Role and functional mechanisms of IL­17/IL­17R signaling in pancreatic cancer (Review).

Interleukin­17 (IL­17), an inflammatory cytokine primarily secreted by T helper 17 cells, serves a crucial role in numerous inflammatory diseases and malignancies via its receptor, IL­17R. In addition to stimulating inflammatory responses, IL­17 exhibits dual functions in tumors, exerting both pro­ and antitumor effects. Pancreatic ductal adenocarcinoma (PDAC) is the most common pancreatic malignancy and accounts for >90% of pancreatic cancer cases. PDAC is characterized by a prominent stromal microenvironment with significant heterogeneity, which contributes to treatment resistance. IL­17/IL­17R signaling has a notable effect on tumorigenesis, the tumor microenvironment and treatment efficacy in various cancer types, including PDAC. However, the specific mechanisms of IL­17/IL­17R signaling in pancreatic cancer remain uncertain. This review presents a brief overview of the current knowledge and recent advances in the role and functional mechanisms of IL­17/IL­17R signaling in pancreatic cancer. Furthermore, the potential of IL­17­targeted therapeutic strategies for PDAC treatment is also discussed.

Drug resistant pancreatic cancer cells exhibit altered biophysical interactions with stromal fibroblasts in imaging studies of 3D co-culture models.

Interactions between tumor and stromal cells are well known to play prominent roles in progression of pancreatic ductal adenocarcinoma (PDAC). As knowledge of stromal crosstalk in PDAC has evolved, it has become clear that cancer associated fibroblasts can play both tumor promoting and tumor suppressive roles through a combination of paracrine crosstalk and juxtacrine interactions involving direct physical contact. Another major contributor to dismal survival statistics for PDAC is development of resistance to chemotherapy drugs, though less is known about how the acquisition of chemoresistance impacts upon tumor-stromal crosstalk. Here, we use time lapse imaging and image analysis to study how co-culture geometry impacts interactions between epithelial and stromal cells. We show that extracellular matrix (ECM) overlay cultures in which stromal cells (pancreatic stellate cells, or normal human fibroblasts) are placed adjacent to PDAC cells (PANC1) result in direct heterotypic cell adhesions accompanied by dramatic fibroblast contractility. We analyze these interactions in co-cultures using particle image velocimetry (PIV) analysis to quantify cell velocities over the course of time lapse movie sequences. We further contrast co-cultures of PANC1 with those containing a drug resistant subline (PANC1-OR) previously established in our lab and find that heterotypic cell-cell interactions are suppressed in the latter relative to the parental line. We use RNA-seq and bioinformatics analysis to identify differential gene expression in PANC1 and PANC1-OR, which shows that negative regulation of cell adhesion molecules, consistent with increased epithelial mesenchymal transition (EMT), is also correlated with reduction in the hetrotypic cell-cell contact necessary for the contractile behavior observed in drug naïve cultures. Overall these findings elucidate the role of drug-resistance in inhibiting an avenue of stromal crosstalk which is associated with tumor suppression and also help to establish cell culture conditions useful for further mechanistic investigation.

Adding-on nivolumab to chemotherapy-stabilized patients is associated with improved survival in advanced pancreatic ductal adenocarcinoma.

