Expression In Pancreatic Ductal Adenocarcinoma Research Articles

Fungal mycobiome drives IL-33 secretion and type 2 immunity in pancreatic cancer.

TH2 cells and innate lymphoid cells 2 (ILC2) can stimulate tumor growth by secreting pro-tumorigenic cytokines such as interleukin-4 (IL-4), IL-5, and IL-13. However, the mechanisms by which type 2 immune cells traffic to the tumor microenvironment are unknown. Here, we show that oncogenic KrasG12D increases IL-33 expression in pancreatic ductal adenocarcinoma (PDAC) cells, which recruits and activates TH2 and ILC2 cells. Correspondingly, cancer-cell-specific deletion of IL-33 reduces TH2 and ILC2 recruitment and promotes tumor regression. Unexpectedly, IL-33 secretion is dependent on the intratumoral fungal mycobiome. Genetic deletion of IL-33 or anti-fungal treatment decreases TH2 and ILC2 infiltration and increases survival. Consistently, high IL-33 expression is observed in approximately 20% of human PDAC, and expression is mainly restricted to cancer cells. These data expand our knowledge of the mechanisms driving PDAC tumor progression and identify therapeutically targetable pathways involving intratumoral mycobiome-driven secretion of IL-33.

PD‐L1 and PD‐L2 expression in pancreatic ductal adenocarcinoma and their correlation with immune infiltrates and DNA damage response molecules

Immunotherapy targeting programmed cell death‐1 (PD‐1) has considerably improved the prognosis of patients with advanced cancers; however, its efficacy in the treatment of pancreatic ductal adenocarcinoma (PDAC) is unfavourable. To address the issue of PDAC immunotherapy, we investigated the expression of two PD‐1 ligands, PD‐L1 and PD‐L2, in PDAC, analysed their role in survival, and explored their correlation with clinicopathological features, immune infiltration, and DNA damage response molecules. Immunohistochemistry was performed on 291 surgically resected PDAC samples. In tumour cells (TCs) and immune cells (ICs), the positivity of PD‐L1 expression was 30 and 20% and that of PD‐L2 expression was 40 and 20%, respectively. Moreover, PD‐L1 expression on TCs correlated with its expression on ICs (p < 0.0001); a similar result was observed for PD‐L2 (p < 0.0001). Nonetheless, no correlation was observed between PD‐L1 and PD‐L2 expression. Positive PD‐L1 expression on TCs was related to N1 stage (p = 0.011) and AJCC II stage (p = 0.002), whereas positive PD‐L2 expression on TCs was associated with high FOXP3+ cell infiltration (p = 0.001) and high BRCA2 expression (p < 0.0001). Survival analysis revealed that positive PD‐L1 (p = 0.046) and PD‐L2 (p = 0.028) expression on TCs was an independent risk factor for unfavourable disease‐specific survival (DSS). Furthermore, positive PD‐L2 expression on TCs was an independent risk factor for lower DSS in the pN0 (p = 0.023), moderate and well tumour differentiation (p = 0.004), low BRCA1 (p = 0.017), wild‐type p53 (p = 0.034), and proficient mismatch repair (p = 0.004) subgroups. Moreover, post‐operative adjuvant chemotherapy could significantly affect DSS, regardless of PD‐L1/PD‐L2 expression status (positive or negative) on TCs, while it only prolonged DSS in PDL1‐ICs(−) (p < 0.0001) and PDL2‐ICs(−) (p < 0.0001) subgroups. This study provides a comprehensive understanding of the roles of PD‐L1 and PD‐L2 in PDAC, supporting anti‐PD‐1 axis immunotherapy for PDAC.

