Polymorphisms in transcription factor binding sites and enhancer regions and pancreatic ductal adenocarcinoma risk.

Genome-wide association studies (GWAS) are a powerful tool for detecting variants associated with complex traits and can help risk stratification and prevention strategies against pancreatic ductal adenocarcinoma (PDAC). However, the strict significance threshold commonly used makes it likely that many true risk loci are missed. Functional annotation of GWAS polymorphisms is a proven strategy to identify additional risk loci. We aimed to investigate single-nucleotide polymorphisms (SNP) in regulatory regions [transcription factor binding sites (TFBSs) and enhancers] that could change the expression profile of multiple genes they act upon and thereby modify PDAC risk. We analyzed a total of 12,636 PDAC cases and 43,443 controls from PanScan/PanC4 and the East Asian GWAS (discovery populations), and the PANDoRA consortium (replication population). We identified four associations that reached study-wide statistical significance in the overall meta-analysis: rs2472632(A) (enhancer variant, OR 1.10, 95%CI 1.06,1.13, p = 5.5 × 10-8), rs17358295(G) (enhancer variant, OR 1.16, 95%CI 1.10,1.22, p = 6.1 × 10-7), rs2232079(T) (TFBS variant, OR 0.88, 95%CI 0.83,0.93, p = 6.4 × 10-6) and rs10025845(A) (TFBS variant, OR 1.88, 95%CI 1.50,1.12, p = 1.32 × 10-5). The SNP with the most significant association, rs2472632, is located in an enhancer predicted to target the coiled-coil domain containing 34 oncogene. Our results provide new insights into genetic risk factors for PDAC by a focused analysis of polymorphisms in regulatory regions and demonstrating the usefulness of functional prioritization to identify loci associated with PDAC risk.

Polymorphic variants involved in methylation regulation: a strategy to discover risk loci for pancreatic ductal adenocarcinoma.

INTRODUCTION: Only a small number of risk factors for pancreatic ductal adenocarcinoma (PDAC) has been established. Several studies identified a role of epigenetics and of deregulation of DNA methylation. DNA methylation is variable across a lifetime and in different tissues; nevertheless, its levels can be regulated by genetic variants like methylation quantitative trait loci (mQTLs), which can be used as a surrogate. MATERIALS AND METHODS: We scanned the whole genome for mQTLs and performed an association study in 14 705 PDAC cases and 246 921 controls. The methylation data were obtained from whole blood and pancreatic cancer tissue through online databases. We used the Pancreatic Cancer Cohort Consortium and the Pancreatic Cancer Case-Control Consortium genome-wide association study (GWAS) data as discovery phase and the Pancreatic Disease Research consortium, the FinnGen project and the Japan Pancreatic Cancer Research consortium GWAS as replication phase. RESULTS: The C allele of 15q26.1-rs12905855 showed an association with a decreased risk of PDAC (OR=0.90, 95% CI 0.87 to 0.94, p=4.93×10-8 in the overall meta-analysis), reaching genome-level statistical significance. 15q26.1-rs12905855 decreases the methylation of a 'C-phosphate-G' (CpG) site located in the promoter region of the RCCD1 antisense (RCCD1-AS1) gene which, when expressed, decreases the expression of the RCC1 domain-containing (RCCD1) gene (part of a histone demethylase complex). Thus, it is possible that the rs12905855 C-allele has a protective role in PDAC development through an increase of RCCD1 gene expression, made possible by the inactivity of RCCD1-AS1. CONCLUSION: We identified a novel PDAC risk locus which modulates cancer risk by controlling gene expression through DNA methylation.

Perioperative management of pancreatic exocrine insufficiency-evidence-based proposal for a paradigm shift in pancreatic surgery.

