Pancreatic Ductal Adenocarcinoma Tumor Tissues Research Articles

Circular RNA circTMEM59 inhibits progression of pancreatic ductal adenocarcinoma by targeting miR-147b/SOCS1: An in vitro study

PurposeThis study aimed to detect the role and mechanism of circTMEM59 in pancreatic ductal adenocarcinoma (PDAC). Methods66 paired PDAC tissues and normal samples were harvested from patients diagnosed and undergoing pancreatic cancer surgery in our hospital. The expression of circTMEM59 in PDAC tissues and cell lines was detected. Based on bioinformatics information, the circTMEM59 mimics, miR-147b mimics, miR-147b inhibitor and si-suppressor of cytokine signaling 1 (SOCS1) were transfected into PDAC cells. The expression levels of circTMEM59, miR-147b and SOCS1 were detected by quantitative real-time polymerase chain reaction (qRT-PCR). RNA interaction was confirmed by dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. Cell invasion and proliferation were evaluated by Transwell and Cell Counting Kit-8 (CCK-8) assays. The protein expression was detected by Western blot. ResultsCircTMEM59 was confirmed to be downregulated in PDAC tumor tissues and cells. Low expression of circTMEM59 was closely correlated with the short survival time and poor clinicopathological characteristics. By up-regulating the expression of circTMEM59 in PDAC cells, cell proliferation, invasion and epithelial-mesenchymal transition (EMT) were inhibited. More importantly, miR-147b could be sponged by circTMEM59, and knockdown of miR-147b inhibited progression of PDAC cells. Further study revealed that SOCS1 was targeted by miR-147b. SOCS1 expression was negatively related to miR-147b expression and positively related to circTMEM59 expression in PDAC tissues. Upregulated miR-147b and downregulated SOCS1 could rescue the effects of circTMEM59 on cell proliferation, EMT and invasion. ConclusionOur data indicated that circTMEM59 inhibited cell proliferation, invasion and EMT of PDAC by regulating miR-147b/SOCS1 axis.

A “bulldozer” driven by anoxic bacteria for pancreatic cancer chemo-immunotherapy

Immune evasion is a major obstacle for pancreatic ductal adenocarcinoma (PDAC) therapy. Inhibition of autophagy can improve antigen presentation and enlarge immunogenic cell death (ICD) effect to generate a strong anti-tumor immune response. However, abundant extracellular matrix dominated by hyaluronic acid (HA) hinders the deep penetration of autophagy inhibitors and ICD inducers. Herein, an intelligent autophagy inhibitor hydroxychloroquine (HCQ) and chemotherapeutic drug doxorubicin (DOX) co-loaded “bulldozer” (HD@HH/EcN) driven by anoxic bacteria was constructed for PDAC chemo-immunotherapy. Results demonstrated that probiotic Escherichia coli 1917 (EcN) could carry hyaluronidases (HAases)-hybrided albumin nanoparticles (HD@HH) to reach PDAC tumor tissue quickly and accurately. Thereafter, HAases can efficiently cleave the tumor matrix barrier and promote HD@HH/EcN to accumulate at tumor hypoxic core significantly. After that, high level of glutathione (GSH) in tumor microenvironment (TME) induces intermolecular disulfide bond in HD@HH nanoparticles breakage, to precisely release HCQ and DOX. DOX can induce ICD effect. Meanwhile, HCQ can amplify DOX induced ICD effect by inhibiting tumor autophagy, which further increase cell surface expression of major histocompatibility complex class I (MHC-I) and augment recruitment of CD8+ T cell to improve immunosuppressive TME. This study provides a new strategy for PDAC chemo-immunotherapy.

Ubiquitin-Specific Protease 43 Impacts Pancreatic Ductal Adenocarcinoma Prognosis by Altering Its Proliferation and Infiltration of Surrounding Immune Cells.

