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Pyrimidine nucleotide biosynthesis is a druggable metabolic dependency of cancer cells, and chemotherapy agents targeting pyrimidine metabolism are the backbone of treatment for many cancers. Dihydroorotate dehydrogenase (DHODH) is an essential enzyme in the de novo pyrimidine biosynthesis pathway that can be targeted by clinically approved inhibitors. However, despite robust preclinical anticancer efficacy, DHODH inhibitors have shown limited single-agent efficacy in phase I clinical trials. Therefore, novel combination therapy strategies are necessary to realize the potential of these drugs. To search for therapeutic vulnerabilities induced by DHODH inhibition, we examined gene expression changes in cancer cells treated with the potent and selective DHODH inhibitor brequinar (BQ). This revealed that BQ treatment causes upregulation of antigen presentation pathway genes and cell surface MHC class I expression. Mechanistic studies showed that this effect is 1) strictly dependent on pyrimidine nucleotide depletion, 2) independent of canonical antigen presentation pathway transcriptional regulators, and 3) mediated by RNA polymerase II elongation control by positive transcription elongation factor B (P-TEFb). Furthermore, BQ showed impressive single-agent efficacy in the immunocompetent B16F10 melanoma model, and combination treatment with BQ and dual immune checkpoint blockade (anti-CTLA-4 plus anti-PD-1) significantly prolonged mouse survival compared to either therapy alone. Our results have important implications for the clinical development of DHODH inhibitors and provide a rationale for combination therapy with BQ and immune checkpoint blockade.

Gating strategy for immune subsets in pancreatic tumor

Pancreatic ductal adenocarcinoma (PDAC) represents 3% of all cancer cases and 7% of all cancer deaths in the United States. Late diagnosis and inadequate response to standard chemotherapies contribute to an unfavorable prognosis and an overall 5-year survival rate of less than 10% in PDAC. Despite recent advances in tumor immunology, tumor-induced immunosuppression attenuates the immunotherapy response in PDAC. To date, studies have focused on IgG-based therapeutic strategies in PDAC. With the recent interest in IgE-based therapies in multiple solid tumors, we explored the MUC1-targeted IgE potential against pancreatic cancer. Our study demonstrates the notable expression of FceRI (receptor for IgE antibody) in tumors from PDAC patients. Our study showed that administration of MUC1 targeted-IgE (mouse/human chimeric anti-MUC1.IgE) antibody at intermittent levels in combination with checkpoint inhibitor (anti-PD-L1) and TLR3 agonist (PolyICLC) induces a robust antitumor response that is dependent on NK and CD8 T cells in pancreatic tumor-bearing mice. Subsequently, our study showed that the antigen specificity of the IgE antibody plays a vital role in executing the antitumor response as nonspecific IgE, induced by ovalbumin (OVA), failed to restrict tumor growth in pancreatic tumor-bearing mice. Utilizing the OVA-induced allergic asthma-PDAC model, we demonstrate that allergic phenotype induced by OVA cannot restrain pancreatic tumor growth in orthotopic tumor-bearing mice. Together, our data demonstrate the novel tumor protective benefits of tumor antigen-specific IgE-based therapeutics in a preclinical model of pancreatic cancer, which can open new avenues for future clinical interventions.

BACKGROUND & AIMS: SIRT5 plays pleiotropic roles via post-translational modifications, serving as a tumor suppressor, or an oncogene, in different tumors. However, the role SIRT5 plays in the initiation and progression of pancreatic ductal adenocarcinoma (PDAC) remains unknown. METHODS: Published datasets and tissue arrays with SIRT5 staining were used to investigate the clinical relevance of SIRT5 in PDAC. Furthermore, to define the role of SIRT5 in the carcinogenesis of PDAC, we generated autochthonous mouse models with conditional Sirt5 knockout. Moreover, to examine the mechanistic role of SIRT5 in PDAC carcinogenesis, SIRT5 was knocked down in PDAC cell lines and organoids, followed by metabolomics and proteomics studies. A novel SIRT5 activator was utilized for therapeutic studies in organoids and patient-derived xenografts. RESULTS: SIRT5 expression negatively regulated tumor cell proliferation and correlated with a favorable prognosis in PDAC patients. Genetic ablation of Sirt5 in PDAC mouse models promoted acinar-to-ductal metaplasia, precursor lesions, and pancreatic tumorigenesis, resulting in poor survival. Mechanistically, SIRT5 loss enhanced glutamine and glutathione metabolism via acetylation-mediated activation of GOT1. A selective SIRT5 activator, MC3138, phenocopied the effects of SIRT5 overexpression and exhibited anti-tumor effects on human PDAC cells. MC3138 also diminished nucleotide pools, sensitizing human PDAC cell lines, organoids, and patient-derived xenografts to gemcitabine. CONCLUSIONS: Collectively, we identify SIRT5 as a key tumor suppressor in PDAC, whose loss promotes tumorigenesis through increased non-canonical utilization of glutamine via GOT1, and that SIRT5 activation is a novel therapeutic strategy to target PDAC.

Incidence of cachexia is highly prevalent in pancreatic ductal adenocarcinoma (PDAC); advanced disease stage directly correlates with decreased muscle and fat mass in PDAC patients. The pancreatic tumor microenvironment is central to the release of systemic factors that govern lipolysis, proteolysis, and muscle and fat degeneration leading to the cachectic phenotype in cancer patients. The current study explores the role of macrophages, a key immunosuppressive player in the pancreatic tumor microenvironment, in regulating cancer cachexia. We observed a negative correlation between CD163-positive macrophage infiltration and muscle-fiber cross sectional area in human PDAC patients. To investigate the role of macrophages in myodegeneration, we utilized conditioned media transplant assays and orthotopic models of PDAC-induced cachexia in immune-competent mice with and without macrophage depletion. We observed that macrophage-derived conditioned medium, in combination with tumor cell-conditioned medium, synergistically promoted muscle atrophy through STAT3 signaling. Furthermore, macrophage depletion attenuated systemic inflammation and muscle wasting in pancreatic tumor-bearing mice. Targeting macrophage-mediated STAT3 activation or macrophage-derived interleukin-1 alpha or interleukin-6 diminished myofiber atrophy. Taken together, the current study identified the critical association between macrophages and cachexia phenotype in pancreatic cancer.

