Normal Pancreatic Ductal Cells Research Articles

RNF43 Inactivation Enhances the B-RAF/MEK Signaling and Creates a Combinatory Therapeutic Target in Cancer Cells.

RING finger 43 (RNF43), a RING-type E3 ubiquitin ligase, is a key regulator of WNT signaling and is mutated in 6-10% of pancreatic tumors. However, RNF43-mediated effects remain unclear, as only a few in vivo substrates of RNF43 are identified. Here, it is found that RNF43-mutated pancreatic cancer cells exhibit elevated B-RAF/MEK activity and are highly sensitive to MEK inhibitors. The depletion of RNF43 in normal pancreatic ductal cells also enhances MEK activation, suggesting that it is a physiologically regulated process. It is confirmed that RNF43 ubiquitinates B-RAF at K499 to promote proteasome-dependent degradation, resulting in reduced MEK activity and proliferative ability in cancer cells. In addition, phosphorylation of B-RAF at T491 suppresses B-RAF ubiquitination by decreasing the interaction between RNF43 and B-RAF. Mutations at K499 in B-RAF are identified in various cancer types. MEK and WNT inhibitors synergistically suppress the growth of RNF43-mutated pancreatic cancer cells in vitro and in vivo. Collectively, the research reveals a novel mechanism by which RNF43 inhibits B-RAF/MEK signaling to suppress tumor growth and provide a new strategy for the treatment of RNF43-inactivated pancreatic cancer.

Droplet-Based Glycan and RNA Sequencing for Profiling the Distinct Cellular Glyco-States in Single Cells.

Plate-based single-cell glycan and RNA sequencing (scGR-seq) is previously developed to realize the integrated analysis of glycome and transcriptome in single cells. However, the sample size is limited to only a few hundred cells. Here, a droplet-based scGR-seq is developed to address this issue by adopting a 10x Chromium platform to simultaneously profile ten thousand cells' glycome and transcriptome in single cells. To establish droplet-based scGR-seq, a comparative analysis of two distinct cell lines is performed: pancreatic ductal adenocarcinoma cells and normal pancreatic duct cells. Droplet-based scGR-seq revealed distinct glycan profiles between the two cell lines that showed a strong correlation with the results obtained by flow cytometry. Next, droplet-based scGR-seq is applied to a more complex sample: peripheral blood mononuclear cells (PBMC) containing various immune cells. The method can systematically map the glycan signature for each immune cell in PBMC as well as glycan alterations by cell lineage. Prediction of the association between the glycan expression and the gene expression using regression analysis ultimately leads to the identification of a glycan epitope that impacts cellular functions. In conclusion, the droplet-based scGR-seq realizes the high-throughput profiling of the distinct cellular glyco-states in single cells.

PCDH1, a poor prognostic biomarker and potential target for pancreatic adenocarcinoma metastatic therapy

BackgroundPancreatic adenocarcinoma (PAAD) is an aggressive solid tumour characterised by few early symptoms, high mortality, and lack of effective treatment. Therefore, it is important to identify new potential therapeutic targets and prognostic biomarkers of PAAD.MethodsThe Cancer Genome Atlas and Genotype-Tissue Expression databases were used to identify the expression and prognostic model of protocadherin 1 (PCDH1). The prognostic performance of risk factors and diagnosis of patients with PAAD were evaluated by regression analysis, nomogram, and receiver operating characteristic curve. Paraffin sections were collected from patients for immunohistochemistry (IHC) analysis. The expression of PCDH1 in cells obtained from primary tumours or metastatic biopsies was identified using single-cell RNA sequencing (scRNA-seq). Real-time quantitative polymerase chain reaction (qPCR) and western blotting were used to verify PCDH1 expression levels and the inhibitory effects of the compounds.ResultsThe RNA and protein levels of PCDH1 were significantly higher in PAAD cells than in normal pancreatic ductal cells, similar to those observed in tissue sections from patients with PAAD. Aberrant methylation of the CpG site cg19767205 and micro-RNA (miRNA) hsa-miR-124-1 may be important reasons for the high PCDH1 expression in PAAD. Up-regulated PCDH1 promotes pancreatic cancer cell metastasis. The RNA levels of PCDH1 were significantly down-regulated following flutamide treatment. Flutamide reduced the percentage of PCDH1 RNA level in PAAD cells Panc-0813 to < 50%. In addition, the PCDH1 protein was significantly down-regulated after Panc-0813 cells were incubated with 20 µM flutamide and proves to be a potential therapeutic intervention for PAAD.ConclusionPCDH1 is a key prognostic biomarker and promoter of PAAD metastasis. Additionally, flutamide may serve as a novel compound that down-regulates PCDH1 expression as a potential treatment for combating PAAD progression and metastasis.

