Browsing by Subject "Pancreatic ductal adenocarcinoma (PDAC)"

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    Activation of the integrated stress response (ISR) pathways in response to Ref-1 inhibition in human pancreatic cancer and its tumor microenvironment
    (Frontiers Media, 2023-04-27) Mijit, Mahmut; Boner, Megan; Cordova, Ricardo A.; Gampala, Silpa; Kpenu, Eyram; Klunk, Angela J.; Zhang, Chi; Kelley, Mark R.; Staschke, Kirk A.; Fishel, Melissa L.; Pediatrics, School of Medicine
    Pancreatic cancer or pancreatic ductal adenocarcinoma (PDAC) is characterized by a profound inflammatory tumor microenvironment (TME) with high heterogeneity, metastatic propensity, and extreme hypoxia. The integrated stress response (ISR) pathway features a family of protein kinases that phosphorylate eukaryotic initiation factor 2 (eIF2) and regulate translation in response to diverse stress conditions, including hypoxia. We previously demonstrated that eIF2 signaling pathways were profoundly affected in response to Redox factor-1 (Ref-1) knockdown in human PDAC cells. Ref-1 is a dual function enzyme with activities of DNA repair and redox signaling, responds to cellular stress, and regulates survival pathways. The redox function of Ref-1 directly regulates multiple transcription factors including HIF-1α, STAT3, and NF-κB, which are highly active in the PDAC TME. However, the mechanistic details of the crosstalk between Ref-1 redox signaling and activation of ISR pathways are unclear. Following Ref-1 knockdown, induction of ISR was observed under normoxic conditions, while hypoxic conditions were sufficient to activate ISR irrespective of Ref-1 levels. Inhibition of Ref-1 redox activity increased expression of p-eIF2 and ATF4 transcriptional activity in a concentration-dependent manner in multiple human PDAC cell lines, and the effect on eIF2 phosphorylation was PERK-dependent. Treatment with PERK inhibitor, AMG-44 at high concentrations resulted in activation of the alternative ISR kinase, GCN2 and induced levels of p-eIF2 and ATF4 in both tumor cells and cancer-associated fibroblasts (CAFs). Combination treatment with inhibitors of Ref-1 and PERK enhanced cell killing effects in both human pancreatic cancer lines and CAFs in 3D co-culture, but only at high doses of PERK inhibitors. This effect was completely abrogated when Ref-1 inhibitors were used in combination with GCN2 inhibitor, GCN2iB. We demonstrate that targeting of Ref-1 redox signaling activates the ISR in multiple PDAC lines and that this activation of ISR is critical for inhibition of the growth of co-culture spheroids. Combination effects were only observed in physiologically relevant 3D co-cultures, suggesting that the model system utilized can greatly affect the outcome of these targeted agents. Inhibition of Ref-1 signaling induces cell death through ISR signaling pathways, and combination of Ref-1 redox signaling blockade with ISR activation could be a novel therapeutic strategy for PDAC treatment.
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    Modeling Pancreatic Cancer Tumor Microenvironment using a Microfluidics Culture System
    (Office of the Vice Chancellor for Research, 2016-04-08) Ajayi, Tolulope O.; Korc, Murray; Conteh, Abass
    Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer-related deaths in the United States, with an overall five year survival rate of 7%. This is partly due to the lack of effective models that simulate the complex PDAC tumor microenvironment and allow for high throughput drug screening. Some of the key features of the PDAC tumor microenvironment are the presence of a dense stroma which impedes effective drug delivery to the pancreatic cancer cells (PCCs), as well as the presence of cancer associated fibroblasts (CAFs) that have been shown to modulate disease progression. The objective of this project is to develop an in vitro microfluidic cell culture system that allows researchers to recapitulate the PDAC tumor environment. The system, Tumor-Microenvironment-on-Chip (T-MOC) is manufactured using a replica molding technique. The chip consist of two polydimethylsiloxane (PDMS) layers separated by a porous membrane for gas exchange. This device forms an enclosed transparent device with input channel for cell entry and inner channels which mimic fluidic transport found in vivo. To analyze the potential of the device to simulate in vivo conditions, PCCs (GFP+) and CAFs (RFP+) were co-cultured with collagen and inserted into the device. Initial data analysis indicates that the device supports the growth of PCCs and allows formation of 3D tumor spheroids. In addition, analysis of GFP and RFP intensity demonstrated the effect of CAFs on PCCs growth, which diminished PCCs growth. This provides evidence that the microfluidic device can be used to replicate tumor environment allowing for future studies to screen potential drug candidates before in vivo studies.