BACKGROUND: Despite exocrine pancreatic insufficiency (EPI) being a significant consequence of pancreatic surgery, there is still no consensus on its perioperative management. This study aimed to evaluate unselective pancreatic enzyme replacement therapy (PERT). METHODS: A prospective, observational study of patients undergoing partial pancreatectomy was conducted. EPI status was assessed pre- and postoperatively, based on three fecal-elastase measurements each. Characteristic symptoms were evaluated by questionnaire. In 85 post-surgical patients, the subjective burden of PERT was measured. RESULTS: 101 patients were followed prospectively. Preoperative EPI screening was available for 83 patients, of which 48% were diagnosed with preexisting EPI. Of those patients with regular exocrine function, 54% developed EPI de novo; this rate being higher following pancreatic head resections (72%) compared to left-sided pancreatectomies (LP) (20%) (p = 0.016). Overall postoperative EPI prevalence was significantly greater following pancreatic head resections (86%) than LP (33%) (p < 0.001). Only young and female patients described a significant burden related to PERT. CONCLUSION: For all patients undergoing pancreatic head resection PERT should be considered beginning prior to surgery, due to the subgroup's high EPI rate and the comparatively low burden of PERT. Patients with LP are at lower risk and should be pre- and postoperatively screened and supplemented accordingly.

Safety and performance of a synthetic sealant patch aimed to prevent postoperative pancreatic fistula after distal pancreatectomy (SHIELDS) - Prospective international multicenter phase II study.

OBJECTIVE: The incidence for clinically relevant postoperative pancreatic fistulas (CR-POPF) in distal pancreatectomy (DP) ranges up to 25%. None of the available sealants significantly reduce CR-POPF. A new biodegradable sealant patch was able to reduce POPF and to achieve bleeding control in a preclinical porcine DP model. The aim of this first-in-human study was to assess the safety and performance of the sealant patch. METHODS: In this multicenter, single-arm study, 40 patients undergoing distal pancreatectomy were prospectively enrolled from 8 centers. Following surgical resection, the transection plane was closed according to the standard of care and manually covered with the sealant patch. As primary endpoint the incidence of CR-POPF up to 30-days postoperatively was evaluated. The secondary endpoints included the assessment of complications and device usability. RESULTS: Among 40 patients after distal pancreatectomy, CR-POPF occurred in 7 (17.5%) up to postoperative day 30. No type C POPF was observed. There was no intraoperative bleeding observed after patch application. CONCLUSION: The results of this international phase II study demonstrate promising results of a new sealant patch regarding the rate of CR-POPF. Randomized studies are now needed to confirm the superiority of the current patch as compared to the best current practice.

Tailoring the Use of Central Pancreatectomy Through Prediction Models for Major Morbidity and Postoperative Diabetes: International Retrospective Multicenter Study.

OBJECTIVE: To develop a prediction model for major morbidity and endocrine dysfunction after CP which could help in tailoring the use of this procedure. SUMMARY BACKGROUND DATA: Central pancreatectomy (CP) is a parenchyma-sparing alternative to distal pancreatectomy for symptomatic benign and pre-malignant tumors in body and neck of the pancreas CP lowers the risk of new-onset diabetes and exocrine pancreatic insufficiency compared to distal pancreatectomy but it is thought to increase the risk of short-term complications including postoperative pancreatic fistula (POPF). METHODS: International multicenter retrospective cohort study including patients from 51 centers in 19 countries (2010-2021). Primary endpoint was major morbidity. Secondary endpoints included POPF grade B/C, endocrine dysfunction, and the use of pancreatic enzymes. Two risk model were designed for major morbidity and endocrine dysfunction utilizing multivariable logistic regression and internal and external validation. RESULTS: 838 patients after CP were included (301 (36%) minimally invasive) and major morbidity occurred in 248 (30%) patients, POPF B/C in 365 (44%), and 30-day mortality in 4 (1%). Endocrine dysfunction in 91 patients (11%) and use of pancreatic enzymes in 108 (12%). The risk model for major morbidity included male sex, age, BMI, and ASA score≥3. The model performed acceptable with an area under curve (AUC) of 0.72(CI:0.68-0.76). The risk model for endocrine dysfunction included higher BMI and male sex and performed well (AUC:0.83 (CI:0.77-0.89)). CONCLUSIONS: The proposed risk models help in tailoring the use of CP in patients with symptomatic benign and premalignant lesions in the body and neck of the pancreas and are readily available via www.pancreascalculator.com.