Tumor progression is known occur in a complex microenvironment that leads to genetic, cellular, and metabolic adaptations. Two articles from Martin et al. and Del Poggetto et al. enlighten us on the role of inflammation and the immune system in guiding the progression of preneoplastic cells to oncogenic transformation and on subsequent tumor evolution.

Identification of clinically actionable molecular subtypes of pancreatic ductal adenocarcinoma (PDAC) is key to improving patient outcome. Intertumoral metabolic heterogeneity contributes to cancer survival and the balance between distinct metabolic pathways may influence PDAC outcome. We hypothesized that PDAC can be stratified into prognostic metabolic subgroups based on alterations in the expression of genes involved in glycolysis and cholesterol synthesis.We performed bioinformatics analysis of genomic, transcriptomic, and clinical data in an integrated cohort of 325 resectable and nonresectable PDAC. The resectable datasets included retrospective The Cancer Genome Atlas (TCGA) and the International Cancer Genome Consortium (ICGC) cohorts. The nonresectable PDAC cohort studies included prospective COMPASS, PanGen, and BC Cancer Personalized OncoGenomics program (POG).On the basis of the median normalized expression of glycolytic and cholesterogenic genes, four subgroups were identified: quiescent, glycolytic, cholesterogenic, and mixed. Glycolytic tumors were associated with the shortest median survival in resectable (log-rank testMetabolic classification specific to glycolytic and cholesterogenic pathways provides novel biological insight into previously established PDAC subtypes and may help develop personalized therapies targeting unique tumor metabolic profiles.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers. A combination of cisplatin (CDDP) and gemcitabine (Gem) treatment has shown favorable clinical results for metastatic disease; both are limited by toxicities and nontargeted delivery. More than 80% of PDAC aberrantly expresses the sialyl Tn (STn) antigen due to the loss of function of the core 1β3-Gal-T–specific molecular chaperone, a specific chaperone for the activity of core 1 β3-galactosyltransferase or C1GalT. Here, we report the development of polymeric nanogels (NGs) loaded with CDDP and coated with an anti-STn antigen–specific antibody (TKH2 monoclonal antibody) for the targeted treatment of PDAC. TKH2-functionalized, CDDP-loaded NGs delivered a significantly higher amount of platinum into the cells and tumors expressing STn antigens. We also confirmed that a synergistic cytotoxic effect of sequential exposure of pancreatic cancer cells to Gem followed by CDDP can be mimicked by the codelivery of CDDP-loaded NGs (NG/CDDP) and free Gem. In a murine orthotopic model of PDAC, combined simultaneous treatment with Gem and targeted NG/CDDP significantly attenuated tumor growth with no detectable acute toxicity. Altogether, these results suggest that combination therapy consisting of Gem followed by TKH2-conjugated CDDP NGs induces highly synergistic therapeutic efficacy against pancreatic cancer. Our results offer the basis for development of combination drug regimens using targeted nanomedicines to increase treatment effectiveness and improve outcomes of PDAC therapy.

Metabolic alterations regulate cancer aggressiveness and immune responses. Given the poor response of pancreatic ductal adenocarcinoma (PDAC) to conventional immunotherapies, we investigated the link between metabolic alterations and immunosuppression. Our metabolic enzyme screen indicated that elevated expression of CD73, an ecto-5'-nucleotidase that generates adenosine, correlates with increased aggressiveness. Correspondingly, we observed increased interstitial adenosine levels in tumors from spontaneous PDAC mouse models. Diminishing CD73 by genetic manipulations ablated in vivo tumor growth, and decreased myeloid-derived suppressor cells (MDSC) in orthotopic mouse models of PDAC. A high-throughput cytokine profiling demonstrated decreased GM-CSF in mice implanted with CD73 knockdowns. Furthermore, we noted increased IFN-γ expression by intratumoral CD4

Cancer-associated cachexia is defined by loss of weight and muscle mass, and by the potential loss of adipose tissue accompanied by insulin resistance and increased resting energy expenditure. Cachexia is most prevalent in pancreatic cancer, the third leading cause of cancer-related deaths. While various factors interact to induce cachexia, the precise mechanisms underlying this clinical condition are not fully understood. Clinically relevant animal models of cachexia are needed given the lack of standard diagnostic methods or treatments for this condition. Described in this article are in vitro and in vivo models used to study the role of macrophages in the induction of cachexia in pancreatic cancer. Included are procedures for isolating and culturing bone marrow-derived macrophages, harvesting tumor- and macrophage-derived conditioned medium, and studying the effect of conditioned medium on C2C12 myotubes. Also described are procedures involving the use of an orthotopic model of pancreatic cancer, including a method for examining skeletal muscle atrophy in this model. © 2020 Wiley Periodicals LLC. Basic Protocol 1: In vitro model of pancreatic tumor-induced cachexia using C2C12 cell lines (myotube model) Support Protocol 1: Molecular evaluation of cachectic markers in C2C12 myotubes using real-time PCR and immunoblotting Basic Protocol 2: In vivo model to study cachectic phenotype in pancreatic tumor-bearing mice Support Protocol 2: Evaluation of cachectic markers in the skeletal muscle of tumor-bearing mice.

