Role In Pancreatic Cancer Progression Research Articles

Nerve Growth Factor from Pancreatic Cancer Cells Promotes the Cancer Progression by Inducing Nerve Cell-Secreted Interleukin-6.

Pancreatic cancer (PC) is a cancer with a poor prognosis, and nerve growth factor (NGF) is involved in the pathogenesis of PC within the unknown exact role. Herein, SW1990 cells and PC12 cells were co-cultured using transwell co-culture system and subsequently revealed that NGF was overexpressed in SW1990 cells and promoted PC12 cell proliferation. Knockdown of NGF expression in SW1990 cells using lentiviral shRNA effectively inhibited NGF expression in SW1990 cells and reduced its stimulatory effect on PC12 cell proliferation. Additionally, NGF in SW1990 cells increased the expression of IL-6, dopamine, and c-FOS, as well as decreased the level of lactate dehydrogenase, in PC12 cells, whereas the inhibition of NGF expression significantly reduced the levels of IL-6, dopamine and c-FOS, indicating the critical role of IL-6/STAT3 signaling in PC progression. Finally, cell proliferation, migration, and invasion were assessed using cell counting kit-8, scratch, and Transwell assays, which showed that activated neurons promoted the proliferation, migration, invasion, and NGF secretion of SW1990 cells through the IL-6/STAT3 pathway. The results revealed that NGF secreted by PC cells played a pivotal role in PC progression via regulating activated neural cells-secreted IL-6, providing new theoretical insights for the treatment of PC.

PAF1/HIF1α axis rewires the glycolytic metabolism to fuel aggressiveness of pancreatic cancer

BackgroundPAF1/PD2 deregulation contributes to tumorigenesis, drug resistance, and cancer stem cell maintenance in Pancreatic Cancer (PC). Recent studies demonstrate that metabolic reprogramming plays a role in PC progression, but the mechanism is poorly understood. Here, we focused on examining the role of PAF1/PD2 in the metabolic rewiring of PC.MethodsCell lines were transfected with shRNAs to knockdown PAF1/PD2. Metabolic genes regulated by PAF1/PD2 were identified by qPCR/western blot, and metabolic assays were performed. Immunoprecipitations/ChIP were performed to identify PAF1/PD2 protein partners and confirm PAF1/HIF1α sub-complex binding to LDHA.ResultsPAF1 and LDHA showed progressively increased expression in human pancreatic tumor sections. Aerobic glycolysis genes were downregulated in PAF1-depleted PC cells. Metabolic assays indicated a decreased lactate production and glucose uptake in knockdown cells. Furthermore, PAF1/PD2 depletion showed a reduced glycolytic rate and increased oxidative phosphorylation by ECAR and OCR analysis. Interestingly, we identified that HIF1α interacts and co-localizes with PAF1, specifically in PC cells. We also observed that the PAF1/PD2-HIF1α complex binds to the LDHA promoter to regulate its expression, reprogramming the metabolism to utilize the aerobic glycolysis pathway preferentially.ConclusionOverall, the results indicate that PAF1/PD2 rewires PC metabolism by interacting with HIF1α to regulate the expression of LDHA.

Selective and effective suppression of pancreatic cancer through MNK inhibition

Objective The study aimed to explore the role of the Wnt/β-catenin signaling pathway in pancreatic cancer progression and chemoresistance, with a focus on identifying specific factors that distinguish between normal and tumor cells, thereby offering potential therapeutic targets. Materials and Methods We analyzed levels of total and phosphorylated eukaryotic translation initiation factor 4E (eIF4E) and β-catenin in pancreatic cancer and normal pancreatic tissues. Functional assays were used to assess the impact of eIF4E phosphorylation on β-catenin signaling, cell proliferation, and chemoresistance, with MNK kinase involvement determined through gene depletion studies. The MNK kinase inhibitor eFT508 was evaluated for its effects on eIF4E phosphorylation, β-catenin activation, and cell viability in both in vitro and in vivo models of pancreatic cancer. Results Both total and phosphorylated eIF4E, along with β-catenin, were significantly elevated in pancreatic cancer tissues compared to normal tissues. Phosphorylation of eIF4E at serine 209 was shown to activate β-catenin signaling, enhance cell proliferation, and contribute to chemoresistance in pancreatic cancer. Importantly, these effects were dependent on MNK kinase activity. Depletion of eIF4E reduced cell viability in both pancreatic cancer and normal cells, while depletion of MNK selectively decreased viability in pancreatic cancer cells. Treatment with eFT508 effectively inhibited eIF4E phosphorylation, suppressed β-catenin activation, and reduced pancreatic cancer cell growth and survival in vitro and in vivo, with minimal impact on normal cells. Conclusions: The MNK-eIF4E-β-catenin axis plays a critical role in pancreatic cancer progression and chemoresistance, distinguishing pancreatic cancer cells from normal cells. Targeting MNK kinases with inhibitors like eFT508 presents a promising therapeutic strategy for pancreatic cancer, with potential for selective efficacy and reduced toxicity.