Comparison of Long-Term Oncologic Outcomes Depending on SLC-6A14 Expression in Pancreatic Ductal Adenocarcinoma

Introduction Tumors alter their metabolism to meet the increasing demand for nutrients of their proliferating cancer cells. SLC6A14 is an amino acid transporter that is highly up-regulated in pancreatic cancer. This study was designed to identify correlation between SLC6A14 expression and long-term oncologic outcomes of patients with pancreatic ductal adenocarcinoma(PDAC). Method Patients who underwent pancreatic resection with PDAC at Gangnam Severance Hospital between 1997–2014 were enrolled. We evaluated immunohistochemically the expression of SLC6A14. SLC6A14 grade 0 and 1 were classified as SLC low, and grade 3 as SLC high. Patients demographics, pathologic findings, recurrence pattern and long-term outcomes were compared between two groups. Result Among 112 patients, 29(25.9%) and 83(74.1%) patients were classified as SLC low and SLC high group, respectively. Patients in SLC low group had a higher body mass index(23.5 vs 21.6, p=0.024) and a higher incidence of hypertension(62.1% vs 32.5%, p=0.005) than SLC high group. Pathologic findings and recurrence patterns were comparable between two groups. There were significant differences in long-term oncologic outcomes.The 1-year and 3-year overall survival were 79.3% and 50.5%, and 85.5% and 31.8% for patients in SLC low and high group, respectively(p=0.268). The 1-year and 3-year disease-free survival were 55.2% and 30.1%, and 50.6% and 20.8% for patients in SLC low and high group, respectively(p=0.518). Conclusion The higher expression of SLC6A14 in associated with worse outcome of overall survival and disease-free survival in patients with PDAC. These results showed that SLC6A14 is a novel therapeutic target for pancreatic cancer.

The MYEOV-MYC association promotes oncogenic miR-17/93-5p expression in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal malignancy worldwide. As metastasis and malignant progression are primarily responsible for the poor clinical outcomes of PDAC, identifying key genes involved in these processes and the underlying molecular mechanisms of PDAC is vital. In this study, by analyzing TCGA PDAC data and matched GTEx data, we found that MYEOV expression is associated with poor survival in PDAC patients and higher in carcinoma tissues than in healthy tissues. Elevated levels of MYEOV led to enhanced cell proliferation, invasion and migration in vitro and in vivo. Transcriptome analysis results revealed that MYEOV mediates global alterations in gene expression profiles in PDAC cells. MiRNA-seq analysis showed that MYEOV regulates the expression levels of miR-17-5p and miR-93-5p, and its depletion resulted in reduced cell proliferation, invasion and migration, as observed in MYEOV-knockdown PDAC cells. These effects are likely due to the ability of MYEOV to regulate enrichment of the transcription factor MYC at the gene promoter regions of the two miRNAs. Furthermore, we identified a complex containing MYEOV and MYC in the nucleus, providing additional evidence for the association of MYEOV with MYC. Taken together, our results suggest that MYEOV promotes oncogenic miR-17/93-5p expression by associating with MYC, contributing to PDAC progression.

Prediction of Tumor-Infiltrating CD20+ B-Cells in Patients with Pancreatic Ductal Adenocarcinoma Using a Multilayer Perceptron Network Classifier Based on Non-contrast MRI

Conventional chemotherapy has limited benefit in pancreatic ductal adenocarcinoma (PDAC), necessitating identification of novel therapeutic targets. Radiomics may enable non-invasive prediction of CD20 expression, a hypothesized therapeutic target in PDAC. To develop a machine learning classifier based on noncontrast magnetic resonance imaging for predicting CD20 expression in PDAC. Retrospective study was conducted on preoperative noncontrast magnetic resonance imaging of 156 patients with pathologically confirmed PDAC from January 2017 to April 2018. For each patient, 1409 radiomics features were selected using minimum absolute contraction and selective operator logistic regression algorithms. CD20 expression was quantified using immunohistochemistry. A multilayer perceptron network classifier was developed using the training and validation set. A log-rank test showed that the CD20-high group (22.37 months, 95% CI: 19.10-25.65) had significantly longer survival than the CD20-low group (14.9 months, 95% CI: 10.96-18.84). The predictive model showed good differentiation in training (area under the curve [AUC], 0.79) and validation (AUC, 0.79) sets. Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were 73.21%, 75.47%, 0.74, 0.76, and 0.73, respectively, for the training set and 69.23%, 80.95%, 0.74, 0.82, and 0.68, respectively, for the validation set. Multilayer perceptron classifier based on noncontrast magnetic resonance imaging scanning can predict the level of CD20 expression in PDAC patients.