BACKGROUND: Immune checkpoint inhibitors (ICIs) are rarely used to treat advanced pancreatic ductal adenocarcinoma (PDAC) due to marginal efficacy. PATIENTS AND METHODS: This study included 92 consecutive patients diagnosed with advanced or recurrent PDAC who received nivolumab-based treatment. Univariate and multivariate analyses were used to identify prognostic factors. A control group of 301 patients with PDAC who achieved disease control with palliative chemotherapy but without ICIs was selected for comparison using propensity score matching (PSM). RESULTS: The median overall survival (OS) since nivolumab treatment was 15.8 (95% confidence interval [CI], 12.5-19.0), 2.4 (95% CI 1.2-3.6), and 1.1 (95% CI 1.0-1.2) months in patients who received add-on nivolumab after achieving disease control with chemotherapy, in those who received concomitant nivolumab and chemotherapy without prerequisite confirmation of disease control, and in those who received nivolumab without concomitant chemotherapy, respectively (P < 0.001). After PSM, the median overall survival (OS) since initiation of the concomitant chemotherapy that achieved disease control was significantly longer (P = 0.026) in patients who received add-on nivolumab (19.8 months; 95% CI 14.5-25.1) than in those who received chemotherapy alone (13.8 months; 95% CI 10.8-16.9). The immune profiling of the tumors in resected patients revealed higher scores of CD8+ T cells to Tregs in patients with add-on nivolumab comparing to those who received chemotherapy alone. CONCLUSION: Adding-on nivolumab was associated with improved OS in patients with advanced PDAC who achieved disease control following chemotherapy.

Kinome state is predictive of cell viability in pancreatic cancer tumor and cancer-associated fibroblast cell lines.

Numerous aspects of cellular signaling are regulated by the kinome-the network of over 500 protein kinases that guides and modulates information transfer throughout the cell. The key role played by both individual kinases and assemblies of kinases organized into functional subnetworks leads to kinome dysregulation driving many diseases, particularly cancer. In the case of pancreatic ductal adenocarcinoma (PDAC), a variety of kinases and associated signaling pathways have been identified for their key role in the establishment of disease as well as its progression. However, the identification of additional relevant therapeutic targets has been slow and is further confounded by interactions between the tumor and the surrounding tumor microenvironment. In this work, we attempt to link the state of the human kinome, or kinotype, with cell viability in treated, patient-derived PDAC tumor and cancer-associated fibroblast cell lines. We applied classification models to independent kinome perturbation and kinase inhibitor cell screen data, and found that the inferred kinotype of a cell has a significant and predictive relationship with cell viability. We further find that models are able to identify a set of kinases whose behavior in response to perturbation drive the majority of viability responses in these cell lines, including the understudied kinases CSNK2A1/3, CAMKK2, and PIP4K2C. We next utilized these models to predict the response of new, clinical kinase inhibitors that were not present in the initial dataset for model devlopment and conducted a validation screen that confirmed the accuracy of the models. These results suggest that characterizing the perturbed state of the human protein kinome provides significant opportunity for better understanding of signaling behavior and downstream cell phenotypes, as well as providing insight into the broader design of potential therapeutic strategies for PDAC.

Pancreatoduodenectomy with superior mesenteric vein resection and non-reconstruction for pancreatic head cancer paying particular attention to hemodynamics.

PURPOSE: Locally advanced pancreatic ductal adenocarcinoma (PDAC) with an unreconstructible superior mesenteric vein (SMV) invasion is one of the criteria of unresectability in the National Comprehensive Cancer Network guidelines. Advances in chemotherapy have improved downstaging and conversion surgery outcomes, thereby broadening surgical options for locally advanced PDAC. However, operations for PDAC with an unreconstructible SMV is less well-documented. If the collateral route is well-developed and can be preserved or reconstructed, SMV resection can be performed without reconstruction. In this paper, we detail our surgical technique and the outcomes for patients undergoing pancreatoduodenectomy with SMV resection and non-reconstruction (PD-SMVR-NR). METHODS: All consecutive patients with pancreatic head cancer who underwent PD at Juntendo University Hospital, Japan, between January 2019 and December 2022 were evaluated from a prospectively maintained preoperative database. Demographic data, clinical history, operative record, morbidity, mortality, and pathologic data were reviewed. RESULTS: Over four years at our Institute, 161 patients with pancreatic head cancer underwent PD, and 86 of these patients underwent PD with portal vein (PV) or SMV resection. There were three patients who underwent PD-SMVR-NR. Each patient had well-developed collateral vessels bypassing the obstructed segment of the SMV. All three patients had no hospital mortality with acceptable complications (Clavien-Dindo grade 2). Two patients achieved R0 resection. CONCLUSION: By understanding the hemodynamics of venous flow and preserving collateral vessels, especially the superior right colic vein arcade and porto-mesenterico-splenic confluence, pancreatoduodenectomy with superior mesenteric vein resection and non-reconstruction can be performed safely.

