (Txn) system, is overexpressed and correlates with poor prognosis in pancreatic cancer patients and can suppress Kras signaling through redox-mediated inhibition of ERK and AKT in lung and breast cancer. Its redox function is maintained by Txn and sulfiredoxin (Srxn), and its tumor promoting functions are activated by post-translational modification. We studied the role of the Txn system in pancreatic neoplasia and cancer by determining how it regulates the phosphorylation of Kras effectors and by determining its association with patient survival. We found that elevated Prdx1 nuclear localization significantly correlated with better patient survival. Our data also demonstrate that the expression of the Txn system is dysregulated, with elevated Prdx1 expression and significantly decreased Txn and Srxn expression in pancreatic lesions of targeted mutant Kras mouse models. This correlated with distinct differences in the interconversion of Prdx1 oligomers that affect its ability to regulate ERK and AKT phosphorylation. Our data also suggest that Prdx1 post-translational modification and oligomerization suppress Prdx1 mediated redox regulation of ERK phosphorylation. We observed distinct differences in Txn expression and in the ability of pTyr-Prdx1 to bind to pERK in a PanIN model of pancreatic neoplasia as compared to an IPMN model, indicating a distinct difference in the function of post-translationally modified Prdx1 in cells with less Txn expression. Modified Txn system function and post-translational regulation may therefore play a significant role in pancreatic tumorigenesis by altering Kras effector phosphorylation and inhibiting the tumor suppressive redox functions of Prdx1., Competing Interests: CONFLICTS OF INTEREST No competing financial interest exist.

Epidemiologic data has linked obesity to a higher risk of pancreatic cancer, but the underlying mechanisms are poorly understood. To allow for detailed mechanistic studies in a relevant model mimicking diet-induced obesity and pancreatic cancer, a high-fat, high-calorie diet (HFCD) was given to P48+/Cre;LSL-KRASG12D (KC) mice carrying a pancreas-specific oncogenic Kras mutation. The mice were randomly allocated to a HFCD or control diet (CD). Cohorts were sacrificed at 3, 6, and 9 months and tissues were harvested for further analysis. Compared to CD-fed mice, HFCD-fed animals gained significantly more weight. Importantly, the cancer incidence was remarkably increased in HFCD-fed KC mice, particularly in male KC mice. In addition, KC mice fed the HFCD showed more extensive inflammation and fibrosis, and more advanced PanIN lesions in the pancreas, compared to age-matched CD-fed animals. Interestingly, we found that the HFCD reduced autophagic flux in PanIN lesions in KC mice. Further, exome sequencing of isolated murine PanIN lesions identified numerous genetic variants unique to the HFCD. These data underscore the role of sustained inflammation and dysregulated autophagy in diet-induced pancreatic cancer development and suggest that diet-induced genetic alterations may contribute to this process. Our findings provide a better understanding of the mechanisms underlying the obesity-cancer link in males and females, and will facilitate the development of interventions targeting obesity-associated pancreatic cancer.

Pancreatitis is more frequent in type 2 diabetes mellitus (T2DM), although the underlying cause is unknown. We tested the hypothesis that ongoing β cell stress and apoptosis in T2DM induces ductal tree proliferation, particularly the pancreatic duct gland (PDG) compartment, and thus potentially obstructs exocrine outflow, a well-established cause of pancreatitis. PDG replication was increased 2-fold in human pancreas from individuals with T2DM, and was associated with increased pancreatic intraepithelial neoplasia (PanIN), lesions associated with pancreatic inflammation and with the potential to obstruct pancreatic outflow. Increased PDG replication in the prediabetic human-IAPP-transgenic (HIP) rat model of T2DM was concordant with increased β cell stress but preceded metabolic derangement. Moreover, the most abundantly expressed chemokines released by the islets in response to β cell stress in T2DM, CXCL1, -4, and -10, induced proliferation in human pancreatic ductal epithelium. Also, the diabetes medications reported as potential modifiers for the risk of pancreatitis in T2DM modulated PDG proliferation accordingly. We conclude that chronic stimulation and proliferation of the PDG compartment in response to islet inflammation in T2DM is a potentially novel mechanism that serves as a link to the increased risk for pancreatitis in T2DM and may potentially be modified by currently available diabetes therapy.

