Analysis Of Pancreatic Ductal Adenocarcinoma Research Articles

Long-term outcomes and risk factors of pancreatic insufficiency after a pancreatoduodenectomy: A retrospective study

BackgroundAn increasing number of patients are achieving long-term survival after pancreatoduodenectomy, meaning that risk assessments of endocrine and exocrine pancreatic insufficiency are needed. Herein, we investigated the risk factors for pancreatic insufficiency after pancreatoduodenectomy by incorporating pancreatic morphologic changes and perioperative factors. MethodsPatients who underwent pancreatoduodenectomy between January 2015 and December 2020 were enrolled in this single-center retrospective study. Clinicopathologic, surgical, and pancreatic morphologic factors were collected, and risk factors for exocrine pancreatic insufficiency and endocrine pancreatic insufficiency were analyzed. Exocrine pancreatic insufficiency was defined as steatorrhea requiring pancreatic enzymes and new onset steatosis, and endocrine pancreatic insufficiency was defined as postoperative new-onset diabetes mellitus. Multivariate analysis was performed. ResultsAmong the 206 patients enrolled, 14% and 24% developed endocrine pancreatic insufficiency and exocrine pancreatic insufficiency, respectively. Multivariate analysis revealed residual pancreatic stent 1 year postoperatively, lymph node metastasis, and postoperative pancreatic atrophy (P-atrophy) as independent risk factors for exocrine pancreatic insufficiency, whereas preoperative glycated hemoglobin levels, residual pancreatic stent, and postoperative main pancreatic duct dilatation were risk factors for endocrine pancreatic insufficiency. Subgroup analysis of pancreatic ductal adenocarcinoma revealed that exocrine pancreatic insufficiency in patients with pancreatic ductal adenocarcinoma was caused by preoperative decreased pancreatic function (high glycated hemoglobin and a low postoperative pancreatic fistula rate), whereas the high incidence of POPF influenced the development of exocrine pancreatic insufficiency in patients without pancreatic ductal adenocarcinoma. ConclusionPostoperative pancreatic atrophy and main pancreatic duct dilatation are risk factors for exocrine pancreatic insufficiency I and endocrine pancreatic insufficiency, respectively, and residual pancreatic stent affects both types of pancreatic dysfunction. Improving the surgical approach and stent management may help prevent these late complications.

Stage analysis of pancreatic ductal adenocarcinoma via network analysis.

This study aimed to introduce a biomarker panel to detect pancreatic ductal adenocarcinoma (PDAC) in the early stage, and also differentiate of stages from each other. PDAC is a lethal cancer with poor prognosis and overall survival. Gene expression profiles of PDAC patients were extracted from the Gene Expression Omnibus (GEO) database. The genes that were significantly differentially expressed (DEGs) for Stages I, II, and III in comparison to the healthy controls were identified. The determined DEGs were assessed via protein-protein interaction (PPI) network analysis, and the hub-bottleneck nodes of analyzed networks were introduced. A number of 140, 874, and 1519 significant DEGs were evaluated via PPI network analysis. A biomarker panel including ALB, CTNNB1, COL1A1, POSTN, LUM, and ANXA2 is presented as a biomarker panel to detect PDAC in the early stage. Two biomarker panels are suggested to recognize other stages of illness. It can be concluded that ALB, CTNNB1, COL1A1, POSTN, LUM, and ANXA2 and also FN1, HSP90AA1, LOX, ANXA5, SERPINE1, and WWP2 beside GAPDH, AKT1, EGF, CASP3 are suitable sets of gene to separate stages of PDAC.

Coordinated single-cell tumor microenvironment dynamics reinforce pancreatic cancer subtype

Bulk analyses of pancreatic ductal adenocarcinoma (PDAC) samples are complicated by the tumor microenvironment (TME), i.e. signals from fibroblasts, endocrine, exocrine, and immune cells. Despite this, we and others have established tumor and stroma subtypes with prognostic significance. However, understanding of underlying signals driving distinct immune and stromal landscapes is still incomplete. Here we integrate 92 single cell RNA-seq samples from seven independent studies to build a reproducible PDAC atlas with a focus on tumor-TME interdependence. Patients with activated stroma are synonymous with higher myofibroblastic and immunogenic fibroblasts, and furthermore show increased M2-like macrophages and regulatory T-cells. Contrastingly, patients with ‘normal’ stroma show M1-like recruitment, elevated effector and exhausted T-cells. To aid interoperability of future studies, we provide a pretrained cell type classifier and an atlas of subtype-based signaling factors that we also validate in mouse data. Ultimately, this work leverages the heterogeneity among single-cell studies to create a comprehensive view of the orchestra of signaling interactions governing PDAC.