Deciphering the SOX4/MAPK1 regulatory axis: a phosphoproteomic insight into IQGAP1 phosphorylation and pancreatic Cancer progression

ObjectiveThis study aims to elucidate the functional role of IQGAP1 phosphorylation modification mediated by the SOX4/MAPK1 regulatory axis in developing pancreatic cancer through phosphoproteomics analysis.MethodsProteomics and phosphoproteomics data of pancreatic cancer were obtained from the Clinical Proteomic Tumor Analysis Consortium (CPTAC) database. Differential analysis, kinase-substrate enrichment analysis (KSEA), and independent prognosis analysis were performed on these datasets. Subtype analysis of pancreatic cancer patients was conducted based on the expression of prognostic-related proteins, and the prognosis of different subtypes was evaluated through prognosis analysis. Differential analysis of proteins in different subtypes was performed to identify differential proteins in the high-risk subtype. Clinical correlation analysis was conducted based on the expression of prognostic-related proteins, pancreatic cancer typing results, and clinical characteristics in the pancreatic cancer proteomics dataset. Functional pathway enrichment analysis was performed using GSEA/GO/KEGG, and most module proteins correlated with pancreatic cancer were selected using WGCNA analysis. In cell experiments, pancreatic cancer cells were grouped, and the expression levels of SOX4, MAPK1, and the phosphorylation level of IQGAP1 were detected by RT-qPCR and Western blot experiments. The effect of SOX4 on MAPK1 promoter transcriptional activity was assessed using a dual-luciferase assay, and the enrichment of SOX4 on the MAPK1 promoter was examined using a ChIP assay. The proliferation, migration, and invasion functions of grouped pancreatic cancer cells were assessed using CCK-8, colony formation, and Transwell assays. In animal experiments, the impact of SOX4 on tumor growth and metastasis through the regulation of MAPK1-IQGAP1 phosphorylation modification was studied by constructing subcutaneous and orthotopic pancreatic cancer xenograft models, as well as a liver metastasis model in nude mice.ResultsPhosphoproteomics and proteomics data analysis revealed that the kinase MAPK1 may play an important role in pancreatic cancer progression by promoting IQGAP1 phosphorylation modification. Proteomics analysis classified pancreatic cancer patients into two subtypes, C1 and C2, where the high-risk C2 subtype was associated with poor prognosis, malignant tumor typing, and enriched tumor-related pathways. SOX4 may promote the occurrence of the high-risk C2 subtype of pancreatic cancer by regulating MAPK1-IQGAP1 phosphorylation modification. In vitro cell experiments confirmed that SOX4 promoted IQGAP1 phosphorylation modification by activating MAPK1 transcription while silencing SOX4 inhibited the proliferation, migration, and invasion of pancreatic cancer cells by reducing the phosphorylation level of MAPK1-IQGAP1. In vivo, animal experiments further confirmed that silencing SOX4 suppressed the growth and metastasis of pancreatic cancer by reducing the phosphorylation level of MAPK1-IQGAP1.ConclusionThe findings of this study suggest that SOX4 promotes the phosphorylation modification of IQGAP1 by activating MAPK1 transcription, thereby facilitating the growth and metastasis of pancreatic cancer.

Revealing splenectomy-driven microRNA hsa-7b-5p’s role in pancreatic cancer progression

Splenectomy often accompanies distal pancreatectomy for pancreatic cancer. However, debates persist on splenic function loss impact. Prior studies in mice revealed splenectomy promotes pancreatic cancer growth by altering CD4/Foxp3 and CD8/Foxp3 ratios. The effect on other immune cells remains unclear. Clinical observations indicate splenectomy induces immunosuppression, heightening recurrence and metastasis risk. Here, we established an orthotopic pancreatic cancer model with splenectomy and observed a significant increase in tumor burden. Flow cytometry revealed elevated MDSCs, CD8+PD-1high+ Tcells, and reduced CD4+ Tcells, CD8+ Tcells, and natural killer cells in tumors. Bulk sequencing identified increased MicroRNA (miRNA) hsa-7b-5p post-splenectomy, correlating with staging and immunosuppression. Similar results were obtained invivo by constructing a KPC-miRNA hsa-7b-5p-sh cell line. These findings suggest that splenectomy enhances the expression of miRNA hsa-7b-5p, inhibits the tumor immune microenvironment, and promotes pancreatic cancer growth.

Exosomes: Emerging Insights into the Progression of Pancreatic Cancer.