Pancreatic ductal adenocarcinoma (PDAC) is a devastating cancer, and the therapy options for PDAC remain restricted. The distinctive tumor immunological microenvironment (TIME) of PDAC, comprising a high number of stromal cells and a limited infiltration of cytotoxic T lymphocytes (CTLs), rendered immunotherapy ineffective. The protein level of ubiquitin-specific protease 43 (USP43) was a prognostic predictor in numerous cancers; however, its function in PDAC is limited. This article focuses on the influence of USP43 expression on PDAC prognosis and TIME alteration. Based on TCGA database and tissue microarray staining, the expression of USP43 in PDAC was evaluated. The association between USP43 and prognosis was then investigated using tissue samples and online databases. In PDAC tumor tissues, the correlation between USP43 expression and clinicopathological characteristics, immune cell infiltration, and prognosis was investigated. The expression of USP43 in PDAC cell lines was evaluated using quantitative polymerase chain reaction. Using a cell counting kit-8 (CCK-8) and a cell colony formation test, the viability of the cells was determined. On the basis of online databases and tissue samples, the link between USP43 and immune cell infiltration around PDAC was also examined. For statistical analyses, the software GraphPad, R, and SPSS 26.0 were utilized. The expression of USP43 was considerably higher in PDAC compared to normal pancreatic tissue in both the TCGA database and the tissue microarrays of PDAC patients (P < 0.001). High USP43 expression was associated with poor overall survival in both the TCGA database and the tissue microarray of PDAC patients (P = 0.046 and 0.021, respectively). USP43 overexpression promoted PANC-1 cell proliferation (P = 0.0018), but USP43 knockdown decreased PANC02 cell proliferation (P < 0.001). According to the TCGA database, USP43 is associated with T cell activation and inhibits CD8+ T cell activation in PDAC, as proven by a study of cell lines. Moreover, in both TCGA and PDAC cell lines, USP43 expression was negatively linked with the chemokine signaling pathway. Overexpression of USP43 is a potential prognostic indicator for PDAC patients. USP43 is a potential biomarker associated with T cell activation, suppression of CD8+ T cell enrichment, and the cytokine signal pathway. Future multicenter studies are needed to confirm our findings and their potential application in the treatment of PDAC patients.

Dysregulated miRNAs modulate tumor microenvironment associated signaling networks in pancreatic ductal adenocarcinoma.

The desmoplastic and complex tumor microenvironment of pancreatic ductal adenocarcinoma (PDAC) has presented tremendous challenges for developing effective therapeutic strategies. Strategies targeting tumor stroma, albeit with great potential, have met with limited success due to the lack of knowledge on the molecular dynamics within the tumor microenvironment (TME). In pursuit of a better understanding of the influence of miRNAs on TME reprogramming and to explore circulating miRNAs as diagnostic and prognostic biomarkers for PDAC, using RNA-seq, miRNA-seq, and single-cell RNA-seq (scRNA-seq), we investigated the dysregulated signaling pathways in PDAC TME modulated by miRNAs from plasma and tumor tissue. Our bulk RNA-seq in PDAC tumor tissue identified 1445 significantly differentially expressed genes with extracellular matrix and structure organization as the top enriched pathways. Our miRNA-seq identified 322 and 49 abnormally expressed miRNAs in PDAC patient plasma and tumor tissue, respectively. We found many of the TME signaling pathways were targeted by those dysregulated miRNAs in PDAC plasma. Combined with scRNA-seq from patient PDAC tumor, our results revealed that these dysregulated miRNAs were closely associated with extracellular matrix (ECM) remodeling, cell-ECM communication, epithelial-mesenchymal transition, as well as immunosuppression orchestrated by different cellular components of TME. The findings of this study could assist the development of miRNA-based stromal targeting biomarkers or therapy for PDAC patients.

A biomimetic nanodrug for enhanced chemotherapy of pancreatic tumors.

Pancreatic ductal adenocarcinoma (PDAC) remains to be one of the highest malignant tumors due to its poor chemotherapeutic efficacy and multidrug resistance. A major reason for the failure in chemotherapy is poor drug accumulation into PDAC tumor tissues due to the overexpressed extracellular matrix (ECM) stroma, which forms a major obstacle limiting the deep tissue penetration of chemotherapeutics. Herein, we report a tumor microenvironment (TME)-responsive nanodrug, based on PDAC cell membrane-coated gold nanocages (AuNCs), to co-deliver the chemotherapeutics (GEM) and nitrogen oxide (NO) donor (L-Arg) to enhance drug accumulation and reduce chemoresistance. The high glutathione (GSH) level can trigger the cleavage of the disulfide bond on nanodrug to release GEM. Moreover, the elevated ROS level could activate L-Arg to generate NO, which synergistically facilitate GEM to penetrate into deep tissues by means of vasodilation and normalization of blood vessels in the PDAC tumor tissue. In addition, AuNCs not only serve as a photothermal agent for chemotherapy, but also generate photoacoustic signals to monitor drug accumulation and distribution. As expected, the strategy demonstrates to be remarkable in treating different xenograft mice models, especially in orthotopic and patient-derived xenograft (PDX) models. The current study defines a useful therapeutic tool for treating PDAC tumors.

Potential role of the bitter taste receptor T2R14 in the prolonged survival and enhanced chemoresponsiveness induced by apigenin.