B-233 Chromatin Accessibility Uncovers KRAS-driven FOSL2 Promoting Pancreatic Ductal Adenocarcinoma Progression Via Upregulating CCL28

Abstract Background Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal human cancer with 5-year survival rate less than 10%. Pancreatic cancer remains a malignancy of poor prognosis and effective therapies are lacking, therefore, studying the pathogenesis and identifying more therapeutic targets are urgently needed for PDAC treatment. The epigenetic mechanisms of PDAC progression are poorly understood. This study aims to identify key transcription factor (TF) by multiomics sequencing to explore the molecular mechanisms of TF with critical roles in PDAC. Methods we used ATAC-seq, H3K27ac ChIP-seq, and RNA-seq to characterized the epigenetic landscape by genetically engineered mouse models (GEMMs) of PDAC with or without KRAS and/or TP53 mutations. Survival of FOSL2 was assessed using Kaplan-Meier method and multivariate Cox regression analysis for patients with PDAC. We performed Cleavage Under Targets and Tagmentation (CUT&amp;Tag) to study the potential targets of FOSL2. CCK8, transwell migration and invasion, RT-qPCR, western blot, IHC, ChIP-qPCR, dual-luciferase reporter, and xenograft model assays were used to explore the functions and underlying mechanisms of FOSL2 in PDAC progression. Results We found that the epigenetic changes were involved in some immuno-suppressed signaling with PDAC progression. Also, we identified a critical regulator FOSL2 which showed enriched open chromatin, H3K27ac signal, and higher RNA expression in KC and KPC than WT. The high expression of FOSL2 was associated with poor prognosis of patients with PDAC. Single-cell RNA-seq data showed that FOSL2 expression was very low in T, B, and acinar cells, and enriched in endothelial, ductal cells and upregulated in cancerous ductal cells compared with normal pancreatic ductal cells. functionally, FOSL2 can not only promote the proliferation, migration and invasion of pancreatic cancer, but also inhibit tumor immunity such as reducing the infiltration of CD8+T cells and increasing the infiltration of regulatory T (Treg) cells.In terms of mechanism, we found that CCL28 was a key target gene of FOSL2 by CUT&amp;Tag sequencing. We confirmed that FOSL2 can regulate the expression of CCL28 by knockdown or overexpression of FOSL2 in vitro. ChIP-qPCR and dual luciferase reporter assays confirmed that FOSL2 activated the transcription of CCL28 by binding to the upstream of CCL28. In vivo mouse assay showed that FOSL2 promoted tumor growth and Treg cell recruitment through CCL28. We also explored the mechanism by which FOSL2 was upregulated in pancreatic cancer and found that KRAS mutation mediated FOSL2 transcription and subsequent CCL28 expression through the MAPK/ERK pathway, which implicated an immuno-suppressed regulatory axis of KRAS/MAPK-FOSL2-CCL28-Treg cells in PDAC development. Conclusion We described the changes of epigenetic landscape during PDAC progression and found that KRAS mutation promoted FOSL2 expression, which recruited more Treg cells by upregulating CCL28 and ultimately led to immunosuppression in pancreatic cancer. Targeting CCL28 with CCL28 antibody can reduce the invasion of Treg cells, which provides a new way to overcome the Treg cell-mediated tumor immune escape in patients with PDAC.

Necroptosis-Related Prognostic Model for Pancreatic Carcinoma Reveals Its Invasion and Metastasis Potential through Hybrid EMT and Immune Escape.

Necroptosis, pro-inflammatory programmed necrosis, has been reported to exert momentous roles in pancreatic cancer (PC). Herein, the objective of this study is to construct a necroptosis-related prognostic model for detecting pancreatic cancer. In this study, the intersection between necroptosis-related genes and differentially expressed genes (DEGs) of pancreatic ductal adenocarcinoma (PDAC) was obtained based on GeneCards database, GEO database (GSE28735 and GSE15471), and verified using The Cancer Genome Atlas (TCGA). Next, a prognostic model with Cox and LASSO regression analysis, and divided the patients into high-risk and low-risk groups. Subsequently, the Kaplan-Meier (KM) survival curve and the receiver operating characteristic (ROC) curves were generated to assess the predictive ability of overall survival (OS) of PC patients. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed to predict the potential biofunction and possible mechanical pathways. The EMTome database and an immune analysis were applied to further explore underlying mechanism. Finally, clinical samples of PDAC patients were utilized to verify the expression of model genes via immunohistochemistry (IHC), and the normal human pancreatic ductal cell line, hTERT-HPNE as well as human pancreatic ductal carcinoma cell lines, PANC-1 and PL45, were used to identify the levels of model genes by Western blot (WB) and immunofluorescence (IF) in vitro. The results showed that 13 necroptosis-related DEGs (NRDEGs) were screened based on GEO database, and finally four of five prognostic genes, including KRT7, KRT19, IGF2BP3, CXCL5, were further identified by TCGA to successfully construct a prognostic model. Univariate and multivariate Cox analysis ultimately confirmed that this prognostic model has independent prognostic significance, KM curve suggested that the OS of low-risk group was longer than high-risk group, and the area under receiver (AUC) of ROC for 1, 3, 5 years was 0.733, 0.749 and 0.667, respectively. A GO analysis illustrated that model genes may participate in cell-cell junction, cadherin binding, cell adhesion molecule binding, and neutrophil migration and chemotaxis, while KEGG showed involvement in PI3K-Akt signaling pathway, ECMreceptor interaction, IL-17 signaling pathway, TNF signaling pathway, etc. Moreover, our results showed KRT7 and KRT19 were closely related to EMT markers, and EMTome database manifested that KRT7 and KRT19 are highly expressed in both primary and metastatic pancreatic cancer, declaring that model genes promoted invasion and metastasis potential through EMT. In addition, four model genes were positively correlated with Th2, which has been reported to take part in promoting immune escape, while model genes except CXCL5 were negatively correlated with TFH cells, indicating that model genes may participate in immunity. Additionally, IHC results showed that model genes were higher expressed in PC tissues than that in adjacent tumor tissues, and WB and IF also suggested that model genes were more highly expressed in PANC-1 and PL45 than in hTERT-HPNE. Tracing of a necroptosis-related prognostic model for pancreatic carcinoma reveals its invasion and metastasis potential through EMT and immunity. The construction of this model and the possible mechanism of necroptosis in PDAC was preliminarily explored to provide reliable new biomarkers for the early diagnosis, treatment, and prognosis for pancreatic cancer patients.