Pancreatic cancer is a very aggressive and fatal malignancy with few therapeutic choices and a poor prognosis. Understanding the molecular pathways that drive its growth is critical for developing effective therapeutic strategies. Exosomes, small extracellular vesicles secreted by numerous cell types, have recently emerged as essential intercellular communication mediators, with implications for tumor growth and metastasis. In this article, we present a review of current knowledge about exosomes and their role in pancreatic cancer progression We discuss the biogenesis and characteristics of exosomes, as well as their cargo and functional significance in tumor growth, immune evasion, angiogenesis, invasion, and metastasis. We further emphasize the potential of exosomes as diagnostic biomarkers and therapeutic targets for pancreatic cancer. Finally, we discuss the challenges and future perspectives in using exosomes to improve patient outcomes in pancreatic cancer.

MLPH regulates EMT in pancreatic adenocarcinoma through the PI3K-AKT signaling pathway.

Pancreatic adenocarcinoma (PAAD) is an extremely malignant tumor, and most patients develop postoperative metastases. Melanophilin (MLPH) is involved in the progression of various tumors, but its molecular mechanisms and role in pancreatic cancer progression are unknown. In this study, differential MLPH expression in cancer tissues and the adjacent tissues was evaluated using the Gene Expression Profiling Interaction Analysis 2 (GEPIA 2) and Human Protein Atlas (HPA) databases. The role of MLPH in PAAD proliferation, invasion, and migration in vitro was explored via clone formation, Cell Counting Kit-8 assay, Transwell assay, and western blot. The in vivo validation of function was performed using a metastatic nude mouse model. The result showed that the pancreatic cancer tissues had significantly higher MLPH expression levels than the noncancerous pancreatic tissues. MLPH expression changes were related to PAAD cell proliferation, invasion, and migration. The western blotting demonstrated that PAAD cells had reduced Epithelial-mesenchymal transition (EMT)-related marker expression. Furthermore, overexpressing MLPH enhanced cell proliferation, migration, and invasion, and increased EMT-related marker expression. The Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis revealed that the molecular mechanism underlying the effect of MLPH on PAAD was significantly related to the PI3K-AKT pathway. LY294002 blocked the MLPH overexpression-mediated enhanced cell invasion and migration and inhibited EMT-associated marker expression. Conversely, 740Y-P reversed the inhibitory effects of MLPH downregulation and led to cell migration, invasion, and EMT. MLPH regulated EMT to mediate PAAD cell invasive migration through the PI3K-AKT pathway. The results indicated that MLPH is a possible target for blocking PAAD metastasis.

Direct regulation of FNIP1 and FNIP2 by MEF2 sustains MTORC1 activation and tumor progression in pancreatic cancer

ABSTRACT MTOR (mechanistic target of rapamycin kinase) complex 1 (MTORC1) orchestrates diverse environmental signals to facilitate cell growth and is frequently activated in cancer. Translocation of MTORC1 from the cytosol to the lysosomal surface by the RRAG GTPases is the key step in MTORC1 activation. Here, we demonstrated that transcription factors MEF2A and MEF2D synergistically regulated MTORC1 activation via modulating its cyto-lysosome shutting. Mechanically, MEF2A and MEF2D controlled the transcription of FNIP1 and FNIP2, the components of the FLCN-FNIP1 or FNIP2 complex that acts as a RRAGC-RRAGD GTPase-activating element to promote the recruitment of MTORC1 to lysosome and its activation. Furthermore, we determined that the pro-oncogenic protein kinase SRC/c-Src directly phosphorylated MEF2D at three conserved tyrosine residues. The tyrosine phosphorylation enhanced MEF2D transcriptional activity and was indispensable for MTORC1 activation. Finally, both the protein and tyrosine phosphorylation levels of MEF2D are elevated in human pancreatic cancers, positively correlating with MTORC1 activity. Depletion of both MEF2A and MEF2D or expressing the unphosphorylatable MEF2D mutant suppressed tumor cell growth. Thus, our study revealed a transcriptional regulatory mechanism of MTORC1 that promoted cell anabolism and proliferation and uncovered its critical role in pancreatic cancer progression. Abbreviation: ACTB: actin beta; ChIP: chromatin immunoprecipitation; EGF: epidermal growth factor; EIF4EBP1: eukaryotic translation initiation factor 4E binding protein 1; FLCN: folliculin; FNIP1: folliculin interacting protein 1; FNIP2: folliculin interacting protein 2; GAP: GTPase activator protein; GEF: guanine nucleotide exchange factors; GTPase: guanosine triphosphatase; LAMP2: lysosomal associated membrane protein 2; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; MEF2: myocyte enhancer factor 2; MEF2A: myocyte enhancer factor 2A; MEF2D: myocyte enhancer factor 2D; MEF2D-3YF: Y131F, Y333F, Y337F mutant; MTOR: mechanistic target of rapamycin kinase; MTORC1: MTOR complex 1; NR4A1: nuclear receptor subfamily 4 group A member 1; RPTOR: regulatory associated protein of MTOR complex 1; RHEB: Ras homolog, mTORC1 binding; RPS6KB1: ribosomal protein S6 kinase B1; RRAG: Ras related GTP binding; RT-qPCR: real time-quantitative PCR; SRC: SRC proto-oncogene, non-receptor tyrosine kinase; TMEM192: transmembrane protein 192; WT: wild-type.