This study demonstrates a novel signaling pathway regulating pancreatic cancer cachexia. These results establish that the Sirt1–Nox4 signaling axis plays an essential role in the manifestation of pancreatic cancer cachexia, and inhibition of this axis abrogates the cachexia syndrome., Approximately one third of cancer patients die due to complexities related to cachexia. However, the mechanisms of cachexia and the potential therapeutic interventions remain poorly studied. We observed a significant positive correlation between SIRT1 expression and muscle fiber cross-sectional area in pancreatic cancer patients. Rescuing Sirt1 expression by exogenous expression or pharmacological agents reverted cancer cell–induced myotube wasting in culture conditions and mouse models. RNA-seq and follow-up analyses showed cancer cell–mediated SIRT1 loss induced NF-κB signaling in cachectic muscles that enhanced the expression of FOXO transcription factors and NADPH oxidase 4 (Nox4), a key regulator of reactive oxygen species production. Additionally, we observed a negative correlation between NOX4 expression and skeletal muscle fiber cross-sectional area in pancreatic cancer patients. Knocking out Nox4 in skeletal muscles or pharmacological blockade of Nox4 activity abrogated tumor-induced cachexia in mice. Thus, we conclude that targeting the Sirt1–Nox4 axis in muscles is an effective therapeutic intervention for mitigating pancreatic cancer–induced cachexia., Graphical Abstract

BackgroundPancreatic Ductal Adenocarcinoma (PDAC) is bad. An immunosuppressive tumor microenvironment (TME) with an excess of immunosuppressive immune cells and cytokine/chemokine factors contribute to local and systemic immunosuppression in PDAC.1 Our laboratory has generated single-cell RNA-Sequencing (scRNA-Seq.) data from spleens derived from PDAC patients and healthy counterparts. This data demonstrates the existence of dendritic cell (DC) subsets with a tolerogenic phenotype. These DCs display increased expression of several markers, including Indoleamine 2,3-dioxygenases (IDO-1 and IDO-2), widely accepted as markers for a specific population of DCs: tolerogenic DCs. These cells evoke an immunosuppressive signal leading to activation of regulatory T cells and MDSCs as well as apoptosis of CD8+ and CD4+ effector T cells.2 3MethodsTo validate our scRNA-Seq. data, we performed pilot investigations harvesting DCs from the spleen of PDAC patients and healthy subjects. Besides examining human specimens, we also investigated the IDO-1 expression on splenic DCs from tumor-bearing mice, orthotopically implanted with LSL-KrasG12D; LSL-Trp53R172H/+; Pdx1-Cre (KPC)-derived cell lines. It is known that tumor-derived exosomes can impact DC-differentiation to a tolerogenic phenotype.4 Exosome purification using differential ultracentrifugation is a well-established method in our lab and optimized for our autopsy samples. We analyzed tumor-derived exosomes for their potential in modulating IDO-1 expression on DCs in in vitro assays. Briefly, we incubated DCs with different exosome concentrations and harvested the cells for RNA-sequencing and flow cytometry.ResultsCompared to normal spleens, DCs from PDAC spleens displayed higher expression of IDO-1 (figure 1). Additionally, KPC-tumor-bearing mice showed higher expression of IDO-1 on DCs from the spleen and blood compared to wild-type mice. Further investigating the influence of PDAC-derived exosomes on marker expression on DCs have shown an apparent increase in expression of IDO-1 when culturing splenic-derived DCs with tumor-derived exosomes (figure 2).ConclusionsWhile tolerogenic DCs are essential in regulating the homeostasis between immune response and immune tolerance,5 several studies have shown IDO-1 overexpression in cancer. Investigating tolerogenic DCs is an essential part of our lab's efforts to understand the nature of the immune response in PDAC. Future directions for this project include determining molecular pathways that regulate the expression of IDO-1. Additionally, we will investigate downstream mechanisms through which exosomes modulate the switch to a tolerogenic phenotype. We also plan to further characterize different splenic DC populations by evaluating their interplay with other immune cells in the context of antigen-specificity and other factors influencing these cells' properties.ReferencesMundry CS, Eberle KC, Singh PK, Hollingsworth MA, Mehla K. Local and systemic immunosuppression in pancreatic cancer: targeting the stalwarts in tumor's arsenal. BBA - Reviews on Cancer 2020;1874(1):188387.Liu M, Wang X, Wang L, Ma X, Gong Z, Zhang S, Li Y. Targeting the IDO1 pathway in cancer: from bench to bedside. Journal of Hematology & Oncology 2018;11(1):100.Hornyák L, Dobos N, Koncz G, Karányi Z, Páll D, Szabó Z, Halmos G, Székvölgyi L. The role of Indoleamine-2,3-Dioxygenase in cancer development, diagnostics, and therapy. Frontiers in immunology 2018;9:1.Bronte V, Pittet MJ. The spleen in local and systemic regulation of immunity. Immunity 2013;39(5):806–818.Domogalla MP, Rostan PV, Raker VK, Steinbrink K. Tolerance through education: how tolerogenic dendritic cells shape immunity. Frontiers in Immunology 2017;8:1764.Ethics ApprovalThis study was approved by the University of Nebraska Medical Center Ethics Board; approval numbers IRB#: 440-16-EP and IRB#: 091-01.Abstract 654 Figure 1Expression of IDO-1 and IDO-2 on DCs from PDAC spleen (blue) .and normal spleen (orange)Abstract 654 Figure 2Change in expression of IDO-1 through treatment of DCs with different concentrations of tumor-derived exosomes

A substantial body of evidence suggests the existence of MUC1-specific antibodies and cytotoxic T cell activities in pancreatic cancer patients. However, tumor-induced immunosuppression renders these responses ineffective. The current study explores a novel therapeutic combination wherein tumor-bearing hosts can be immunologically primed with their own antigen, through opsonization with a tumor antigen-targeted antibody, mAb-AR20.5. We evaluated the efficacy of immunization with this antibody in combination with PolyICLC and anti-PD-L1. The therapeutic combination of mAb-AR20.5 + anti-PD-L1 + PolyICLC induced rejection of human MUC1 expressing tumors and provided a long-lasting, MUC1-specific cellular immune response, which could be adoptively transferred and shown to provide protection against tumor challenge in human MUC1 transgenic (MUC.Tg) mice. Furthermore, antibody depletion studies revealed that CD8 cells were effectors for the MUC1-specific immune response generated by the mAb-AR20.5 + anti-PD-L1 + PolyICLC combination. Multichromatic flow cytometry data analysis demonstrated a significant increase over time in circulating, activated CD8 T cells, CD3+CD4-CD8-(DN) T cells, and mature dendritic cells in mAb-AR20.5 + anti-PD-L1 + PolyICLC combination-treated, tumor-bearing mice, as compared to saline-treated control counterparts. Our study provides a proof of principle that an effective and long-lasting anti-tumor cellular immunity can be achieved in pancreatic tumor-bearing hosts against their own antigen (MUC1), which can be further potentiated using a vaccine adjuvant and an immune checkpoint inhibitor.

