Pancreatic Cancer Initiation Research Articles

Abstract B023: Unravelling fibroinflammatory and immune signatures for pancreatic cancer early detection

Abstract Pancreatic cancer is associated with late-stage diagnosis and poor patient prognosis. The disease is characterised by chronic dysregulated immunity and inflammation. Moreover, chronic pancreatitis is linked with an increased risk of pancreatic cancer. Tissue remodelling during disease progression involves a complex network of cells and a crosstalk between cancer cells, stromal components and immune cells, but it remains poorly explored. Thus, to improve the outcome of patients, there is a need for better understanding of biological changes associated with the initiation and progression of pancreatic cancer at the molecular and spatial levels. Using samples obtained from our Accelerated Diagnosis of neuroEndocrine and Pancreatic TumourS (ADEPTS) biobank, we have evaluated blood samples for the discovery of non- invasive biomarkers to discriminate patients with pancreatic cancer from symptomatic patients without cancer. In this pilot study, the transcriptome of peripheral blood mononuclear cells (PBMCs), isolated using a ficoll gradient was explored to identify PDAC-associated mRNA signatures. Moreover, the Olink® Explore Inflammation and Oncology panels were performed in a cohort of 40 patients with early stage (I-II) PDAC, 40 chronic pancreatitis samples and 40 control patients with benign symptomatic upper GI diseases. To validate and enrich these results, a panel of inflammatory and immune markers including immunoglobulins, cytokines and chemokines was also run using multiplex techniques. Symptoms observed in our cohort were also analysed together with clinical (e.g diabetic status, biochemistry profile) and demographic data (age, sex, ethnicity, post code etc). We have identified mRNA transcriptome signatures and differentially expressed proteins associated with inflammatory and immunological processes in PDAC compared to benign symptomatic samples. Our results offer potential diagnostic utility for early-stage disease. Additionally, our unique cohort of patient samples comprising of those with confirmed PDAC and those presenting to clinic with benign disease and similar non-specific symptoms, allows for the development of non-invasive diagnostic tests with better translational applicability. Future work will involve the validation of these findings in a larger patient cohort and the use of NanoString GeoMx® Digital Spatial Profiler to perform whole transcriptome and proteome profiling in human chronic pancreatic and pancreatic cancer tissue samples. Citation Format: Kyra Fraser, Maria Rosado, Stephen P Pereira, Pilar Acedo. Unravelling fibroinflammatory and immune signatures for pancreatic cancer early detection [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr B023.

Earliest Metabolic Changes Associated with the Initiation of Pancreatic Cancer.

Pancreatic cancer is usually detected at a late stage, when tumors have already metastasized; therefore, it has a poor prognosis with a 5-year survival rate of 11% to 12%. A key to targeting this high mortality is to develop methods for detecting the disease at a stage in which it is still local to the pancreas. However, this needs a better understanding of the events that govern pancreatic cancer oncogenesis. In this issue of Cancer Research, Neuß and colleagues report metabolic changes associated with acinar-to-ductal metaplasia (ADM), an initiating event that leads to the formation of precursor lesions for pancreatic ductal adenocarcinoma (PDAC). Their findings reveal a switch to aerobic glycolysis, increased c-MYC signaling, and increased serine metabolism as driving factors for the ADM process. These findings are important as they demonstrate that metabolic changes that drive the proliferation and metastasis of full-blown PDAC begin in the earliest lesions. The data not only provide insights into how PDAC develops but also a potential explanation for previously described findings, such as circulating lesion cells can be detected even when no carcinoma in situ is present. In summary, this article is highly relevant for furthering our understanding of how metabolic reprogramming drives the earliest events leading to PDAC development and could lay the groundwork for developing methods for early detection or intervention. See related article by Neuß et al., p. 2297.

Unveiling the Culprit: IL17 Signaling in the Pancreatic Epithelium Drives Tumorigenesis.

IL17 signaling promotes pancreatic cancer development, yet the cell compartment responsible for the protumorigenic function of IL17 has not been defined. In this article, Castro-Pando and colleagues demonstrate that IL17/IL17 receptor A signaling in the pancreatic epithelium is critical for pancreatic cancer initiation and for establishing immunosuppression, whereas its signaling in the immune compartment is dispensable. This work provides an important mechanistic insight on the role of IL17 signaling and identifies a potential new immune checkpoint as a target in pancreatic cancer. See related article by Castro-Pando et al., p. 1170.