Global lipid remodelling by hypoxia aggravates migratory potential in pancreatic cancer while maintaining plasma membrane homeostasis

Hypoxia plays an important role in pancreatic cancer progression. It drives various metabolic reprogramming in cells including that of lipids, which in turn, can modify the structure and function of cell membranes. Homeostatic adaptation of membranes is well-recognized, but how and if it is regulated in hypoxic pancreatic cancer and its relation to aggressive phenotype and metastasis remains elusive. Here we show hypoxia-induced extensive global lipid remodelling spanning changes in lipid classes, unsaturation levels, glyceryl backbone and acyl chain lengths. No major modulation of plasma membrane biophysical properties revealed a decoupling of lipidome modulation from membrane properties under hypoxia. This was supported by observing minor changes in the lipidome of plasma membranes under hypoxia. Further, hypoxia increased migration and invasion underpinned by reduced actin volume, cell cortical stiffness and facile tether dynamics. In conclusion, we demonstrate buffering of the lipidome alterations leading to a homeostatic membrane response. These findings will help to understand the hypoxic regulation of pancreatic membrane homeostasis and identify tangible theranostic avenues.

Downregulation of circ-STK39 suppresses pancreatic cancer progression by sponging mir-140-3p and regulating TRAM2-mediated epithelial-mesenchymal transition.

Pancreatic cancer (PC) is amongst the most lethal gastrointestinal tumors, which is the seventh leading reason of cancer-related mortality worldwide. Previous studies have indicated that circular RNAs (circRNAs), which is a new type of endogenous noncoding RNA (ncRNA), can mediate tumor progression in diverse tumor types including PC. Whereas precise roles regarding circRNAs and their underlying regulatory mechanisms in PC remain unknown. In the current study, we employed next generation sequencing (NGS) to characterize abnormally expressed circRNAs among PC tissues. Next, we assessed expression levels of one identified circRNA, circ-STK39, in PC cell lines and tissues. Then, using bioinformatics analysis, luciferase reporter, Transwell migration, EdU and CCK-8 assays, we examined the regulatory mechanisms and targets of circ-STK39. Finally, our group explored the circ-STK39 role in PC tumor growth and metastasis in vivo. Our team discovered that circ-STK39 expression increased in PC tissues and cells, suggesting that circ-STK39 may have a role in PC progression. Downregulation of circ-STK39 inhibited PC proliferation and migration. Bioinformatics and luciferase reporter outcomes demonstrated that TRAM2 and miR-140-3p were circ-STK39 downstream targets. TRAM2 overexpression reversed the miR-140-3p overexpression effects upon migration, proliferation and the epithelial-mesenchymal transition (EMT). In this regard, we showed that circ-STK39 downregulation led to decreased migration, proliferation and the EMT of PC via the miR-140-3p/TRAM2 axis.

RETRACTED ARTICLE: Palmitoyl transferases act as novel drug targets for pancreatic cancer

BackgroundPancreatic adenocarcinoma (PAAD) is one of the most leading causes of cancer-related death across the world with the limited efficiency and response rate of immunotherapy. Protein S-palmitoylation, a powerful post-translational lipid modification, is well-known to regulate the stability and cellular distribution of cancer-related proteins, which is mediated by a family of 23 palmitoyl transferases, namely zinc finger Asp-His-His-Cys-type (ZDHHC). However, whether palmitoyl transferases can determine tumor progression and the efficacy of immunotherapy in PAAD remains unknown.MethodsBioinformatics methods were used to identify differential ZDHHCs expression in PAAD. A systematic pan-cancer analysis was conducted to assess the immunological role of ZDHHC3 using RNA sequencing data from The Cancer Genome Atlas database. In vivo Panc 02 subcutaneous tumor model validated the anti-tumor effect of knockdown of ZDHHC3 or intraperitoneal injection of 2-bromopalmitate (2-BP), a typical broad-spectrum palmitoyl transferases inhibitor. Furthermore, we explored therapeutic strategies with combinations of 2-BP with PD-1/PD-L1-targeted immunotherapy in C57BL/6 mice bearing syngeneic Panc 02 pancreatic tumors.ResultsZDHHC enzymes were associated with distinct prognostic values of pancreatic cancer. We identified that ZDHHC3 expression promotes an immunosuppressive tumor microenvironment in PAAD. 2-BP suppressed pancreatic-tumor cell viability and tumor sphere-forming activities, as well as increased cell apoptosis in vitro, without affecting normal human pancreatic ductal epithelial cells. Furthermore, genetic inactivation of ZDHHC3 or intraperitoneal injection of 2-BP impeded tumor progression in Panc 02 pancreatic tumors with enhanced anti-tumor immunity. 2-BP treatment significantly enhanced the therapeutic efficacy of PD-1/PD-L1 inhibitors in Panc 02 pancreatic tumors.ConclusionThis study revealed some ZDHHC enzyme genes for predicting the prognosis of pancreatic cancer, and demonstrated that ZDHHC3 plays a critical oncogenic role in pancreatic cancer progression, highlighting its potential as an immunotherapeutic target of pancreatic cancer. In addition, combination therapy of 2-BP and PD-1/PD-L1 achieved synergic therapy effects in a mouse model of pancreatic cancer.

