Pancreatic Cancer Progression Research Articles

Abstract A039: Silencing MICAL2 expression in pancreatic cancer cells reduces IL-1A expression and inhibits tumor growth through a CD8+ T cell dependent mechanism

Abstract Introduction: Pancreatic cancer is characterized by desmoplastic, fibroinflammatory stroma. The crosstalk between cancer cells and their surrounding tumor microenvironment (TME) promotes disease progression, metastasis, and chemoresistance. We identified MICAL2 as a super-enhancer-associated gene in pancreatic cancer. MICAL2 (molecule interacting with Cas-L) proteins are flavin monooxygenases that promote actin depolymerization and indirectly regulate SRF transcription. In other work, we have found that MICAL2 promotes pancreatic cancer growth and progression. This study evaluated how MICAL2 pancreatic cancer cell expression modulates the PDAC tumor microenvironment. Methods: RNA-Seq analysis performed on human pancreas cancer cells (AsPC-1) before and after MICAL2 KD revealed differential regulation of IL-1α. We validated the expression of IL-1α in multiple human and mouse pancreas cancer cell lines by q-PCR. We next exposed human (h) and mouse (m) PSCs to conditioned media (CM) from cancer cells before and after MICAL2 KD and checked the expression of a-SMA, fibronectin, and Col1A and IL-6 genes by qPCR. KrasG12D/+; Trp53R172H/+; Pdx1-cre (KPC) cells with and without MICAL2 were orthotopically injected to assess the in vivo tumor growth and metastasis. Sc-RNA seq and Immunophenotyping were performed on Shcontrol (ShCNT) and MICAL2 (M2KD) KD tumors. CD8+ T cell depletion was done using an antibody-mediated approach. The adoptive transfer of CD8+ T cells extracted from MICAL2 KD tumors was done by tail vein injection. Results: MICAL2 KD resulted in the downregulation of the IL-1α gene in both human and mouse pancreas cancer cell lines (50% reduction, p<0.05). Human and mouse pancreatic stellate cells (hPSCs and mPSCs) co-cultured with cancer cells CM showed significant downregulation of a-SMA, fibronectin, Col1A, and IL-6 upon MICAL2 KD as compared to hPSCs and mPSCs co-cultured with ShCNT cells. Orthotopic injections of KPC MICAL2 KD cells led to decreased tumor growth as compared to ShCNT (0.26 gm vs. 1 gm, p = 0.008). Immunofluorescence (IF) revealed less α-SMA, PDGF-α, and IL-6 expression and reduced deposition of collagen and fibronectin in MICAL2 KD tumors. Single-cell RNA seq and flow cytometry studies of tumors harvested from both groups showed significantly increased infiltration of activated cytotoxic CD8+ T cells in MICAL2 KD tumors which was further confirmed by IF. Antibody-mediated depletion of CD8+ T cells in MICAL2 KD tumors abrogated their reduced tumor growth in both immune-hot and immune-cold KPC cell lines. Adoptive transfer of CD8+ T cells extracted from M2KD tumors significantly reduced ShCNT flank tumor growth. Conclusion: These data reveal that MICAL2 expression mediates tumor-stromal crosstalk through IL1A and creates an immunosuppressive environment in PDAC and suggests MICAL2 may be an attractive immunomodulatory target for pancreatic cancer therapy. Ongoing work is focused on dissecting the role of MICAL2 in priming the metastatic niche through the remodeling of the TME. Citation Format: Bharti Garg, EvanGeline Mose, Edgar Esparza, Jay Patel, Sarah Sass, Alexei Martsinkovskiy, Dawn Jacquish, Herve Tiriac, Andrew M. Lowy. Silencing MICAL2 expression in pancreatic cancer cells reduces IL-1A expression and inhibits tumor growth through a CD8+ T cell dependent mechanism [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 A039.

Abstract A023: Cytokine loss leads to decreased tumor differentiation and a more aggressive phenotype