Abstract B046: Restricted cellular plasticity of human pancreatic ductal cells into a pluripotent state

Abstract Cancer cells undergo plasticity against stress for the survival of the fittest. Pancreatic ductal adenocarcinoma (PDAC) also shows intratumoral transcriptional heterogeneity with cell plasticity, which correlates with phenotypical aggressiveness and therapeutic resistance. Cell fates are determined by master transcription factors (TFs, also called “pioneer factors”) and their co-factors by opening up chromatin and establishing competence for gene expression specific to each cell type during normal development. Force expression of various combinations of pioneer factors can switch cell fate into other lineages, including induced pluripotent stem cells (“iPSC”). Since pluripotent stem cells do not have the cancer hallmarks of uncontrolled cell growth and migration, hypothetically, a fully reprogrammed cancer iPSC should regain gene programs to control these hallmarks of cancer. Thus, we and others have reprogrammed cancer cells into pluripotent stem cell-like cells by introducing pluripotent pioneer factors. However, intriguingly, despite the nature of the high plasticity of cancer, complete reprogramming of cancers to a pluripotent state is impeded in most cases, enabling us to study and model cancer progression. Our further studies confirm that, upon reprogramming, most PDAC cells lose the original PDAC phenotypes to some extent but remain in plasticity states during reprogramming. Herein, we further update on our efforts to optimize the reprogramming of normal pancreatic ductal epithelial cell line (PDEC) and PDAC derived from patients through the Sendai virus, which can most robustly transfer genes regardless of cell types. While control cells (e.g., acinar cells and fibroblast) were fully reprogrammed into iPSC cells, both PDEC and PDAC were impeded from being fully reprogrammed into pluripotency. Intriguingly, a subset of normal PDEC cells as well as some PDAC cell acquired a “partial reprogramming marker” upon reprogramming, suggesting that PDEC cells are stalled in early developmental states. Therefore, we now conclude that normal and cancerous pancreatic ductal cell states have an intrinsic mechanism that blocks complete reprogramming into a pluripotent state, and the oncogenic pathway is poised for activation, despite the nature of the high plasticity of PDAC. Identifying the factors responsible for maintaining this impenetrable cancer chromatin landscape is ideal for nominating therapeutic targets for intercepting PDAC plasticity. This work is supported by OHSU/CEDAR project award 68182-939-000. Citation Format: Dmytro Grygoryev, Taelor Ekstrom, Jason M. Link, Rosalie C. Sears, Jungsun Kim. Restricted cellular plasticity of human pancreatic ductal cells into a pluripotent state [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr B046.

Abstract A077: PancreaCult™ Organoid Medium Kits support the robust establishment and expansion of human pancreatic duct organoids

Abstract Organoid culture is a novel in vitro culture method that promotes the growth of primary and PSC-derived cells in three-dimensional culture to generate structures that recapitulate tissue morphology. We have developed PancreaCult™ Organoid Medium Kits (Human), which combine PancreaCult™ Organoid Initiation Medium (OIM) and serum-free PancreaCult™ Organoid Growth Medium (OGM) into a robust and standardized workflow for the establishment and expansion of pancreatic duct organoids. To establish organoids, fresh or cryopreserved islet-depleted exocrine tissue was seeded in Corning® Matrigel® domes and cultured in PancreaCult™ OIM. After 3 days, the medium was changed to PancreaCult™ OGM and the organoids were passaged and maintained in this medium thereafter, and passaged as fragments every 4 - 7 days. Organoids were successfully established from all 5 donors with a 2- to 6-fold expansion in cell numbers every 7 - 14 days. Real-time PCR and immunocytochemistry demonstrated that these organoids express pancreatic duct markers (PDX1, SOX9, KRT19, CFTR, CA2, and MUC1), as well as proliferation and stem cell markers, Ki-67 and LGR5, respectively. Pancreatic duct organoids could be maintained for at least 10 passages (n = 3) and cryopreserved as fragments that could be used for rapid re-establishment of cultures at later time points. Organoids could also be dissociated and re-seeded in Prostaglandin E2-free PancreaCult™ OGM supplemented with ROCK inhibitor, Y-27632 and 10% FBS on Transwell® inserts to create 2D monolayers. In addition to normal pancreatic duct cultures, PancreaCult™ OGM supported the efficient long-term expansion of 4 pre-established pancreatic ductal adenocarcinoma (PDAC) organoid lines and maintained the mutational profile of the parent line after 5 passages, as determined through whole exome sequencing of 29 cancer-associated genes. Through the optional removal of epidermal growth factor (EGF), PancreaCult™ OGM can be modified to suppress normal cell growth to select for tumor cells with activating KRAS mutations. Our results demonstrate that PancreaCult™ Organoid Medium Kits provide a robust and flexible in vitro culture system for the establishment and expansion of normal pancreatic duct cells, as well as the long-term expansion of PDAC organoids. Citation Format: Nina Quiskamp, Angela Tsai, Joanna Pan, Misha Hasan, George Chang, Isabella T. Tai, Allen C. Eaves, Sharon A. Louis, Ryan K. Conder. PancreaCult™ Organoid Medium Kits support the robust establishment and expansion of human pancreatic duct organoids [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr A077.