Pancreatic Epithelial IL17/IL17RA Signaling Drives B7-H4 Expression to Promote Tumorigenesis.

IL17 is required for the initiation and progression of pancreatic cancer, particularly in the context of inflammation, as previously shown by genetic and pharmacological approaches. However, the cellular compartment and downstream molecular mediators of IL17-mediated pancreatic tumorigenesis have not been fully identified. This study examined the cellular compartment required by generating transgenic animals with IL17 receptor A (IL17RA), which was genetically deleted from either the pancreatic epithelial compartment or the hematopoietic compartment via generation of IL17RA-deficient (IL17-RA-/-) bone marrow chimeras, in the context of embryonically activated or inducible Kras. Deletion of IL17RA from the pancreatic epithelial compartment, but not from hematopoietic compartment, resulted in delayed initiation and progression of premalignant lesions and increased infiltration of CD8+ cytotoxic T cells to the tumor microenvironment. Absence of IL17RA in the pancreatic compartment affected transcriptional profiles of epithelial cells, modulating stemness, and immunological pathways. B7-H4, a known inhibitor of T-cell activation encoded by the gene Vtcn1, was the checkpoint molecule most upregulated via IL17 early during pancreatic tumorigenesis, and its genetic deletion delayed the development of pancreatic premalignant lesions and reduced immunosuppression. Thus, our data reveal that pancreatic epithelial IL17RA promotes pancreatic tumorigenesis by reprogramming the immune pancreatic landscape, which is partially orchestrated by regulation of B7-H4. Our findings provide the foundation of the mechanisms triggered by IL17 to mediate pancreatic tumorigenesis and reveal the avenues for early pancreatic cancer immune interception. See related Spotlight by Lee and Pasca di Magliano, p. 1130.

Resolution of Acinar Dedifferentiation Regulates Tissue Remodeling in Pancreatic Injury and Cancer Initiation

Background and AimsAcinar to ductal metaplasia (ADM) is crucial in the development of pancreatic ductal adenocarcinoma (PDAC). However, our understanding of the induction and resolution of ADM remains limited. We conducted comparative transcriptome analyses to identify conserved mechanisms of ADM in mouse and human. MethodsWe identified Sox4 among the top upregulated genes. We validated the analysis by RNA in situ hybridization (ISH). We performed experiments in mice with acinar-specific deletion of Sox4 (Ptf1a: CreER; Rosa26-LSL-YFPLSL-YFP; Sox4fl/fl ) with and without an activating mutation in Kras (KrasLSL-G12D/+). Mice were given caerulein to induce pancreatitis. We performed phenotypic analysis by immunohistochemistry, tissue decellularization and single cell RNA sequencing. ResultsWe demonstrated that Sox4 is reactivated in ADM and PanINs. Contrary to findings in other tissues, Sox4 actually counteracts cellular dedifferentiation and helps maintain tissue homeostasis. Moreover, our investigations unveiled the indispensable role of Sox4 in the specification of mucin-producing cells and tuft-like cells from acinar cells. We identified Sox4-dependent non-cell-autonomous mechanisms regulating the stromal reaction during disease progression. Notably, Sox4-inferred targets are activated upon KRAS inactivation and tumor regression. ConclusionsOur results indicate that our transcriptome analysis can be used to investigate conserved mechanisms of tissue injury. We demonstrate that Sox4 restrains acinar dedifferentiation and is necessary for the specification of acinar-derived metaplastic cells in pancreatic injury and cancer initiation and is activated upon Kras ablation and tumor regression in mice. By uncovering novel potential strategies to promote tissue homeostasis, our findings offer new avenues for preventing the development of PDAC.