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy with a poor prognosis. Tumor hypoxia plays an active role in promoting tumor progression, malignancy, and resistance to therapy in PDAC. We present evidence that nab-paclitaxel–gemcitabine (NPG) and/or a hypoxic tumor microenvironment (TME) up-regulate heme oxygenase-1 (HO-1), providing a survival advantage for tumors. Using PDAC cells in vitro and a PDAC mouse model, we found that NPG chemotherapy up-regulated expression of HO-1 in PDAC cells and increased its nuclear translocation. Inhibition of HO-1 with ZnPP and SnPP sensitized PDAC cells to NPG-induced cytotoxicity (p &lt, 0.05) and increased apoptosis (p &lt, 0.05). Additionally, HO-1 expression was increased in gemcitabine-resistant PDAC cells (p &lt, 0.05), and HO-1 inhibition increased GEM-resistant PDAC sensitivity to NPG (p &lt, 0.05). NPG combined with HO-1 inhibitor inhibited tumor size in an orthotopic model. In parallel, HO-1 inhibition abrogated the influx of macrophages and FoxP3+ cells, while increasing the proportion of CD8+ infiltration in the pancreatic tumors. These effects were mediated primarily by reducing expression of the immunosuppressive cytokine IL-10.

Recent years have witnessed an increased incidence of pancreatic adenocarcinoma (PDAC). Pancreatic tumors are poorly immunogenic; current immunotherapeutic strategies largely focus on boosting adaptive immunity while ignoring immunosuppressed innate immune players such as natural killer cells (NKs). NK cells respond to tumor insults by generating IFN-γ for T-cell activation. Multiple studies suggest that tumor cells evade NK cell-mediated killing by 1) developing “escape variants” and 2) regulating inhibitory and activating receptors on NK cells, imparting anergic/exhaustive phenotype inside the pancreatic tumor microenvironment. We posit that a therapeutic combination that not only overturns tumor-mediated NKs dysfunction but also boosts cytotoxic CD8 T cells will provide long-lasting therapeutic benefits in PDAC. Given this, we explored the efficacy of a unique therapeutic combination, tumor antigen-targeted IgE antibody (humanized anti-MUC1.IgE) in combination of anti-PD-L1 (for relieving T-cell exhaustion) and PolyICLC (for dendritic cell maturation) in a preclinical model of pancreatic cancer using mice transgenic for human MUC1 and FcϵRI (hMUC1/hFcϵRI). This therapeutic combination induced MUC1 specific rejection of two different human MUC1-expressing pancreatic tumor cell lines (Panc02.MUC1, KPC.MUC1) and prolonged the overall survival of mice challenged with subcutaneous and orthotopic tumors as compared to control counterparts. Additionally, this combination generated CD8 T-cell memory response as evidenced by MUC1 specific rejection/delays of tumors in mice rechallenged with MUC1-expressing tumors. Cytokine/chemokine profiling of anti-MUC1.IgE+anti-PD-L1+PolyICLC treated tumors further demonstrates a reduction in proinflammatory cytokines as compared to control counterparts. Most importantly, NK and CD8 T cells were involved in cell-mediated antitumor responses, as in vivo depletion of these subtypes abrogated the tumor-protective benefits in mice bearing orthotopic tumors. Anti-MUC1.IgE+anti-PD-L1+PolyICLC combination appears to increase circulating NKs and reverse NK cell exhaustion inside pancreatic tumor microenvironment. Additional data suggest that this therapeutic combination boosts tumor cell killing by NK cells in antibody-dependent cell cytotoxicity assays (ADCC). In sum, this is the first study to show that specific stimulation of IgE/FcϵRI axis in combination with PolyICLC and anti-PD-L1 can activate both CD8 T and NK cell effector pathways and provide long-lasting tumor-protective benefits against pancreatic cancer. This abstract is also being presented as Poster A48. Citation Format: Kamiya Mehla, Thomas C. Caffrey, Kelly A. O'Connel, Raghupathy Madiyalakan, Christopher F. Nicodemus, Michael A. Hollingsworth. A novel NK cell-targeted therapeutic strategy against pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr PR15.

Hypoxic microenvironment found in pancreatic ductal adenocarcinoma and other solid tumors is central to physiological and metabolic alterations of immune cells that significantly impact tumor growth dynamics. Hypoxic adaptations in the immune cells are primarily mediated by the stabilization of hypoxia-inducible factor-1 alpha (HIF-1α), which regulates cellular metabolism by modulating glycolysis and other interconnected metabolic pathways. HIF-1α plays distinct roles in M1 and M2 macrophage polarization, which, in turn, regulates tumor cell immune escape and growth. In this chapter, we describe a real-time PCR-based assay to monitor the transcript levels of Arg1 and Nos2 to assess the status of tumor-induced macrophage polarization under hypoxic conditions. This method can be effectively utilized to delineate the genes critical for M1/M2 polarization in the hypoxic tumor microenvironment and would provide opportunities to develop immunomodulating therapies to regulate the tumor growth, progression, and metastatic dissemination.