Complementary techniques for the reliable characterisation of tissue samples: A case study on pancreatic tumours analysed by means of X-ray fluorescence analysis and IR spectroscopy.

An improvement in the reliability and comparability of tissue characterization results is crucial for enabling further progress in cancer detection and the assessment of therapeutic effects. This can only be achieved by integrating quantitative methods into well-established qualitative characterization routines. This case study presents a hybrid metrological approach for tissue characterisation including vibrational Fourier Transform InfraRed (FTIR) spectroscopy and traceable reference-free X-Ray Fluorescence analysis (XRF). Through the combination of spatially resolved qualitative molecular information with quantitative elemental concentrations an all-encompassing sample characterisation can be provided. The study was performed on tissue sections of syngeneic murine pancreatic ductal adenocarcinoma KPC (KrasG12D/+; Trp53R172H/+; Pdx-1-Cre) tumours ex-vivo. Sections from healthy pancreatic tissues, sham-exposed tumours and tumours subjected to low dose radiotherapy treatment (2 Gray and 6 Gray) were analysed using both methods. Additional sample integrity studies using Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy at the carbon and nitrogen K-edges were performed to assess the effect of sample aging and XRF investigations on the samples. Results showed an increase in the concentrations of elemental biomarkers, including S, K and amide I structures in malignant pancreatic tissue compared to healthy pancreatic tissue. The exposure of tumours to 6 Gy radiation decreases the levels of these elements towards a phenotype seen in the healthy pancreas. A protocol for hybrid investigations is presented, with emphasis on the sample preparation, minimizing the impact of consecutive applied methods on their measurands, and ensuring the compatibility and reliability of achieved results. The study demonstrates the cancer recognition capabilities, and the sensitivity for low dosage radiotherapy treatment monitoring for each method individually and assesses the potential of combining molecular fingerprinting with non-destructive quantitative elemental information for tissue sample characterization.

Impact on survival of sarcopenia, systemic inflammatory response and anthropometric factors after pancreatectomy for resectable pancreatic adenocarcinoma.

INTRODUCTION: Pancreatic adenocarcinoma (PDAC) is becoming a public health issue with a 5-years survival rate around 10%. Patients with PDAC are often sarcopenic, which impacts postoperative outcome. At the same time, overweight population is increasing and adipose tissue promotes tumor related-inflammation. With several studies supporting independently these data, we aimed to assess if they held an impact on survival when combined. METHODS: We included 232 patients from two university hospitals (CHU de Lille, Institut Paoli Calmette), from January 2011 to December 2018, who underwent Pancreaticoduodenectomy (PD) for resectable PDAC. Preoperative CT scan was used to measure sarcopenia and visceral fat according to international cut-offs. Neutrophil to lymphocyte (NLR) and platelet to lymphocyte ratios (PLR) were used to measure inflammation. For univariate and multivariate analyses, the Cox proportional-hazard model was used. P-values below 0.05 were considered significant. RESULTS: Sarcopenic patients with visceral obesity were less likely to survive than the others in multivariate analysis (OS, HR 1.65, p= 0.043). Cutaneous obesity did not influence survival. We also observed an influence on survival when we studied sarcopenia with visceral obesity (OS, p= 0.056; PFS, p = 0.014), sarcopenia with cutaneous obesity (PFS, p= 0.005) and sarcopenia with PLR (PFS, p= 0.043). This poor prognosis was also found in sarcopenic obese patients with high PLR (OS, p= 0.05; PFS, p= 0.01). CONCLUSION: Sarcopenic obesity was associated with poor prognosis after PD for PDAC, especially in patients with systemic inflammation. Pre operative management of these factors should be addressed in pancreatic cancer patients.