Abstract 5325: Cytokine CCL9, new downstream target of oncogene Kras to modulate acinar-to-ductal metaplasia during pancreatic cancer initiation

Abstract Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal types of cancer with a current five-year survival rate at 12% in the US, and is dominated by oncogenic Kras mutations. Accumulating evidence showed that PDAC can be originated from acinar-to-ductal metaplasia (ADM). In this process, pancreatic acini harboring oncogenic Kras mutations are transdifferentiated to a duct-like phenotype that further progresses to become pancreatic intraepithelial neoplasia (PanIN) lesions, giving rise to PDAC. Although ADM formation is commonly observed in KrasG12D transgenic mouse models of PDAC, the exact mechanisms of how oncogenic KrasG12D modulates this process remain unclear. Here, we unveil a new downstream target of oncogenic Kras, cytokine CCL9 during ADM formation. Either exogenously treating primary pancreatic acini with recombinant CCL9 or ectopically expressing CCL9 in primary pancreatic acini resulted in ADM formation in a 3D organoid culture system. Furthermore, knockdown of CCL9 in KrasG12D-expressed acini reduced KrasG12D-induced ADM. Higher levels of reactive oxygen species (ROS) were detected in the KrasG12D-expressed pancreatic acini, and knockdown of CCL9 in these acini decreased ROS levels. Overexpression of CCL9 in primary pancreatic acini elevated cellular ROS of pancreatic acinar cells. Furthermore, depletion of ROS in 3D organoid culture of CCL9-expressed acini reduced CCL9-induced ADM formation. In transgenic mice of p48cre:KrasG12D, blockade of CCL9 through its specific neutralizing antibody attenuated ADM formation as well as PanIN structures. Altogether, our results indicated oncogenic KrasG12D initiates PDAC through a new downstream target molecule, CCL9, to enhance ROS levels of pancreatic acinar cells. Citation Format: Geou-Yarh (Stancy) Liou, Justin K. Messex, Crystal J. Byrd. Cytokine CCL9, new downstream target of oncogene Kras to modulate acinar-to-ductal metaplasia during pancreatic cancer initiation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5325.

Abstract 6984: Investigating the function of the OSM-OSMR axis in pancreatic ductal adenocarcinoma (PDAC)

Abstract Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal forms of cancer, characterized by a low survival rate and a significant global mortality impact. The interaction between PDAC and the immune system is complex and plays a crucial role in the progression of the disease. PDAC creates an immunosuppressive tumor microenvironment, which hampers the ability of immune cells to effectively infiltrate the tumor and mount an anti-cancer immune response. Additionally, there is an imbalance of cytokines, with an overabundance of immunosuppressive factors and a deficiency in pro-inflammatory cytokines. This hostile immunological landscape contributes to the aggressive nature of PDAC and hinders the success of immunotherapies and adjuvant treatments. One cytokine of particular interest is oncostatin M (OSM), a member of the interleukin-6 (IL-6) family. OSM has been implicated in the regulation of cancer and has been associated with poor overall survival in pancreatic cancer and other malignancies. Similar to other cytokines, OSM is secreted by immune cells and acts as a regulator of the inflammatory microenvironment surrounding the tumor. The levels of OSM in this milieu can potentially influence cancer development and regulation through multiple mechanisms. Despite the growing understanding of cytokines in cancer, research on the role of OSM in PDAC is still limited and requires further investigation to identify potential therapeutic targets. Therefore, there is a critical need to delve deeper into the functions of OSM and its receptor, oncostatin M receptor (OSMR), in the initiation and progression of pancreatic cancer. As such, our goal is to examine the functions of OSM and its receptor (OSMR) in initiating and advancing pancreatic cancer to better comprehend the role of the OSM-OSMR axis in PDAC, both in vivo and in vitro. Citation Format: Yuan Sui, Tony Hunter. Investigating the function of the OSM-OSMR axis in pancreatic ductal adenocarcinoma (PDAC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6984.

Abstract 4441: The epigenetic factor BMI1 regulates metabolism and tumorigenesis in human pancreatic cancer cells