Bitter taste receptors (T2Rs) are G protein‑coupled receptors originally detected in the gustatory system. More recently, T2Rs have been shown to be expressed in extra‑oral cells eliciting non‑gustatory functions. Emerging evidence has suggested a potential role for T2R signaling in diverse pathophysiological conditions, including cancer. -The aim of the present study was to evaluate the expression of T2R14 in pancreatic ductal adenocarcinoma (PDAC) and to assess its involvement in the anticancer effects induced by apigenin, a natural ligand of T2R14. For this purpose, T2R14 expression was explored in PDAC tumor tissue and tumor‑derived cell lines. Using the cell lines expressing the highest levels of T2R14, its effects on chemoresponsiveness and migration upon activation with apigenin were investigated invitro. To the best of our knowledge, the present study was the first to confirm the expression of the T2R family member T2R14 in PDAC. Patients with relatively high levels of T2R14 expression exhibited significantly prolonged overall survival compared with that of patients with low T2R14 expression. Furthermore, novel functions for apigenin were revealed; notably, apigenin was shown to elicit cytotoxic, anti‑migratory and chemosensitizing effects to 5‑fluoruracil (5‑FU) and to 5‑FU, leucovorin, irinotecan and oxaliplatin in pancreatic cancer cells. In conclusion, the present study extended the evidence for the anticancer effects of apigenin and strongly indicated the functional relevance of T2R14 in PDAC, even though their respective underlying pathways appear to be independent of each other.

Stroma-targeted nanoparticles that remodel stromal alignment to enhance drug delivery and improve the antitumor efficacy of Nab-paclitaxel in pancreatic ductal adenocarcinoma models

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal solid tumors. A dense desmoplastic and specifically aligned stroma plays integral roles in the progression of PDAC, and inhibits drug penetration to impede treatment. However, direct depletion of stromal components for PDAC therapy interferes with the stromal balance, possibly accelerating tumor progression. Specific fiber alignment of the extracellular matrix, the most significant type of stroma topology in PDAC, is an important feature of PDAC and often overlooked. Here, we found that the alignment of collagen fibers, as determined by second harmonic generation (SHG) imaging, negatively correlated with pancreatic cancer prognosis. We report an integrated, two-step strategy for PDAC treatment, utilizing pretreatment with polymer-lipid-peptide nanoparticles that deliver inhibitors of lysyl oxidase like 2 (LOXL2) and discoidin domain receptor 1 (DDR1), followed by treatment with albumin-bound-paclitaxel (Nab-paclitaxel). The LOXL2 and DDR1 inhibitors intervene with collagen crosslinking and matrix metallopeptidase 1 (MMP1) expression to remodel stromal alignment without decreasing the collagen content, thus facilitating the transport of Nab-paclitaxel through the stromal barrier to enhance drug penetration and accumulation in the PDAC tumor tissue. Through this mechanism, the combined strategy resulted in significant antitumor efficacy in PDAC orthotopic xenograft mice. The current work highlights the key role of stromal alignment in therapeutics transport through stromal barriers. The strategy of remodeling stromal alignment may represent a promising approach for improving drug delivery in other stroma-rich tumors and fibrosis-related diseases.

The interleukin-1 axis and the tumor immune microenvironment in pancreatic ductal adenocarcinoma

Interleukin-1 (IL-1) plays a key role in carcinogenesis and several IL-1-targeted therapeutics are under investigation for the treatment of pancreatic ductal adenocarcinoma (PDAC). We sought to broaden our understanding of how the family of IL-1 ligands and receptors impact the tumor immune landscape and patient survival in PDAC. Gene expression data and DNA methylation data for IL1A, IL1B, IL1RN, IL1R1, IL1R2, and IL1RAP was attained from The Cancer Genome Atlas (TCGA) database and cross validated using the National Center for Biotechnology Information (NCBI) Gene Expression Omnibus (GEO) database. Immune cell-type abundance was estimated using CIBERSORTx. Further confirmatory soluble protein analysis and peripheral blood immunophenotyping were performed on available tissue samples from our institution. 169 PDAC patients and 50 benign pancreatic TCGA-based samples were analyzed. IL1A (p < 0.001), IL1RN (p < 0.001), IL1R2 (p < 0.001), and IL1RAP (p = 0.006) were markedly increased in PDAC tumor tissue compared to benign pancreatic tissue. Furthermore, expression of IL1A, IL1B and IL1R1 were positively correlated with gene expression of immune checkpoints PVR, CD274, CD47, CD80, and HLA-A/B/C (p < 0.001). IL1B and IL1R1 were correlated to expression of PDCD1, CD86, CTLA4 and IDO1 (<0.001). Low expression of IL1RN (p = 0.020), IL1R2 (p = 0.015), and IL1RAP (p = 0.003) and high expression of IL1B (p = 0.031) were correlated with increased patient survival. At the protein level, IL-1β was correlated with increased peripheral central memory CD4+ and CD8+ T-cells as well as decreased Th2 cells. These findings suggest that the IL-1 axis plays a complex and pivotal role in the host immune response to PDAC.