Proteogenomic landscape of human pancreatic ductal adenocarcinoma in an Asian population reveals tumor cell-enriched and immune-rich subtypes.

We report a proteogenomic analysis of pancreatic ductal adenocarcinoma (PDAC). Mutation-phosphorylation correlations identified signaling pathways associated with somatic mutations in significantly mutated genes. Messenger RNA-protein abundance correlations revealed potential prognostic biomarkers correlated with patient survival. Integrated clustering of mRNA, protein and phosphorylation data identified six PDAC subtypes. Cellular pathways represented by mRNA and protein signatures, defining the subtypes and compositions of cell types in the subtypes, characterized them as classical progenitor (TS1), squamous (TS2-4), immunogenic progenitor (IS1) and exocrine-like (IS2) subtypes. Compared with the mRNA data, protein and phosphorylation data further classified the squamous subtypes into activated stroma-enriched (TS2), invasive (TS3) and invasive-proliferative (TS4) squamous subtypes. Orthotopic mouse PDAC models revealed a higher number of pro-tumorigenic immune cells in TS4, inhibiting T cell proliferation. Our proteogenomic analysis provides significantly mutated genes/biomarkers, cellular pathways and cell types as potential therapeutic targets to improve stratification of patients with PDAC.

Differentially Expressed Genes Enrichment Analysis of Pancreatic Ductal Adenocarcinoma and Pancreatic Intraepithelial Neoplasia; an In Silico Study

Abstract Introduction/Objective Pancreatic ductal adenocarcinoma (PDAC) is a leading cause of cancer-related death in the United States. Determining the genetic alterations involved in the formation of PDAC and its precursor, pancreatic intraepithelial neoplasia (PanIN), may lead to earlier detection and new therapeutic options. We performed an analysis of the genetic alterations responsible for the progression of the normal pancreatic tissue to PanIN and ultimately from PanIN to PDAC. Methods/Case Report Initially, we used the continuous bioinformatic analysis in such a way that the RNA-seq datasets were extracted from the Biojupies database. We separately analyzed two datasets that included PDAC and PanIN, where their differentially expressed genes (DEGs) were obtained by comparison with controls. A Venn diagram was drawn to visualize the overlapping and non-overlapping DEGs in both groups. Using the Enrichr and ShinyGO databases, we examined the cell signaling pathways and ontologies of up/down-regulated genes. We mapped the protein network of important genes involved in cancer pathways by the STRING database. Finally, the shared and non-shared candidate proteins in the PDAC and PanIN pathways with the GEPIA database were confirmed in human samples. Results (if a Case Study enter NA) We found six shared genes in PDAC and PanIN including RAC1, RAP1A, ITGA5, RHOA, FZD2, and FN1, which appear to take part in the transition of PanIN to PDAC. Our result showed that the aforementioned genes are critical in the cell cycle, angiogenesis, and cell death processes. In the next step, the DEGs analysis in both PDAC and PanIN revealed the role of candidate genes (COX5B, NME2, MGLL, and PAICS for PanIN and PRKCA, PLCG2, NOS3, and PTK2 for PDAC) in cellular aging, MAPK, and PI3K/Akt signaling pathways. Conclusion Our findings showed that the overexpression of RAC1, RAP1A, ITGA5, RHOA, FZD2, and FN1 may have an important role in PanIN shifting to PDAC.