Abstract Dysregulation of epigenetic factors is a key component of tumorigenesis. BMI1, a member of the polycomb repressor complex 1 (PRC1), is an oncogenic factor studied in many types of cancer, including pancreatic ductal adenocarcinoma (PDAC). PDAC is the third most common cause of cancer-related death in the United States and investigation of the biology involved in transformation is critical for improving outcomes in this devastating disease. In PDAC, BMI1 is required for initiation of pancreatic cancer in mice and enhances in vitro growth of human and murine tumor cell lines. CRISPR-mediated knock out of BMI1 results in reduced subcutaneous and orthotopic tumor growth in mice and decreased expression of genes related to metabolism, specifically glycolysis, and cell proliferation. BMI1 has also been implicated in regulation of metabolism in other epithelial tumor types, including ovarian cancer. Given these preliminary findings, we hypothesized that loss of BMI1 in multiple human PDAC cell lines would result in altered metabolic activity, reducing the growth and tumorigenic properties of these cells. We demonstrated that BMI1 expression is higher in PDAC cell lines compared to normal pancreatic epithelial cells and normal human donor pancreatic tissue. Following CRISPR-mediated BMI1 knock out in human PDAC cell lines, we investigated the alterations to metabolism using metabolic flux analysis. Loss of BMI1 resulted in lower basal and compensatory rates of glycolysis and increased oxygen consumption rates compared to wild-type cells. Metabolomic analysis demonstrated reduction in all the enzymes involved in the glycolysis pathway with loss of BMI1. Cell growth was reduced by loss of BMI1 in vitro, and orthotopic injection into mice of human cells with BMI1 knock out resulted in decreased tumor size compared to wild-type, recapitulating these findings in vivo. Together, these data identify a role of BMI1 in promotion of tumor growth through regulation of metabolism in pancreatic cancer. Experiments are ongoing to determine the underlying mechanism of this regulation and implications on therapeutic targeting with BMI1/PRC1 complex inhibitors in conjunction with traditional chemotherapy. Citation Format: Jamie N. Mills, Dominik Awad, Heather K. Schofield, Joyce K. Thompson, Hannah Watkoske, Damien Sutton, Nicholas Nedzesky, Donovan Drouillard, Zeribe Nwosu, Carlos Espinoza, Yaqing Zhang, Annachiara Del Vecchio, Christopher J. Halbrook, Marina Pasca di Magliano, Costas A. Lyssiotis, Filip Bednar. The epigenetic factor BMI1 regulates metabolism and tumorigenesis in human pancreatic cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4441.

Macrophage-induced reactive oxygen species in the initiation of pancreatic cancer: a mini-review.

Pancreatic inflammation is a risk factor for the development of pancreatic cancer. Increased presence of inflammatory macrophages can be found in response to a KRAS mutation in acinar cells or in response to experimentally-induced pancreatitis. Inflammatory macrophages induce pancreatic acinar cells to undergo dedifferentiation to a duct-like progenitor stage, a process called acinar-to-ductal metaplasia (ADM). Occurrence of ADM lesions are believed to be the initiating event in tumorigenesis. Here we will discuss how macrophage-induced oxidative stress contributes to ADM and how ADM cells shape the fibrotic stroma needed for further progression.

Screening Metabolic Biomarkers in KRAS Mutated Mouse Acinar and Human Pancreatic Cancer Cells via Single-Cell Mass Spectrometry.

Pancreatic cancer is a highly aggressive and rapidly progressing disease, often diagnosed in advanced stages due to the absence of early noticeable symptoms. The KRAS mutation is a hallmark of pancreatic cancer, yet the underlying mechanisms driving pancreatic carcinogenesis remain elusive. Cancer cells display significant metabolic heterogeneity, which is relevant to the pathogenesis of cancer. Population measurements may obscure information about the metabolic heterogeneity among cancer cells. Therefore, it is crucial to analyze metabolites at the single-cell level to gain a more comprehensive understanding of metabolic heterogeneity. In this study, we employed a 3D-printed ionization source for metabolite analysis in both mice and human pancreatic cancer cells at the single-cell level. Using advanced machine learning algorithms and mass spectral feature selection, we successfully identified 23 distinct metabolites that are statistically significantly different in KRAS mutant human pancreatic cancer cells and mouse acinar cells bearing the oncogenic KRAS mutation. These metabolites encompass a variety of chemical classes, including organic nitrogen compounds, organic acids and derivatives, organoheterocyclic compounds, benzenoids, and lipids. These findings shed light on the metabolic remodeling associated with KRAS-driven pancreatic cancer initiation and indicate that the identified metabolites hold promise as potential diagnostic markers for early detection in pancreatic cancer patients.

Pancreatic Cancer Treatment Targeting the HGF/c-MET Pathway: The MEK Inhibitor Trametinib.