Background: There is strong evidence linking inflammation and the development of pancreatic ductal adenocarcinoma. Cyclooxygenase-2 (COX-2) and COX-2-derived PGE 2 are overexpressed in human and murine pancreatic ductal adenocarcinoma. Several studies have demonstrated an important role of COX-2-derived PGE 2 in tumor-stroma interactions; however, the direct growth effects of prostaglandin E 2 (PGE 2 ) on pancreatic ductal adenocarcinoma cells is less well defined. Our aim was to investigate the effects of PGE 2 on pancreatic ductal adenocarcinoma cell growth and to characterize the underlying mechanisms., Methods: Human pancreatic ductal adenocarcinoma cell lines, Panc-1 and MIA PaCa-2, were treated with PGE 2 in varying doses (0-10 μM). Effects on the phosphorylation of ERK1/2 were evaluated by Western blot. Colony formation was observed for cells treated with PGE 2 for 11 days. DNA synthesis was determined by (3H)-thymidine incorporation assay. Gene expression of E-type prostaglandin (EP)2/EP4 receptors and their correlation with survival in patients with pancreatic ductal adenocarcinoma were assessed using the RNA-Seq data set from The Cancer Genome Atlas Research Network., Results: PGE 2 decreased the size and number of colonies in Panc-1 but not MIA PaCa-2 cells. In the Panc-1 cells, PGE 2 activated PKA/CREB and decreased phosphorylation of ERK1/2, which was reversed by an EP4 receptor antagonist, while an EP2 receptor antagonist had no effect. In contrast, in MIA PaCa-2 cells, PGE 2 had no effect on ERK1/2 phosphorylation. Treatment of both Panc-1 and MIA PaCa-2 cells with forskolin/IBMX decreased ERK1/2 phosphorylation. Finally, PGE 2 decreased DNA synthesis only in Panc-1 cells, which was reversed by an EP4 receptor antagonist. In human pancreatic ductal adenocarcinoma, high EP2 and low EP4 gene expression was correlated to worse median overall survival (15.6 vs 20.8 months, log-rank P = .017)., Conclusion: Our study provides evidence that PGE 2 can inhibit directly pancreatic ductal adenocarcinoma cell growth through an EP4-mediated mechanism. Together with our gene expression and survival analysis, this observation suggests a protective role of EP4 receptors in human pancreatic ductal adenocarcinoma that expresses E-type prostaglandin receptors., (Copyright © 2017 Elsevier Inc. All rights reserved.)

The contributions of the innate immune system to the development of pancreatic cancer are still ill defined. Inflammatory macrophages can initiate metaplasia of pancreatic acinar cells to a duct-like phenotype (acinar-to-ductal metaplasia [ADM]), which then gives rise to pancreatic intraepithelial neoplasia (PanIN) when oncogenic KRas is present. However, it remains unclear when and how this inflammatory macrophage population is replaced by tumor-promoting macrophages. Here, we demonstrate the presence of interleukin-13 (IL-13), which can convert inflammatory into Ym1+ alternatively activated macrophages, at ADM/PanIN lesions. We further show that Ym1+ macrophages release factors, such as IL-1ra and CCL2, to drive pancreatic fibrogenesis and tumorigenesis. Treatment of mice expressing oncogenic KRas under an acinar cell-specific promoter with a neutralizing antibody for IL-13 significantly decreased the accumulation of alternatively activated macrophages at these lesions, resulting in decreased fibrosis and lesion growth., (Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.)