Neoplastic cell enrichment of tumor tissues using coring and laser microdissection for proteomic and genomic analyses of pancreatic ductal adenocarcinoma

BackgroundThe identification of differentially expressed tumor-associated proteins and genomic alterations driving neoplasia is critical in the development of clinical assays to detect cancers and forms the foundation for understanding cancer biology. One of the challenges in the analysis of pancreatic ductal adenocarcinoma (PDAC) is the low neoplastic cellularity and heterogeneous composition of bulk tumors. To enrich neoplastic cells from bulk tumor tissue, coring, and laser microdissection (LMD) sampling techniques have been employed. In this study, we assessed the protein and KRAS mutation changes associated with samples obtained by these enrichment techniques and evaluated the fraction of neoplastic cells in PDAC for proteomic and genomic analyses.MethodsThree fresh frozen PDAC tumors and their tumor-matched normal adjacent tissues (NATs) were obtained from three sampling techniques using bulk, coring, and LMD; and analyzed by TMT-based quantitative proteomics. The protein profiles and characterizations of differentially expressed proteins in three sampling groups were determined. These three PDACs and samples of five additional PDACs obtained by the same three sampling techniques were also subjected to genomic analysis to characterize KRAS mutations.ResultsThe neoplastic cellularity of eight PDACs ranged from less than 10% to over 80% based on morphological review. Distinctive proteomic patterns and abundances of certain tumor-associated proteins were revealed when comparing the tumors and NATs by different sampling techniques. Coring and bulk tissues had comparable proteome profiles, while LMD samples had the most distinct proteome composition compared to bulk tissues. Further genomic analysis of bulk, cored, or LMD samples demonstrated that KRAS mutations were significantly enriched in LMD samples while coring was less effective in enriching for KRAS mutations when bulk tissues contained a relatively low neoplastic cellularity.ConclusionsIn addition to bulk tissues, samples from LMD and coring techniques can be used for proteogenomic studies. The greatest enrichment of neoplastic cellularity is obtained with the LMD technique.

Loss of FGFR4 promotes the malignant phenotype of PDAC

Transcriptomic analyses of pancreatic ductal adenocarcinoma (PDAC) have identified two major epithelial subtypes with distinct biology and clinical behaviours. Here, we aimed to clarify the role of FGFR1 and FGFR4 in the definition of aggressive PDAC phenotypes. We found that the expression of FGFR4 is exclusively detected in epithelial cells, significantly elevated in the classical PDAC subtype, and associates with better outcomes. In highly aggressive basal-like/squamous PDAC, reduced FGFR4 expression aligns with hypermethylation of the gene and lower levels of histone marks associated with active transcription in its regulatory regions. Conversely, FGFR1 has more promiscuous expression in both normal and malignant pancreatic tissues and is strongly associated with the EMT phenotype but not with the basal-like cell lineage. Regardless of the genetic background, the increased proliferation of FGFR4-depleted PDAC cells correlates with hyperactivation of the mTORC1 pathway both in vitro and in vivo. Downregulation of FGFR4 in classical cell lines invariably leads to the enrichment of basal-like/squamous gene programs and is associated with either partial or full switch of phenotype. In sum, we show that endogenous levels of FGFR4 limit the malignant phenotype of PDAC cells. Finally, we propose FGFR4 as a valuable marker for the stratification of PDAC patients.

P53-driven lipidome influences non-cell-autonomous lysophospholipids in pancreatic cancer

Adaptation of the lipid metabolism participates in cancer pathogenesis, facilitating energy storage and influencing cell fate and control of molecular signalling. The tumour suppressor protein p53 is a molecular hub of cell metabolism, supporting antioxidant capabilities and counteracting oncogene-induced metabolic switch. Despite extensive work has described the p53-dependent metabolic pathways, a global profiling of p53 lipidome is still missing. By high-throughput untargeted lipidomic analysis of pancreatic ductal adenocarcinoma (PDAC) cells, we profile the p53-dependent lipidome, revealing intracellular and secreted lysophospholipids as one of the most affected class. Lysophospholipids are hydrolysed forms of phospholipids that results from phospholipase activity, which can function as signalling molecules, exerting non-cell-autonomous effects and instructing cancer microenvironment and immunity. Here, we reveal that p53 depletion reduces abundance of intracellular lysophosphatidyl-choline, -ethanolamine and -serine and their secretion in the extracellular environment. By integrating this with genomic and transcriptomic studies from in vitro models and human PDAC patients, we identified potential clinically relevant candidate p53-dependent phospholipases. In particular PLD3, PLCB4 and PLCD4 expression is regulated by p53 and chromatin immunoprecipitation followed by deep sequencing (ChIP-seq) indicates a direct transcriptional control on their chromatin accessible genomic loci. Consistently, PLD3, PLCB4 and PLCD4 expression correlates with p53 mutational status in PDAC patients, and these genes display prognostic significance. Overall, our data provide insights into lipidome rewiring driven by p53 loss and identify alterations of lysophospholipids as a potential molecular mechanism for p53-mediated non-cell-autonomous molecular signalling that instructs cancer microenvironment and immunity during PDAC pathogenesis.