Abstract Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest cancers with a 5-year survival rate of only 11% and approximately half the patients present with distant metastasis at the time of diagnosis. PDAC is accompanied by pronounced alterations in stromal responses and immune surveillance programs, which are now recognized as some of the major drivers in PDAC tumor evolution. The role of immune modulators in driving aggressiveness of PDAC is poorly understood. We investigate how the loss of host-derived IL-12 and IL-23 in murine models of pancreatic cancer can lead to changes in changes in tumor morphology, cellular differentiation, and tumor immune microenvironment. In orthotopic tumors isolated from IL-12 and IL-23 knockout mice tumor morphology is altered and appears to be less differentiated. Noticeably, ductal area decreases in tumors from IL-23 and IL-12 knockout mice. Single cell RNA sequencing of tumors isolated from IL-12 and IL-23 knockout mice reveals a cluster of tumor cells with decreased gastric gene expression. Gastric genes such as TFF1, TFF2, MUC5AC, GKN1, and GKN2 have been implicated in pancreatic cancer development, progression, and tumor subtype. The classical pancreatic tumor subtype designation correlates with better differentiated pancreatic tumors as opposed to the more poorly differentiated tumors in the basal subtype. The classical expression signature is characterized by the expression of GATA6 and other epithelial cell terminal differentiation genes and includes several of these gastric genes. We hypothesize that loss of IL-12 and IL-23 leads to loss of tumor differentiation and to a more aggressive phenotype. Citation Format: Whitney J. Bell, Nancy Kren, Yan Wang, Jennifer Modliszewski, Yi Xu, Meijiang Guan, Kathleen DelGiorno, Jen Jen Yeh, Yuliya Pylayeva-Gupta. Cytokine loss leads to decreased tumor differentiation and a more aggressive phenotype [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 A023.

Abstract A076: Spatial genomic expression profiling reveals metastatic gene markers in mucinous cystic carcinoma of the pancreas and regional lymph nodes

Abstract Pancreatic cancer is a highly lethal disease characterized by low detectability in its early stages, leading to limited treatment options in advanced stages. Mucinous cystic carcinoma (MCC) is a rare subtype of pancreatic cancer that produces mucin. In this study, we investigated the genetic characteristics of MCC and its metastatic potential. Using spatial genomic analysis, we observed the upregulation of several genes in MCC, including CPA1 and CPB1, which encode carboxypeptidases produced by the pancreas. These genes were highly expressed in both the pancreatic tumor and regional lymph nodes, suggesting their potential as gene markers for the metastatic potential of MCC. Moreover, we observed co-localization and upregulation of genes encoding chymotrypsin-like-elastase in both the pancreatic tissue and lymph nodes, indicating their potential involvement in metastasis. Furthermore, we observed significant elevation in the expression of pancreatic enzymes encoded by PRSS1, PRSSA, CLPS, and PLAG2GA in both the pancreatic tissue and lymph nodes. The presence of PRSS1 and PRSSA in the lymph node suggests the presence of cancer cells in the lymphatic system, which in turn promotes tumor growth, invasion, and metastasis. Additionally, elevated expression of CLPS in the lymph nodes may be associated with altered lipid metabolism and the breakdown of fat molecules in the tumor microenvironment. This upregulation was accompanied by increased levels of SPARC, an extracellular matrix protein, in both tissues, emphasizing the correlation between metastatic potential and tumorigenesis. Notably, commonly observed tumor markers for pancreatic cancer, such as SMAD4, did not exhibit upregulation in our MCC case, indicating alternative mechanisms of tumor development in this particular subtype. Additionally, we noted heightened expression of the CA 19-9 antigen, a valuable marker for monitoring the progression of pancreatic cancer. In conclusion, our findings reveal the upregulation of several gene markers in this rare subtype of pancreatic cancer and regional lymph nodes. Understanding the expression patterns of these markers can aid in identifying potential therapeutic targets and detecting metastatic potential at an early stage for MCC. Citation Format: Chirag S. Gopinath, Arshia Ghodrati, Lusine Demirkhanyan, Manu Gnanamony, Joseph A. Norton, Sonia T. Orcutt, Christopher S. Gondi. Spatial genomic expression profiling reveals metastatic gene markers in mucinous cystic carcinoma of the pancreas and regional lymph nodes [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 A076.

Abstract B097: Tomatidine inhibits ATF4 activity and induces ferroptosis to limit pancreatic cancer progression