Glucocorticoid receptor regulates PD-L1 and MHC-I in pancreatic cancer cells to promote immune evasion and immunotherapy resistance

Despite unprecedented responses of some cancers to immune checkpoint blockade (ICB) therapies, the application of checkpoint inhibitors in pancreatic cancer has been unsuccessful. Glucocorticoids and glucocorticoid receptor (GR) signaling are long thought to suppress immunity by acting on immune cells. Here we demonstrate a previously undescribed tumor cell-intrinsic role for GR in activating PD-L1 expression and repressing the major histocompatibility complex class I (MHC-I) expression in pancreatic ductal adenocarcinoma (PDAC) cells through transcriptional regulation. In mouse models of PDAC, either tumor cell-specific depletion or pharmacologic inhibition of GR leads to PD-L1 downregulation and MHC-I upregulation in tumor cells, which in turn promotes the infiltration and activity of cytotoxic T cells, enhances anti-tumor immunity, and overcomes resistance to ICB therapy. In patients with PDAC, GR expression correlates with high PD-L1 expression, low MHC-I expression, and poor survival. Our results reveal GR signaling in cancer cells as a tumor-intrinsic mechanism of immunosuppression and suggest that therapeutic targeting of GR is a promising way to sensitize pancreatic cancer to immunotherapy.

Clinicopathological significance of MYL9 expression in pancreatic ductal adenocarcinoma.

BackgroundPancreatic ductal adenocarcinoma is one of the most aggressive malignancies, and often involves invasion and distant metastasis from the early tumor stages. Myosin II reportedly plays a key role in regulating tumor progression and metastasis.AimsWe examined whether myosin regulatory light polypeptide 9 (MYL9) regulates cancer cell proliferation.Methods and resultsTo investigate the expression pattern and clinical significance of MYL9 in pancreatic ductal adenocarcinoma, we performed immunohistochemical analysis of samples collected from 101 patients with pancreatic ductal adenocarcinoma. The expression of MYL9 was investigated to evaluate its functional role and contribution to proliferation and apoptosis in pancreatic ductal adenocarcinoma cells in vitro. The results showed that MYL9 was predominantly expressed in the cytoplasm and membrane of pancreatic ductal adenocarcinoma cells. Multivariate analysis indicated that MYL9 acted as an independent prognostic factor for overall survival and distant metastasis‐free survival. MYL9 expression was strongly associated with malignancy in in vitro analyses, including proliferation and anti‐apoptotic activities.ConclusionsOur findings suggest that MYL9 is an independent prognostic factor of pancreatic ductal adenocarcinoma. MYL9 is a crucial biomarker and potential therapeutic target for pancreatic ductal adenocarcinoma.

ERK Inhibition Improves Anti-PD-L1 Immune Checkpoint Blockade in Preclinical Pancreatic Ductal Adenocarcinoma.

Patients with pancreatic ductal adenocarcinoma (PDAC) do not benefit from immune checkpoint blockade (ICB) along the PD-1/PD-L1 axis. Variable PD-L1 expression in PDAC indicates a potential access issue of PD-L1-targeted therapy. To monitor target engagement of PD-L1-targeted therapy, we generated a PD-L1-targeted PET tracer labeled with zirconium-89 (89Zr). As the MAPK signaling pathway (MEK and ERK) is known to modulate PD-L1 expression in other tumor types, we used [89Zr]Zr-DFO-anti-PD-L1 as a tool to noninvasively assess whether manipulation of the MAPK signaling cascade could be leveraged to modulate PD-L1 expression and thereby immunotherapeutic outcomes in PDAC. In this study, we observed that the inhibition of MEK or ERK is sufficient to increase PD-L1 expression, which we hypothesized could be leveraged for anti-PD-L1 immune checkpoint therapy. We found that the combination of ERK inhibition and anti-PD-L1 therapy corresponded with a significant improvement of overall survival in a syngeneic mouse model of PDAC. Furthermore, IHC analysis indicates that the survival benefit may be CD8+ T-cell mediated. The therapeutic and molecular imaging tool kit developed could be exploited to better structure clinical trials and address the therapeutic gaps in challenging malignancies such as PDAC.