Diagnostic and Prognostic Role of Extracellular Vesicles in Pancreatic Cancer: Current Evidence and Future Perspectives

Pancreatic cancer is one of the most aggressive tumors, with a dismal prognosis due to poor detection rates at early stages, rapid progression, post-surgical complications, and limited effectiveness of conventional oncologic therapies. There are no consistently reliable biomarkers or imaging modalities to accurately diagnose, classify, and predict the biological behavior of this tumor. Therefore, it is imperative to develop new and improved strategies to detect pancreatic lesions in the early stages of cancerization with greater sensitivity and specificity. Extracellular vesicles, including exosome and microvesicles, are membrane-coated cellular products that are released in the outer environment. All cells produce extracellular vesicles; however, this process is enhanced by inflammation and tumorigenesis. Based on accumulating evidence, extracellular vesicles play a crucial role in pancreatic cancer progression and chemoresistance. Moreover, they may represent potential biomarkers and promising therapy targets. The aim of the present review is to review the current evidence on the role of extracellular vesicles in pancreatic cancer.

Circ_0058058 Drives the Malignant Phenotypes and Immune Evasion of Pancreatic Cancer by the MicroRNA-557-Dependent Regulation of PDL1.

Pancreatic cancer (PC) is one of the most deadly malignancies in the world. Recently, circular RNAs play crucial roles in PC progression. However, the functions of circ_0058058 in PC are barely known. The expression of circ_0058058, microRNA-557-5p (miR-557), and programmed cell death receptor ligand 1 (PDL1) was detected by quantitative real-time polymerase chain reaction. Functional experiments were implemented to disclose the effect of circ_0058058 deficiency on PC cell proliferation, apoptosis, invasion, angiogenesis, and immune escape. The binding relationship between miR-557 and circ_0058058 or PDL1 was identified by dual-luciferase reporter assay and RNA immunoprecipitation assay. In vivo assay was used to disclose the impact of circ_0058058 silencing on tumor formation in vivo. Circ_0058058 was highly expressed in PC tissues and cell lines. Knockdown of circ_0058058 repressed cell proliferation, invasion, angiogenesis, and immune escape while contributed to apoptosis in PC cells. Mechanically, circ_0058058 worked as a molecular sponge of miR-557 to regulate PDL1 expression. Moreover, circ_0058058 showed a promotional effect on tumor growth in vivo. Our findings suggested that circ_0058058 served as miR-557 sponge to upregulate PDL1, thereby triggering PC proliferation, invasion, angiogenesis, and immune escape.

Bioinformatics-Based Analysis: Noncoding RNA-Mediated COL10A1 Is Associated with Poor Prognosis and Immune Cell Infiltration in Pancreatic Cancer.

Background Collagen type X alpha 1 (COL10A1) is a structural component of the extracellular matrix that is aberrantly expressed in a variety of cancer tissues. However, its role in pancreatic cancer progression is not well understood. Methods The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), and Gene Expression Profiling Interaction Analysis (GEPIA) data were employed to explore the expression of COL10A1 in normal and tumor tissues and its prognostic value in pancreatic adenocarcinoma. The clinical data of pancreatic cancer in TCGA were used to explore the relationship between COL10A1 and clinical features. Genes coexpressed with COL10A1 were explored using multiple databases and analyzed for functional enrichment. In addition, the lncRNA/miRNA/COL10A1 axis that may be involved in COL10A1 regulation in pancreatic cancer was explored by constructing a competitive endogenous RNA (ceRNA) regulatory axis. Finally, COL10A1 was analyzed for correlation with immune cell infiltration and various immune checkpoint molecules in pancreatic cancer. Results It was found that the expression of COL10A1 was significantly increased in pancreatic cancer tissues. High expression of COL10A1 was related to the clinicopathological characteristics and the worse prognosis of pancreatic cancer patients. The TUG1/miR-144-3p/COL10A1 axis was identified as the most likely upstream noncoding RNA pathway for COL10A1 in pancreatic cancer. Besides, in pancreatic adenocarcinoma, the expression level of COL10A1 showed a significant positive correlation with tumor immune cell infiltration, biomarkers of immune cells, and expression of immune checkpoint molecules. Conclusion COL10A1 is an early diagnostic marker, and its high expression correlates with immune infiltration in pancreatic cancer. The TUG1/miR-144-3p/COL10A1 axis was identified as the most likely upstream noncoding RNA pathway for COL10A1 in pancreatic cancer.