Abstract Pancreatic ductal adenocarcinoma (PDAC) is an aggressive cancer with a five-year survival rate of 12%. Current therapies are often ineffective due to metastasis and an immunosuppressive tumor microenvironment (TME). Activating Transcription Factor 4 (ATF4), a master regulator of cellular stress, is exploited by cancer cells to promote their survival and protect cells from ferroptosis. Prior published work and data reported in our study provide evidence that high ATF4 expression in the PDAC TME correlates with worse overall survival in PDAC patients. Tomatidine, a natural steroidal alkaloid, has been associated with inhibition of ATF4-dependent signaling in multiple disease settings. We hypothesized that tomatidine targets ATF4-dependent signaling leading to ferroptosis mediated cell death in pancreatic cancer. We discovered in vitro tomatidine treatment of pancreatic cancer cells inhibits tumor growth by MTT cell viability assay and reduced the protein expression of p4EBP1/Total 4EBP1 (downstream of ATF4) in a dose dependent manner. In vivo tomatidine treatment (5mg/kg daily intraperitoneally) significantly reduced pancreatic tumor growth. RNA-sequencing of tomatidine treated vs. vehicle treated human and murine pancreatic cancer cells validated targeting of ATF4 related stress regulatory genes. Further, immunofluorescence revealed that ATF4 preferentially localized in the cytoplasm instead of nucleus in presence of tomatidine suggesting tomatidine inhibited nuclear translocation of ATF4, rendering ATF4 ineffective to work as a transcription factor. Further, chromatin immunoprecipitation revealed that tomatidine reduced the transcriptional binding activity of ATF4 with its downstream genes. Tomatidine significantly enhanced gemcitabine chemosensitivity in 3D ECM-hydrogels and in an orthotopic model of pancreatic cancer in vivo. RNA sequencing suggested ferroptosis mediated cell death was a top hit in tomatidine treated pancreatic cancer cells. Therefore, we validated how tomatidine affects the ferroptosis pathway in pancreatic cancer cells by looking at lipid peroxidation via C11 Bodipy staining, immunoblotting for the antioxidant protein Glutathione peroxidase 4 (GPX4) and assessing the changes in the oxygen consumption rate (OCR) using the seahorse assay. Tomatidine treatment was associated with increased lipid peroxidation, decreased GPX4 protein expression, and enhanced mitochondrial biogenesis in PDAC cells. This study highlights a possible novel therapeutic approach utilizing a plant derived metabolite, tomatidine, to target ATF4 activity and cause ferroptosis mediated cancer cell death leading to tumor burden control and chemotherapy sensitization in the PDAC tumor microenvironment. Citation Format: Debasmita Mukherjee, Srija Chakraborty, Lena Bercz, Liliana D’Alesio, Jessica Wedig, Molly A. Torok, Timothy Pfau, Hannah Lathrop, Shrina Jasani, Abigail Guenther, Jake McGue, Daniel Adu-Ampratwum, James R. Fuchs, Timothy L. Frankel, Maciej Pietrzak, Stacey Culp, Anne M. Strohecker, Aleksander Skardal, Thomas A. Mace. Tomatidine inhibits ATF4 activity and induces ferroptosis to limit pancreatic cancer progression [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 B097.

Abstract B035: Investigating the roles of GLI transcription factors in the pancreatic cancer microenvironment

Abstract Pancreatic ductal adenocarcinoma (PDA) remains a difficult cancer to treat due to an extensive and complex tumor microenvironment. In particular, intercellular signaling between tumor cells, fibroblasts and immune cells is a key contributor to pancreatic tumor growth. One of these signals, the Hedgehog (HH) pathway, is a known feature of PDA. Pancreatic tumor cells secrete HH ligands, which signal in a paracrine fashion to fibroblasts in the tumor microenvironment. Notably, the role of HH signaling is complicated, with reports suggesting both tumor-promoting and tumor-restraining functions in pancreatic cancer. GLI proteins (GLI1-3) are the transcriptional effectors of the HH pathway; their contribution to pancreatic tumor growth is equally complex. This study seeks to investigate the contribution of GLI1-3 in PDA progression. Our lab has demonstrated that Gli1-3 are expressed in pancreatic fibroblasts and that all three Glis functionally contribute to pancreatic cancer progression through effects on immune cell infiltration. To further explore the mechanisms of GLI function, we have generated a novel mouse model carrying endogenous, epitope-tagged Gli alleles (Gli1FLAG/FLAG;Gli2HA/HA;Gli3V5/V5). This model will allow us to define GLI protein processing and localization as well as the identification of target genes to elucidate the contribution of GLI-driven transcriptional programs that regulate tumor immune infiltration in PDA. Citation Format: Paola Isabel Medina-Cabrera, Michael Scales, Nina Steele, Benjamin Allen, Marina Pasca di Magliano. Investigating the roles of GLI transcription factors in the pancreatic cancer microenvironment [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 B035.

Abstract B048: Targeting PPARG to block obesity-associated pancreatic cancer progression