Hypoxic microenvironment found in pancreatic ductal adenocarcinoma and other solid tumors is central to physiological and metabolic alterations of immune cells that significantly impact tumor growth dynamics. Hypoxic adaptations in the immune cells are primarily mediated by the stabilization of hypoxia-inducible factor-1 alpha (HIF-1α), which regulates cellular metabolism by modulating glycolysis and other interconnected metabolic pathways. HIF-1α plays distinct roles in M1 and M2 macrophage polarization, which, in turn, regulates tumor cell immune escape and growth. In this chapter, we describe a real-time PCR-based assay to monitor the transcript levels of Arg1 and Nos2 to assess the status of tumor-induced macrophage polarization under hypoxic conditions. This method can be effectively utilized to delineate the genes critical for M1/M2 polarization in the hypoxic tumor microenvironment and would provide opportunities to develop immunomodulating therapies to regulate the tumor growth, progression, and metastatic dissemination.

Pancreatic cancer has a dismal 5 year survival rate of 5.5% that has not been improved over the past 25 years despite an enormous amount of effort. Thus, there is an urgent need to identify truly novel yet druggable protein targets for drug discovery. The human protein DnaJ homologue subfamily A member 1 (DNAJA1) was previously shown to be downregulated 5-fold in pancreatic cancer cells and has been targeted as a biomarker for pancreatic cancer, but little is known about the specific biological function for DNAJA1 or the other members of the DnaJ family encoded in the human genome. Our results suggest the overexpression of DNAJA1 suppresses the stress response capabilities of the oncogenic transcription factor, c-Jun, and results in the diminution of cell survival. DNAJA1 likely activates a DnaK protein by forming a complex that suppresses the JNK pathway, the hyperphosphorylation of c-Jun, and the anti-apoptosis state found in pancreatic cancer cells. A high-quality nuclear magnetic resonance solution structure of the J-domain of DNAJA1 combined with a bioinformatics analysis and a ligand affinity screen identifies a potential DnaK binding site, which is also predicted to overlap with an inhibitory binding site, suggesting DNAJA1 activity is highly regulated.

Pancreatic cancer is the third leading cause of cancer-associated deaths in the United States. We have recently demonstrated that endoplasmic reticulum (ER) stress correlates with improved survival in human pancreatic cancer patients on gemcitabine therapy. Cancer cell stemness is a significant contributor of poor response to therapy and disease recurrence. We also observed that inducing ER stress can diminish stemness in cancer cells. Hence, to investigate the mechanism of ER stress-mediated alterations in diminishing cancer stemness, we investigated the impact of ER stress on transcriptomic alterations by performing RNAseq studies. We subjected cancer cells to treatment with thapsigargin and the harvested mRNA was utilized for RNAseq analysis. We observed significant alterations in mRNA expression levels of the stemness-associated gene set, which also showed significant enrichment in Ingenuity pathway analysis. Hence, our studies demonstrate that ER stress regulates stemness at the transcriptional level. Our ongoing and future studies will target individual genes/pathways to identify their relative contributions to ER stress-mediated regulation of stemness. Considering the role of stemness in disease recurrence, our studies will provide novel mechanistic insights that may lead to novel therapies for targeting disease recurrence in pancreatic cancer. Citation Format: Appolinaire Olou, Kamiya Mehla, Pankaj Singh. Endoplasmic reticulum stress disrupts stemness-related transcriptional regulatory network: Implication for therapy response in cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1160.

Aberrant glucose metabolism is one of the hallmarks of cancer that facilitates cancer cell survival and proliferation. Here, we demonstrate that MUC1, a large, type I transmembrane protein that is overexpressed in several carcinomas including pancreatic adenocarcinoma, modulates cancer cell metabolism to facilitate growth properties of cancer cells. MUC1 occupies the promoter elements of multiple genes directly involved in glucose metabolism and regulates their expression. Furthermore, MUC1 expression enhances glycolytic activity in pancreatic cancer cells. We also demonstrate that MUC1 expression enhances in vivo glucose uptake and expression of genes involved in glucose uptake and metabolism in orthotopic implantation models of pancreatic cancer. The MUC1 cytoplasmic tail is known to activate multiple signaling pathways through its interactions with several transcription factors/coregulators at the promoter elements of various genes. Our results indicate that MUC1 acts as a modulator of the hypoxic response in pancreatic cancer cells by regulating the expression/stability and activity of hypoxia-inducible factor-1α (HIF-1α). MUC1 physically interacts with HIF-1α and p300 and stabilizes the former at the protein level. By using a ChIP assay, we demonstrate that MUC1 facilitates recruitment of HIF-1α and p300 on glycolytic gene promoters in a hypoxia-dependent manner. Also, by metabolomic studies, we demonstrate that MUC1 regulates multiple metabolite intermediates in the glucose and amino acid metabolic pathways. Thus, our studies indicate that MUC1 acts as a master regulator of the metabolic program and facilitates metabolic alterations in the hypoxic environments that help tumor cells survive and proliferate under such conditions.

Advances in understanding the biology of tumour progression and metastasis have clearly highlighted the importance of aberrant tumour metabolism, which supports not only the energy requirements but also the enormous biosynthetic needs of tumour cells. Such metabolic alterations modulate glucose, amino acid and fatty-acid-dependent metabolite biosynthesis and energy production. Although much progress has been made in understanding the somatic mutations and expression genomics behind these alterations, the regulation of these processes by microRNAs (miRNAs) is only just beginning to be appreciated. This Review focuses on the miRNAs that are potential regulators of the expression of genes whose protein products either directly regulate metabolic machinery or serve as master regulators, indirectly modulating the expression of metabolic enzymes. We focus particularly on miRNAs in pancreatic cancer.