Pancreatic cancer is characterized by fibrosis/desmoplasia in the tumor microenvironment, which is primarily mediated by pancreatic stellate cells and cancer-associated fibroblasts. HGF/c-MET signaling, which is instrumental in embryonic development and wound healing, is also implicated for its mitogenic and motogenic properties. In pancreatic cancer, this pathway, along with its downstream signaling pathways, is associated with disease progression, prognosis, metastasis, chemoresistance, and other tumor-related factors. Other features of the microenvironment in pancreatic cancer with the HGF/c-MET pathway include hypoxia, angiogenesis, metastasis, and the urokinase plasminogen activator positive feed-forward loop. All these attributes critically influence the initiation, progression, and metastasis of pancreatic cancer. Therefore, targeting the HGF/c-MET signaling pathway appears promising for the development of innovative drugs for pancreatic cancer treatment. One of the primary downstream effects of c-MET activation is the MAPK/ERK (Ras, Ras/Raf/MEK/ERK) signaling cascade, and MEK (Mitogen-activated protein kinase kinase) inhibitors have demonstrated therapeutic value in RAS-mutant melanoma and lung cancer. Trametinib is a selective MEK1 and MEK2 inhibitor, and it has evolved as a pivotal therapeutic agent targeting the MAPK/ERK pathway in various malignancies, including BRAF-mutated melanoma, non-small cell lung cancer and thyroid cancer. The drug's effectiveness increases when combined with agents like BRAF inhibitors. However, resistance remains a challenge, necessitating ongoing research to counteract the resistance mechanisms. This review offers an in-depth exploration of the HGF/c-MET signaling pathway, trametinib's mechanism, clinical applications, combination strategies, and future directions in the context of pancreatic cancer.

Computational insights into KRAS G12C inhibition: exploring possible repurposing of Azacitidine and Ribavirin

Kirsten rat sarcoma (KRAS) stands out as the most prevalent mutated oncogene, playing a crucial role in the initiation and progression of various cancer types, including colorectal, lung and pancreatic cancer. The oncogenic modifications of KRAS are intricately linked to tumor development and are identified in 22% of cancer patients. This has spurred the necessity to explore inhibition mechanisms, with the aim of investigating and repurposing existing drugs for diagnosing cancers dependent on KRAS G12C In this investigation, 26 nucleoside-based drugs were collected from literature to assess their effectiveness against KRAS G12C. The study incorporates in-silico molecular simulations and molecular docking examinations of these nucleoside-derived drugs with the KRAS G12C protein using Protein Data Bank (PDB) ID: 5V71. The docking outcomes indicated that two drugs, Azacitidine and Ribavirin, exhibited substantial binding affinities of −8.7 and −8.3 kcal/mol, respectively. These drugs demonstrated stability in binding to the active site of the protein during simulation studies. Root mean square deviation (RMSD) analyses indicated that the complexes closely adhered to an equilibrium RMSD value ranging from 0.17 to 0.2 nm. Additionally, % occupancies, bond angles and the length of hydrogen bonds were calculated. These findings suggest that Azacitidine and Ribavirin may potentially serve as candidates for repurposing in individuals with KRAS-dependent cancers. Communicated by Ramaswamy H. Sarma

Abstract B055: Hyperinsulinemia acts via acinar cell insulin receptors to drive obesity-associated pancreatic cancer initiation

Abstract The rising incidence of pancreatic cancer is largely driven by increased prevalence of obesity and type 2 diabetes (T2D). Hyperinsulinemia is a cardinal feature of obesity and T2D, and is associated with increased cancer incidence and mortality. Whether insulin alone plays a causal role in increasing cancer risk by directly affecting the tumor cell of origin remains unclear. Our previous studies demonstrated that genetically reducing production of insulin suppressed formation of pancreatic intraepithelial neoplasia (PanIN) pre-cancerous lesions in mice with mutant Kras. However, consistent with a role for insulin in modulating the immune system, we saw changes in fibrosis, as well as changes in the transcriptomes of immune cells in the pancreas in mice with reduced insulin. Thus, it remained unclear whether hyperinsulinemia exerted its effects directly on the cells that give rise to PanINs or indirectly on the tumor microenvironment. Here, we tested whether insulin receptor (Insr) in KrasG12D-expressing pancreatic acinar cells was necessary for the effects of diet-induced hyperinsulinemia on pancreatic cancer development. Loss of Insr in KrasG12D-expressing acinar cells did not halt the development of hyperinsulinemia or weight gain associated with high fat diet consumption in mice. However, solely reducing Insr expression in KrasG12D-expressing acinar cells significantly reduced formation of PanIN and tumors. Mechanistically, proteomic analyses suggested that insulin and Insr coordinately regulate the production of digestive enzymes, the main function of acinar cells, by modulating the activity of the spliceosome, ribosome, and secretory machinery. Consistent with this adding insulin to TGF-alpha treated wild-type acini ex vivo increased their conversion into ductal structures and this was blocked by treatment with trypsin inhibitor. Additionally, loss of Insr also reduced the formation of duct-like structures in acinar explants after TGF-alpha stimulation and made them insensitive to insulin. Collectively, these data demonstrated that insulin action on the insulin receptor in acinar cells promotes conditions that cooperate with Kras signaling to increase the risk of developing pancreatic cancer especially in the context of hyperinsulinemia and obesity. Citation Format: Anni M.Y. Zhang, Yi Han Xia, Jeffrey S.H. Lin, Ken H. Chu, Wei Chuan K. Wang, Titine J.J. Ruiter, Jenny C.C. Yang, Nan Chen, Justin Chhuor, Shilpa Patil, Haoning H. Cen, Elizabeth J. Rideout, Vincent R. Richard, David F. Schaeffer, Rene P. Zahedi, Christoph H. Borchers, James D. Johnson, Janel L. Kopp. Hyperinsulinemia acts via acinar cell insulin receptors to drive obesity-associated pancreatic cancer initiation [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr B055.