Abstract Pancreatic ductal adenocarcinoma (PDA) is the 3rd leading cause of cancer-related death in the United States and one of the few cancers for which incidence is increasing. This trend in increased incidence has been attributed in part to obesity. Obesity is associated with increased risk of pancreatic cancer and advanced disease stage in patients, concordant with rodent studies showing that obesity accelerates tumorigenesis and metastasis. Although studies have largely focused on the role of inflammation in obesity-associated pancreatic cancer, the cancer cell-autonomous mechanisms by which lipid availability in obesity impacts tumorigenesis remain quite poorly understood. Given the abundant evidence for dysregulated lipid metabolism in tumors, I hypothesized that cancer cells are primed to exploit exogenous lipids in obesity, accelerating disease progression. By mapping lipid-protein interactions in tumor and metastasis-enriched RNA-seq networks, I identified the nuclear hormone receptor PPARG as a potential mediator of obesity-associated lipid signaling in pancreatic cancer. PPARG is an attractive prospective mediator of obesity-associated PDA progression because it is a metabolic regulator activated by a broad set of lipid ligands, suggesting a dual role in lipid sensing and metabolic control. PPARG is also positioned at an interesting junction in PDA etiology; PPARG agonists are used to treat diabetes (a PDA risk factor) and have previously been studied for anti-cancer effects. However, PPARG agonists have seen little clinical success in and recent work has suggested that their use may even increase bladder cancer risk. PPARG is overexpressed in pancreatic tumors where it is associated with poor prognosis, further casting doubt on its anti-tumorigenic function. In my own studies, I found that PPARG agonists had no effect on tumor viability, while the PPARG antagonist T0070907 reduced organoid viability in vitro. Modeling the convergent effects of PPARG and obesity, I supplemented organoids with a mixture of lipids in the presence of PPARG antagonist and found that lipids boosted the viability of both tumor and metastatic organoids dependent on PPARG activity in vitro. These results suggest that PPARG can mediate the pro-tumorigenic function of exogenous lipids. As the incidence of both obesity and pancreatic cancer continue to rise, defining the role of PPARG in PDA could have significant implications for the development of new strategies to treat or prevent obesity-associated cancer. Citation Format: L. Paige Ferguson. Targeting PPARG to block obesity-associated pancreatic cancer progression [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 B048.

Abstract B098: Oncogenic KRAS relies on β1 integrin expression to drive pancreatic neoplasia and PDAC development

Abstract Oncogenic Kras drives cancer progression through cooperation with multiple cellular factors, many of which are yet to be determined. The β1 integrins, a family of extracellular matrix receptors, are strong candidates; they are implicated in many aspects of cancer progression including cell growth and survival signaling, cell migration and metastasis. Additionally, multiple studies have identified β1 integrins within the interactome of oncogenic Kras. We are investigating the potential cooperation if β1 integrins in Kras-mediated oncogenesis using genetic perturbations within the tamoxifen-inducible and conditional Ptf1a-CreERTM; LSL- KrasG12D (p48-KCER) model of pancreatic cancer. Conditional deletion of the β1 integrins from the adult pancreas produced minimal tissue abnormalities; there were no obvious tissue defects at 6 months post induction, although there was some evidence of pancreatitis at 1 year post induction. However, deletion of the β1 integrins within the KCER model of pancreatic cancer (KCER-Δβ1) resulted in a profound suppression of pancreatic disease progression. There was no detectable neoplasias at 3 months post-induction and minimally detectable neoplasias at 6 months post-induction, compared to prominent neoplasia development and stromal expansion in the control KCER mice at these time-points. Moderate stromal expansion was observed in KCER-Δβ1 mice at 6 months post-induction despite the lack of neoplasia development. To investigate the mechanisms of this integrin-KRAS cooperation, we conditionally deleted the expression of two canonical integrin signaling molecules, the integrin-linked kinase (ILK) and the focal adhesion kinase (FAK). Neither the ILK knockout (KCER-ΔILK) nor the FAK knockout (KCER-ΔFAK) phenocopied the KCER-Δβ1 mice, as both developed neoplasias and stromal expansion at 3 months post-induction and beyond. To explore the role of integrin activation, we next deleted expression of the integrin-cytoskeleton linker molecule Talin-1 in the KCER model. Surprisingly, even though Talin-1 is key to integrin activation, the KCER-ΔTalin-1 mice also failed to phenocopy the KCER-Δβ1, showing ample neoplasia development at 3 and 6 months post-induction, and trending towards faster disease progression at later stages. These combined results demonstrate crucial cooperation between oncogenic Kras and β1 integrins to drive pancreatic cancer progression, and point to non-canonical β1 integrin functions in mediating this cooperation. Citation Format: John L. Muschler, Ge Huang, Alexander C. Smith, Rosalie C. Sears. Oncogenic KRAS relies on β1 integrin expression to drive pancreatic neoplasia and PDAC development [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 B098.

Abstract A025: Autotaxin-lysolipid signaling suppresses a CCL11- eosinophil axis to promote pancreatic cancer progression