Although histone deacetylase inhibitors (HDACi) are a promising class of anti-cancer drugs, thus far, they have been unsuccessful in early phase clinical trials for pancreatic ductal adenocarcinoma (PDAC). One potential reason for their poor efficacy is the tumor stroma, where cancer-associated fibroblasts (CAFs) are a prominent cell type and a source of resistance to cancer therapies. Here, we demonstrate that stromal fibroblasts contribute to the poor efficacy of HDACi's in PDAC. HDACi-treated fibroblasts show increased biological aggressiveness and are characterized by increased secretion of pro-inflammatory tumor-supportive cytokines and chemokines. We find that HDAC2 binds to the enhancer and promoter regions of pro-inflammatory genes specifically in CAFs and in silico analysis identified AP-1 to be the most frequently associated transcription factor bound in these regions. Pharmacologic inhibition of pathways upstream of AP-1 suppresses the HDACi-induced inflammatory gene expression and tumor-supportive responses in fibroblasts. Our findings demonstrate that the combination of HDACi's with chemical inhibitors of the AP-1 signaling pathway attenuate the inflammatory phenotype of fibroblasts and may improve the efficacy of HDACi in PDAC and, potentially, in other solid tumors rich in stroma.

Importance: According to the 2012 International Consensus Guidelines, the diagnostic criterion of intraductal papillary mucinous neoplasms (IPMNs) involving the main duct (MD IPMNs) or the main and branch ducts (mixed IPMNs) of the pancreatic system is a main pancreatic duct (MPD) diameter of 5.0 mm or greater on computed tomography (CT) or magnetic resonance imaging (MRI). However, surgical resection is recommended for patients with an MPD diameter of 10.0 mm or greater, which is characterized as a high-risk stigma. An MPD diameter of 5.0 to 9.0 mm is not an indication for immediate resection., Objectives: To determine an appropriate cutoff (ie, one with high sensitivity and negative predictive value) of the MPD diameter on CT or MRI as a prognostic factor for malignant disease and to propose a new management algorithm for patients with MD or mixed IPMNs., Design, Setting, and Participants: This retrospective cohort study included 103 patients who underwent surgical resection for a preoperative diagnosis of MD or mixed IPMN and in whom IPMN was confirmed by surgical pathologic findings at a single institution from July 1, 1996, to December 31, 2015., Main Outcomes and Measures: Malignant disease was defined as high-grade dysplasia or invasive adenocarcinoma on results of surgical pathologic evaluation. An appropriate MPD diameter on preoperative CT or MRI to predict malignant disease was determined using a receiver operating characteristic curve analysis. The prognostic value of the new management algorithm that incorporated the new MPD diameter cutoff was evaluated., Results: Among the 103 patients undergoing resection for an MD or mixed IPMN (59 men [57.3%]; 44 women [42.7%]; median [range] age, 71 [48-86] years), 64 (62.1%) had malignant disease. Diagnostic accuracy for malignant neoplasms was highest at an MPD diameter cutoff of 7.2 mm (area under the receiver operating characteristic curve, 0.70; 95% CI, 0.59-0.81). An MPD diameter of 7.2 mm or greater was also an independent prognostic factor for malignant neoplasms (odds ratio, 12.76; 95% CI, 2.43-66.88; P = .003) on logistic regression analysis after controlling for preoperative variables. The new management algorithm, which included an MPD diameter of 7.2 mm or greater as one of the high-risk stigmata, had a higher sensitivity (100%), negative predictive value (100%), and accuracy (66%) for malignant disease than the 2012 version of the International Consensus Guidelines (95%, 57%, and 63%, respectively)., Conclusions and Relevance: In this single-center, retrospective analysis, an MPD diameter of 7.2 mm was identified as an optimal cutoff for a prognostic factor for malignant disease in MD or mixed IPMN. These data support lowering the accepted criteria for MPD diameter when selecting patients for resection vs surveillance so as not to overlook cancer in IPMN.