Abstract A109: Single-cell epigenomic analysis reveals an important role of the receptor kinase Ror2 in the erosion of cellular identity during pancreatic carcinogenesis

Abstract Introduction The major driver for pancreatic ductal adenocarcinoma (PDAC) is oncogenic KRAS. However, adult acinar cells, a probable origin of PDAC, are largely refractory to KrasG12D-mediated oncogenic transformation. With the concomitant loss of transcription factors that regulate acinar cell differentiation, such as Pdx1 (Pancreatic and Duodenal Homeobox 1), acinar cells undergo a rapid cell identity switch, known as acinar-to-ductal metaplasia (ADM). How loss of cell identity cooperates with oncogenic Kras to induce pancreatic transformation is largely unclear. Methods To elucidate mechanisms responsible for the accelerated cellular reprogramming in KrasG12D;Pdx1f/f animals, single-cell ATAC-seq (Assay for Transposase-Accessible Chromatin using sequencing) from frozen pancreatic bulk tissue was performed. Chromatin accessibility states were captured at early stages of carcinogenesis and correlated to RNA-seq data. Differentially regulated genes were validated by multiplex RNAscope and immunohistochemistry staining and functionally studied in pancreatic cancer cell lines. Results Single-cell ATAC-seq proved a powerful tool for defining cell-type identity, cellular reprogramming and target genes in early metaplastic transformation of pancreatic tissue. Notably, acinar cells of KrasG12D;Pdx1f/f animals as well as a proportion of metaplastic lesions in both, KrasG12D and KrasG12D;Pdx1f/f mice, showed elevated accessibility and expression of the Ror2 (Receptor Tyrosine Kinase Like Orphan Receptor 2) gene. As a receptor tyrosine kinase, Ror2 controls noncanonical Wnt signaling and other essential signaling pathways, such as PI3K/AKT or Ras-MAPK. Genetic ablation of Ror2 in a mouse model of pancreatic neoplasia resulted in a shift in ADM cell identity, enriching ADM lesions with a senescent duct cell phenotype. In PDAC, ROR2 expression correlates with the more aggressive basal-like subtype. Overexpression of ROR2 in pancreatic cancer cell lines with a classical differentiation induced epithelial-to-mesenchymal transition, characterized by the downregulation of multiple epithelial markers and upregulation of mesenchymal genes. Knockout of ROR2 in pancreatic cancer cells significantly decreased cell proliferation. Conclusions Our in-depth sequencing data revealed that expression of KrasG12D with the concomitant loss of Pdx1 leads to vast alterations of acinar cell identity. We identified the receptor kinase Ror2 as a regulator of pancreatic cancer initiation and driver of pancreatic cancer cell aggressiveness. Citation Format: Simone Benitz, Malak Nasser, Alexander Steep, Jonathan Preall, Ujjwal Mahajan, Ian Loveless, Erick Davis, Hui-Ju Wen, Daniel Long, Michaela Louw, Samuel Zwernik, Donald Rempinski, Jacee Moore, Daniel Salas-Escabillas, Thomas Metzler, Ling Huang, Nina Steele, Ivonne Regel, Filip Bednar, Howard Crawford. Single-cell epigenomic analysis reveals an important role of the receptor kinase Ror2 in the erosion of cellular identity during pancreatic carcinogenesis [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr A109.