Abstract Among all cancer types, pancreatic ductal adenocarcinoma (PDAC) has one of the worst outcomes. In recent studies, metabolic and microenvironmental reprogramming in PDAC has been shown to facilitate tumor progression by promoting immune escape mechanisms, however these mechanisms are still poorly understood. Recently, our lab established that autotaxin (ATX) - lysophosphatidic acid (LPA) signaling in PDAC enhances tumorigenicity, but the immunomodulatory function of this signal pathway remains largely unexplored. We now show that ablation of the LPA-producing enzyme autotaxin (ATX) in PDAC cells can reduce tumor burden in mice and reprogram the tumor immune microenvironment by increasing tumor eosinophil infiltration. The functional role of eosinophils in the context of PDAC is a poorly understood area. The presence of eosinophils in pancreatic cancer has been reported in a few case reports: for example, prior studies identified neutrophils and eosinophils together as a group, expressing high levels of CD66b. We confirmed the presence of eosinophils in PDAC in mice as well as patients, and we found that rare patient samples with the highest intratumoral eosinophil abundance had the longest survival rates. Genetic or pharmacologic ATX inhibition increased intratumoral eosinophils, which promote tumor cell apoptosis locally and suppress tumor progression. When eosinophils were present, primary tumor growth was modestly reduced, but metastatic spread was greatly reduced. Mechanistically, ATX suppresses eosinophil accumulation via an autocrine feedback loop wherein ATX-LPA signaling negatively regulates activity of AP-1 transcription factor c-Jun, in turn suppressing expression of potent eosinophil chemoattractant CCL11 (Eotaxin-1). This is the first study that highlights the anti-tumor potential of eosinophils in pancreatic cancer. Citation Format: Sohinee Bhattacharyya, Chet Oon, Holly Sandborg, Terry Morgan, Mara H. Sherman. Autotaxin-lysolipid signaling suppresses a CCL11- eosinophil axis to promote pancreatic cancer progression [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 A025.

Abstract C054: Topographical investigation of metabolites in excised squares (TIMES2): Mapping in vivo of metabolic heterogeneity in pancreatic tumors

Abstract Background: Pancreatic cancer is a lethal malignancy characterized by complex intratumoral metabolic reprogramming and intercellular nutrient sharing between cells in the tumor microenvironment (TME) that promote pancreatic cancer progression. However, this crosstalk, as well as regional variation in perfusion and oxygenation, can lead to metabolic heterogeneity that has not been appreciated by metabolomics of whole tumors. Here we quantify amino acids and tricarboxylic acid cycle (TCA) intermediates using a novel methodology that allows us to portray global tumor metabolite heterogeneity in a tumor. Methods: Human PaTu-8902 or murine HY19636 (from female KPC mice p48-Cre+, KRASLSL-G12D/+, Trp53lox/+) pancreatic cancer cell lines were orthotopically injected into pancreata of NCr nude mice (n=3) or C57BL/6 mice (n=2). Mice were euthanized after 3-5 weeks and tumors were harvested. Tumor slices were further sectioned into 1mm x 1mm x 1mm cubes using a custom-made multisectional slicing device and each cube location was recorded. Each cube was extracted using methanol, water, and chloroform with labelled amino acid standards, derivitized, and resolved using gas chromatography-mass spectrometry (DB-35MS column with Agilent 7890B gas chromatograph coupled to a single quadrupole 5977B mass spectrometer). 22 metabolites (15 amino acids, 5 TCA intermediates, lactate, and pyruvate) were identified by unique fragments and retention time compared to known standards. Peaks were picked using OpenChrom and analyzed using MATLAB. Data was analyzed using Graphpad Prism. Principal Component Analysis (PCA) was visualized using Python on a Jupyter notebook. Results: Both orthotopic human and murine pancreatic tumors demonstrated striking levels of intratumoral metabolite heterogeneity. Glycine, glutamine, and proline were the amino acids with the highest coefficient of variance, while leucine, isoleucine, and serine had the lowest coefficient of variance. α-ketoglutarate and succinate were the TCA intermediates with highest coefficient of variance. Lactate had the lowest coefficient of variance among all examined metabolites. Spatial mapping of each metabolite demonstrated distinct regions with varying abundance levels of metabolites. PCA demonstrated 75% of variance was carried by PC1 and 10% carried by PC2. Conclusions: This study reveals insights into the degree of intratumoral heterogeneity present in pancreatic tumors that illustrate the difficulty of in vivo metabolomics analysis and suggest that high-resolution (single cell) metabolomics techniques will be critical to study metabolism in the complex TME. Citation Format: Peter Yu, Robert Banh, Stephen Martis, Douglas Biancur, Albert Sohn, Elaine Lin, Keisuke Yamamoto, Benjamin Greenbaum, Alec Kimmelman. Topographical investigation of metabolites in excised squares (TIMES2): Mapping in vivo of metabolic heterogeneity in pancreatic tumors [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 C054.