Prognostic value of neutrophil to lymphocyte ratio in patients with advanced pancreatic ductal adenocarcinoma treated with systemic chemotherapy.

OBJECTIVES: Although systemic chemotherapy for pancreatic ductal adenocarcinoma (PDAC) has made progress, ensuring long-term survival remains difficult. There are several reports on the usefulness of neutrophil-to-lymphocyte ratio (NLR) in predicting the prognosis of PDAC, but few reports in systemic chemotherapy. We hereby investigated the usefulness of NLR in systemic chemotherapy for PDAC. MATERIALS AND METHODS: A retrospective study was conducted on patients with advanced PDAC treated with first-line systemic chemotherapy. Cox regression hazards models were performed to analyze the association between baseline patient characteristics and the initial treatment response, and overall survival (OS). RESULTS: A total of 60 patients with PDAC were enrolled. At baseline, there were significant differences in NLR and carbohydrate antigen 19-9 (CA19-9), as well as the selection rate of combination chemotherapy, between patients with partial response or stable disease and those with progressive disease. Univariate and multivariate analysis showed that NLR < 3.10, combination chemotherapy, and CA19-9 < 1011 U/mL were significant and independent predictive factors of the initial treatment response. Meanwhile, NLR < 3.10 and combination chemotherapy were independently associated with longer OS. Moreover, OS was significantly prolonged in patients with NLR < 3.10, regardless of whether combination chemotherapy or monotherapy. Patients with NLR < 3.10 at baseline had a significantly higher conversion rate to third-line chemotherapy and a longer duration of total chemotherapy. CONCLUSIONS: This study suggests that NLR may be a useful marker for predicting the initial treatment response to first-line chemotherapy and the prognosis for patients with advanced PDAC.

Induction of oxidative- and endoplasmic-reticulum-stress dependent apoptosis in pancreatic cancer cell lines by DDOST knockdown.

The dolichyl-diphosphooligosaccharide-protein glycosyltransferase non-catalytic subunit (DDOST) is a key component of the oligosaccharyltransferase complex catalyzing N-linked glycosylation in the endoplasmic reticulum lumen. DDOST is associated with several cancers and congenital disorders of glycosylation. However, its role in pancreatic cancer remains elusive, despite its enriched pancreatic expression. Using quantitative mass spectrometry, we identify 30 differentially expressed proteins and phosphopeptides (DEPs) after DDOST knockdown in the pancreatic ductal adenocarcinoma (PDAC) cell line PA-TU-8988T. We evaluated DDOST / DEP protein-protein interaction networks using STRING database, correlation of mRNA levels in pancreatic cancer TCGA data, and biological processes annotated to DEPs in Gene Ontology database. The inferred DDOST regulated phenotypes were experimentally verified in two PDAC cell lines, PA-TU-8988T and BXPC-3. We found decreased proliferation and cell viability after DDOST knockdown, whereas ER-stress, ROS-formation and apoptosis were increased. In conclusion, our results support an oncogenic role of DDOST in PDAC by intercepting cell stress events and thereby reducing apoptosis. As such, DDOST might be a potential biomarker and therapeutic target for PDAC.

Peritoneal washing cytology status as a crucial prognostic determinant in patients with localized pancreatic ductal adenocarcinoma who underwent curative-intent resection following preoperative chemoradiotherapy.