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    A Plasma-Derived Protein-Metabolite Multiplexed Panel for Early-Stage Pancreatic Cancer
    (Oxford University Press, 2019-04-01) Fahrmann, Johannes F.; Bantis, Leonidas E.; Capello, Michela; Scelo, Ghislaine; Dennison, Jennifer B.; Patel, Nikul; Murage, Eunice; Vykoukal, Jody; Kundnani, Deepali L.; Foretova, Lenka; Fabianova, Eleonora; Holcatova, Ivana; Janout, Vladimir; Feng, Ziding; Yip-Schneider, Michele; Zhang, Jianjun; Brand, Randall; Taguchi, Ayumu; Maitra, Anirban; Brennan, Paul; Max Schmidt, C.; Hanash, Samir; Surgery, School of Medicine
    BACKGROUND: We applied a training and testing approach to develop and validate a plasma metabolite panel for the detection of early-stage pancreatic ductal adenocarcinoma (PDAC) alone and in combination with a previously validated protein panel for early-stage PDAC. METHODS: A comprehensive metabolomics platform was initially applied to plasmas collected from 20 PDAC cases and 80 controls. Candidate markers were filtered based on a second independent cohort that included nine invasive intraductal papillary mucinous neoplasm cases and 51 benign pancreatic cysts. Blinded validation of the resulting metabolite panel was performed in an independent test cohort consisting of 39 resectable PDAC cases and 82 matched healthy controls. The additive value of combining the metabolite panel with a previously validated protein panel was evaluated. RESULTS: Five metabolites (acetylspermidine, diacetylspermine, an indole-derivative, and two lysophosphatidylcholines) were selected as a panel based on filtering criteria. A combination rule was developed for distinguishing between PDAC and healthy controls using the Training Set. In the blinded validation study with early-stage PDAC samples and controls, the five metabolites yielded areas under the curve (AUCs) ranging from 0.726 to 0.842, and the combined metabolite model yielded an AUC of 0.892 (95% confidence interval [CI] = 0.828 to 0.956). Performance was further statistically significantly improved by combining the metabolite panel with a previously validated protein marker panel consisting of CA 19-9, LRG1, and TIMP1 (AUC = 0.924, 95% CI = 0.864 to 0.983, comparison DeLong test one-sided P= .02). CONCLUSIONS: A metabolite panel in combination with CA19-9, TIMP1, and LRG1 exhibited substantially improved performance in the detection of early-stage PDAC compared with a protein panel alone.