TGFβ has both tumor suppressive and tumor promoting effects in colon cancer. Also, TGFβ can affect the extent and composition of inflammatory cells present in tumors, contextually promoting and inhibiting inflammation. While colon tumors display intratumoral inflammation, the contributions of TGFβ to this process are poorly understood. In human patients, we found that epithelial loss of TGFβ signaling was associated with increased inflammatory burden; yet overexpression of TGFβ was also associated with increased inflammation. These findings were recapitulated in mutant APC models of murine tumorigenesis, where epithelial truncation of TGFBR2 led to lethal inflammatory disease and invasive colon cancer, mediated by IL8 and TGFβ1. Interestingly, mutant APC mice with global suppression of TGFβ signals displayed an intermediate phenotype, presenting with an overall increase in IL8-mediated inflammation and accelerated tumor formation, yet with a longer latency to the onset of disease observed in mice with epithelial TGFBR-deficiency. These results suggest that the loss of TGFβ signaling, particularly in colon epithelial cells, elicits a strong inflammatory response and promotes tumor progression. This implies that treating colon cancer patients with TGFβ inhibitors may result in a worse outcome by enhancing inflammatory responses.

Importance: Patients with periampullary adenocarcinomas have widely variable survival. These cancers are traditionally categorized by their anatomic location of origin, namely, the duodenum, ampulla, distal common bile duct (CBD), or head of the pancreas. However, they can be alternatively subdivided histopathologically into intestinal or pancreaticobiliary (PB) types, which may more accurately estimate prognosis., Objectives: To identify factors associated with survival in patients with periampullary adenocarcinomas and to compare survival between those having intestinal-type or PB-type cancers originating from the duodenum, ampulla, or distal CBD with those having pancreatic ductal adenocarcinoma (PDAC)., Design, Setting, and Participants: This study was a retrospective analysis of medical records in a prospectively maintained database. Three pathologists separately evaluated histopathologic phenotypes at a university-based tertiary referral center. Study participants were all patients (N = 510) who underwent pancreatoduodenectomy for adenocarcinoma between January 1995 and December 2014., Main Outcome and Measure: Overall survival., Results: This study identified 510 patients (mean [SD] age, 66.1 [10.9] years; 245 female [48%]) who underwent pancreatoduodenectomy for adenocarcinomas: 13 duodenal, 110 ampullary, 43 distal CBD, and 344 PDAC. The median overall survival was 61.2 (interquartile range [IQR], 22.0-111.0), 70.4 (IQR, 26.7-147.7), 40.6 (IQR, 15.2-59.6), and 31.4 (IQR, 17.3-86.3) months for patients with cancers of the duodenum, ampulla, distal CBD, or pancreas, respectively (P = .01), indicating a significant difference between the 4 tumor anatomic locations. Most duodenal (61.5% [8 of 13]) and ampullary (51.8% [57 of 110]) cancers were intestinal type, and most distal CBD tumors were PB type (86.0% [37 of 43]). Those with intestinal-type duodenal, ampullary, or distal CBD adenocarcinomas had longer median overall survival than those with PB type (71.7 vs 33.3 months, P = .02) or PDAC (31.4 months, P = .003). There was no survival difference between PB-type cancers and PDAC (33.3 vs 31.4 months, P = .66). On multivariable analysis, histologic grade (hazard ratio [HR], 1.98; 95% CI, 1.56-2.52; P < .001), histopathologic phenotype (HR, 1.75; 95% CI, 1.16-2.64; P = .008), and nodal status (HR, 1.45; 95% CI, 1.12-1.87; P = .05) were significantly associated with survival, while anatomic location was not., Conclusions and Relevance: Histopathologic phenotype is a better prognosticator of survival in patients with periampullary adenocarcinomas than tumor anatomic location. Those with PB-type duodenal, ampullary, or distal CBD adenocarcinomas have survival similar to those with PDAC.