Ehmt2 inactivation in pancreatic epithelial cells shapes the transcriptional landscape and inflammation response of the whole pancreas.

Introduction: The Euchromatic Histone Methyl Transferase Protein 2 (EHMT2), also known as G9a, deposits transcriptionally repressive chromatin marks that play pivotal roles in the maturation and homeostasis of multiple organs. Recently, we have shown that Ehmt2 inactivation in the mouse pancreas alters growth and immune gene expression networks, antagonizing Kras-mediated pancreatic cancer initiation and promotion. Here, we elucidate the essential role of Ehmt2 in maintaining a transcriptional landscape that protects organs from inflammation. Methods: Comparative RNA-seq studies between normal postnatal and young adult pancreatic tissue from Ehmt2 conditional knockout animals (Ehmt2 fl/fl ) targeted to the exocrine pancreatic epithelial cells (Pdx1-Cre and P48 Cre/+ ), reveal alterations in gene expression networks in the whole organ related to injury-inflammation-repair, suggesting an increased predisposition to damage. Thus, we induced an inflammation repair response in the Ehmt2 fl/fl pancreas and used a data science-based approach to integrate RNA-seq-derived pathways and networks, deconvolution digital cytology, and spatial transcriptomics. We also analyzed the tissue response to damage at the morphological, biochemical, and molecular pathology levels. Results and discussion: The Ehmt2 fl/fl pancreas displays an enhanced injury-inflammation-repair response, offering insights into fundamental molecular and cellular mechanisms involved in this process. More importantly, these data show that conditional Ehmt2 inactivation in exocrine cells reprograms the local environment to recruit mesenchymal and immunological cells needed to mount an increased inflammatory response. Mechanistically, this response is an enhanced injury-inflammation-repair reaction with a small contribution of specific Ehmt2-regulated transcripts. Thus, this new knowledge extends the mechanisms underlying the role of the Ehmt2-mediated pathway in suppressing pancreatic cancer initiation and modulating inflammatory pancreatic diseases.

Decreased survival in patients with pancreatic cancer may be associated with an increase in histopathological expression of inflammasome marker NLRP3.

Pancreatic cancer is a malignant neoplasm that, despite its low frequency, has a 5-year survival rate of less than 10%. The study of different histopathological markers has allowed a better understanding of the onset and development of this type of tumor as well as facilitating an approach to clinical variables based on their diagnostic, prognostic, and predictive value. In this sense, the NLRP3 protein of the inflammasome has been shown to be a component of great relevance in the initiation and progression of pancreatic cancer, although the value of this biomarker in patients has not yet been clarified. In this study, we selected 41 patients with pancreatic cancer and followed them for 60 months (5 years), evaluating their NLRP3 expression using immunohistochemical techniques. Furthermore, by performing Kaplan-Meier curves, we evaluated the survival of these patients in relation to their NLRP3 expression. Our results show that a significant percentage of our cohort had high expression of this component (90.74%) and that there is an inverse relationship between the expression of NLRP3 and patient survival. High levels of NLRP3 expression are related to lower survival and worse prognosis in these patients, possibly due to an ineffective immune system response and increased tumor-promoted inflammation. Future studies should be aimed at confirming these results in larger groups and evaluating various clinical strategies based on this knowledge.

Cancer-Associated Fibroblast Induces Acinar-to-Ductal Cell Transdifferentiation and Pancreatic Cancer Initiation Via LAMA5/ITGA4 Axis