Genome analyses of pancreatic ductal adenocarcinoma: Current status and future perspectives

Genome analyses of pancreatic ductal adenocarcinoma: Current status and future perspectives

Metabolic detection and systems analyses of pancreatic ductal adenocarcinoma through machine learning, lipidomics, and multi-omics.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers, characterized by rapid progression, metastasis, and difficulty in diagnosis. However, there are no effective liquid-based testing methods available for PDAC detection. Here we introduce a minimally invasive approach that uses machine learning (ML) and lipidomics to detect PDAC. Through greedy algorithm and mass spectrum feature selection, we optimized 17 characteristic metabolites as detection features and developed a liquid chromatography-mass spectrometry-based targeted assay. In this study, 1033 patients with PDAC at various stages were examined. This approach has achieved 86.74% accuracy with an area under curve (AUC) of 0.9351 in the large external validation cohort and 85.00% accuracy with 0.9389 AUC in the prospective clinical cohort. Accordingly, single-cell sequencing, proteomics, and mass spectrometry imaging were applied and revealed notable alterations of selected lipids in PDAC tissues. We propose that the ML-aided lipidomics approach be used for early detection of PDAC.

Abstract LBA024: IL-36γ induces immune infiltration and suppresses tumor growth in a syngeneic mouse model for pancreatic cancer

Abstract Pancreatic cancer (PC) is one of the most aggressive and lethal types of cancer. It is the third leading cause of cancer-related mortality in U.S., accounting for 6% of annual death. Immunotherapeutic strategies such as immune checkpoint inhibitors have shown great success in a number of tumor types, but only with limited activity in patients with PC. Pancreatic tumor is characterized by the presence of dense stromal tissue which primarily consists of immune-suppressive fibroblasts. The immune microenvironment remains dysfunctional due to the lack of tumor infiltrating lymphocytes (TILs) and immune stimulatory molecules. Proinflammatory cytokines play a pivotal role in regulating tumor immunogenicity and antitumor immunity. Elucidating the role of proinflammatory host mediators can contribute to the development of new therapies for PC. IL-36γ, a proinflammatory mediator is important for the IL-23/IL-17-dominated inflammation and induces Th1 immune responses. The role of IL-36γ in pancreatic tumor immunity has not been well studied. In this study, we examined the expression and functional regulation of IL-36γ in PC cells and found that IL-36γ cytokine treatment induces immune infiltration and suppresses tumor growth in a murine PC model. Immunohistochemical (IHC) analysis of pancreatic ductal adenocarcinoma (PDAC) specimens showed minimal IL-36γ positive staining, thus indicating very low expression of IL-36γ in PDAC. Intratumoral treatment with recombinant IL-36γ in a syngeneic mouse model of PDAC significantly inhibited tumor growth (57.8% inhibition after two weeks of treatment) without any significant animal weight loss compared to the vehicle control. Flow cytometry analysis showed increased infiltration of lymphocyte subsets (CD45+ and CD3+ cells) in tumors derived from the IL-36γ treated mice. Further studies are ongoing to investigate the effect of IL-36γ treatment on dendritic cells and macrophages in PDAC tumors. Our study establishes the potential role of IL-36γ in promoting antitumor immune responses and lay the foundation for clinical application in PC (This work was supported by TGen’s Women Philanthropy Council). Citation Format: Kuntal Halder, Daniel D Von Hoff, Haiyong Han. IL-36γ induces immune infiltration and suppresses tumor growth in a syngeneic mouse model for pancreatic cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr LBA024.