ELK3 Mediated by ZEB1 Facilitates the Growth and Metastasis of Pancreatic Carcinoma by Activating the Wnt/β-Catenin Pathway.

Rapid progression and metastasis are the major causes of death in patients with pancreatic ductal adenocarcinoma (PDAC). ELK3, a member of the ternary complex factor (TCF), has been associated with the initiation and progression of various cancers. However, the role of ELK3 in PDAC is not yet fully understood. Online databases and immunohistochemistry were used to analyze the ELK3 levels in PDAC tissues. The function of ELK3 was confirmed by a series of in vivo and in vitro studies. Western blotting and immunofluorescence were used to detect the molecular mechanisms of PDAC. ChIP-qPCR was used to study the mechanism responsible for the elevation of ELK3 expression in PDAC. The ELK3 levels were higher in PDAC tissues than in adjacent normal tissues. Functionally, we demonstrated that ELK3 acted as an oncogene to promote PDAC tumorigenesis and metastasis. Further study suggested that ELK3 promoted PDAC cell migration and invasion by activating the Wnt/β-catenin pathway, and proved that ZEB1 could directly bind to the promoter of ELK3 to increase its transcription. Finally, both were associated with the patients’ clinicopathological features and worse overall survival. Conclusively, our findings enrich the role of ELK3 in PDAC, and provide potential avenues for exploring more effective biomarkers and therapeutic strategies for the treatment of PDAC.

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.

SOX9 is a critical regulator of TSPAN8-mediated metastasis in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is the deadliest cancer mainly owing to its proclivity to early metastasis and the lack of effective targeted therapeutic drugs. Hence, understanding the molecular mechanisms underlying early invasion and metastasis by PDAC is imperative for improving patient outcomes. The present study identified that upregulation of TSPAN8 expression in PDAC facilitates metastasis in vivo and in vitro. We found SOX9 as a key transcriptional regulator of TSPAN8 expression in response to EGF stimulation. SOX9 modulation was sufficient to positively regulate endogenous expression of TSPAN8, with concomitant in vitro phenotypic changes such as loss of cell–matrix adherence and increased invasion. Moreover, increased SOX9 and TSPAN8 levels were shown to correlate in human pancreatic cancer specimens and downregulated in vitro by EGFR tyrosine kinase inhibitors. High expression of SOX9 and TSPAN8 has been associated with tumor stage, poor prognosis and poor patient survival in PDAC. In conclusion, this study highlights the importance of the EGF-SOX9-TSPAN8 signaling cascade in the control of PDAC invasion and implies that TSPAN8 may be a promising novel therapeutic target for the treatment of PDAC.

Keratin 17 testing in pancreatic cancer needle aspiration biopsies predicts survival.

Although pancreatic ductal adenocarcinoma (PDAC) has one of the lowest 5-year survival rates of all cancers, differences in survival exist between patients with clinically identical characteristics. The authors previously demonstrated that keratin 17 (K17) expression in PDAC, measured by RNA sequencing or immunohistochemistry (IHC), is an independent negative prognostic biomarker. Only 20% of cases are candidates for surgical resection, but most patients are diagnosed by needle aspiration biopsy (NAB). The aims of this study were to determine whether there was a correlation in K17 scores detected in matched NABs and surgical resection tissue sections and whether K17 IHC in NAB cell block specimens could be used as a negative prognostic biomarker in PDAC. K17 IHC was performed for a cohort of 70 patients who had matched NAB cell block and surgical resection samples to analyze the correlation of K17 expression levels. K17 IHC was also performed in cell blocks from discovery and validation cohorts. Kaplan-Meier and Cox proportional hazards regression models were analyzed to determine survival differences in cases with different levels of K17 IHC expression. K17 IHC expression correlated in matched NABs and resection tissues. NAB samples were classified as high for K17 when ≥80% of tumor cells showed strong (2+) staining. High-K17 cases, including stage-matched cases, had shorter survival. K17 has been identified as a robust and independent prognostic biomarker that stratifies clinical outcomes for cases that are diagnosed by NAB. Testing for K17 also has the potential to inform clinical decisions for optimization of chemotherapeutic interventions.