Immortalization-upregulated protein promotes pancreatic cancer progression by regulating NPM1/FHL1-mediated cell-cycle-checkpoint protein activity

Immortalization-upregulated protein (IMUP) plays a vital role in cell proliferation and tumor progression. However, its role in pancreatic ductal adenocarcinoma (PDAC) remains unclear. Here, we select IMUP as an alternative gene based on GeneChip analysis of clinical PDAC tissues and transcriptome data from The Cancer Genome Atlas. IMUP expression is upregulated in PDAC tumor tissues. Moreover, high IMUP expression correlates with poor prognosis, while IMUP depletion inhibits PDAC cell proliferation and colony formation capacity in vitro, and decreases xenograft tumor growth in vivo. IMUP downregulation leads to cell-cycle arrest in the S phase. IMUP knockdown increases the expression of four-and-a-half LIM domain protein 1 (FHL1), which regulates the phosphorylation of cell division cycle 25A (CDC25A) by cycle checkpoint kinase 1 (CHK1) and promotes cytoplasmic distribution of CDC25A by interaction with 14–3-3ξ. Furthermore, FHL1 knockdown restores the effects induced by IMUP depletion. Liquid chromatography tandem mass spectrometry and immunoprecipitation analysis further show that IMUP interacts directly with nucleophosmin (NPM1) and enhances its stability. DNA methylation sequencing shows that FHL1 promoter methylation decreases when IMUP is downregulated. Overexpression of NPM1 can increase the methylation level of FHL1, thereby decreasing its expression. Our study provides a novel perspective on IMUP/NPM1/FHL1-mediated cell-cycle arrest by regulating CDC25A phosphorylation in PDAC. These findings may provide a new therapeutic target for PDAC.Graphical abstract

Proteogenomic Characterization of Human Pancreatic Cancer

Introduction: Recent genomic and transcriptomic analyses of human pancreatic ductal adenocarcinoma (PDAC) identified substantial genomic alterations and genes for which expression was altered with a cancer-related profile. However, these data have yet to provide molecular targets for diagnosis or clinical therapy. Here, we report proteogenomic analysis of PDAC. Methods: We collected PDAC tumor tissues and matched blood samples from consecutive 196 patients with PDAC who underwent surgery at Seoul National University Hospital from March 2010 to December 2016. DNA, RNA, and proteins were extracted from these samples, and proteogenomic analyses were performed. Subtypes of PDAC were identified using integrated clustering and pathway analysis. Functional experiments for polymorphonuclear myeloid-derived suppressor cells (PMN-MDSC) mediated inhibition of T cell proliferation were done using orthotopic pancreatic cancer models. Results: Mutation-phosphorylation correlations identified signaling pathways associated with somatic mutations in significantly mutated genes. mRNA-protein abundance correlations revealed oncogene and tumor suppressor candidates correlating with patient survival. Integrated clustering of mRNA, protein, and phosphorylation data identified six PDAC subtypes (Sub1-6), which were indistinguishable using mRNA data alone. mRNA and protein signatures defining Sub1-6 revealed that Sub1, Sub2-4, and Sub5-6 were precursor, invasive, and immunogenic tumors, respectively. In the Sub2-4 group, proliferation was highest for Sub4; Sub6 in the Sub5-6 group had an increased pancreatic secretion capacity. Orthotopic mouse PDAC models revealed higher numbers of pro-tumorigenic immune cells in Sub4 tumors, inhibiting T cell proliferation. Conclusions: Our proteogenomic analysis provides therapeutic targets and improves understanding of cancer biology and patient stratification in PDAC.