Poor response to cancer therapy due to resistance remains a clinical challenge. The present study establishes a widely prevalent mechanism of resistance to gemcitabine in pancreatic cancer, whereby increased glycolytic flux leads to glucose addiction in cancer cells and a corresponding increase in pyrimidine biosynthesis to enhance the intrinsic levels of deoxycytidine triphosphate (dCTP). Increased levels of dCTP diminish the effective levels of gemcitabine through molecular competition. We also demonstrate that MUC1-regulated stabilization of hypoxia inducible factor-1α (HIF-1α) mediates such metabolic reprogramming. Targeting HIF-1α or de novo pyrimidine biosynthesis, in combination with gemcitabine, strongly diminishes tumor burden. Finally, reduced expression of TKT and CTPS, which regulate flux into pyrimidine biosynthesis, correlates with better prognosis in pancreatic cancer patients on fluoropyrimidine analogs.

Pancreatic cancer is a fourth leading cause of cancer death in United States. Recent advances in tumor immunology have provided evidence for immune surveillance against pancreatic cancer. Previous studies have documented the presence of specific antibodies and cytotoxic T cell activities to Mucin 1 (MUC1), an antigen that is expressed in most pancreatic cancers. Hence, MUC1 remains a candidate for immunotherapeutic strategies for pancreatic cancer. Numerous attempts have been made to target this mucin glycoprotein; however, these efforts have shown only moderate success in part due to the complexity of the pancreatic tumor microenvironment. Previously, administration of murine monoclonal antibody BrevaRexAb-AR20.5 alone produced MUC1 specific immune response in a phase I study of advanced cancer patients, including increased human anti-MUC1 antibody levels and MUC1 specific T cell response in few patients. Though this was a phase I study, modest changes in tumor marker (CA15.3) but no anecdotal anti-tumor activity was observed in this small group of patients. Moving forward it is obvious that future immunization strategies should include other immune-modulators to amplify MUC1 specific immune responses of mAbAR20.5 and enhance other factors that contribute to tumor rejection. To that end, we investigated the anti-tumor effect of mAbAR20.5 in combination with anti-PD-L1 and poly (I:C) in murine models of pancreatic adenocarcinoma using human MUC1 expressing transgenic (hMUC1.Tg) mice, which are immunologically tolerant to MUC1. The therapeutic combination of mAb-AR20.5+anti-PD-L1+Poly (I:C) induced rejection or significant inhibition of tumor growth for two different MUC1 expressing pancreatic tumor cell lines, which was accompanied by persistent MUC1 specific memory immune response, which could be adoptively transferred to other mice and shown to protect against subsequent tumor challenge. We show that the anti-tumor response was effected by CD8 T cells, as their abrogation attenuated the anti-tumor response. Flow cytometric analysis of immunized mice demonstrated progressive increases in activated CD8 T cells in the peripheral circulation of combination treated mice. Together, these data support the hypothesis that targeting checkpoint induced immunosuppression (anti-PD-L1) together with the use of toll-like receptor 3 agonist as an adjuvant (poly (I:C) ) enhances the capacity of mAbAR20.5 to induce specific cell mediated immune responses to MUC1, which in turn provide long lasting anti-tumor response against pancreatic tumors. Our study supports the rapid translation of this strategy into clinical trials for pancreatic cancer patients. Citation Format: Kamiya Mehla, James A. Grunkemeyer, Kelly A. O'Connell, Maria M. Steele, Thomas Caffrey, Ragupathy Madiyalakan, Christopher F. Nicodemus, Michael A. Hollingsworth. AR20.5-based novel immunotherapy for pancreatic cancer. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2016 Oct 20-23; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2017;5(3 Suppl):Abstract nr A30.

Background: Aberrant energy metabolism is a hallmark of cancer. To fulfill the increased energy requirements, tumor cells secrete cytokines/factors inducing muscle and fat degradation in cancer patients, a condition known as cancer cachexia. It accounts for nearly 20% of all cancer-related deaths. However, the mechanistic basis of cancer cachexia and therapies targeting cancer cachexia thus far remain elusive. A ketogenic diet, a high-fat and low-carbohydrate diet that elevates circulating levels of ketone bodies (i.e., acetoacetate, β-hydroxybutyrate, and acetone), serves as an alternative energy source. It has also been proposed that a ketogenic diet leads to systemic metabolic changes. Keeping in view the significant role of metabolic alterations in cancer, we hypothesized that a ketogenic diet may diminish glycolytic flux in tumor cells to alleviate cachexia syndrome and, hence, may provide an efficient therapeutic strategy. Results: We observed reduced glycolytic flux in tumor cells upon treatment with ketone bodies. Ketone bodies also diminished glutamine uptake, overall ATP content, and survival in multiple pancreatic cancer cell lines, while inducing apoptosis. A decrease in levels of c-Myc, a metabolic master regulator, and its recruitment on glycolytic gene promoters, was in part responsible for the metabolic phenotype in tumor cells. Ketone body-induced intracellular metabolomic reprogramming in pancreatic cancer cells also leads to a significantly diminished cachexia in cell line models. Our mouse orthotopic xenograft models further confirmed the effect of a ketogenic diet in diminishing tumor growth and cachexia. Conclusions: Thus, our studies demonstrate that the cachectic phenotype is in part due to metabolic alterations in tumor cells, which can be reverted by a ketogenic diet, causing reduced tumor growth and inhibition of muscle and body weight loss.

MUC1, a type I transmembrane protein, is significantly overexpressed and aberrantly glycosylated in tumors of epithelial origin. By virtue of its aberrant signaling due to loss of apical-basal polarity in cancer, MUC1 regulates the metabolite flux at multiple levels. Serving as a transcriptional co-activator, MUC1 directly regulates expression of metabolic genes. By regulating receptor tyrosine kinase signaling, MUC1 facilitates production of biosynthetic intermediates required for cell growth. Also, via direct interactions, MUC1 modulates the activity/stability of enzymes and transcription factors that directly regulate metabolic functions. Additionally, by modulation of autophagy, levels of reactive oxygen species, and metabolite flux, MUC1 facilitates cancer cell survival under hypoxic and nutrient-deprived conditions. This article provides a comprehensive review of recent literature on novel metabolic functions of MUC1.