An Exploration of Oral-Gut Pathogens Mediating Immune Escape of Pancreatic Cancer via miR-21/PTEN Axis.

Oral-gut pathogens are closely associated with pancreatic cancer, such as Campylobacter jejuni, Clostridium difficile, Enterococcus faecalis, Escherichia coli, Fusobacterium nucleatum, Helicobacter pylori, Porphyromonas gingivalis, and Vibrio cholera, but the related mechanisms remain not well understood. Phosphatase and tensin homolog (PTEN, a widely known tumor suppressor) play a key role in the anti-cancer immune system. Pancreatic cancer cells with PTEN loss are often in the immunosuppressive tumor microenvironment regulated by myeloid-derived suppressor cells (MDSCs), regulatory T cells (Tregs), and M2 macrophages, which are regarded as the mechanism in the immune escape of cancers. The miR-21, as an oncogene in human cancers, plays an important role in pancreatic cancer progression, downregulates the levels of PTEN, and may promote cancer to evade host immune surveillance. Some oral-gut pathogens have been found to promote miR-21 expression and reduce PTEN expression. On the other hand, most gut pathogens infection is thought to produce reactive oxygen species (ROS) or activate inflammatory cytokines, which may also induce ROS-mediated miR-21 expression. These pathogens' infection is involved with the cell density of MDSCs, Tregs, and M2 macrophages. Therefore, it is quite reasonable to propose that oral-gut pathogens possibly promote pancreatic cancer escaping from host immune surveillance by activating the miR-21/PTEN axis and immune-suppressive cells. The present exploration suggests that an increased understanding of the pattern of the effects of gut pathogens on the miR-21/PTEN axis will lead to better insights into the specific mechanisms associated with the immune escape of pancreatic cancer caused by oral-gut microbiota.

Circ_0092367 Inhibits EMT and Gemcitabine Resistance in Pancreatic Cancer via Regulating the miR-1206/ESRP1 Axis.

Gemcitabine is the first-line treatment for patients with pancreatic cancer (PC), yet most patients develop resistance to gemcitabine. Recent studies showed that circular RNAs (circRNAs) have important regulatory roles in PC progression and chemoresistance. In this study, the ability of circRNA circ_0092367 to enhance gemcitabine efficacy was tested and the underlying molecular mechanism of circ_0092367 was investigated. The expression levels of circ_0092367, miR-1206, and ESRP1 were measured using qRT-PCR experiments. The effects of circ_0092367, miR-1206, and ESRP1 on PC cell lines exposed to gemcitabine were examined by CCK-8 assays. We performed luciferase assays to determine the relationship between circ_0092367 and miR-1206 and between miR-1206 and ESRP1. We demonstrated that circ_0092367 was significantly downregulated in PC tissues and cell lines, and a high expression of circ_0092367 was associated with improved survival in patients with PC. Gain- and loss-of-function assays revealed that circ_0092367 inhibited epithelial–mesenchymal transition (EMT) phenotypes and sensitized PC cells to gemcitabine treatment in vitro and in vivo. Cytoplasmic circ_0092367 could directly repress the levels of miR-1206 and thus upregulate the expression of ESRP1, thereby inhibiting EMT and enhancing the sensitivity of PC cells to gemcitabine treatment. Our findings show that circ_0092367 plays a crucial role in sensitizing PC cells to gemcitabine by modulating the miR-1206/ESRP1 axis, highlighting its potential as a valuable therapeutic target in PC patients.