BACKGROUND: Prognostic implications of peritoneal washing cytology (CY) in patients with localized pancreatic ductal adenocarcinoma (PDAC) undergoing surgical resection following preoperative chemoradiotherapy (CRT) remain unclear. This study aimed to elucidate the prognostic significance and predictors of a positive CY status (CY+) after preoperative CRT. METHODS: Clinical data from 141 patients with localized PDAC who underwent curative-intent resection after preoperative CRT were retrospectively analyzed to examine the association between CY+ and clinicopathological factors and survival. RESULTS: CY+ was observed in six patients (4.3%). The CY+ group exhibited significantly higher preoperative serum levels of CA19-9 and a substantially greater incidence of tumor location in the pancreatic body or tail, along with pathological invasion to the anterior pancreatic capsule, than the CY- group. The CY+ group had a significantly higher incidence of peritoneal recurrence compared with the CY- group (83.3% vs. 18.5%, p = 0.002). Overall survival (OS) and recurrence-free survival (RFS) after surgery were significantly shorter in the CY+ group than in the CY- group (CY+ vs. CY-: 18.3 vs. 46.2 months, p = 0.001, and 8.9 vs. 17.7 months, p = 0.009, respectively). Multivariate analyses identified CY+ as an independent prognostic factor for worse OS (hazard ratio 5.00, 95% confidence interval 1.03-12.31) and RFS (hazard ratio 2.58, 95% confidence interval 1.04-6.43). Local invasion grade on imaging before CRT, limited histological response to CRT, and absence of adjuvant chemotherapy were independent predictors of worse OS and RFS. CONCLUSION: Despite the relatively low incidence of CY+ after preoperative CRT, it emerged as an independent prognostic factor in patients with localized PDAC undergoing curative-intent resection following preoperative CRT.

TIM-4 increases the proportion of CD4+CD25+FOXP3+ regulatory T cells in the pancreatic ductal adenocarcinoma microenvironment by inhibiting IL-6 secretion.

BACKGROUND: Currently, creating more effector T cells and augmenting their functions is a focal point in pancreatic ductal adenocarcinoma (PDAC) treatment research. T cell immunoglobulin domain and mucin domain molecule 4 (TIM-4), known for promoting cancer progression in various malignancies, is implicated in the suppressive immune microenvironment of tumors. Analyzing of the role of TIM-4 in the immune regulation of PDAC can offer novel insights for immune therapy. METHODS: We analyzed the TIM-4 expression in tumor specimens from PDAC patients. Meanwhile, multiple fluorescent immunohistochemical staining was used to study the distribution characteristics of TIM-4, and through tissue microarrays, we explored its correlation with patient prognosis. The influence of TIM-4 overexpression on cell function was analyzed using RNA-seq. Flow cytometry and ELISA were used for verification. Finally, the relationship between TIM-4 and T lymphocytes was analyzed by tissue microarray, and the impacts of TIM-4 on T cell subsets were observed by cell coculture technology and a mouse pancreatic cancer in situ model. RESULTS: In PDAC, TIM-4 is mainly expressed in tumor cells and negatively correlated with patient prognosis. TIM-4 influences the differentiation of Treg by inhibiting IL-6 secretion in pancreatic cancer cells and facilitates the proliferation of pancreatic cancer in mice. Additionally, the mechanism may be through the CD8+ effector T cells (CD8+Tc). CONCLUSION: TIM-4 has the potential to be an immunotherapeutic target or to improve the efficacy of chemotherapy for PDAC.

[Synchronous primary multiple cancer: distal cholangiocarcinoma of the intrapancreatic common bile duct and intraductal papillary mucinous tumor associated with ductal adenocarcinoma of the pancreatic tail]. / Sinkhronnyi pervichno-mnozhestvennyi rak: distal'naya kholangiokartsinoma intrapankreaticheskoi chasti obshchego zhelchnogo protoka i vnutriprotokovaya papillyarnaya mutsinoznaya opukhol' v assotsiatsii s protokovoi adenokartsinomoi khvosta podzheludochnoi zhelezy.

We present a combination of distal cholangiocarcinoma of the intrapancreatic common bile duct and intraductal papillary mucinous tumor associated with ductal adenocarcinoma of the pancreatic tail. This clinical case is unique. When analyzing the literature, we found no any case of similar primary multiple malignant tumor. Importantly, final diagnosis of simultaneous malignant pancreatobiliary neoplasia is possible only via intraoperative biopsy after adequate morphological dissection and research of resected organ complex including molecular genetic analysis due to identical histological and immunohistochemical picture of ductal neoplasia.