Peripheral and Portal Venous KRAS ctDNA Detection as Independent Prognostic Markers of Early Tumor Recurrence in Pancreatic Ductal Adenocarcinoma.

BACKGROUND: KRAS circulating tumor DNA (ctDNA) has shown biomarker potential for pancreatic ductal adenocarcinoma (PDAC) but has not been applied in clinical routine yet. We aim to improve clinical applicability of ctDNA detection in PDAC and to study the impact of blood-draw site and time point on the detectability and prognostic role of KRAS mutations. METHODS: 221 blood samples from 108 PDAC patients (65 curative, 43 palliative) were analyzed. Baseline peripheral and tumor-draining portal venous (PV), postoperative, and follow-up blood were analyzed and correlated with prognosis. RESULTS: Significantly higher KRAS mutant detection rates and copy numbers were observed in palliative compared to curative patients baseline blood (58.1% vs 24.6%; P = 0.002; and P < 0.001). Significantly higher KRAS mutant copies were found in PV blood compared to baseline (P < 0.05) samples. KRAS detection in pre- and postoperative and PV blood were significantly associated with shorter recurrence-free survival (all P < 0.015) and identified as independent prognostic markers. KRAS ctDNA status was also an independent unfavorable prognostic factor for shorter overall survival in both palliative and curative cohorts (hazard ratio [HR] 4.9, P = 0.011; HR 6.9, P = 0.008). CONCLUSIONS: KRAS ctDNA detection is an independent adverse prognostic marker in curative and palliative PDAC patients-at all sites of blood draw and a strong follow-up marker. The most substantial prognostic impact was seen for PV blood, which could be an effective novel tool for identifying prognostic borderline patients-guiding future decision-making on neoadjuvant treatment despite anatomical resectability. In addition, higher PV mutant copy numbers contribute to an improved technical feasibility.

Effective sealing of biliary and pancreatic fistulas with a novel biodegradable polyurethane-based tissue sealant patch.

BACKGROUND: To date, no approved sealants for the prevention of postoperative pancreatic fistulas (POPFs) or bile leakage are available. The aim of the study is to assess the feasibility of a new synthetic and biodegradable polyurethane-based sealant patch (PBSP) for hepato-pancreato-biliary (HPB) surgery. METHODS: Benchmarking of the PBSP with commercially available products with a historical use in HPB surgery (Tachosil®, Hemopatch®, Surgicel® and Veriset®) was followed by performance testing in randomized controlled porcine animal studies. These studies focused on haemostasis as well as the prevention of POPFs and bile leakage. RESULTS: The newly designed PBSP demonstrated the strongest adherence to liver tissue compared to Tachosil®, Hemopatch® and Veriset®. The new patch was the only patch with complete intra- and postoperative hemostasis (72 h after application) compared to Tachosil and Veriset in a porcine liver abrasion study on 12 animals. In addition, the new patch demonstrably prevents the development of POPFs. The rate of postoperative pancreatitis and clinically relevant POPFs was significantly lower compared to the control groups in a porcine pancreatic fistula model based on 14 animals (14-day follow-up). Furthermore, the incidence of biloma after 7 days, considered as significant bile leakage, was significantly lower in the new PBSP compared to the Veriset® group. The PBSP was as effective as suturing in a porcine bile leakage model (7-day follow-up). CONCLUSION: The PBSP induces constant hemostasis in the context of liver resection and prevents pancreatic fistulas and bile leakage. The promising preclinical data implicate clinical trials for further evaluation of this newly developed patch.

Simultaneous Distal Pancreatic Resection and Hyperthermic Intraperitoneal Chemotherapy (HIPEC) for Peritoneal Carcinomatosis in Adenocarcinoma of the Pancreas - A Case Report.