Single-cell analysis of pancreatic ductal adenocarcinoma identifies a novel fibroblast subtype associated with poor prognosis but better immunotherapy response

The current pathological and molecular classification of pancreatic ductal adenocarcinoma (PDAC) provides limited guidance for treatment options, especially for immunotherapy. Cancer-associated fibroblasts (CAFs) are major players of desmoplastic stroma in PDAC, modulating tumor progression and therapeutic response. Using single-cell RNA sequencing, we explored the intertumoral heterogeneity among PDAC patients with different degrees of desmoplasia. We found substantial intertumoral heterogeneity in CAFs, ductal cancer cells, and immune cells between the extremely dense and loose types of PDACs (dense-type, high desmoplasia; loose-type, low desmoplasia). Notably, no difference in CAF abundance was detected, but a novel subtype of CAFs with a highly activated metabolic state (meCAFs) was found in loose-type PDAC compared to dense-type PDAC. MeCAFs had highly active glycolysis, whereas the corresponding cancer cells used oxidative phosphorylation as a major metabolic mode rather than glycolysis. We found that the proportion and activity of immune cells were much higher in loose-type PDAC than in dense-type PDAC. Then, the clinical significance of the CAF subtypes was further validated in our PDAC cohort and a public database. PDAC patients with abundant meCAFs had a higher risk of metastasis and a poor prognosis but showed a dramatically better response to immunotherapy (64.71% objective response rate, one complete response). We characterized the intertumoral heterogeneity of cellular components, immune activity, and metabolic status between dense- and loose-type PDACs and identified meCAFs as a novel CAF subtype critical for PDAC progression and the susceptibility to immunotherapy.

CT Simplified Radiomic Approach to Assess the Metastatic Ductal Adenocarcinoma of the Pancreas.

The aim of this study was to perform a simplified radiomic analysis of pancreatic ductal adenocarcinoma based on qualitative and quantitative tumor features and to compare the results between metastatic and non-metastatic patients. A search of our radiological, surgical, and pathological databases identified 1218 patients with a newly diagnosed pancreatic ductal adenocarcinoma who were referred to our Institution between January 2014 and December 2018. Computed Tomography (CT) examinations were reviewed analyzing qualitative and quantitative features. Two hundred eighty-eight patients fulfilled the inclusion criteria and were included in this study. Overall, metastases were present at diagnosis in 86/288 patients, while no metastases were identified in 202/288 patients. Ill-defined margins and a hypodense appearance on portal-phase images were significantly more common among patients with metastases compared to non-metastatic patients (p < 0.05). Metastatic tumors showed a significantly larger size and significantly lower arterial index, perfusion index, and permeability index compared to non-metastatic tumors (p < 0.05). In the management of pancreatic ductal adenocarcinoma, early detection and correct staging are key elements. The study of computerized tomography characteristics of pancreatic ductal adenocarcinoma showed substantial differences, both qualitative and quantitative, between metastatic and non-metastatic disease.

Regulation of ABCG2 expression by Wnt5a through FZD7 in human pancreatic cancer cells.

ATP-binding cassette subfamily G member 2 (ABCG2), a member of the ABC transporter superfamily, has been implicated in the development of chemotherapeutic drug resistance in cancer cells. However, the regulators of ABCG2 expression and their roles in anticancer drug resistance have not been fully characterized, especially in the context of pancreatic cancer. The aim of the present study was to investigate whether ABCG2 contributed to drug resistance in pancreatic cancer and to elucidate its regulatory molecular pathways. Using immunohistochemical analysis of pancreatic ductal adenocarcinoma and adjacent healthy tissue samples, the present study identified a positive correlation between ABCG2 and Wnt5a, a member of the Wnt family of secreted proteins. It was also determined that treatment with recombinant human Wnt5a protein could upregulate the expression of ABCG2 in the Capan-2 human pancreatic cancer cell line and enhance its resistance to gemcitabine. The upregulation of ABCG2 by Wnt5a was inhibited by small interfering RNA silencing of Frizzled class receptor 7 (FZD7) or by FZD7 inhibitors. Moreover, both FZD7 silencing or inhibition of its function attenuated gemcitabine resistance induced by Wnt5a in Capan-2 cells. Therefore, the present findings suggested that Wnt5a and FZD7 acted as upstream regulators of ABCG2 expression and that FZD7 may be an essential factor for Wnt5a-induced gemcitabine resistance in pancreatic cancer cells.

PDX-derived organoids model in vivo drug response and secrete biomarkers.