Distance-depending transcriptome changes of pancreatic stellate cells in paracrine pancreatic ductal adenocarcinoma co-culture models.

Pancreatic stellate cells (PSC) are one source of cancer-associated fibroblasts (CAF) and play, therefore, an essential role in pancreatic ductal adenocarcinoma (PDA). Paracrine signalling between PDA cells and CAF has been widely studied, yet external influences on paracrine crosstalk are poorly understood. This study aimed to gain a deeper insight into the communication of PSC and cancer cells under different co-culture conditions via analysis of PSC gene expression profiles. Two contactless co-culture models with tumor cells from the p48-Cre; lox-stop-lox-KrasG12D/+; lox-stop-lox-Trp53R172H/+ mouse model (KPC) and murine PSC separated through a microporous membrane and grown in different compartments (standard co-culture) or on different sides of the same membrane (inverse co-culture), were established. RNA-Sequencing analysis of PSC mRNA was performed 24 h and 72 h after co-culture with KPC cells. For selected genes, results were confirmed by quantitative RT-PCR and immunocytochemistry. Standard co-culture displayed 19 differentially expressed genes (DEG) at 24 h and 52 DEG at 72 h. In inverse co-culture, 800 DEG at 24 h and 2213 DEG at 72 h were enriched. PSC showed great heterogeneity in their gene expression profiles; however, mutually regulated genes of both co-cultures, such as VCAN and CHST11, could be identified. VCAN-protein-protein interaction-network analysis revealed several shared genes between co-culture models, such as SDC4 and FN1. In conclusion, PSC show a varying susceptibility to cancer cell signals depending on the co-culture method, with intensified transcriptome changes with closer proximity.

Adhesion of pancreatic tumor cell clusters by desmosomal molecules enhances early liver metastases formation.

Desmosomes are intercellular adhesion complexes providing mechanical coupling and tissue integrity. Previously, a correlation of desmosomal molecule expression with invasion and metastasis formation in several tumor entities was described together with a relevance for circulating tumor cell cluster formation. Here, we investigated the contribution of the desmosomal core adhesion molecule desmoglein-2 (DSG2) to the initial steps of liver metastasis formation by pancreatic cancer cells using a novel ex vivo liver perfusion mouse model. We applied the pancreatic ductal adenocarcinoma cell line AsPC-1 with and without a knockout (KO) of DSG2 and generated mouse lines with a hepatocyte-specific KO of the known interacting partners of DSG2 (DSG2 and desmocollin-2). Liver perfusion with DSG2 KO AsPC-1 cells led to smaller circulating cell clusters and a reduced number of cells adhering to murine livers compared to control cells. While this was independent of the expression levels of desmosomal adhesion molecules in hepatocytes, we show that increased cluster size of cancer cells, which correlates with stronger cell-cell adhesion and expression of desmosomal molecules, is a major factor contributing to the early phase of metastatic spreading. In conclusion, impaired desmosomal adhesion results in reduced circulating cell cluster size, which is relevant for seeding and attachment of metastatic cells to the liver.

The Significance of Circulating Tumor Cells in Pancreatic Cancer.

The notion that technically resectable pancreatic ductal adenocarcinoma presents as localized disease is now known to be inaccurate. Evidence supports that most patients have subclinical systemic dissemination at the time of diagnosis. It is now widely accepted that both a local and systemic component of disease coexist, each requiring treatment of improved survival and potential cure. The advent of multiagent chemotherapy regimens has resulted in a modest improvement in survival. Consequently, this article will emphasize the expanding potential and significance of circulating tumor cells in the prognostication and management of patients with pancreatic cancer.