Identification of prognostic lipid droplet-associated genes in pancreatic cancer patients via bioinformatics analysis

BackgroundPancreatic cancer is the fourth leading cause of cancer deaths in the United States both in females and in males, and is projected to become the second deadliest cancer by 2030. The overall 5-year survival rate remains at around 10%. Cancer metabolism and specifically lipid metabolism plays an important role in pancreatic cancer progression and metastasis. Lipid droplets can not only store and transfer lipids, but also act as molecular messengers, and signaling factors. As lipid droplets are implicated in reprogramming tumor cell metabolism and in invasion and migration of pancreatic cancer cells, we aimed to identify lipid droplet-associated genes as prognostic markers in pancreatic cancer.MethodsWe performed a literature search on review articles related to lipid droplet-associated proteins. To select relevant lipid droplet-associated factors, bioinformatics analysis on the GEPIA platform (data are publicly available) was carried out for selected genes to identify differential expression in pancreatic cancer versus healthy pancreatic tissues. Differentially expressed genes were further analyzed regarding overall survival of pancreatic cancer patients.Results65 factors were identified as lipid droplet-associated factors. Bioinformatics analysis of 179 pancreatic cancer samples and 171 normal pancreatic tissue samples on the GEPIA platform identified 39 deferentially expressed genes in pancreatic cancer with 36 up-regulated genes (ACSL3, ACSL4, AGPAT2, BSCL2, CAV1, CAV2, CAVIN1, CES1, CIDEC, DGAT1, DGAT2, FAF2, G0S2, HILPDA, HSD17B11, ICE2, LDAH, LIPE, LPCAT1, LPCAT2, LPIN1, MGLL, NAPA, NCEH1, PCYT1A, PLIN2, PLIN3, RAB5A, RAB7A, RAB8A, RAB18, SNAP23, SQLE, VAPA, VCP, VMP1) and 3 down-regulated genes (FITM1, PLIN4, PLIN5). Among 39 differentially expressed factors, seven up-regulated genes (CAV2, CIDEC, HILPDA, HSD17B11, NCEH1, RAB5A, and SQLE) and two down-regulation genes (BSCL2 and FITM1) were significantly associated with overall survival of pancreatic cancer patients. Multivariate Cox regression analysis identified CAV2 as the only independent prognostic factor.ConclusionsThrough bioinformatics analysis, we identified nine prognostic relevant differentially expressed genes highlighting the role of lipid droplet-associated factors in pancreatic cancer.

Molecular characterization of pancreatic cancers as seen in the SLUG gene revealing cancer progression.

433 Background: The SLUG gene plays an important role in EMT by repressing E-cadherin and promotes metastasis. Previous data suggest that overexpressed SLUG gene in pancreatic cancer (PC) showing a high frequency of metastasis and poor prognosis. As SLUG contribution to characteristics or metastatic features remains elusive, we clarified its functional roles in PC progression. Methods: A total of 2958 pancreatic tumors were analyzed using Whole Transcriptome sequencing, NextGen Sequencing (NGS) (NextSeq, 592 gene panel) or Whole Exome Sequencing (WES) (NovaSeq) (Caris Life Sciences, Phoenix, AZ). Microsatellite instability (MSI) status was tested by fragment analysis, immunohistochemistry (IHC) and NGS. PD-L1 expression was tested by IHC. Tumor mutational burden (TMB) was measured by counting all mutations found per tumor (a universal cutoff point of ≧10 mutations per MB). Immune cell fraction was calculated by quanTIseq (Finotello 2019, Genome Medicine). Results: A total of 1274 primary and 1684 metastatic pancreatic tumors were included for this study. They were divided equally into four classes in each group, according to their SLUG expression levels. Tumors in the highest quartile of SLUG expression (QH) showed significantly higher frequency in peritoneal-retroperitoneal-omentum metastasis (15.0%) compared to the lowest quartile (QL) (4.8%) (p = .0001). Similar trends were seen in the abdomen (6% vs 1%, p = .001) and bone (2.8% vs 0.0%, p = .005). However, liver (55.0% in QH vs 63.1% in QL) and lung (2.8% vs 14.1%) metastasis occurred most frequently in QL and the least frequently in QH (p = .0197 and p = .001, respectively). This data indicated that tumors with high SLUG gene expression levels tend to lead to disseminated metastasis, and with low expression levels, they tend to spread intravascularly. We detected significant differences among genetic mutations in ATM (5.7% in QL vs 1.8% in QH, p < 0.001) and APC (2.9% vs 0.5%, p < 0.001), and Wnt signaling expressions were higher in QL (4.6%) than QH (0.7%) (p < 0.001). Binary TMB-H and MSI-H tumors had higher frequencies in QL (2.7% and 2.1%) compared to QH (0.3% and 0.1%) (p < 0.001 in both). Contrastingly, PD-L1 expression levels were higher in QH (23.4%) compared to QL (11.0%) (p < 0.001) and had a linear relationship with the expression levels. The median values of the population of B cells, M1 and M2 macrophages were significantly higher in QH compared to QL, but those of myeloid dendritic and CD8+T cells conversely decrease as the SLUG expression increases. Conclusions: Our data indicated the SLUG expression level could determine the tumor characteristics in progression, especially the pattern of metastasis in PC, and it could possibly predict the prognosis and/or therapeutic effects. We also showed immune oncologic markers which have some relationships with SLUG expressions. Further investigation is warranted to better understand SLUG gene functions.