Patient-derived organoid models are proving to be a powerful platform for both basic and translational studies. Here we conduct a methodical analysis of pancreatic ductal adenocarcinoma (PDAC) tumor organoid drug response in paired patient-derived xenograft (PDX) and PDX-derived organoid (PXO) models grown under WNT-free culture conditions. We report a specific relationship between area under the curve value of organoid drug dose response and in vivo tumor growth, irrespective of the drug treatment. In addition, we analyzed the glycome of PDX and PXO models and demonstrate that PXOs recapitulate the in vivo glycan landscape. In addition, we identify a core set of 57 N-glycans detected in all 10 models that represent 50%–94% of the relative abundance of all N-glycans detected in each of the models. Last, we developed a secreted biomarker discovery pipeline using media supernatant of organoid cultures and identified potentially new extracellular vesicle (EV) protein markers. We validated our findings using plasma samples from patients with PDAC, benign gastrointestinal diseases, and chronic pancreatitis and discovered that 4 EV proteins are potential circulating biomarkers for PDAC. Thus, we demonstrate the utility of organoid cultures to not only model in vivo drug responses but also serve as a powerful platform for discovering clinically actionable serologic biomarkers.

Abstract PR02: Matched metastatic pancreatic ductal adenocarcinoma biopsies and organoid models reveal tumor cell transcriptional plasticity and subtype-specific microenvironmental crosstalk

Abstract The majority of patients with pancreatic ductal adenocarcinoma (PDAC) present with metastatic disease at diagnosis and have median survival times of less than 12 months. Recent studies have demonstrated that PDAC tumors with distinct transcriptional signatures are associated with different clinical outcomes, and that the tumor microenvironment may contribute to PDAC pathogenesis. In parallel, there are ongoing efforts to understand if patient-derived organoid models can be used as functional surrogates for an individual patient’s disease. However, it remains unclear if patient transcriptional phenotypes are preserved in their matched organoid models. Here, we describe a pipeline that permits both direct characterization of the PDAC liver metastatic niche via single-cell RNA-sequencing and functional assessment of PDAC tumor biology in patient-matched organoid models. Starting from core needle biopsies of metastatic PDAC lesions containing 50-100k viable cells, we simultaneously perform (1) low-input single-cell RNA-sequencing using Seq-Well and (2) three-dimensional organoid culture generation. We have applied this approach to profile 21 patients and their matched early passage organoid models. Our pipeline yields high-quality single-cell measurements across diverse cell types—both tumor and nontumor stromal—enabling a principled dissection of tumor intrinsic and extrinsic factors. Evaluation of clinically relevant transcriptional signatures (e.g., basal-like vs. classical) revealed extensive heterogeneity at the single-cell level and identified new, hybrid expression states. We also observed evidence of significant subtype-specific crosstalk between immune populations and tumor cells—specifically between T cells and tumor cells originating from basal-like tumors. Serial sampling at different stages of treatment revealed transcriptional shifts in tumor cells suggestive of significant plasticity. We similarly found that organoids derived from basal-like tumors exhibited considerable plasticity in vitro and had decreased fitness in standard organoid culture conditions, suggesting the need for distinct environments to support specific transcriptional subtypes. Overall, our approach provides actionable insights into the heterogeneity and plasticity of human PDAC, as well as a pipeline and framework for the analysis of PDAC and other cancers. This abstract is also being presented as Poster A50. Citation Format: Peter S. Winter, Srivatsan Raghavan, Andrew W. Navia, Hannah Williams, Jennyfer Galvez-Reyes, Radha Kalekar, Ashir Borah, Alan DenAdel, Manisha Raghavan, Kristen Lowder, Nolawit Mulugeta, Junning Wang, Emma Reilly, Lauren Brais, Lorin Crawford, James McFarland, James M. Cleary, Jonathan Nowak, Brian M. Wolpin, Andrew J. Aguirre, William C. Hahn, Alex K. Shalek. Matched metastatic pancreatic ductal adenocarcinoma biopsies and organoid models reveal tumor cell transcriptional plasticity and subtype-specific microenvironmental crosstalk [abstract]. In: Proceedings of the AACR Special Conference on the Evolving Landscape of Cancer Modeling; 2020 Mar 2-5; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2020;80(11 Suppl):Abstract nr PR02.

Cross-Species Single-Cell Analysis of Pancreatic Ductal Adenocarcinoma Reveals Antigen-Presenting Cancer-Associated Fibroblasts.