Exosomal miR-485-3p derived from pancreatic ductal epithelial cells inhibits pancreatic cancer metastasis through targeting PAK1.

Cell competition is an important feature in pancreatic cancer (PC) progression, but the underlying mechanism remains elusive. This study aims to explore the role of exosomes derived from normal pancreatic ductal epithelial cells involved in PC progression. PC cells and pancreatic stellate cells (PSCs) were treated with exosomes isolated from pancreatic ductal epithelial cells. Cell proliferation was assessed by CCK8 assays. Cell migration and invasion were assessed by Transwell assays. PC and matched adjacent non-tumor tissue specimens were obtained from 46 patients pathologically diagnosed with PC at Peking University First Hospital from 2013 to 2017. Tissue miR-485-3p and p21-activated kinase-1 (PAK1) expression was examined by real-time polymerase chain reaction (RT-PCR), and the relationship of the two was analyzed using Pearman's product-moment correlation. The clinical significance of miR-485-3p was analyzed using the Chi-square test, Wilcoxon rank-sum test, and Fisher exact probability, respectively. The binding of miR-485-3p to PAK1 5'-untranslated region (5'-UTR) was examined by luciferase assay. PC cells were xenografted into nude mice as a PC metastasis model. Exosomes from pancreatic ductal epithelial cells suppressed PC cell migration and invasion as well as the secretion and migration of PSCs. MiR-485-3p was enriched in the exosomes of pancreatic ductal epithelial cells but deficient in those of PC cells and PSCs, in accordance with the lower level in PSCs and PC cells than that in pancreatic ductal cells. And the mature miR-485-3p could be delivered into these cells by the exosomes secreted by normal pancreatic duct cells, to inhibit PC cell migration and invasion. Clinical data analysis showed that miR-485-3p was significantly decreased in PC tissues (P < 0.05) and was negatively associated with lymphovascular invasion (P = 0.044). As a direct target of miR-485-3p, PAK1 was found to exert an inhibitory effect on PC cells, and there was a significantly negative correlation between the expression levels of miR-485-3p and PAK1 (r = -0.6525, P < 0.0001) in PC tissues. Moreover, miR-485-3p could suppress PC metastasis in vivo by targeting p21-activated kinase-1. Exosomal miR-485-3p delivered by normal pancreatic ductal epithelial cells into PC cells inhibits PC metastasis by directly targeting PAK1. The restoration of miR-485-3p by exosomes or some other vehicle might be a novel approach for PC treatment.

Spectral Library-Based Single-Cell Proteomics Resolves Cellular Heterogeneity.

Dissecting the proteome of cell types and states at single-cell resolution, while being highly challenging, has significant implications in basic science and biomedicine. Mass spectrometry (MS)-based single-cell proteomics represents an emerging technology for system-wide, unbiased profiling of proteins in single cells. However, significant challenges remain in analyzing an extremely small amount of proteins collected from a single cell, as a proteome-wide amplification of proteins is not currently feasible. Here, we report an integrated spectral library-based single-cell proteomics (SLB-SCP) platform that is ultrasensitive and well suited for a large-scale analysis. To overcome the low MS/MS signal intensity intrinsically associated with a single-cell analysis, this approach takes an alternative approach by extracting a breadth of information that specifically defines the physicochemical characteristics of a peptide from MS1 spectra, including monoisotopic mass, isotopic distribution, and retention time (hydrophobicity), and uses a spectral library for proteomic identification. This conceptually unique MS platform, coupled with the DIRECT sample preparation method, enabled identification of more than 2000 proteins in a single cell to distinguish different proteome landscapes associated with cellular types and heterogeneity. We characterized individual normal and cancerous pancreatic ductal cells (HPDE and PANC-1, respectively) and demonstrated the substantial difference in the proteomes between HPDE and PANC-1 at the single-cell level. A significant upregulation of multiple protein networks in cancer hallmarks was identified in the PANC-1 cells, functionally discriminating the PANC-1 cells from the HPDE cells. This integrated platform can be built on high-resolution MS and widely accepted proteomic software, making it possible for community-wide applications.