Abstract C093: Dysregulated spliceosomal components promote pancreatic cancer progression

Abstract Dysregulated RNA splicing factors have been widely reported in tumorigenesis, but their involvement in pancreatic ductal adenocarcinoma (PDAC) is not well understood. We found that two proteins involved in different stages of spliceosome assembly contribute to PDAC tumorigenesis by regulating alternative splicing, either through direct or indirect interaction with RNA. First, we showed that the splicing factor SRSF1—an RNA-binding protein involved in early spliceosome assembly—can induce pancreatitis and accelerate KRASG12D-mediated PDAC by activating the MAPK pathway. Moreover, the expression of SRSF1 decreased in morphologically normal pancreatic cells expressing KRASG12D to maintain cellular homeostasis. Second, we found that breast cancer amplified sequence 2 (BCAS2, also known as SPF27)—a spliceosome scaffold protein associated with conformational changes—also contributes to PDAC progression. Although BCAS2 does not bind RNA directly, it can regulate alternative splicing events in a sequence-specific manner by promoting the usage of specific 5’ splice sites. BCAS2 promotes the inclusion of exon 21, which has a weak 5' splice site, in the SOS Ras/Rac Guanine Nucleotide Exchange Factor 1 (SOS1) pre-mRNA, resulting in a more oncogenic isoform. These studies not only improve our understanding of the oncogenic role of aberrant alternative splicing, but also provide insights into the mechanisms of alternative-splicing regulation at different stages of spliceosome assembly. Citation Format: Ledong Wan, Kuan-Ting Lin, Mohammad A. Rahman, Yuma Ishigami, Alexander J. Kral, Dillon Voss, Zhikai Wang, Mads A. Jensen, John E. Wilkinson, Youngkyu Park, David A. Tuveson, Adrian R. Krainer. Dysregulated spliceosomal components promote pancreatic cancer progression [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 C093.

FBXO31 is upregulated by METTL3 to promote pancreatic cancer progression via regulating SIRT2 ubiquitination and degradation

FBXO31, a member of F-box family to comprise of SCF complex, contributes to a pivotal role in cancer progression. However, the possible involvements of FBXO31 in PC are unelucidated. Here, we reported that FBXO31 was overexpressed in PC patients, which was negatively associated with survival in PC patients. Furthermore, FBXO31 significantly enhanced growth, migration and invasion of PC cells in vitro. Consistently, FBXO31 overexpression promoted tumor growth in nude mice. Mechanistically, SIRT2 was a target of FBXO31 and interacted with FBXO31. Protein half-life and ubiquitination analysis demonstrated that FBXO31 promoted proteasome-dependent degradation of SIRT2. In addition, FBXO31 binds to sirtuin-type domain of SIRT2. Moreover, SIRT2 is required for the oncogenic role of FBXO31 in PC progression. Impressively, METTL3 induced m6A modification of FBXO31 and up-regulated FBXO31 expression, subsequently leading to SIRT2 down-regulation in PC cells. The results showed that METTL3 enhanced FBXO31 mRNA translation in YTHDF1-dependent manner. Taken together, we suggest that METTL3–FBXO31–SIRT2 axis was involved in PC tumorigenesis, which could identify new targets for PC treatment.

Pancreatic cancer progression and mortality predicted by depression and anxiety: a systematic review and meta-analysis protocol.

Although the relationship between psychological factors and pancreatic cancer outcomes has been widely discussed, controversy remains. We will for the first time systematically summarize the literature to explore the correlation of anxiety and depression to the prognosis of patients with pancreatic cancer. The findings will fill existing research gaps, informing healthcare providers about better psychological care and medical treatment. The following databases will be retrieved from their inception to July 2023: Cochrane Library, MEDLINE (PubMed), Web of Science, EMBASE, and four Chinese databases (Chinese National Knowledge Infrastructure, Wanfang Database, Chinese Biomedical Literature Database, and Chongqing VIP Chinese Science and Technology Periodical Database). The World Health Organization Clinical Trials Registry, Chinese Clinical Registry, and ClinicalTrials.gov will be searched to identify other related studies. A manual search will be performed to identify missing eligible studies based on the reference list of selected articles. The search will focus on studies published in Chinese or English. To assess the risk of bias in the selected articles, Newcastle-Ottawa Quality Assessment Scale (NOS) will be used for the cohort study. Funnel plots and Egger's test will be used to assess whether publication bias exists. Moreover, the Grading of Recommendations Assessment Development and Evaluation (GRADE) will be utilized to analyze the credibility of the results from selected articles. Two independent evaluators will implement the study selection and data extraction, as well as evaluate the risk of bias and evidence quality. Data will be analyzed using Stata 16.0. Trial registration: PROSPERO registration number is CRD42022366232.

Nudt21-mediated alternative polyadenylation of MZT1 3′UTR contributes to pancreatic cancer progression

Alternative polyadenylation (APA) is an important post-transcriptional regulatory mechanism and is involved in many diseases, but its function and mechanism in regulating pancreatic cancer (PC) pathogenesis remain unclear. In this study, we found that the 3' UTR shortening of MZT1 was the most prominent APA event in PC liver metastases. The short-3'UTR isoform exerted a stronger effect in promoting cell proliferation and migration both invitro and invivo. NUDT21, a core cleavage factor involved in APA, promoted the usage of proximal polyadenylation sites (PASs) on MZT1 mRNA by binding to the UGUA element located upstream of the proximal PAS. High percentage of distal polyA site usage index of MZT1 was significantly associated with a better prognosis. These findings demonstrate a crucial mechanism that NUDT21-mediated APA of MZT1 could promote the progression of PC. Our findings provided a better understanding of the connection between PC progression and APA machinery.