Pancreatic cancer remains one of the biggest challenges in oncology, as most patients are diagnosed in a stage of regional lymphatic or systemic spread of the disease. 10% of the patients present with peritoneal carcinomatosis upon diagnosis. In the past decades, cytoreductive surgery (CRS) combined with hyperthermic intraoperative intraperitoneal chemotherapy (HIPEC) has been developed and presents a new, individualized treatment option for patients with peritoneal disseminated cancer. This case report presents the case of a 39-year-old male with the initial diagnosis of a carcinoma of the pancreatic tail with localized peritoneal carcinomatosis. As an individualized approach, neoadjuvant chemotherapy was recommended with an option for a second exploration. Re-Staging revealed a reduction in tumor size. Cytoreductive surgery (CRS) including a distal splenopancreatectomy was performed and followed by HIPEC. Postoperatively, the patient developed a clinically relevant pancreatic fistula, however recovered and was able to receive adjuvant chemotherapy. Taken together, in pancreatic cancer with localized peritoneal carcinomatosis CRS and HIPEC are a valid option in highly selective cases with potential extended overall survival and an acceptable quality of life.

Receptor-independent modulation of cAMP-dependent protein kinase and protein phosphatase signaling in cardiac myocytes by oxidizing agents.

The contraction and relaxation of the heart is controlled by stimulation of the ß1-adrenoreceptor (AR) signaling cascade, which leads to activation of cAMP-dependent protein kinase (PKA) and subsequent cardiac protein phosphorylation. Phosphorylation is counteracted by the main cardiac protein phosphatases, PP2A and PP1. Both kinase and phosphatases are sensitive to intramolecular disulfide formation in their catalytic subunits that inhibits their activity. Additionally, intermolecular disulfide formation between PKA type I regulatory subunits (PKA-RI) has been described to enhance PKA's affinity for protein kinase A anchoring proteins, which alters its subcellular distribution. Nitroxyl donors have been shown to affect contractility and relaxation, but the mechanistic basis for this effect is unclear. The present study investigates the impact of several nitroxyl donors and the thiol-oxidizing agent diamide on cardiac myocyte protein phosphorylation and oxidation. Although all tested compounds equally induced intermolecular disulfide formation in PKA-RI, only 1-nitrosocyclohexalycetate (NCA) and diamide induced reproducible protein phosphorylation. Phosphorylation occurred independently of ß1-AR activation, but was abolished after pharmacological PKA inhibition and thus potentially attributable to increased PKA activity. NCA treatment of cardiac myocytes induced translocation of PKA and phosphatases to the myofilament compartment as shown by fractionation, immunofluorescence, and proximity ligation assays. Assessment of kinase and phosphatase activity within the myofilament fraction of cardiac myocytes after exposure to NCA revealed activation of PKA and inhibition of phosphatase activity thus explaining the increase in phosphorylation. The data suggest that the NCA-mediated effect on cardiac myocyte protein phosphorylation orchestrates alterations in the kinase/phosphatase balance.

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

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

Characterization of RARRES1 Expression on Circulating Tumor Cells as Unfavorable Prognostic Marker in Resected Pancreatic Ductal Adenocarcinoma Patients.

BACKGROUND: In pancreatic ductal adenocarcinoma (PDAC), the characterization of circulating tumor cells (CTCs) opens new insights into cancer metastasis as the leading cause of cancer-related death. Here, we focused on the expression of retinoic acid receptor responder 1 (RARRES1) on CTCs as a novel marker for treatment failure and early relapse. METHODS: The stable isotope labeling of amino acids in cell culture (SILAC)-approach was applied for identifying and quantifying new biomarker proteins in PDAC cell lines HPDE and its chemoresistant counterpart, L3.6pl-Res. Fifty-five baseline and 36 follow-up (FUP) peripheral blood samples were processed via a marker-independent microfluidic-based CTC detection approach using RARRES1 as an additional marker. RESULTS: SILAC-based proteomics identified RARRES1 as an abundantly expressed protein in more aggressive chemoresistant PDAC cells. At baseline, CTCs were detected in 25.5% of all PDAC patients, while FUP analysis (median: 11 months FUP) showed CTC detection in 45.5% of the resected patients. CTC positivity (≥3 CTC) at FUP was significantly associated with short recurrence-free survival (p = 0.002). Furthermore, detection of RARRES1 positive CTCs was indicative of an even earlier relapse after surgery (p = 0.001). CONCLUSIONS: CTC detection in resected PDAC patients during FUP is associated with a worse prognosis, and RARRES1 expression might identify an aggressive subtype of CTCs that deserves further investigation.