KNTC1 as a putative tumor oncogene in pancreatic cancer

PurposeRecent studies have demonstrated that kinetochore-associated protein 1 (KNTC1) plays a significant role in the carcinogenesis of numerous types of cancer. This study aimed to explore the role and possible mechanisms of KNTC1 in the development of pancreatic cancer.Methods and resultsWe analyzed differentially expressed genes by RNA sequencing in three paired pancreatic cancer and para-cancerous tissue samples and found that the expression of KNTC1 was significantly upregulated in pancreatic cancer. A Cancer and Tumor Gene Map pan-analysis showed that high expression of KNTC1 was related to poor prognosis in 9499 tumor samples. With immunohistochemical staining, we found that the high expression of KNTC1 in pancreatic cancer was related to pathological grade and clinical prognosis. Similarly, RT-PCR results indicated that the expression of KNTC1 was higher in three groups of pancreatic cancer cell lines (BxPC-3, PANC-1, and SW1990) than in normal pancreatic ductal cells. We introduced lentivirus-mediated shRNA targeting KNTC1 into PANC-1 and SW1990 cells and found that KNTC1 knockdown significantly decreased cell growth and increased cell apoptosis compared to the control group cells. Bioinformatic analysis of the cell expression profile revealed that differential genes were mainly enriched in the cell cycle, mitosis, and STAT3 signaling pathways, and co-immunoprecipitation confirmed an interaction between KNTC1 and cell division cycle associated 8.ConclusionsKNTC1 could be linked to the pathophysiology of pancreatic cancer and may be an early diagnostic marker of cervical precancerous lesions.

Targeting ASCT2-mediated glutamine metabolism inhibits proliferation and promotes apoptosis of pancreatic cancer cells.

Some tumor cells have a high rate of glutamine uptake and exhibit glutamine addiction. Alanine-serine cysteine-preferring transporter 2 (ASCT2) is a major mediator of glutamine supply in many tumor cells, but the underlying effects and mechanisms of ASCT2 in pancreatic cancer (PC) are largely unknown. Our results show that ASCT2 expression is significantly higher in PC than in normal pancreatic duct cells and pancreas. Utilizing the Kaplan–Meier Plotter database, a high expression of SLC1A5 mRNA was significantly associated with poor overall survival (OS) in patients with PC. shRNA-mediated inhibition of ASCT2 function in vitro can significantly decrease glutamine consumption, α-ketoglutarate (α-KG) production and ATP generation and increase the reactive oxygen species (ROS) level. Moreover, the antioxidant N-acetylcysteine partially attenuated the increase in the ROS levels and reduced ATP generation. These data suggest that ASCT2 mediates glutamine metabolism and maintains redox homeostasis in PC. To further investigate whether ASCT2 is involved in PC cell growth, we blocked ASCT2 activity with the ASCT2 inhibitor l-γ-glutamyl-p-nitroanilide (GPNA) and silenced the expression of ASCT2 with specific shRNAs. We found that the growth of PC cells was significantly inhibited. Additionally, knockdown of ASCT2 induced apoptosis through the Akt/mTOR signaling pathway. Furthermore, the loss of ASCT2 in BxPC-3 cell xenografts significantly inhibited tumor growth in vivo, and this effect was associated with an increase in cleaved caspase-3 expression and a decrease in Ki67 staining. Taken together, our results show that ASCT2 may be utilized as a putative therapeutic target for PC.

CircRNF13 Promotes the Malignant Progression of Pancreatic Cancer through Targeting miR-139-5p/IGF1R Axis.

Background Mounting evidence has shown circular RNAs (circRNAs) play an important role in the initiation and progression of pancreatic cancer (PC). Meanwhile, circRNAs may serve as the biomarkers for the diagnosis, treatment, and prognosis of PC. Therefore, it is urgent to elucidate the function and underlying mechanism of circRNAs in the development of PC. Methods The Cancer-Specific CircRNA Database (CSCD), Circular RNA Interactome database (circinteractome database), and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) were used to verify the expression level of circRNF13 in PC cell lines. Fluorescence in situ hybridization (FISH) and RNase protection assay were used to detect the localization and structure of circRNF13. Then, cell functional experiments were employed to estimate the proliferated, migrated, and invasive abilities in PC. Furthermore, bioinformatic tools, luciferase dual reporter assay, and RT-qPCR were used to investigate the interaction among circRNF13, miR-139-5p, and IGF1R. Eventually, the rescue functional experiments were employed to confirm that circRNF13 targeted the miR-139-5p/IGF1R axis to participate in the development of PC. Results CircRNF13 was overexpressed in PC cell lines compared with the normal pancreatic duct cell line. Additionally, inhibition of circRNF13 impaired the proliferation, migration, and invasion of PC cells. CircRNF13 could serve as the molecular sponge of miR-139-5p to inhibit its association with IGF1R that eventually accelerated the malignant progression of PC. Conclusion CircRNF13 serves as a competitive endogenous RNA of IGF1R to inhibit the function of miR-139-5p that eventually reinforces the malignant phenotype of PC.