Transcription factor DDIT3 is a potential driver in pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal and aggressive tumor that affects the digestive tract, leading to high mortality and poor survival rates. The purpose of the present study was to evaluate the expression levels of DNA damage-inducible transcript 3 (DDIT3) in pancreatic cancer and to investigate its effects in in vitro and in vivo experiments. Bioinformatics analysis indicated that DDIT3 expression was higher in pancreatic cancer tumor tissues and associated with a poor prognosis. Positive or strong positive DDIT3 expression was observed in PDAC, and no or weak expression was observed in normal pancreatic tissues. It was also highly expressed in PDAC cells, while being expressed at lower levels in normal pancreatic ductal epithelial cells. Transfection of short hairpin RNA targeting the DDIT3 gene reduced the proliferation, migration and invasion of PANC-1 cells. In vivo, in an in situ implantation tumor model with Pan02 cells, the size and weight of the tumors were reduced in the DDIT3 knockdown Pan02 cell-implanted group. These data suggested that DDIT3 represents a novel predictive biomarker for the potential treatment of patients presenting with PDAC.

Insights into gemcitabine resistance in pancreatic cancer: association with metabolic reprogramming and TP53 pathogenicity in patient derived xenografts.

BACKGROUND: With poor prognosis and high mortality, pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignancies. Standard of care therapies for PDAC have included gemcitabine for the past three decades, although resistance often develops within weeks of chemotherapy initiation through an array of possible mechanisms. METHODS: We reanalyzed publicly available RNA-seq gene expression profiles of 28 PDAC patient-derived xenograft (PDX) models before and after a 21-day gemcitabine treatment using our validated analysis pipeline to identify molecular markers of intrinsic and acquired resistance. RESULTS: Using normalized RNA-seq quantification measurements, we first identified oxidative phosphorylation and interferon alpha pathways as the two most enriched cancer hallmark gene sets in the baseline gene expression profile associated with intrinsic gemcitabine resistance and sensitivity, respectively. Furthermore, we discovered strong correlations between drug-induced expression changes in glycolysis and oxidative phosphorylation genes and response to gemcitabine, which suggests that these pathways may be associated with acquired gemcitabine resistance mechanisms. Thus, we developed prediction models using baseline gene expression profiles in those pathways and validated them in another dataset of 12 PDAC models from Novartis. We also developed prediction models based on drug-induced expression changes in genes from the Molecular Signatures Database (MSigDB)'s curated 50 cancer hallmark gene sets. Finally, pathogenic TP53 mutations correlated with treatment resistance. CONCLUSION: Our results demonstrate that concurrent upregulation of both glycolysis and oxidative phosphorylation pathways occurs in vivo in PDAC PDXs following gemcitabine treatment and that pathogenic TP53 status had association with gemcitabine resistance in these models. Our findings may elucidate the molecular basis for gemcitabine resistance and provide insights for effective drug combination in PDAC chemotherapy.

Role of glycosylation-related gene MGAT1 in pancreatic ductal adenocarcinoma.

Background: pancreatic ductal adenocarcinoma (PDAC) is a malignant tumor with a very poor prognosis and a complex tumor microenvironment, which plays a key role in tumor progression and treatment resistance. Glycosylation plays an important role in processes such as cell signaling, immune response and protein stability. Materials and methods: single-cell RNA sequencing data and spatial transcriptome data were obtained from GSE197177 and GSE224411, respectively, and RNA-seq data and survival information were obtained from UCSC Xena and TCGA. Multiple transcriptomic data were comprehensively analyzed to explore the role of glycosylation processes in tumor progression, and functional experiments were performed to assess the effects of MGAT1 overexpression on PDAC cell proliferation and migration. Results: In PDAC tumor samples, the glycosylation level of macrophages was significantly higher than that of normal samples. MGAT1 was identified as a key glycosylation-related gene, and its high expression was associated with better patient prognosis. Overexpression of MGAT1 significantly inhibited the proliferation and migration of PDAC cells and affected intercellular interactions in the tumor microenvironment. Conclusion: MGAT1 plays an important role in PDAC by regulating glycosylation levels in macrophages, influencing tumor progression and improving prognosis.MGAT1 is a potential therapeutic target for PDAC and further studies are needed to develop targeted therapeutic strategies against MGAT1 to improve clinical outcomes.