Common variability in oestrogen-related genes and pancreatic ductal adenocarcinoma risk in women.

The incidence of pancreatic ductal adenocarcinoma (PDAC) is different among males and females. This disparity cannot be fully explained by the difference in terms of exposure to known risk factors; therefore, the lower incidence in women could be attributed to sex-specific hormones. A two-phase association study was conducted in 12,387 female subjects (5436 PDAC cases and 6951 controls) to assess the effect on risk of developing PDAC of single nucleotide polymorphisms (SNPs) in 208 genes involved in oestrogen and pregnenolone biosynthesis and oestrogen-mediated signalling. In the discovery phase 14 polymorphisms showed a statistically significant association (P < 0.05). In the replication none of the findings were validated. In addition, a gene-based analysis was performed on the 208 selected genes. Four genes (NR5A2, MED1, NCOA2 and RUNX1) were associated with PDAC risk, but only NR5A2 showed an association (P = 4.08 × 10-5) below the Bonferroni-corrected threshold of statistical significance. In conclusion, despite differences in incidence between males and females, our study did not identify an effect of common polymorphisms in the oestrogen and pregnenolone pathways in relation to PDAC susceptibility. However, we validated the previously reported association between NR5A2 gene variants and PDAC risk.

Serum midkine as non-invasive biomarker for detection and prognosis of non-small cell lung cancer.

Lung cancer continues to be the leading cause for cancer-related deaths in men and women worldwide. Sufficient screening tools enabling early diagnosis are essential to improve patient outcomes. The aim of this study was to evaluate serum midkine (S-MK) both as a diagnostic and prognostic biomarker in non-small cell lung cancer (NSCLC). This single-center analysis included 59 NSCLC patients counting 30 squamous cell cancers and 29 adenocarcinomas. Preoperative S-MK concentration was determined using ELISA. Patients were followed up to five years. S-MK was found to be significantly overexpressed in patients with NSCLC compared to healthy controls (p < 0.001). The discriminative power of S-MK to differentiate NSCLC subjects from controls was fairly high with an area under the receiver operating characteristic curve of 0.83 (p < 0.001). Optimal sensitivity of 92% and reasonable specificity of 68% was reached at a threshold of 416 pg/ml S-MK. Patients with high S-MK concentration showed a significantly shorter overall survival compared to patients with low S-MK expression (p < 0.05). In conclusion, S-MK is overexpressed in patients with NSCLC and serves as an independent prognostic factor for overall survival. S-MK may thus be considered as an additional non-invasive biomarker not only for NSCLC screening but also for outcome prediction.

Oxidant sensor in the cGMP-binding pocket of PKGIα regulates nitroxyl-mediated kinase activity.

Despite the mechanisms for endogenous nitroxyl (HNO) production and action being incompletely understood, pharmacological donors show broad therapeutic promise and are in clinical trials. Mass spectrometry and site-directed mutagenesis showed that chemically distinct HNO donors 1-nitrosocyclohexyl acetate or Angeli's salt induced disulfides within cGMP-dependent protein kinase I-alpha (PKGIα), an interdisulfide between Cys42 of the two identical subunits of the kinase and a previously unobserved intradisulfide between Cys117 and Cys195 in the high affinity cGMP-binding site. Kinase activity was monitored in cells transfected with wildtype (WT), Cys42Ser or Cys117/195Ser PKGIα that cannot form the inter- or intradisulfide, respectively. HNO enhanced WT kinase activity, an effect significantly attenuated in inter- or intradisulfide-deficient PKGIα. To investigate whether the intradisulfide modulates cGMP binding, real-time imaging was performed in vascular smooth muscle cells expressing a FRET-biosensor comprising the cGMP-binding sites of PKGIα. HNO induced FRET changes similar to those elicited by an increase of cGMP, suggesting that intradisulfide formation is associated with activation of PKGIα. Intradisulfide formation in PKGIα correlated with enhanced HNO-mediated vasorelaxation in mesenteric arteries in vitro and arteriolar dilation in vivo in mice. HNO induces intradisulfide formation in PKGIα, inducing the same effect as cGMP binding, namely kinase activation and thus vasorelaxation.