Abstract PO-067: A multi-omics study in patient-derived organoids reveals MNX1-HNF1B axis to be indispensable for intraductal mucinous papillary neoplasm lineages

Abstract Chromatin architecture governs cell lineages by regulating the specific gene expression; however, its role in the diversity of cancer development remains unknown. Among pancreatic cancers, pancreatic ductal adenocarcinoma (PDAC) and invasive carcinoma with an associated intraductal papillary mucinous neoplasms (invasive IPMNs) arise from two distinct precursors, and their fundamental differences remain obscure. Here, we hypothesized that chromatin profiles may clarify their intrinsic molecular features. We originally established 28 human organoids from distinct subtypes of pancreatic tumors, including IPMN, invasive IPMN, and PDAC as well as from normal ductal cells and performed exome-seq, RNA-seq, ATAC-seq, ChIP-seq, Hi-C, and phenotypic analyses with shRNA or CRISPR interference. Established organoids successfully reproduced the histology of primary tumors. IPMN and invasive IPMN organoids specifically harbored GNAS, RNF43, and KLF4 mutations and showed the distinct lineage related expression profiles compared to PDAC. In addition, chromatin accessibility profiles well stratified the respective tumor groups. Notably, this analysis supported the histological features of tumor subtypes; gastric IPMN gained the stomach-specific accessible regions and the accessible pattern of invasive IPMN linked to diverse gastrointestinal tissues. In contrast, PDAC was characterized by the significant loss of chromatin accessibility seen in normal pancreatic ductal cells. Footprint analysis of transcription factors (TFs) identified specific TFs that are enriched in each tumor subtype. Of note we found the footprint of HNF1B to be active in IPMN lineages but not in PDAC. To address its biological significance, we analyzed the effects of HNF1B by knockdown (KD) experiments and revealed that HNF1B is biologically indispensable for IPMN lineages. We further identified MNX1 as an upstream regulator of HNF1B expression, another TF expressed in multipotent pancreatic progenitor cells. ChIP experiment revealed the enriched binding of MNX1 on the promoter elements of HNF1B in invasive IPMN. Importantly, KD or CRISPR interference of MNX1 impaired the survival of the organoids from invasive IPMN. Moreover, the correlated and high expression patterns of MNX1 and HNF1B in IPMN lineages were validated in a set of human tissues. To identify the common downstream genes of MNX1 and HNF1B, we analyzed RNA-seq and ATAC-seq after KD of the two genes. We found that MNX1-HNF1B axis governed a set of genes including MYC, SOX9, and OLFM4, which are known to regulate stem cell properties in gastrointestinal epithelium. Lastly, to get a broader view of chromatin architecture in these tumors, we performed Hi-C. We found that HNF1B target genes to be three-dimensionally condensed in the genome of invasive IPMN but not in that of PDAC, supporting the functional importance of those genes in invasive IPMN. Collectively, our organoid analyses unraveled the different lineage related chromatin structures correlating to the specific biological behaviors in pancreatic tumor subtypes. Citation Format: Hiroyuki Kato, Keisuke Tateishi, Keisuke Yamamoto, Dousuke Iwadate, Hiroaki Fujiwara, Takuma Nakatsuka, Koji Miyabayashi, Yotaro Kudo, Ijichi Hideaki, Kazuhiko Koike, Mitsuhiro Fujishiro. A multi-omics study in patient-derived organoids reveals MNX1-HNF1B axis to be indispensable for intraductal mucinous papillary neoplasm lineages [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2021 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2021;81(22 Suppl):Abstract nr PO-067.

Carcinoembryonic antigen as a specific glycoprotein ligand of rBC2LCN lectin on pancreatic ductal adenocarcinoma cells

The rBC2LCN lectin, known as a stem cell marker probe that binds to an H type 3 fucosylated trisaccharide motif, was recently revealed to also bind to pancreatic ductal adenocarcinoma (PDAC) cells. A lectin‐drug conjugate was generated by fusing rBC2LCN with a cytocidal toxin, and it showed a strong anticancer effect in in vitro and in vivo PDAC models. However, it is unclear which molecules are carrier proteins of rBC2LCN on PDAC cells. In this study, we identified a rBC2LCN‐positive glycoprotein expressed in PDAC. Tumor lysates of PDAC patient‐derived xenografts (PDXs) were coprecipitated with rBC2LCN lectin and analyzed by liquid chromatography–mass spectrometry. A total of 343 proteins were initially identified. We used a web‐based database to select five glycoproteins and independently evaluated their expression in PDAC by immunohistochemistry (IHC). Among them, we focused on carcinoembryonic antigen 5 (CEA) as the most cancer‐specific carrier protein in PDAC, as it showed the most prominent difference in expression rate between PDAC cells (74%) and normal pancreatic duct cells (0%, P > .0001). rBC2LCN lectin and CEA colocalization in PDAC samples was confirmed by double‐staining analysis. Furthermore, rBC2LCN‐precipitated fractions were blotted with an anti‐CEA polyclonal antibody (pAb), and CEA pAb–precipitated fractions were blotted with rBC2LCN lectin. The results demonstrate that CEA is in fact a ligand of rBC2LCN lectin.