High CXCR4 expression in pancreatic ductal adenocarcinoma as characterized by an inflammatory tumor phenotype with potential implications for an immunotherapeutic approach.

4021 Background: Immunotherapy is considered ineffective in the majority of patients with pancreatic ductal adenocarcinoma (PDAC), a consequence of a highly immunosuppressive tumor microenvironment (TME). However, treatment induced inhibition of CXC chemokine receptor 4 (CXCR4) and programmed cell death protein-1 (PD-1) in the COMBAT trial caused T cell infiltration and tumor regression in a subset of PDAC patients. Elucidating a phenotype that predicts response is clinically relevant. We performed a comprehensive molecular landscape study in PDAC evaluating CXCR4 RNA expression. Methods: 3,647 PDAC specimens were centrally analysed. NextGen DNA sequencing (NextSeq, 592 gene panel or NovaSeq, whole-exome sequencing), whole-transcriptome RNA sequencing (NovaSeq) and immunohistochemistry (Caris Life Sciences, Phoenix, AZ) were performed. Gene expression is reported as TPM (Transcripts per million). Pathway gene enrichment analyses were done using GSEA (Subramaniam 2015, PNAS). Immune cell fraction was calculated by QuantiSeq (Finotello 2019, Genome Medicine). The cohort was stratified in quartiles according to CXCR4 RNA expression status. Results: Overall, CXCR4 expression was higher in primary tumors compared to distant metastasis (38 vs. 28 TPM, p &lt; 0.0001). CXCR4-high (top quartile: &gt; 59 TPMs), when compared to CXCR4-low (bottom quartile: &lt; 17 TPM) PDACs, were characterized by a high prevalence of mutations in signal transduction pathway genes (e.g. GNAS: 3.6 vs. 0.5%), an increased infiltration of immune cells (e.g. CD8+ T cells, M1 macrophages), and a higher expression of HLA-DRA and HLA-E (all p &lt; 0.0001). We detected an upregulation of CXCL9, CXCL10, CXCL12, CCL5, IDO1 and LAG3 in CXCR4-high compared to CXCR4-low tumors. In contrast, lower PD-L1 expression (17.4 vs. 13.1%, p = 0.02), genomic loss of heterozygosity (17.4 vs. 10.8%), and a lower frequency of gene amplifications in ERBB2 (2.1 vs. 0.1%), TNFRSF14 (2.0 vs. 0.1%), and TP53 (82 vs. 73%, all p &lt; 0.0001) were observed. Moreover, CXCR4-high expression was associated with a better survival (HR: 1.417, 95% CI [1.168-1.72], p &lt; 0.001). Conclusions: This is the first study comprehensively investigating the molecular landscape of PDACs according to CXCR4 RNA expression. High CXCR4 expression is associated with an improved survival and a pro-inflammatory phenotype that may identify a subset of tumors with greater responsiveness to immunotherapeutic approaches.

Histamine receptor 1 (HRH1): A new therapeutic target for pancreatic cancer?