Identifying a novel IRF3/circUHRF1/miR-1306-5p/ARL4C axis in pancreatic ductal adenocarcinoma progression

ABSTRACT Pancreatic ductal adenocarcinoma (PDAC) is considered one most aggressive and lethal cancer types worldwide. While its underlying mechanisms are still poorly understood. CircRNAs play essential roles in various biological progression, including PDAC. Here, our results found that circUHRF1 was highly expressed in PDAC tumor tissues compared with normal tissues. Next, Cell or animal models were constructed, CCK-8, cell colony, EdU, flow cytometry assay, transwell migration, and Western blot assays were applied. CircUHRF1 knockdown influenced PDAC cell proliferation, apoptosis, migration and EMT level in vitro, and tumor growth in vivo. Subsequently, bioinformatics analysis, AGO2-RIP, RNA pull-down, and dual-luciferase reporter assays were used to explore the downstream targets in PDAC progression. Our findings suggest that circUHRF1 regulated ARL4C expression to promote PDAC progression through sponging miR-1306-5p. The role of miR-1306-5p in PDAC cellular progression has been elucidated, and the expression association between miR-1306-5p and circUHRF1 or ARL4C in PDAC tissues was analyzed. Furthermore, circUHRF1 expression in PDAC cells could be transcriptionally regulated by IRF3. Collectively, our study demonstrated the role of IRF3/circUHRF1/miR-1306-5p/ARL4C axis in PDAC progression. Our results suggest that circUHRF1 is one promising diagnosis or therapeutic target for PDAC management. Abbreviations : CircRNA; Circular RNAPDAC; pancreatic ductal adenocarcinomaUHRF1; Ubiquitin-like with PHD and RING finger domain 1ARL4C; ADP Ribosylation Factor Like GTPase 4CRIP; RNA immunoprecipitationEDU; 5-Ethynyl-2ʹ-deoxyuridineEMT; epithelial to mesenchymal transitionAGO2; Argonaute RISC Catalytic Component 2CCK8; Cell counting Kit-8IRF3; Interferon Regulatory Factor 3

Genome-wide identification and characterization of circular RNA m6A modification in pancreatic cancer

BackgroundN6-methyladenosine (m6A) is the most abundant modification of RNA in eukaryotic cells and play critical roles in cancer. While most related studies focus on m6A modifications in linear RNA, transcriptome-wide profiling and exploration of m6A modification in circular RNAs in cancer is still lacking.MethodsFor the detection of m6A modification in circRNAs, we developed a new bioinformatics tools called Circm6A and applied it to the m6A-seq data of 77 tissue samples from 58 individuals with pancreatic ductal adenocarcinoma (PDAC).ResultsCircm6A performs better than the existing circRNA identification tools, which achieved highest F1 score among these tools in the detection of circRNAs with m6A modifications. By using Circm6A, we identified a total of 8807 m6A-circRNAs from our m6A-seq data. The m6A-circRNAs tend to be hypermethylated in PDAC tumor tissues compared with normal tissues. The hypermethylated m6A-circRNAs were associated with a significant gain of circRNA-mRNA coexpression network, leading to the dysregulation of many important cancer-related pathways. Moreover, we found the cues that hypermethylated m6A-circRNAs may promote the circularization and translation of circRNAs.ConclusionsThese comprehensive findings further bridged the knowledge gaps between m6A modification and circRNAs fields by depicting the m6A-circRNAs genomic landscape of PDAC patients and revealed the emerging roles played by m6A-circRNAs in pancreatic cancer. Circm6A is available at https://github.com/canceromics/circm6a.

Abstract PR-001: Ex vivo co-culture system with patient-derived organoids to assess CXCR4 inhibitor as an immune modulating agent for human pancreas adenocarcinoma