Proteomic Investigation of Glyceraldehyde-Derived Intracellular AGEs and Their Potential Influence on Pancreatic Ductal Cells.

Glyceraldehyde-derived advanced glycation end products (AGEs) play an important role in the pathogenesis of many diseases including cancer. Accumulation of intracellular AGEs could stimulate cancer induction and facilitate cancer progression. We evaluated the toxic effect of glyceraldehyde-derived intracellular AGEs on normal and malignant pancreatic ductal cells by assessing the cell viability, toxicity, and oxidative stress, followed by proteomic analysis. Our functional studies showed that pancreatic cancer cells (PANC-1 and MIA PaCa-2) were more resistant to glyceraldehyde treatment compared to normal pancreatic ductal epithelial cells (HPDE), while cytotoxicity effects were observed in all cell types. Furthermore, using 13C isotopic labeled glyceraldehyde, the proteomic data revealed a dose-dependent increment of the number of glycation adducts in both these cell types. HPDE cells showed a higher number of intracellular AGEs compared to cancer cells. At a molecular level, the glycations in the lysine residues of proteins showed a concurrent increase with the concentration of the glyceraldehyde treatment, while the arginine glycations appeared to be less affected by the glyceraldehyde doses. Further pathway analysis of these glycated proteins suggested that the glycated proteins participate in important biological processes that are major hallmarks of cancer initiation and progression, including metabolic processes, immune response, oxidative stress, apoptosis, and S100 protein binding.

Upregulated MicroRNA-483-3p is an Early Event in Pancreatic Ductal Adenocarcinoma (PDAC) and as a Powerful Liquid Biopsy Biomarker in PDAC.

BackgroundThere is an urgent need for the development of effective noninvasive biomarkers for early pancreatic cancer diagnosis. MicroRNAs (miRNAs) are promising candidates that can be identified in peripheral blood and can act as “liquid biopsy” biomarkers. miR-483-3p is overexpressed in the tumor tissue of pancreatic duct adenocarcinoma, but its potential as noninvasive biomarker remains unknown.MethodsWe conducted locked nucleic acid in situ hybridization (LNA-ISH) for miR-483-3p in archival tissues of 107 patients with PDAC. We also used immunohistochemistry to evaluate SMAD4 expression, the putative miR-483-3p target gene. miR-483-3p expression level was also assessed using quantitative real-time PCR (qRT-PCR) in serum and serum exosome samples from 63 patients with PDAC and 22 healthy individuals.ResultsLNA-ISH showed that miR-483-3p was overexpressed in PDAC and PanIN tissues compared to normal pancreatic duct cells. miR-483-3p expression levels correlated with increases in PanIN lesion grade. miR-483-3p expression negatively correlated with Smad4 expression (γ=−0.770, p<0.0001) in PDAC and PanIN tissues. Circulating miR-483-3p levels were significantly elevated in the serum and serum exosomes of PDAC patients compared to healthy controls (p<0.0001 and p<0.01, respectively). Specifically, serum miR-483-3p levels were able to distinguish patients with early stage (≤2cm) PDAC from healthy controls with an AUC of 0.83 [95% CI, 0.70–0.96]. Higher serum exosomal miR-483-3p levels predicted worse survival in PDAC patients and serum exosomal miR-483-3p also proved to be an independent prognostic factor for PDAC (hazard ratio = 3.307; 95% CI=1.104 to 9.903; p=0.033). In vitro studies also showed that miR-483-3p promoted pancreatic cancer cell migration and invasion.ConclusionmiR-483-3p overexpression occurs early in PDAC development and is present in premalignant PanIN lesions. Serum miR-483-3p may act as an early PDAC diagnostic biomarker and serum exosomal miR-483-3p may be a PDAC prognostic biomarker.

DNA damage induced by KP372-1 hyperactivates PARP1 and enhances lethality of pancreatic cancer cells with PARP inhibition

The overall prognosis for pancreatic cancer remains dismal and potent chemotherapeutic agents that selectively target this cancer are critically needed. Elevated expression of NAD(P)H:quinone oxidoreductase 1 (NQO1) is frequent in pancreatic cancer, and it offers promising tumor-selective targeting. Recently, KP372-1 was identified as a novel NQO1 redox cycling agent that induces cytotoxicity in cancer cells by creating redox imbalance; however, the mechanistic basis of KP372-1-induced cytotoxicity remains elusive. Here, we show that KP372-1 sensitizes NQO1-expressing pancreatic cancer cells and spares immortalized normal pancreatic duct cells, hTERT-HPNE. Notably, we found that KP372-1 is ~ 10- to 20-fold more potent than β-lapachone, another NQO1 substrate, against pancreatic cancer cells. Mechanistically, our data strongly suggest that reactive oxygen species produced by NQO1-dependent redox cycling of KP372-1 cause robust DNA damage, including DNA breaks. Furthermore, we found that KP372-1-induced DNA damage hyperactivates the central DNA damage sensor protein poly(ADP-ribose) polymerase 1 (PARP1) and activates caspase-3 to initiate cell death. Our data also show that the combination of KP372-1 with PARP inhibition creates enhanced cytotoxicity in pancreatic cancer cells. Collectively, our study provides mechanistic insights into the cytotoxicity instigated by KP372-1 and lays an essential foundation to establish it as a promising chemotherapeutic agent against cancer.