BACKGROUND & AIMSPancreatic ductal adenocarcinoma (PDAC) is characterized by desmoplastic stroma surrounding most tumors. Activated stromal fibroblasts, namely Cancer-associated fibroblasts (CAFs), play a major role in PDAC progression. Here we analyzed if CAFs influence acinar cells and impact PDAC initiation, namely “Acinar to Ductal Metaplasia” (ADM). ADM connection with PDAC pathophysiology is indicated but not yet established. Hence, we hypothesized that CAF secretome might play a significant role in ADM in PDAC initiation. METHODSMouse and human acinar cell organoids, acinar cells cocultured with CAFs and exposed to CAF-conditioned media (CAF-CM), acinar cell explants, and CAF cocultures, etc., were examined by qRT-PCR, RNA-seq, immunoblotting and confocal microscopy. Data from LC-MS/MS analysis of CAF CM and RNAseq data of acinar cells post-CM exposure were integrated using bioinformatics tools to identify molecular mechanism for CAF-induced ADM. Using confocal microscopy, immunoblotting, and qRT-PCR analysis, we validated the depletion of key signaling axis in cell-line, acinar explant coculture, and mCAFs. RESULTSClose association of acino-ductal (UEA1, Amylase, Ck19) markers and mCAFs (α-SMA) in LSL-KrasG12D/+; LSL-Trp53R172H/+; Pdx1Cre (KPC) and LSL-KrasG12D/+; Pdx1Cre (KC) autochthonous progression tumor tissue was observed. Caerulein treatment-induced mCAFs increased Ck19 and decreased Amylase in wild-type (WT) and KC pancreas. Likewise, acinar-mCAF cocultures revealed induction of ductal transdifferentiation in cell-line, acinar-organoid, and explant coculture formats in WT and KC mice pancreas. Proteomic and transcriptomic data integration revealed a novel Laminin5/Integrinα4/Stat3 axis responsible for CAF-mediated acinar to ductal cell transdifferentiation. CONCLUSIONResults collectively suggest the first evidence for CAF-influenced acino-ductal phenotypic switchover, thus highlighting tumor micro-environment role in the pancreatic carcinogenesis inception.

HNF1A plays a context-dependent role in pancreatic cancer initiation and progression

HNF1A plays a context-dependent role in pancreatic cancer initiation and progression

The role of predictive and prognostic values of inflammatory markers in acute pancreatitis: a narrative review

Pancreatitis is an inflammatory condition affecting the pancreas and is classified into 2 types, acute and chronic, which can manifest in various forms. This review article summarizes the role of predictive and prognostic values of inflammatory markers in the pathogenesis of acute pancreatitis, mainly focused on preclinical and clinical studies. It includes serum amyloid A (SAA), monocyte chemotactic protein-1 (MCP-1), erythrocyte sedimentation rate (ESR), interleukin-6 (IL-6), C-reactive protein (CRP), IL-10, myeloperoxidase, pentraxin 3, and plasminogen activator inhibitor 1. SAA3 plays a crucial role in developing acute pancreatitis by triggering a receptor-interacting protein 3–dependent necroptosis pathway in acinar cells. Targeting SAA3 could be a potential strategy for treating acute pancreatitis. The recruitment of monocytes/macrophages and the activation of the systemic MCP-1 signaling pathway play a role in the progression of pancreatitis, and blocking MCP-1 may have a suppressive effect on the development of pancreatic fibrosis. The ESR can predict severe acute pancreatitis with slightly lower accuracy than CRP. When ESR and CRP levels are combined at 24 hours, they predict severe acute pancreatitis accurately. IL-6 plays a crucial role in activating the Janus kinase/signal transducers and activators of the transcription pathway, exacerbating pancreatitis and contributing to the initiation and progression of pancreatic cancer. Endogenous IL-10 plays a crucial role in controlling the regenerative phase and limiting the severity of fibrosis and glandular atrophy induced by repeated episodes of acute pancreatitis in mice. The predictive and diagnostic roles of these inflammatory factors in pancreatitis were introduced in detail in this review.

Roles of differently polarized macrophages in the initiation and progressionof pancreatic cancer.

During development of pancreatic cancer macrophage-mediated inflammatory processes and the formation of cancerous lesions are tightly connected. Based on insight from mouse models we provide an overview on the functions of classically-activated pro-inflammatory and alternatively-activated anti-inflammatory macrophages in the initiation and progression of pancreatic cancer. We highlight their roles in earliest events of tumor initiation such as acinar-to-ductal metaplasia (ADM), organization of the fibrotic lesion microenvironment, and growth of low-grade (LG) lesions. We then discuss their roles as tumor-associated macrophages (TAM) in progression to high-grade (HG) lesions with a cancerous invasive phenotype and an immunosuppressive microenvironment. Another focus is on how targeting these macrophage populations can affect immunosuppression, fibrosis and responses to chemotherapy, and eventually how this knowledge could be used for novel therapy approaches for patients with pancreatic ductal adenocarcinoma (PDA).