Abstract PO-001: Increased growth differentiation factor 15 serum levels in pancreatic cancer patients

Abstract Pancreatic cancer has poor outcomes with a 5-year survival rate of 9%. Growth differentiation factor 15 (GDF15) has been shown to play a role in pancreatic cancer progression and tumor growth. It is a stress response cytokine that plays a role in inflammation and cellular metabolism. Signaling via its receptor, glial cell derived neurotropic factor family receptor alpha like (GFRAL), GDF15 influences metabolic homeostasis and immune regulation, which may contribute to favorable energy utilization and immune suppression in pancreatic cancer tumors. We hypothesized that GDF15 levels are associated with pancreatic cancer tumor stage and clinical outcomes. GDF15 levels were measured in human serum from healthy control patients and patients diagnosed with pancreatic cancer. Serum samples and associated clinical data were obtained from an IRB approved institutional repository. In healthy control patients, GDF15 had a mean level of 598 pg/mL (SD +/- 304 pg/mL, n=150). Contrastingly, in a cohort of pancreatic cancer patients across various stages of disease, GDF15 levels were significantly higher with a mean of 2294 pg/mL (SD +/- 2005 pg/mL, n=152) (p-value < 0.0001). GDF15 levels were associated with pancreatic cancer stage (p-value = 0.1824, n=150). GDF15 levels were compared for a subset of pancreatic cancer patients who underwent surgical resection; there was a trend for increased levels of GDF15 in patients who received neoadjuvant treatment compared to those that did not receive neoadjuvant treatment (P-value = 0.0674, n=106). When GDF15 levels measured at the time of surgical resection were compared among patients that later developed recurrence and those that did not, GDF15 levels trended to be lower in patients who did not develop recurrence (p-value = 0.3004, n=52). Additionally, the mean GDF15 serum levels for surgical resection patients whose survival status was deceased (2392 pg/mL, SD +/- 1947 pg/mL, n=36) compared to those that are still alive (1907 pg/mL, SD +/- 1416 pg/mL, n=70) on the date of last follow-up were higher (p-value = 0.1295). Overall, these results showed that GDF15 is significantly elevated in pancreatic cancer patients compared to healthy control patients. In our cohort there is an associated trend between increased GDF15 and the administration of neoadjuvant chemotherapy treatment, increasing pancreatic cancer stage, recurrence and decreased survival. We appreciated trends with GDF-15 serum levels and clinical outcomes, which need to be further validated in a larger cohort of patients. These results suggest that GDF15 or its receptor, GFRAL, may be effective novel targets for the treatment of pancreatic cancer patients. Citation Format: Veronica R. Placencio-Hickok, Arsen Osipov, Sejal Mehta, Subhash D. Katewa, Jiping Zha, Andrew E. Hendifar. Increased growth differentiation factor 15 serum levels in pancreatic cancer patients [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2020 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2020;80(22 Suppl):Abstract nr PO-001.

Implications of Perineural Invasion on Disease Recurrence and Survival After Pancreatectomy for Pancreatic Head Ductal Adenocarcinoma.

To describe PNI and to evaluate its impact on disease-free (DFS) and overall survival (OS) in patients with resected pancreatic ductal adenocarcinoma (PDAC). Although PNI is a prognostic factor for survival in many GI cancers, there is limited knowledge regarding its impact on tumor recurrence, especially in ''early stage disease'' (PDAC ≤20 mm, R0/ N0 PDAC). This multicenter retrospective study included patients undergoing PDAC resection between 2009 and 2014. The association of PNI with DFS and OS was analyzed using Cox proportional-hazards models. PNI was found in 87% of 778 patients included in the study, with lower rates in PDAC ≤20 mm (78.7%) and in R0/N0 tumors (70.6%). PNI rate did not differ between patients who underwent neoadjuvant therapy and upfront surgery (88% vs 84%, P = 0.08). Although not significant at multivariate analysis ( P = 0.07), patients with PNI had worse DFS at univariate analysis (median DFS: 20 vs 15 months, P < 0.01). PNI was the only independent predictor of DFS in R0/N0 tumors (hazard ratio [HR]: 2.2) and in PDAC ≤ 20 mm (HR: 1.8). PNI was an independent predictor of OS in the entire cohort (27 vs 50 months, P = 0.01), together with G3 tumors, pN1 status, carbohydrate antigen (CA) 19.9 >37 and pain. PNI represents a major determinant of tumor recurrence and patients' survival in pancreatic cancer. The role of PNI is particularly relevant in early stages, supporting the hypothesis that invasion of nerves by cancer cells has a driving role in pancreatic cancer progression.