Pancreatic ductal adenocarcinoma (PDAC) is the most common and lethal (5-year survival <10%) type of pancreatic cancer and the 3rd leading cause of cancer death in the U.S. Current treatment options (surgery, radiotherapy, and chemotherapy) rarely produce a cure. New and effective therapies for PDAC are thus an important, urgent need. As a novel approach to address this unmet need, we explored whether G protein-coupled receptors (GPCRs), in particular GPCRs with FDA-approved drugs (which could be repurposed), have altered expression in PDAC compared to healthy pancreatic tissue or cells. We undertook a comprehensive analysis of GPCRs (comparing GPCR expression in PDAC samples in The Cancer Genome Atlas [TCGA] with that in The Genotype-Tissue Expression [GTEx] database) and identified numerous GPCRs with higher expression in PDAC. One such GPCR, histamine receptor H1 (HRH1), which is targeted by many FDA-approved antihistamines, has ~30-fold higher mRNA expression in PDAC. We found that high HRH1 expression is an unfavorable prognostic marker for PDAC. However, the roles of HRH1 in PDAC are unknown. We hypothesized that HRH1 is functional and contributes to the phenotype of PDAC. We initially assessed the mRNA and protein expression of HRH1 in human PDAC cell lines. RNAseq data from The Cancer Cell Line Encyclopedia (CCLE) database revealed that HRH1 is the main histamine receptor expressed in multiple human PDAC cell lines: AsPC-1, MIA PaCa-2, PANC-1 and BxPC-3 (5-19 transcripts/million [TPM] compared to the other 3 HRHs [≤ 0.6 TPM]). We confirmed those results by qPCR. Proteomic analysis (PMID: 31978347 and PMID: 28375945) has identified HRH1 protein expression in AsPC-1, MIA PaCa2 and PANC-1: HRH1 had a strong protein-RNA correlation (Pearson correlation= 0.64 and Spearman correlation= 0.72). We next tested if HRH1 is functional in PDAC cells. We treated BxPC-3 cells with histamine (10µM) and with the FDA-approved HRH1 inhibitors/antihistamines loratadine or clemastine (both 1µM) in a wound healing assay. We found that histamine, via HRH1, increased BxPC-3 cell migration. Moreover, histamine (in a time- and concentration-dependent manner) increased intracellular Ca2+ in BxPC-3, AsPC-1 and Capan-2 cells. Multiple HRH1 antagonists blocked this response. We also found high expression of HRH1 (by qPCR) in pancreatic tumors of KPC (LSL-KrasG12D/+; Trp53f/f; Ptf1a-Cre) mice, which spontaneously develop pancreatic cancer. We isolated cancer cell lines from the KPC pancreatic tumors by multiple passage of the cells and found that: 1) the cells highly express HRH1 mRNA and 2) histamine increases intracellular Ca2+ via HRH1, i.e., inhibition by multiple HRH1 antihistamines. Together, these data indicate the presence and functional activity of HRH1 in human PDAC and a mouse model and suggest that HRH1 may be a novel therapeutic target for PDAC.

A48 USE OF ENDOSCOPIC ULTRASOUND FINE NEEDLE ASPIRATE AND ENDOSCOPIC ULTRASOUND FINE NEEDLE BIOPSY FOR DETECTION OF GATA6 EXPRESSON IN PANCREATIC DUCTAL ADENOCARINCOMA

Abstract Background GATA6 is a transcription factor that can be used to distinguish between the basal-like and classical subtypes of pancreatic ductal adenocarcinoma (PDAC). The basal-like subtype has been demonstrated to be less responsive to modified FOLFIRINOX chemotherapy and thus can be used to predict response to specific chemotherapies. To date, GATA6 expression has only been evaluated in surgically resected PDAC specimens. Less than 15% of patients with PDAC are eligible for surgery. Endoscopic ultrasound guided fine-needle aspirate (EUS-FNA) and biopsy (EUS-FNB) can potentially help assess GATA6 expression in PDAC and in turn, help guide personalized treatment selection in all cases of PDAC. Aims The primary objective of this study was to explore the yield of EUS-FNA and EUS-FNB for the detection of GATA6 among patients with PDAC. The study also aimed to explore the impact of lesion location on sample adequacy and type of fixative on validity of GATA6 staining. Methods This study was conducted from November 2017 to October 2019. Consecutive patients with a diagnosis of PDAC confirmed by biopsy were included. Patients underwent either EUS-FNB or EUS-FNA to obtain tissues samples. Samples were fixed in either neutral buffered formalin (NBF) or a methanol based buffered solution (Cytolyt) and evaluated by a specialized cytopathology team. Fisher’s exact test was used and a p-value ≤0.05 was considered to indicate statistical significance. Results Forty-four patients were included in the study. Twenty-three (52%) patients were male and the median age of patients was 67.5 years. Twenty-five lesions were located in the head and neck of the pancreas, 14 were located in the body, and 4 were located in the tail. One patient was found to have a local recurrence of PDAC at the surgical bed of a previous Whipple procedure. Eighteen lesions were sampled by EUS-FNA and 26 were sampled using EUS-FNB. Thirty-eight (86%) samples were adequate for assessment of GATA6. Sampling technique (p=0.68) and fixative type (p=1.00) did not appear to affect sample adequacy. Compared to pancreatic body or tail specimens, samples obtained from the head or neck of the pancreas were more likely to be inadequate for analysis (p=0.03). Conclusions EUS-FNA and EUS-FNB samples are efficacious methods of assessing GATA6 expression in PDAC. This is the first predictor of treatment response that has been demonstrated to be obtained without surgical resection. Neither EUS needle type or alcohol fixation before cell block preparation appear to impact GATA6 detection. Lesions in the pancreatic head or neck appear to be associated with higher rates of sample inadequacy. Larger, prospective studies are required to confirm our findings. Funding Agencies None