Cancer cachexia is a systemic syndrome characterized by progressive weight loss of the patient due to muscle wasting and fat depletion with or without anorexia. About 80% of pancreatic ductal adenocarcinoma (PDAC) patients exhibits cachectic phenotype and it significantly contributes in mortality and morbidity of the disease. In present study we have evaluated the effect of bioactive molecule silibinin on pancreatic cancer progression and cachectic properties by utilizing in vitro as well as in vivo models of PDAC. We observed that silibinin inhibits growth and induces apoptosis in multiple pancreatic cancer cell lines in a dose-dependent manner. We also observed silibinin-mediated reduction in the expression of key glycolytic genes and inhibition of glucose uptake and lactate secretion. By performing LC-MS/MS based metabolomics, we observed that silibinin treatment leads to global metabolic alterations in pancreatic cancer cells. Pancreatic cancer cells treated with silibinin exhibited reduced expression of c-MYC level, a key metabolic regulator. Furthermore, we observed that silibinin-mediated STAT3 inhibition leads to reduced c-MYC expression. Ectopic expression of constitutively active STAT3 significantly attenuated the effect of silibinin on c-MYC expression and metabolic phenotype of pancreatic cancer cells. Silibinin treatment also inhibited tumor growth and progression of cachexia. Silibinin treatment to tumor-bearing mice also lead to increased food intake, increased grip strength and body coordination. Overall, our results demonstrate that silibinin exhibits anti-cachectic and anti-cancerous properties by inducing metabolic reprogramming in pancreatic cancer cells. Citation Format: Surendra K. Shukla, Aneesha Dasgupta, Kamiya Mehla, Venugopal Gunda, Enza Vernucci, Joshua Soucheck, Gennifer Goode, Ryan King, Anusha Mishra, Ibha Rai, Sangeetha Natrajan, Nina Chaika, Fang Yu, Pankaj K. Singh. Silibinin exhibits anti-cachectic and anti-cancerous property by modulating metabolic properties of pancreatic cancer cells. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 10.

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) is the clinical syndrome of persistent lung inflammation caused by various direct and indirect stimuli. Despite advances in the understanding of disease pathogenesis, few therapeutic have emerged for ALI/ARDS. Thus, in the present study we evaluated the therapeutic potential of ethyl gallate (EG), a plant flavanoid in the context of ALI using in vivo (BALB/c) and in vitro models (human monocytes). Our in vivo data supports the view that EG alleviates inflammatory condition in ALI as significant reduction in BALF neutrophils, ROS, proinflammatory cytokines and albumin levels were observed with the single i.p of EG post LPS exposure. Also, histochemical analysis of mice lung tissue demonstrated that EG restored LPS stimulated cellular influx inside the lung airspaces. Unraveling the mechanism of action, our RT-PCR and western blot analysis suggest that enhanced expression of HO-1 underlies the protective effect of EG on ROS level in mice lung tissue. Induction of HO-1 in turn appears to be mediated by Nrf2 nuclear translocation and consequent activation and ablation of Nrf2 activity through siRNA notably abrogated the EG induced protective effect in LPS induced human monocytes. Furthermore, our results indicate that EG generated moderate amounts of H2O2 could induce Nrf2 translocation in the in vitro systems. However, given the insignificant amount of H2O2 recorded in the injected material in the in vivo system, additional mechanism for EG action could not be excluded. Nevertheless our results highlight the protective role of EG in ALI and provide the novel insight into its usefulness as a therapeutic tool for the treatment of ALI.

Next-generation sequencing strategies have opened new vistas for molecular plant breeding. The sequence information obtained by the advent of next-generation sequencing provides a valuable tool not only for improving domesticated crops but also for investigating the natural evolution of crops. Such information provides an enormous potential for sustainable agriculture. In this review, we discuss how such sequencing approaches have transformed exome sequencing into a practical utility that has enormous potential for crop improvement in agriculture. Furthermore, we also describe the future of crop improvement beyond the exome sequencing strategies.

Background Pancreatic cancer is the fourth leading cause of cancer related deaths in the United States with a five-year survival rate of 6%. It is characterized by extremely aggressive tumor growth rate and high incidence of metastasis. One of the most common and profound biochemical phenotypes of animal and human cancer cells is their ability to metabolize glucose at high rates, even under aerobic conditions. However, the contribution of metabolic interrelationships between tumor cells and cells of the surrounding microenvironment to the progression of cancer is not well understood. We evaluated differential expression of metabolic genes and, hence, metabolic pathways in primary tumor and metastases of patients with pancreatic adenocarcinoma. Methods and Findings We analyzed the metabolic gene (those involved in glycolysis, tri-carboxylic acid pathway, pentose-phosphate pathway and fatty acid metabolism) expression profiles of primary and metastatic lesions from pancreatic cancer patients by gene expression arrays. We observed two principal results: genes that were upregulated in primary and most of the metastatic lesions; and genes that were upregulated only in specific metastatic lesions in a site-specific manner. Immunohistochemical (IHC) analyses of several metabolic gene products confirmed the gene expression patterns at the protein level. The IHC analyses also revealed differential tumor and stromal expression patterns of metabolic enzymes that were correlated with the metastasis sites. Conclusions Here, we present the first comprehensive studies that establish differential metabolic status of tumor and stromal components and elevation of aerobic glycolysis gene expression in pancreatic cancer.

Next-generation sequencing strategies have opened new vistas for molecular plant breeding. The sequence information obtained by the advent of next-generation sequencing provides a valuable tool not only for improving domesticated crops but also for investigating the natural evolution of crops. Such information provides an enormous potential for sustainable agriculture. In this review, we discuss how such sequencing approaches have transformed exome sequencing into a practical utility that has enormous potential for crop improvement in agriculture. Furthermore, we also describe the future of crop improvement beyond the exome sequencing strategies.