Abstract Introduction: Immune checkpoint blockade either alone or in combination with chemotherapy has been ineffective in pancreatic ductal adenocarcinoma (PDAC) likely due to underlying immunosuppressive pathways. The C-X-C chemokine receptor type 4 (CXCR4)/chemokine (C-X-C motif) ligand 12 (CXCL12) axis is a key immunosuppressive pathway where CXCL12 released by cancer-associated fibroblasts (CAF) binds to its receptor CXCR4 expressed by cytotoxic CD8+ T cells (CTL) which results in their decreased abundance within tumors. Encouraging preclinical and clinical data from mouse PDAC models and human PDAC tumor sections have shown T cell tumor accumulation after co-inhibition of CXCR4 and PD1/PDL1, however number of tumor regressions were limited. Results: To further explore the mechanism by which inhibition of the CXCR4/CXCL12 pathway modulates the immune TME in triggering an anti-tumor immune response in human PDAC, we generated an autologous co-culture system with patient-derived tumor organoids (PDTO) and peripheral blood mononuclear cells (PBMC). PDAC tumor tissue from surgical resection was used to generate lines of PDTO that recapitulate the histological and genetic characteristics of the original tumor. We demonstrate that tumor-specific reactive T cells can be obtained in PDAC by co-culture with autologous PDTO, with up to 5% of CD8+ T cells producing IFNγ after tumor organoid stimulation. No T cell reactivity was observed against normal pancreatic organoids, and blocking tumor MHC I/MHC II decreased the proportion of activated T cells. Ex vivo migration assays were established to better understand the role of CXCL12 in PDAC tumor T cell exclusion. Tumor organoids attracted autologous PBMC and addition of recombinant CXCL12 decreased PBMC migration, while treatment of PBMC with the CXCR4 inhibitor AMD3100, rescued the number of PBMCs that were able to migrate towards the tumor organoids. PBMC infiltrated PDTO-containing but not empty Matrigel domes. Addition of AMD3100 increased PBMC infiltration within the Matrigel dome containing PDTOs. Finally, we found that pre-treatment of PBMC with AMD3100 increased T cell reactivity against PDTO, and that T cell activation was further increased when stimulated with PDTO pre-treated with chemotherapy. Conclusions: We found that CXCL12 modulates the migration of T cells towards tumor organoids generated from pancreatic cancer tissue, and that inhibition of CXCR4 not only increases the migration potential, but also increases tumor-specific T cell activation. The use of ex vivo autologous co-culture and migration assays provide a unique strategy to identify modulators that may enhance T cell mediated neoplastic cell death to guide therapeutic intervention in PDAC. Citation Format: Emily Alouani, Ilenia Pellicciotta, Winston Wong, Alexander S. Thomas, Michael D. Kluger, Anna M. Chiarella, Anil K. Rustgi, Gulam A. Manji. Ex vivo co-culture system with patient-derived organoids to assess CXCR4 inhibitor as an immune modulating agent for human pancreas adenocarcinoma [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 PR-001.

CIRBP Knockdown Attenuates Tumourigenesis and Improves the Chemosensitivity of Pancreatic Cancer via the Downregulation of DYRK1B

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignancies worldwide with very limited treatment options. Cold-inducible RNA binding protein (CIRBP) plays promoting roles in several types of cancers, but its function remains unclear in PDAC. Here, we found that the expression of CIRBP was upregulated in PDAC tumor tissues and was significantly associated with poor prognosis. Knockdown of CIRBP in PANC-1 and SW1990 cells inhibited proliferation, migration and invasion in vitro and suppressed tumor growth in vivo. Moreover, CIRBP knockdown enhanced the antitumour effects of gemcitabine treatment in PANC-1 and SW1990 cells, whereas CIRBP overexpression exerted the opposite effects. Mechanistically, CIRBP promoted PDAC malignancy and chemoresistance via upregulation of dual-specificity tyrosine-Y-phosphorylation regulated kinase 1B (DYRK1B). Indeed, knockdown of CIRBP sensitized pancreatic tumors to gemcitabine treatment by diminishing DYRK1B expression and increasing the ratio of ERK/p38 activity. Our findings suggest that CIRBP overexpression facilitates PDAC progression and gemcitabine resistance by upregulating DYRK1B expression and inhibiting the ERK/p38 signaling pathway, highlighting CIRBP as a potential new therapeutic target for PDAC.

Low Serum miR-607 Level as a Potential Diagnostic and Prognostic Biomarker in Patients of Pancreatic Ductal Adenocarcinoma: A Preliminary Study.

Background One of the microRNAs (miRNAs) known to be associated with cancer development is miR-607. The aim of this study is to investigate the clinical significance and diagnostic and prognostic value of miR-607 and to explore its potential role in pancreatic ductal adenocarcinoma (PDAC). Methods The expression levels of miR-607 were assessed by quantitative real-time polymerase chain reaction (qRT-PCR). The correlation between miR-607 expression and clinical characteristics was analyzed by the Chi-square test. Overall survival (OS) and progression-free survival (PFS) were evaluated via the Kaplan–Meier method, and the association between miR-607 expression and OS was investigated by the Cox proportional hazard analysis. The diagnostic value was estimated via receiver operating characteristic (ROC) curve analysis. The effect of miR-607 overexpression on cell migration, invasion, and epithelial-mesenchymal transition (EMT) was determined by wound-healing, Transwell invasion, and Western blotting assays. Results miR-607 levels were downregulated in PDAC tumor tissues compared with normal tissues. Also, low miR-607 levels were observed in serum samples from PDAC patients than that in healthy controls. The miR-607 level was found to be closely correlated with lymphatic metastasis and liver metastasis, perineural invasion, and OS and PFS, and the low miR-607 level was an independent prognostic factor for the poor OS of PDAC patients. Furthermore, the area under the curve (AUC) of serum miR-607 for discriminating PDAC patients was 0.785 with a sensitivity of 0.647 and a specificity of 0.772, which was better than those for CA19-9 (AUC: 0.702, sensitivity: 0.607, specificity: 0.736) and CEA (AUC: 0.648, sensitivity: 0.542, specificity: 0.670). The AUC (0.863), sensitivity (0.766), and specificity (0.831) of their combination in the diagnosis of PDAC were better than those for alone. Moreover, ectopic overexpression of miR-607 could inhibit cell migration and invasion of BxPc-3 and PANC-1 cells by decreasing EMT ability. Conclusions Low serum miR-607 level may serve as a potential diagnostic and prognostic biomarker through regulation of tumor metastasis in PDAC patients.