Increased Nuclear Transporter KPNA2 Contributes to Tumor Immune Evasion by Enhancing PD-L1 Expression in PDAC.

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest malignancies and is known for its high resistance and low response to treatment. Tumor immune evasion is a major stumbling block in designing effective anticancer therapeutic strategies. Karyopherin alpha 2 (KPNA2), a member of the nuclear transporter family, is elevated in multiple human cancers and accelerates carcinogenesis. However, the specific role of KPNA2 in PDAC remains unclear. In this study, we found that expression of KPNA2 was significantly upregulated in PDAC compared to adjacent nontumor tissue and its high expression was correlated with poor survival outcome by analyzing the GEO datasets. Similar KPNA2 expression pattern was also found in both human patient samples and KPC mouse models through IHC staining. Although KPNA2 knockdown failed to impair the vitality and migration ability of PDAC cells in vitro, the in vivo tumor growth was significantly impeded and the expression of immune checkpoint ligand PD-L1 was reduced by silencing KPNA2. Furthermore, we uncovered that KPNA2 modulated the expression of PD-L1 by mediating nuclear translocation of STAT3. Collectively, our data suggested that KPNA2 has the potential to serve as a promising biomarker for diagnosis in PDAC.

Abstract IA011: Conventional dendritic cells as regulators of therapeutic response in pancreas cancer

Abstract In these studies, we utilized spontaneous models of pancreatic and lung cancer to examine how neo-antigenicity shapes tumor immunity and progression. As expected, neoantigen expression during lung adenocarcinoma development leads to T cell-mediated immunity and disease restraint. By contrast, neoantigen expression in pancreatic ductal adenocarcinoma (PDAC) resulted in exacerbation of the inflammatory and fibrotic tumor microenvironment that drives disease progression and metastasis. Pathogenic TH17 responses are responsible for this neoantigen-induced tumor progression in PDAC. Underlying these divergent T cell responses in pancreas and lung cancer are differences in infiltrating conventional dendritic cells (cDCs). Overcoming cDC deficiency in early- stage PDAC leads to disease restraint, while restoration of cDC function thru treatment with both CD40 agonists and FLT3L in advanced PDAC restores tumor-restraining immunity and enhances responsiveness to radiation therapy. Citation Format: David G. DeNardo. Conventional dendritic cells as regulators of therapeutic response in pancreas cancer [abstract]. In: Proceedings of the AACR Virtual Special Conference on the Evolving Tumor Microenvironment in Cancer Progression: Mechanisms and Emerging Therapeutic Opportunities; in association with the Tumor Microenvironment (TME) Working Group; 2021 Jan 11-12. Philadelphia (PA): AACR; Cancer Res 2021;81(5 Suppl):Abstract nr IA011.

Long non-coding RNA CERS6-AS1 facilitates the oncogenicity of pancreatic ductal adenocarcinoma by regulating the microRNA-15a-5p/FGFR1 axis.