Aberrant activation of embryonic signaling pathways is frequent in pancreatic ductal adenocarcinoma (PDA), making developmental regulators therapeutically attractive. Here we demonstrate diverse functions for pancreatic and duodenal homeobox 1 (PDX1), a transcription factor indispensable for pancreas development, in the progression from normal exocrine cells to metastatic PDA. We identify a critical role for PDX1 in maintaining acinar cell identity, thus resisting the formation of pancreatic intraepithelial neoplasia (PanIN)-derived PDA. Upon neoplastic transformation, the role of PDX1 changes from tumor-suppressive to oncogenic. Interestingly, subsets of malignant cells lose PDX1 expression while undergoing epithelial-to-mesenchymal transition (EMT), and PDX1 loss is associated with poor outcome. This stage-specific functionality arises from profound shifts in PDX1 chromatin occupancy from acinar cells to PDA. In summary, we report distinct roles of PDX1 at different stages of PDA, suggesting that therapeutic approaches against this potential target need to account for its changing functions at different stages of carcinogenesis. These findings provide insight into the complexity of PDA pathogenesis and advocate a rigorous investigation of therapeutically tractable targets at distinct phases of PDA development and progression., (© 2016 Roy et al.; Published by Cold Spring Harbor Laboratory Press.)

Pancreatic ductal adenocarcinoma (PDA) is a devastating malignancy with limited and modest clinical treatments. High-throughput technologies and accurate disease models now provide a comprehensive picture of the diverse molecular signaling pathways and cellular processes governing PDA tumorigenesis. Central among these is oncogenic KRAS, a mediator of cellular plasticity, metabolic reprogramming, and inflammatory and paracrine signaling required for tumor development and maintenance. Biological aggressiveness is further conferred by a highly fibrotic and immunosuppressive PDA microenvironment that also acts as a barrier to effective drug delivery. The regulation of these mechanisms and their implications for early cancer detection, chemoprevention and therapy are discussed., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

In this study, we sought to determine the incidence of post-transplant complications including acute cellular rejection (ACR), infection, and post-transplant lymphoproliferative disease (PTLD) in mucosal allograft biopsies in patients with small bowel transplant at our institution. We retrospectively reviewed pathology reports from 5675 small bowel allograft biopsies from 99 patients and analyzed the following: indications for biopsy, frequency and grade of ACR, the presence of infectious agents, results of workup for potential PTLD, results of C4d immunohistochemistry (IHC), features of chronic mucosal injury, and findings in concurrent native bowel biopsies. Findings from 42 allograft resection specimens were also correlated with prior biopsy findings. Indeterminate, mild, moderate, and severe ACR were seen in 276 (4.9%), 409 (7.2%), 100 (1.8%), and 207 (3.6%) of biopsies, respectively. Although ACR may show histologic overlap with mycophenolate mofetil toxicity, we found the analysis of concurrent native bowel biopsies to be helpful in this distinction. Adenovirus was the most common infectious agent seen (11%), and we routinely performed adenovirus IHC on biopsies. Eighteen patients (18%) developed PTLD, 83% of which were EBV associated, but only 28% of PTLD cases were diagnosed on mucosal allograft biopsies. C4d IHC did not correlate with the presence of donor-specific antibodies in limited cases., (© 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objective: This study aimed to evaluate Plectin-1 expression as a biomarker of malignant risk for intraductal papillary mucinous neoplasms (IPMNs)., Methods: Plectin-1 immunohistochemistry (IHC) was performed retrospectively on surgical (n = 71) and cytological (n = 33) specimens from Mayo Clinic Jacksonville and UCLA Medical Center, including IPMNs with low-grade dysplasia, high-grade dysplasia (HGD), or an associated invasive adenocarcinoma., Results: Plectin-1 expression was increased in invasive adenocarcinoma compared with adjacent in situ IPMN (P = 0.005), as well as the in situ HGD component of IPMNs with invasive cancer compared with HGD of IPMNs without invasive cancer (P = 0.02). Plectin IHC discriminated IPMNs with invasive adenocarcinoma from noninvasive IPMN (area under the curve [AUC] of 0.79, 75% sensitivity, and 85% specificity) but was insufficient for discriminating HGD IPMN from low-grade dysplasia IPMNs in surgical resections (AUC of 0.67, 56% sensitivity, and 64% specificity) or fine-needle aspiration specimens (AUC of 0.45)., Conclusions: Although Plectin-1 IHC has insufficient accuracy to be used as a definitive biomarker for malignant risk in the evaluation of IPMN biopsy or cytological specimens, increased Plectin-1 expression observed in both invasive cancer and in situ HGD of malignant IPMNs suggests that it might be successfully leveraged as a cyst fluid biomarker or molecular imaging target., Competing Interests: K.A.K. is affiliated with iTi Health, where a plectin targeting peptide imaging agent is licensed. All other authors declare no direct conflict of interest in relation to the present study..