Gasdermin C as a potential prognostic biomarker and its correlation with immune infiltration in pancreatic ductal adenocarcinoma.

e16256 Background: Although pyroptosis is critical for macrophages against pathogen infection, its role in cancer cells remains elusive. GSDMC is a pyroptosis executioner newly identified in cancer cells and have been shown to facilitate inflammatory tumor death. However, the expression of GSDMC in Pancreatic Ductal Adenocarcinoma (PDAC), its prognostic significance and possible impact on reshaping tumor immune microenviroment in PDAC is still unknown. Methods: We investigated the expression level of GSDMC using TNM plotter with TCGA and GTEx databases, the prognostic value of GSDMC in PDAC using Kaplan-Meier plotter with TCGA, GTEx and TCGA databases. The correlations between GSDMC and immune infiltration in PDAC were calculated using TIMER2.0 and TIDE with TCGA database. We further validated the prognostic value of GSDMC with immunohistochemistry(IHC) staining on a tissue microarray of 172 cases of PDAC patients receiving treatment in our institution. Correlations between expression of GSDMC and tumor infiltration lymphacytes(TILs) cells were also analyzed on tissue samples of those 172 PDAC patients. Results: TNM plotter analysis shows that the expression of GSDMC in PDAC tumor tissue is 10.49 folds higher than it is in pancreatic normal tissues (p = 8.86*e-56). Results from Kaplan-Meier plotter analysis shows high expression of GSDMC is significantly correlated with poorer overall survival(OS), HR = 1.8(1.19−2.71) logrank P = 0.004 and shorter relapse free survival (RFS), HR = 4.6(1.94−10.88), Logrank P = 0.00014 in PDAC. Analysis with TIMER2.0 and TIDE platform shows that expression of GSDMC is positively correlated with immunosuppressive cells, Cancer Associated Fiberblast (CAF) and Meyloid Derived Tumor Suprresso Cells(MDTSC). IHC staining analysis results is also consistent with aformentioned bioinformatic analysis, showing that high GSDMC expression correlated with shorter OS and reduced Tils infiltration. Conclusions: Our findings suggest that high expression of GSDMC is related to poor prognosis and compromised immune cell infiltration in PDAC. GSDMC holds promise for serving as a valuable prognostic marker and therapeutic target in PDAC.

Long non‑coding RNA PCED1B‑AS1 promotes pancreatic ductal adenocarcinoma progression by regulating the miR‑411‑3p/HIF‑1α axis.

An increasing number of studies have shown that long non-coding RNAs (lncRNAs) are crucially involved in tumorigenesis. However, the biological functions, underlying mechanisms and clinical value of lncRNA PC-esterase domain containing 1B-antisense RNA 1 (PCED1B-AS1) in pancreatic ductal adenocarcinoma (PDAC) have not been determined, to the best of our knowledge. In the present study, the expression of PCED1B-AS1, microRNA (miR)-411-3p and hypoxia inducible factor (HIF)-1α mRNA in 47 cases of PDAC tissues were detected using reverse transcription-quantitative (RT-q)PCR. Moreover, the effects of PCED1B-AS1 on the biological behaviors of PDAC cells were assessed using Cell Counting Kit-8, EdU staining and Transwell assays. Bioinformatics analysis, RT-qPCR, western blotting, dual luciferase reporter gene and RNA immunoprecipitation assays were performed to determine the regulatory relationships between PCED1B-AS1, miR-411-3p and HIF-1α. We demonstrated that PCED1B-AS1 was significantly upregulated in PDAC tumor tissues, and its expression was associated with advanced Tumor-Node-Metastasis stage and lymph node metastasis. PCED1B-AS1 knockdown inhibited PDAC cell proliferation, invasion as well as epithelial-mesenchymal transition (EMT) in vitro. Mechanistically, PCED1B-AS1 was shown to target miR-411-3p, resulting in the upregulation of HIF-1α. In conclusion, PCED1B-AS1 expression was upregulated in PDAC tissues and cells, and it participated in promoting the proliferation, invasion and EMT of cancer cells by modulating the miR-411-3p/HIF-1α axis.