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    Plasminogen deficiency suppresses pancreatic ductal adenocarcinoma disease progression
    (Wiley, 2024) Chowdhury, Nayela N.; Yang, Yi; Dutta, Ananya; Luo, Michelle; Wei, Zimu; Abrahams, Sara R.; Revenko, Alexey S.; Shah, Fenil; Miles, Lindsey A.; Parmer, Robert J.; de Laat, Bas; Wolberg, Alisa S.; Luyendyk, James P.; Fishel, Melissa L.; Flick, Matthew J.; Pediatrics, School of Medicine
    Pancreatic ductal adenocarcinoma (PDAC) is a highly fatal metastatic disease associated with robust activation of the coagulation and fibrinolytic systems. However, the potential contribution of the primary fibrinolytic protease plasminogen to PDAC disease progression has remained largely undefined. Mice bearing C57Bl/6-derived KPC (KRasG12D , TRP53R172H ) tumors displayed evidence of plasmin activity in the form of high plasmin-antiplasmin complexes and high plasmin generation potential relative to mice without tumors. Notably, plasminogen-deficient mice (Plg- ) had significantly diminished KPC tumor growth in subcutaneous and orthotopic implantation models. Moreover, the metastatic potential of KPC cells was significantly diminished in Plg- mice, which was linked to reduced early adhesion and/or survival of KPC tumor cells. The reduction in primary orthotopic KPC tumor growth in Plg- mice was associated with increased apoptosis, reduced accumulation of pro-tumor immune cells, and increased local proinflammatory cytokine production. Elimination of fibrin(ogen), the primary proteolytic target of plasmin, did not alter KPC primary tumor growth and resulted in only a modest reduction in metastatic potential. In contrast, deficiencies in the plasminogen receptors Plg-RKT or S100A10 in tumor cells significantly reduced tumor growth. Plg-RKT reduction in tumor cells, but not reduced S100A10, suppressed metastatic potential in a manner that mimicked plasminogen deficiency. Finally, tumor growth was also reduced in NSG mice subcutaneously or orthotopically implanted with patient-derived PDAC tumor cells in which circulating plasminogen was pharmacologically reduced. Collectively, these studies suggest that plasminogen promotes PDAC tumor growth and metastatic potential, in part through engaging plasminogen receptors on tumor cells.
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    RelA Is an Essential Target for Enhancing Cellular Responses to the DNA Repair/Ref-1 Redox Signaling Protein and Restoring Perturbated Cellular Redox Homeostasis in Mouse PDAC Cells
    (Frontiers Media, 2022-03-24) Mijit, Mahmut; Wireman, Randall; Armstrong, Lee; Gampala, Silpa; Hassan, Zonera; Schneeweis, Christian; Schneider, Guenter; Zhang, Chi; Fishel, Melissa L.; Kelley, Mark R.; Pediatrics, School of Medicine
    Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest cancers with a poor response to current treatment regimens. The multifunctional DNA repair-redox signaling protein Ref-1 has a redox signaling function that activates several transcriptional factors (TFs) including NF-κB (RelA), STAT3, AP-1. These have been implicated in signaling in PDAC and associated with cancer progression and therapy resistance. Numerous studies have shown a role for RelA in PDAC inflammatory responses and therapy resistance, little is known as to how these inflammatory responses are modulated through Ref-1 redox signaling pathways during pancreatic pathogenesis. RelA and STAT3 are two major targets of Ref-1 and are important in PDAC pathogenesis. To decipher the mechanistic role of RelA in response to Ref-1 inhibition, we used PDAC cells (KC3590) from a genetically engineered Kras G12D-driven mouse model that also is functionally deficient for RelA (Parent/Vector) or KC3590 cells with fully functional RelA added back (clone 13; C13). We demonstrated that RelA deficient cells are more resistant to Ref-1 redox inhibitors APX3330, APX2009, and APX2014, and their sensitivity is restored in the RelA proficient cells. Knockdown of STAT3 did not change cellular sensitivity to Ref-1 redox inhibitors in either cell type. Gene expression analysis demonstrated that Ref-1 inhibitors significantly decreased IL-8, FOSB, and c-Jun when functional RelA is present. We also demonstrated that PRDX1, a known Ref-1 redox modulator, contributes to Ref-1 inhibitor cellular response. Knockdown of PRDX1 when functional RelA is present resulted in dramatically increased PDAC killing in response to Ref-1 inhibitors. The enhanced cell killing was not due to increased intracellular ROS production. Although Ref-1 inhibition decreased the NADP/NADPH ratio in the cells, the addition of PRDX1 knockdown did not further this redox imbalance. This data suggests that the mechanism of cell killing following Ref-1 inhibition is at least partially mediated through RelA and not STAT3. Further imbalancing of the redox signaling through disruption of the PRDX1-Ref-1 interaction may have therapeutic implications. Our data further support a pivotal role of RelA in mediating Ref-1 redox signaling in PDAC cells with the Kras G12D genotype and provide novel therapeutic strategies to combat PDAC drug resistance.
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    Sugar-Coated Proteins Pave the Way to Improving Pancreatic Cancer Diagnosis
    (Elsevier, 2016-01-28) Korc, Murray; Department of Medicine, IU School of Medicine