Ethnopharmacological relevance Galls from Pistacia integerrima Linn. (kakadshringhi) have been used as therapeutic agent for various inflammatory diseases in Indian system of traditional medicine. However, the active constituents underlying the medicinal properties of the Pistacia integerrima Linn. have not been thoroughly investigated yet. Aim of the study Deregulated expression of cell adhesion molecules (CAMs) on vascular endothelium aggravates the inflammatory condition in various chronic diseases. In this work, we aimed to identify the active constituent from leaf gall of Pistacia integerrima Linn. using CAMs expression assay in activity guided purification, followed by determining the molecular mechanism of action. Material and methods Cell based ELISA for LPS induced CAMs expression in human vein endothelial cells (HUVECs) was used for the activity guided isolation form Pistacia galls followed by structural determination of active constituent using IR, MS and NMR spectroscopy. Mechanism of action of the active constituent was investigated by western blot, RT-PCR and EMSA experiments. Results In our study, ethyl gallate (EG) was identified as the active constituent of Pistacia integerrima Linn. for mediating its anti-inflammatory activity. It significantly attenuated LPS induced ICAM-1 and VCAM-1 at the protein and mRNA levels. At a functional level, it inhibited the adhesion of neutrophils to LPS activated endothelium. To identify its mechanism of action, we demonstrated that EG inhibited LPS induced cell adhesion molecules expression by blocking AP-1 transcription factor without affecting nuclear transcription factor-κB (NF-κB). Conclusion Our results suggest that EG could be useful as a lead molecule for developing therapeutic agent for various inflammatory diseases.

The chromosomal region 1q21 has been linked to atopic dermatitis in previous studies. Seven polymorphic repeats were identified in a 0.5 Mb region of chromosome 1q21 encompassing a small proline-rich protein (SPRR) gene cluster, a few S100 gene family members, loricin, and several uncharacterized genes. These repeats were genotyped by fragment length polymorphism analysis in 133 atopic case-parent trios, of which 111 probands had atopic asthma. Our trio-based analysis for association with atopy and atopic asthma revealed no significant allelic or genotypic association for any of the seven loci tested. However, a significant association was observed with locus 5 (3.65 Mb of contig NT_032962) and log(10) serum IgE levels (F = 3.93, P = 0.0008). Results were also replicated in an independent case-control cohort (N (p) = 165, N (c) = 166), where a significant association with log(10) serum IgE levels was observed in the patient group (P = 0.0005). Interestingly, locus 5 is 6.2 kb upstream of a late cornified envelope-like proline-rich 1 (LELP1) gene which encodes a novel small proline rich protein. Further, we have also found a significant association of rs7534334 (tagged SNP from LELP1) SNP with log(10) serum IgE levels in the patient group (P = 0.0029). Thus, our results identify a chromosomal region in close proximity to a novel gene and highlight the need for intense research on LELP1 and other genes close by with respect to atopic disorders.

MUC1, a type-I transmembrane protein, is significantly overexpressed in pancreatic cancer. High expression of MUC1 in pancreatic cancer correlates with poor prognosis. Pancreatic tumors demonstrate significant hypoxia, which causes stabilization of HIF-1α, a key modulator of glycolytic gene expression. Recently, we observed that MUC1 occupies multiple HIF-1α–regulated glycolytic gene promoters. By performing in vitro and in vivo studies we observed that MUC1 overexpression causes up-regulation of glucose uptake, lactate release and expression of genes involved in glucose metabolism in pancreatic cancer cell lines. Based on these data we hypothesized that MUC1 regulates the stabilization/activity of HIF-1α to facilitate the glycolytic phenotype in pancreatic cancer. To investigate the regulation of HIF-1α by MUC1, we performed lentiviral shRNA-mediated knock down of HIF-1α in MUC1-overexpressing S2-013 and Capan1 pancreatic cancer cells and assayed for glucose uptake, lactate release and glycolytic gene expression. We observed that knocking down HIF-1α abrogated the MUC1-induced up-regulation of glucose metabolism. To investigate if MUC1 physically interacts with HIF-1α, we performed co-immunoprecipitation assays by utilizing a mAb against the cytoplasmic tail of MUC1. Our results indicated significant interaction between MUC1 and HIF-1α. Additionally, by performing chromatin immunoprecipitation we observed that MUC1 co-occupies the promoter regions of ENO1 and PGM2 glycolytic genes along with HIF-1α. MUC1 also increased HIF-1α activity by facilitating P300 recruitment and resultantly enhancing histone3 lysine9 acetylation on the MUC1-occupied promoters. By performing 1H-13C HSQC NMR experiments on the methanol extracts from MUC1-overexpressing or control S2-013 cells cultured with 13C-glucose, we observed an increased glycolytic flux and faster glucose turnover in pancreatic cancer cells. Furthermore, MUC1 overexpression caused a reduction in the levels of 2-oxoglutarate, a substrate for prolyl hydroxylases that regulate HIF stability. Thus, MUC1-mediated reduction in 2-oxoglutarate levels indirectly stabilizes HIF-1α by reducing the activity of prolyl hydroxylases. Overall, our results demonstrate that MUC1 serves as a novel metabolic regulator in pancreatic cancer that facilitates glycolytic flux by increasing HIF-1α stability and activity. Citation Format: Vinee Purohit, Nina V. Chaika, Teklab Gebregiworgis, Prakash Radhakrishnan, Bo Zhang, Kamiya Mehla, Fang Yu, Keith R. Johnson, Robert Powers, Michael A. Hollingsworth, Pankaj K. Singh. MUC1 and HIF-1α signaling interactions modulate glucose flux in pancreatic cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5391. doi:10.1158/1538-7445.AM2013-5391

Author details The Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA. Department of Chemistry, University of Nebraska—Lincoln, Lincoln, NE 68588, USA. Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198, USA. Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE 68198, USA. Department of Surgery, University of Nebraska Medical Center, Omaha, NE 68198, USA. Department of Biostatistics, University of Nebraska Medical Center, Omaha, NE 68198, USA. Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA. Department of Genetic Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE 68198, USA.