X-aptamers targeting Thy-1 membrane glycoprotein in pancreatic ductal adenocarcinoma

Modified DNA aptamers incorporated with amino-acid like side chains or drug-like ligands can offer unique advantages and enhance specificity as affinity ligands. Thy-1 membrane glycoprotein (THY1 or CD90) was previously identified as a biomarker candidate of neovasculature in pancreatic ductal adenocarcinoma (PDAC). The current study developed and evaluated modified DNA X-aptamers targeting THY1 in PDAC. The expression and glycosylation of THY1 in PDAC tumor tissues were assessed using immunohistochemistry and quantitative proteomics. Bead-based X-aptamer library that contains 108 different sequences was used to screen for high affinity THY1 X-aptamers. The sequences of the X-aptamers were analyzed with the next-generation sequencing. The affinities of the selected X-aptamers to THY1 were quantitatively evaluated with flow cytometry. Three high affinity THY1 X-aptamers, including XA-B217, XA-B216 and XA-A9, were selected after library screening and affinity binding evaluation. These three X-aptamers demonstrated a high binding affinity and specificity to THY1 protein and the THY1 expressing cell lines, using THY1 antibody as a comparison. The development of these X-aptamers provides highly specific and non-immunogenic affinity ligands for THY1 binding in the context of biomarker development and clinical applications. They could be further exploited to assist molecular imaging of PDAC targeting THY1.

Cancer-initiating cells in human pancreatic cancer organoids are maintained by interactions with endothelial cells.

Pancreatic ductal adenocarcinoma (PDAC) shows poor prognosis and high malignancy due to the presence of cancer-initiating cells (CICs) and characteristics of the tumor microenvironment (TME). Organoids are useful for studying PDAC, and establishing organoids is dependent on stem cell growth factors, including Wnt signaling. Herein, using a conventional organoid culture system, we demonstrated that CD44(+)CD24(+) and CD44(+)CD24(+)EpCAM(+) CICs were enriched >65% in a PDAC patient-derived organoid. CICs expressing CD44 formed lumen structures by gathering into circles. Additionally, organoid-derived CD44(-) cancer cells were capable of organoid re-formation and could be re-programed as CD44-expressing CICs in the organoid culture system. To mimic a TME absent artificial stem cell growth factors, a PDAC organoid with vascular niche was established. CICs in the PDAC tumor organoid were maintained by paracrine effects and direct interactions with endothelial cells. Interestingly, CD44(+) cells in PDAC tumor tissue were detected primarily in the vascular niche. Inhibiting both Wnt and Notch signaling in endothelial cells suppressed organoid formation and the maintenance of CD24(+)CD44(+) CICs. Collectively, our results suggest that PDAC patient-derived organoids maintain CICs by interacting with endothelial cells via Wnt and Notch pathways.

Investigation of the association between C-X-C motif chemokine receptor subunits and tumor infiltration levels and prognosis in patients with early-stage pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is one of the malignancies with the highest morality rate due to postoperative local invasion and distant metastasis. Although C-X-C motif chemokine receptor (CXCR) subunits have been reported as prognostic indicators in gastric cancer, the prognostic value of CXCR subunits in PDAC remains poorly understood. In the present study, the expression levels and biological functions of CXCR subunits were investigated using multiple publicly accessible bioinformatic platforms and databases. Survival analysis was used to evaluate the prognostic value of CXCR subunits in 112 early-stage PDAC cases by setting the median expression levels as the cut-off values. A nomogram was constructed to combine CXCR subunit expression levels and clinical data for prognosis prediction. Moreover, the association between CXCR subunit expression levels and tumor infiltration levels were detected in PDAC. The expression levels of CXCR subunits were elevated in PDAC tumor tissues. In the multivariate Cox proportional risk regression model, high CXCR2, CXCR4 and CXCR6 expression levels in early-stage PDAC were associated with a more favorable prognosis. Further, it was demonstrated that the differential expression levels of CXCR subunits in PDAC for combined survival analysis could contribute to risk stratification. The nomogram model demonstrated the contribution of CXCR subunits and clinical features in the prognosis of PDAC. Gene Set Enrichment Analysis suggested that CXCR subunits serve a role in immunomodulatory functions. The expression levels and somatic copy number alterations of CXCR subunits were associated with tumor infiltration levels in PDAC. CXCR subunits were associated with prognosis in patients with early-stage PDAC and may be potential drug targets for the treatment of pancreatic cancer.