Cancer-associated fibroblasts (CAF) are major players in the progression and drug resistance of pancreatic ductal adenocarcinoma (PDAC). CAFs constitute a diverse cell population consisting of several recently described subtypes, although the extent of CAF heterogeneity has remained undefined. Here we use single-cell RNA sequencing to thoroughly characterize the neoplastic and tumor microenvironment content of human and mouse PDAC tumors. We corroborate the presence of myofibroblastic CAFs and inflammatory CAFs and define their unique gene signatures in vivo. Moreover, we describe a new population of CAFs that express MHC class II and CD74, but do not express classic costimulatory molecules. We term this cell population "antigen-presenting CAFs" and find that they activate CD4+ T cells in an antigen-specific fashion in a model system, confirming their putative immune-modulatory capacity. Our cross-species analysis paves the way for investigating distinct functions of CAF subtypes in PDAC immunity and progression. SIGNIFICANCE: Appreciating the full spectrum of fibroblast heterogeneity in pancreatic ductal adenocarcinoma is crucial to developing therapies that specifically target tumor-promoting CAFs. This work identifies MHC class II-expressing CAFs with a capacity to present antigens to CD4+ T cells, and potentially to modulate the immune response in pancreatic tumors.See related commentary by Belle and DeNardo, p. 1001.This article is highlighted in the In This Issue feature, p. 983.

Gemcitabine enhances the transport of nanovector-albumin-bound paclitaxel in gemcitabine-resistant pancreatic ductal adenocarcinoma

The mechanism for improved therapeutic efficacy of the combination therapy with nanoparticle albumin-bound paclitaxel (nAb-PTX) and gemcitabine (gem) for pancreatic ductal adenocarcinoma (PDAC) has been ascribed to enhanced gem transport by nAb-PTX. Here, we used an orthotopic mouse model of gem-resistant human PDAC in which increasing gem transport would not improve the efficacy, thus revealing the importance of nAb-PTX transport. We aimed to evaluate therapeutic outcomes and transport of nAb-PTX to PDAC as a result of (1) encapsulating nAb-PTX in multistage nanovectors (MSV); (2) effect of gem on caveolin-1 expression. Treatment with MSV/nAb-PTX + gem was highly efficient in prolonging animal survival in comparison to other therapeutic regimens. MSV/nAb-PTX + gem also caused a substantial increase in tumor PTX accumulation, significantly reduced tumor growth and tumor cell proliferation, and increased apoptosis. Moreover, gem enhanced caveolin-1 expression in vitro and in vivo, thereby improving transport of nAb-PTX to PDAC. This data was confirmed by analysis of PDACs from patients who received gem-based neo-adjuvant chemotherapy. In conclusion, we found that nAb-PTX treatment of gem-resistant PDAC can be enhanced by (1) gem through up-regulation of caveolin-1 and (2) MSV through increasing accumulation of nAb-PTX in the tumor.

Lymph node ratio, tumour volume but not size are a good prognostic factors after resection of pancreatic ductal adenocarcinoma analysis of high volume centre

Lymph node ratio, tumour volume but not size are a good prognostic factors after resection of pancreatic ductal adenocarcinoma analysis of high volume centre

Splice variants as novel targets in pancreatic ductal adenocarcinoma

Despite a wealth of genomic information, a comprehensive alternative splicing (AS) analysis of pancreatic ductal adenocarcinoma (PDAC) has not been performed yet. In the present study, we assessed whole exome-based transcriptome and AS profiles of 43 pancreas tissues using Affymetrix exon array. The AS analysis of PDAC indicated on average two AS probe-sets (ranging from 1–28) in 1,354 significantly identified protein-coding genes, with skipped exon and alternative first exon being the most frequently utilised. In addition to overrepresented extracellular matrix (ECM)-receptor interaction and focal adhesion that were also seen in transcriptome differential expression (DE) analysis, Fc gamma receptor-mediated phagocytosis and axon guidance AS genes were also highly represented. Of note, the highest numbers of AS probe-sets were found in collagen genes, which encode the characteristically abundant stroma seen in PDAC. We also describe a set of 37 ‘hypersensitive’ genes which were frequently targeted by somatic mutations, copy number alterations, DE and AS, indicating their propensity for multidimensional regulation. We provide the most comprehensive overview of the AS landscape in PDAC with underlying changes in the spliceosomal machinery. We also collate a set of AS and DE genes encoding cell surface proteins, which present promising diagnostic and therapeutic targets in PDAC.