Background: Long-term survival (LTS) is uncommon for patients with pancreatic ductal adenocarcinoma (PDAC). We sought to identify factors that predict 10-year, LTS after resection of PDAC., Methods: We identified all patients with PDAC who underwent resection at UCLA after 1990 and included all patients eligible for observed LTS (1/1/1990-12/31/2004). An independent pathologist reconfirmed the diagnosis of PDAC in patients with LTS. Logistic regression was used to predict LTS on the basis of patient and tumor characteristics., Results: Of 173 included patients, 53% were male, median age at diagnosis was 66 years, and median survival was 23 months. The rate of observed LTS was 12.1% (n = 21). Age, sex, number of lymph nodes evaluated, margin status, lymphovascular invasion, and adjuvant chemotherapy and radiation were not associated with LTS. The following were associated with LTS on bivariate analysis: low AJCC stage (Ia, Ib, IIa) (P = .034), negative lymph node status (P = .034), low grade (well-, moderately-differentiated) (P = .001), and absence of perineural invasion (P = .019). Only low grade (odds ratio 7.17, P = .012) and absent perineural invasion (odds ratio 3.28, P = .036) were independently associated with increased odds of LTS. Our multivariate model demonstrated good discriminatory power for LTS, as indicated by a c-statistic of 0.7856., Conclusion: Absence of perineural invasion and low tumor grade were associated with greater likelihood of LTS. Understanding the tumor biology of LTS may provide critical insight into a disease that is typically marked by aggressive behavior and limited survival., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Unlabelled: Pancreatic ductal adenocarcinoma (PDAC) has a characteristically dense stroma comprised predominantly of cancer-associated fibroblasts (CAF). CAFs promote tumor growth, metastasis, and treatment resistance. This study aimed to investigate the molecular changes and functional consequences associated with chemotherapy treatment of PDAC CAFs. Chemoresistant immortalized CAFs (R-CAF) were generated by continuous incubation in gemcitabine. Gene expression differences between treatment-naïve CAFs (N-CAF) and R-CAFs were compared by array analysis. Functionally, tumor cells (TC) were exposed to N-CAF- or R-CAF-conditioned media and assayed for migration, invasion, and viability in vitro Furthermore, a coinjection (TC and CAF) model was used to compare tumor growth in vivo R-CAFs increased TC viability, migration, and invasion compared with N-CAFs. In vivo, TCs coinjected with R-CAFs grew larger than those accompanied by N-CAFs. Genomic analysis demonstrated that R-CAFs had increased expression of various inflammatory mediators, similar to the previously described senescence-associated secretory phenotype (SASP). In addition, SASP mediators were found to be upregulated in response to short duration treatment with gemcitabine in both immortalized and primary CAFs. Inhibition of stress-associated MAPK signaling (P38 MAPK or JNK) attenuated SASP induction as well as the tumor-supportive functions of chemotherapy-treated CAFs in vitro and in vivo These results identify a negative consequence of chemotherapy on the PDAC microenvironment that could be targeted to improve the efficacy of current therapeutic regimens., Implications: Chemotherapy treatment of pancreatic cancer-associated fibroblasts results in a proinflammatory response driven by stress-associated MAPK signaling that enhances tumor cell growth and invasiveness. Mol Cancer Res; 14(5); 437-47. ©2016 AACR., (©2016 American Association for Cancer Research.)