Salicylaldehyde-derived piperazine-functionalized hydrazone ligand-based Pt(II) complexes: inhibition of EZH2-dependent tumorigenesis in pancreatic ductal adenocarcinoma, synergism with PARP inhibitors and enhanced apoptosis.

Piperazine is an important functional unit of many clinically approved drugs, including chemotherapeutic agents. In the current study, methyl piperazine was incorporated and eight salicylaldehyde-derived piperazine-functionalized hydrazone ONN-donor ligands (L) and their Pt(II) complexes (L-PtCl) were prepared. The structures of all these ligands (L1-L8) and Pt(II) complexes (C1-C8) were determined using 1H and 13C NMR, UV-vis, FT-IR and HR-ESI MS analyses, whereas the structures of C1, C5, C6, C7 and C8 were determined in the solid state using single crystal X-ray diffraction analysis. Solution state stabilities of C3, C4, C5 and C6 were determined via time-dependent UV-vis spectroscopy. All these complexes (C1-C8) were studied for their anticancer effect in pancreatic ductal adenocarcinoma cells, including BxPC3, MIAPaCa-2 and PANC1 cells. C1-C8 displayed a potential cytotoxic effect in all these cancer cells, among which C5, C6 and C8 showed the strongest inhibitory effect in comparison with standard chemotherapeutic agents, including 5-fluorouracil (5-FU), cisplatin (CP), oxaliplatin and doxorubicin (DOX). C5, C6 and C8 suppressed the growth of pancreatic cancer cells in a dose-dependent manner. Moreover, C5, C6 and C8 inhibited clonogenic potential and invasion ability and induced apoptosis in PANC1 cells. Importantly, C5, C6 and C8 synergized the anticancer effect with PARP inhibitors, including olaparib, veliparib and niraparib, in pancreatic cancer cells, thus suggesting an important role of C5, C6 and C8 in induction of apoptosis in combination with PARP inhibitors. C5 combined with PARP inhibitors induced caspase3/7 activity and suppressed ATP production. Mechanistically, C5, C6 and C8 inhibited EZH2 protein expression to suppress EZH2-dependent tumorigenesis. Overall, these results highlighted the importance of these piperazine-functionalized Pt(II) complexes as potential anticancer agents to suppress pancreatic ductal adenocarcinoma tumorigenesis by targeting the EZH2-dependent pathway.

DKK1-SE recruits AP1 to activate the target gene DKK1 thereby promoting pancreatic cancer progression.

Super-enhancers are a class of DNA cis-regulatory elements that can regulate cell identity, cell fate, stem cell pluripotency, and even tumorigenesis. Increasing evidence shows that epigenetic modifications play an important role in the pathogenesis of various types of cancer. However, the current research is far from enough to reveal the complex mechanism behind it. This study found a super-enhancer enriched with abnormally active histone modifications in pancreatic ductal adenocarcinoma (PDAC), called DKK1-super-enhancer (DKK1-SE). The major active component of DKK1-SE is component enhancer e1. Mechanistically, AP1 induces chromatin remodeling in component enhancer e1 and activates the transcriptional activity of DKK1. Moreover, DKK1 was closely related to the malignant clinical features of PDAC. Deletion or knockdown of DKK1-SE significantly inhibited the proliferation, colony formation, motility, migration, and invasion of PDAC cells in vitro, and these phenomena were partly mitigated upon rescuing DKK1 expression. In vivo, DKK1-SE deficiency not only inhibited tumor proliferation but also reduced the complexity of the tumor microenvironment. This study identifies that DKK1-SE drives DKK1 expression by recruiting AP1 transcription factors, exerting oncogenic effects in PDAC, and enhancing the complexity of the tumor microenvironment.