CREB activation drives acinar to ductal reprogramming and promote pancreatic cancer progression in animal models of alcoholic chronic pancreatitis.

In vivo induction of alcoholic chronic pancreatitis (ACP) causes significant acinar damage, increased fibroinflammatory response, and heightened activation of cyclic response element binding protein 1 (CREB) when compared with alcohol (A) or chronic pancreatitis (CP) mediated pancreatic damage. However, the study elucidating the cooperative interaction between CREB and the oncogenic Kras G12D/+ ( Kras* ) in promoting pancreatic cancer progression with ACP remains unexplored. Experimental ACP induction was established in multiple mouse models, followed by euthanization of the animals at various time intervals during the recovery periods. Tumor latency was determined in these mice cohorts. Here, we established CREB deletion ( Creb fl/fl ) in Ptf1a CreERTM/+ ;LSL-Kras G12D+/- (KC) genetic mouse models (KCC -/- ). Western blot, phosphokinase array, and qPCR were used to analyze the pancreata of Ptf1a CreERTM+/- , KC and KCC -/- mice. The pancreata of ACP-induced KC mice were subjected to single-cell RNA sequencing (scRNAseq). Further studies involved conducting lineage tracing and acinar cell explant cultures. ACP induction in KC mice had detrimental effects on the pancreatic damage repair mechanism. The persistent existence of acinar cell-derived ductal lesions demonstrated a prolonged state of hyperactivated CREB. Persistent CREB activation leads to acinar cell reprogramming and increased pro-fibrotic inflammation in KC mice. Acinar-specific Creb ablation reduced advanced PanINs lesions, hindered tumor progression, and restored acinar cell function in ACP-induced mouse models. Our findings demonstrate that CREB cooperates with Kras* to perpetuate an irreversible ADM and PanIN formation. Moreover, CREB sustains oncogenic activity to promote the progression of premalignant lesions toward cancer in the presence of ACP.

99mTc]Tc-labeled cyc-DX600-HYNIC as a SPECT probe for ACE2-specific pancreatic cancer imaging.

As a regulator in renin-angiotensin-aldosterone system, angiotensin-converting enzyme 2 (ACE2) closely correlated with tumor progression of pancreatic cancer, meantime, was easily affected by a variety of factors. [99mTc]Tc-cyc-DX600 SPECT was established as an ACE2-specific imaging protocol to figure out the ACE2 status in pancreatic tumor. BALB/C-NU mice were used to prepare the subcutaneous cell derived xenograft (CDX) models with HEK-293T or HEK-293T/hACE2 cells to validate ACE2 specificity of [99mTc]Tc-cyc-DX600 SPECT and establish SPECT imaging protocol. On the basis of [99mTc]Tc-cyc-DX600 SPECT and [18F]F-FDG PET/CT, ACE2-dependence on tumor size and tumor metabolism were further verified on orthotopic pancreatic cancer model with KPC cells. Immunohistochemical analysis was used to demonstrate the findings on ACE2 SPECT. [99mTc]Tc-cyc-DX600 was of superior tumor uptake in HEK-293T/hACE2 CDX than wild type (6.74 ± 0.31 %ID/mL vs 1.83 ± 0.26 %ID/mL at 1.5 h post injection (p.i.); 3.14 ± 0.31 %ID/mL vs 1.16 ± 0.15 %ID/mL at 4.5 h p.i.). For the CDX models with PANC-1 cells, a significant negative correlation between the slope of tumor volume and tumor uptake was observed (r = -0.382 for the 1-4th day; r = -0.146 for the 1-5th day; r = -0.114 for the 1-6th day; r = -0.152 for the 1-7th day; but P > 0.05 for all). For orthotopic pancreatic cancer model, the linear correlation between FDG PET and ACE2 SPECT of the pancreatic lesions was negative (r = -0.878), the quantitative values of ACE2 SPCET was positively correlated with the volume of primary lesions (r = 0.752) and also positively correlated with the quantitative values of ACE2 immunohistochemical analysis (r = 0.991). Conclusively, [99mTc]Tc-cyc-DX600 SPECT is an ACE2-specific imaging protocol with clinical translational potential, adding multidimensional information on the disease progression of pancreatic cancer.

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-Derived Immunoglobulin G and Pancreatic Cancer.