The long non-coding RNA CERS6 antisense RNA 1 (CERS6-AS1) has critical regulatory roles in breast cancer progression. Here, we determined CERS6-AS1 expression in pancreatic ductal adenocarcinoma (PDAC) and the roles of CERS6-AS1 in PDAC carcinogenesis. The mechanisms underlying the regulatory actions of CERS6-AS1 in PDAC cells were elucidated in detail. CERS6-AS1 expression was evidently increased in PDAC tissues and cell lines. Patients with PDAC having high CERS6-AS1 expression had shorter overall survival periods than those having low CERS6-AS1 expression. Functionally, the knockdown of CERS6-AS1 attenuated the proliferation, migration, and invasion and stimulated apoptosis of PDAC cells in vitro. Additionally, CERS6-AS1 depletion decreased PDAC tumor growth in vivo. Mechanistically, CERS6-AS1 could competitively bind to microRNA-15a-5p (miR-15a-5p) and effectively work as a molecular sponge in PDAC cells, resulting in the upregulation of fibroblast growth factor receptor 1 (FGFR1), a direct target of miR-15a-5p. Rescue experiments revealed that miR-15a-5p downregulation or FGFR1 restoration rescued the effects of CERS6-AS1 knockdown on the behaviors of PDAC cells. In conclusion, CERS6-AS1 promoted the oncogenicity of PDAC by serving as a competing endogenous RNA to sequester miR-15a-5p and increase FGFR1 expression, which highlights the potential of the CERS6-AS1/miR-15a-5p/FGFR1 pathway as an effective target for cancer therapy.

Clinical implication of Pin1 expression in pancreatic ductal adenocarcinoma

Purpose: The prognosis of pancreatic ductal adenocarcinoma (PDAC) is poor even after curative surgical resection. Therefore, discovering new important factors controlling PDAC progression is essential. Pin1 overexpression is seen in several malignancies and is reported to promote tumor progression through activation of transcriptional factors such as NF-kappaB, STAT3, and FOXC1. However, no reports have focused on the expression levels of Pin1 in PDAC. Therefore, we thought to evaluate Pin1 expression in PDAC, investigate the correlations with clinicopathological variables, and determine whether Pin1 is a promising therapeutic target in PDAC patients. Experimental Design: The expression levels of Pin1 and related factors were evaluated by immunohistochemical staining. Moreover, the relationship between Pin1 expression and clinicopathological features or prognosis in 120 PDAC patients were investigated. Results: Pin1 expression was increased in some cases of PDAC, and was associated with vascular invasion in PDAC. The univariate and multivariate analyses revealed that high Pin1 expression in PDAC was an independent factor for poor prognosis. Pin1 enhanced activation of transcriptional factors such as STAT3 and FOXC1, resulted in aggressive tumor progression. Increased Pin1 expression induced tumor growth by accelerating cell proliferation and inhibiting cell apoptosis. Moreover, Pin1 overexpression promoted tumor invasion by enhancing EMT. As these results, the incidence of hematogenous recurrence was significantly higher in PDAC with high Pin1 expression. Conclusions: Pin1 overexpression is associated with aggressive tumor progression and poor prognosis in PDAC; therefore, Pin1 is an excellent biomarker for predicting its malignant status and is a promising therapeutic target in patients with PDAC.

A pilot study of estrogen receptor (ER) expression in pancreatic ductal adenocarcinoma (PDAC).

Pancreatic ductal adenocarcinoma (PDAC) is the most common pancreatic neoplasm with 5-year survival as low as 6%. It is therefore imperative to explore potential treatment avenues to improve survival in these groups of patients. Anti-estrogenic hormone therapy (AEHT) is well-tolerated and has been used in estrogen receptor (ER) subgroups of breast cancer. ER is a type of sex hormone receptor which have been reported to be expressed inconsistently in pancreatic cancer. This study aims to identify the presence of ER in PDAC specimens to guide potential use of AEHT in the management of unresectable PDAC. This is a retrospective case control study of 10 patients (5 males, 5 females) who underwent pancreatic resections for PDAC from 2011 to 2012. Sections of the post-operative specimens were prepared and sent for ER staining. Pancreatic tissue specimens that were analysed included (I) ductal epithelial cells; (II) acinar cells; (III) islet cells; (IV) intralobular stromal cells; and (V) adenocarcinoma cells. Intralobular stromal cells were positively stained for ER in 7/10 (70%) of the cases, but were of weak intensity and patchy in distribution. Islet cells (<1%) stained for ER in 3/10 (30%) of the cases. Ductal epithelial cells, acinar cells and adenocarcinoma cells stained negative for ER in all of the cases. This pilot study did not detect the presence of ER expression in PDAC. ER expression in intralobular stromal and islet cells which was previously unreported, were noted in our study. The role of AEHT in pancreatic cancer remains uncertain and does not appear to be of value at present.