Derivation of normal pancreatic duct cells from human primary tissue and their stepwise genetic modification in vitro

Derivation of normal pancreatic duct cells from human primary tissue and their stepwise genetic modification in vitro

Trefoil Factor 2 Regulates Proliferation and Apoptosis of Pancreatic Cancer Cells and LPS-Induced Normal Pancreatic Duct Cells by β-Catenin Pathway.

IntroductionPancreatic cancer (PC) is a malignant tumor with poor prognosis. This study aimed to determine the role of trefoil factor 2 (TFF2) in the proliferation and apoptosis of LPS-induced normal pancreatic duct cells and pancreatic cancer cells through β-catenin pathway.MethodsTFF2 expression in normal pancreatic duct cells, pancreatic cancer cells and LPS-induced normal pancreatic duct cells was detected by RT-qPCR analysis and Western blot analysis. The transfection effects in pancreatic cancer cells and LPS-induced normal pancreatic duct cells were analyzed by RT-qPCR analysis. After indicated transfection, proliferation, apoptosis and inflammation of these cells were respectively detected by CCK-8 assay, TUNEL assay and certain ELISA kits. Expression of β-catenin pathway-related proteins was analyzed by Western blot analysis. Co-immunoprecipitation assay determined the combination of TFF2 and β-catenin.ResultsTFF2 expression was increased in pancreatic cancer cells and LPS-induced HPDE cells compared with HPDE cells. According to TFF2 expression in these cells, PanC-1 cells and 5 μg/mL LPS were selected. In addition, TFF2 interference decreased the proliferation and promoted the apoptosis of PanC-1 cells and LPS-induced HPDE cells. However, TFF2 interference did not obviously change the levels of TNF-α, IL-1β and IL-6 in PanC-1 cells and LPS-induced HPDE cells. Furthermore, TFF2 interference suppressed the expression of β-catenin, c-Myc, Cyclin D1 and BIRC5 in PanC-1 cells and LPS-induced HPDE cells. TFF2 was demonstrated to combine with β-catenin.DiscussionTFF2 interference inhibits proliferation and promotes apoptosis of PanC-1 cells and LPS-induced HPDE cells by suppressing β-catenin pathway.

2019P - Protein tyrosine phosphatase non-receptor type 3 (PTPN3) could be a new therapeutic target for pancreatic cancer

BackgroundPancreatic cancer (PC) is a refractory disease and we have not an effective therapeutic strategy yet. Therefore, the development of a new therapeutic procedure is urgently required. Recently, protein tyrosine phosphatase (PTP) has been attracted as a new therapeutic target for some types of cancers. However, the biological significance of PTP in PC has never been elucidated yet. In the present study, to develop effective therapeutic strategy for refractory PC, the biological significance of PTP non-receptor type 3 (PTPN3) in PC is investigated. MethodsThree pancreatic ductal adenocarcinoma cell (PDAC) lines were used as target cells. Inhibition or overexpression of PTPN3 was performed using PTPN3 siRNA/shRNA and plasmid, respectively. Protein expression was analyzed by western blot and immunostaining. Proliferation assay was performed by MTT assay. Migration and invasion were estimated by time-lapse imaging and matrigel invasion assay. Mice xenograft experiments were performed using BALB/c nude mice. Twenty-three surgically resected human PC specimens were used for immunostaining. Results1) PTPN3 is highly expressed in PC cells compared to that in normal pancreatic duct cells by immunostaining. 2) Inhibition of PTPN3 significantly decreased migration and invasion in PDAC through inhibition of epithelial mesenchymal transition (EMT) and matrix metalloproteinase (MMP)-2 expression. 3) PTPN3 inhibition significantly decreased proliferation in vitro in PDAC. 4) PTPN3 overexpression led to increased proliferation, migration and invasion in PDAC. 5) Tumor volume in mice injected with PTPN3-inhibited PDAC was significantly lower than that in control mice. The expressions of Ki-67 and VEGF in PTPN3-inhibited PDAC were lower than those in control. 6) Signaling from PTPN3 was through PI3K and MAPK signaling pathways. 7) When intensity of PTPN3 expression was divided into 2 groups; weak and strong, intensity of PTPN3 expression was positively correlated with tumor size (T factor) and clinical staging. ConclusionsThese results suggest that PTPN3 contributes to the induction of malignant phenotypes of pancreatic cancer and that PTPN3 could be a new effective and specific therapeutic target for PC. Legal entity responsible for the studyKyushu University Hospital, Cancer Therapy and Research. FundingHas not received any funding. DisclosureAll authors have declared no conflicts of interest.