Immunoglobulin (Ig) is traditionally believed to be produced solely by B cells. Nonetheless, mounting evidence has demonstrated that various types of Igs are extensively expressed in many cell types. Among them, IgG is found to be highly expressed in cancer cells and is thus labeled as cancer-derived IgG. Cancer-derived IgG shares identical fundamental structures with B cell-derived IgG, but displays several unique characteristics, including restricted variable region sequences and unique glycosylation modifications for those expressed by epithelial cancers. Cancer-derived IgG plays multiple crucial roles in carcinogenesis, including facilitating cancer invasion and metastasis, enhancing cancer stemness, contributing to chemoresistance, and remodeling the tumour microenvironment. Recent studies have discovered that cancer-derived sialylated IgG (SIA-IgG) is extensively expressed in pancreatic cancer cells and is predominantly located in the cytoplasm and on the cell membrane. Cancer-derived IgG expressed by pancreatic cancer presents a restrictive variable region sequence and contains a unique sialylation site of the Fab region. Functionally, cancer-derived IgG participates in pancreatic cancer progression via different mechanisms, such as promoting proliferation, facilitating migration and invasion, resisting apoptosis, inducing inflammation, and modulating the tumour microenvironment. SIA-IgG has shown potential as a clinical biomarker. The expression of SIA-IgG is associated with poor tumour differentiation, metastasis, and chemoresistance in pancreatic cancer. High expression of SIA-IgG can serve as an independent prognostic factor for pancreatic cancer. Additionally, SIA-IgG expression elevated with malignant progression for the precursor lesions of pancreatic cancer. These findings present a prospect of applying cancer-derived IgG as a novel diagnostic and therapeutic target in the management of pancreatic cancer, and aiding in overcoming the challenge in the treatment of this stubborn malignancy.

Downregulation of miR-503-5p Promotes the Development of Pancreatic Cancer by Targeting Cyclin E2.

This study aimed to elucidate the role of microRNA-503 (miR-503) in pancreatic cancer (PC) progression and the underlying regulatory mechanisms. We acquired miR-503-3p and miR-503-5p expression data along with survival times of PC and normal samples from the UCSC Xena database. Using the t-test, we compared the expression of miR-503-3p and miR-503-5p between PC and normal samples, and evaluated their prognostic significance via Kaplan-Meier survival analysis. The expression of miR-503-5p in PC cells was detected by quantitative PCR. We subsequently overexpressed miR-503-5p in PC cells and examined cell viability, apoptosis, and migration through CCK8 assay, flow cytometry, and Transwell assay, respectively. Potential functional targets were identified using miRTarBase and validated by dual-luciferase reporter assay. Both miR-503-3p and miR-503-5p expression were found to be downregulated in PC; however, only miR-503-5p was linked to cancer prognosis based on public data. In vitro experiments demonstrated that overexpression of miR-503-5p substantially decreased cell viability, induced apoptosis, caused G0/G1 arrest, and inhibited cell migration. miR-503-5p was found to target cyclin E2 (CCNE2), and overexpression of CCNE2 could counteract the effects of miR-503-5p on PC cells. Conclusion: The downregulation of miR-503-5p enhances the progression of PC by targeting CCNE2. The detection of miR-503-5p expression may provide valuable insights for the prevention and prognostic evaluation of PC.

E74-like ETS transcription factor 1 promotes the progression of pancreatic cancer by regulating doublecortin-like kinase 1/Janus kinase/signal transducer and activator of transcription pathway

E74-like ETS transcription factor 1 promotes the progression of pancreatic cancer by regulating doublecortin-like kinase 1/Janus kinase/signal transducer and activator of transcription pathway

The small-molecule drug homoharringtonine targets HSF1 to suppress pancreatic cancer progression.

Heat shock factor 1 (HSF1), an essential transcription factor for stress response, is exploited by various tumors to facilitate their initiation, progression, invasion, and migration. Amplification of HSF1 is widely regarded as an indicator in predicting cancer severity, the likelihood of treatment failure and reduced patient survival. Notably, HSF1 is markedly amplified in 40% of pancreatic cancer (PC), which typically have limited treatment options. HSF1 has been proven to be a promising therapeutic target for multiple cancers. However, a direct small molecule HSF1 inhibitor with sufficient bioactivity and reliable safety has not been developed clinically. In this study, we successfully established a high-throughput screening system utilizing luciferase reporter assay specifically designed for HSF1, which leads to the discovery of a potent small molecule inhibitor targeting HSF1. Homoharringtonine (HHT) selectively inhibited PC cell viability with high HSF1 expression and induced a markedly stronger tumor regression effect in the subcutaneous xenograft model than the comparator drug KRIBB11, known for its direct action on HSF1. Moreover, HHT shows promise in countering the resistance encountered with HSP90 inhibitors, which have been observed to increase heat shock response intensity in clinical trials. Mechanistically, HHT directly bound to HSF1, suppressing its expression and thereby inhibiting transcription of HSF1 target genes. In conclusion, our work presents a preclinical discovery and validation for HHT as a HSF1 inhibitor for PC treatment.