Hourglass, a compass navigating global and regional heterogeneity of pancreatic cancer†.

Advances in the digital pathology field have facilitated the characterization of histology samples for both clinical and preclinical research. However, uncovering subtle correlations between bioimaging, clinical and molecular parameters requires extensive statistical analysis. As a user-friendly software, Hourglass, simplifies multiparametric dataset analysis through intuitive data visualization and statistical tools. Systemic analysis of interleukin-6 (IL-6)/pStat3 signaling pathway through Hourglass revealed differences in regional immune cell composition within tumors. Moreover, these regional disparities were partially mediated by sex. Overall, Hourglass simplifies information extraction from complex datasets, resolving overlooked regional and global spatial tumor differences. © 2024 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Type 1 Autoimmune Pancreatitis in Europe: Clinical Profile and Response to Treatment.

BACKGROUND & AIMS: Autoimmune pancreatitis (AIP) is an immune-mediated disease of the pancreas with distinct pathophysiology and manifestations. Our aims were to characterize type 1 AIP in a large pan-European cohort and study the effectiveness of current treatment regimens. METHODS: We retrospectively analyzed adults diagnosed since 2005 with type 1 or not-otherwise-specified AIP in 42 European university hospitals. Type 1 AIP was uniformly diagnosed using specific diagnostic criteria. Patients with type 2 AIP and those who had undergone pancreatic surgery were excluded. The primary end point was complete remission, defined as the absence of clinical symptoms and resolution of the index radiologic pancreatic abnormalities attributed to AIP. RESULTS: We included 735 individuals with AIP (69% male; median age, 57 years; 85% White). Steroid treatment was started in 634 patients, of whom 9 (1%) were lost to follow-up. The remaining 625 had a 79% (496/625) complete, 18% (111/625) partial, and 97% (607/625) cumulative remission rate, whereas 3% (18/625) did not achieve remission. No treatment was given in 95 patients, who had a 61% complete (58/95), 19% partial (18/95), and 80% cumulative (76/95) spontaneous remission rate. Higher (≥0.4 mg/kg/day) corticosteroid doses were no more effective than lower (<0.4 mg/kg/day) doses (odds ratio, 0.428; 95% confidence interval, 0.054-3.387) and neither was a starting dose duration >2 weeks (odds ratio, 0.908; 95% confidence interval, 0.818-1.009). Elevated IgG4 levels were independently associated with a decreased chance of complete remission (odds ratio, 0.639; 95% confidence interval, 0.427-0.955). Relapse occurred in 30% of patients. Relapses within 6 months of remission induction were independent of the steroid-tapering duration, induction treatment duration, and total cumulative dose. CONCLUSIONS: Patients with type 1 AIP and elevated IgG4 level may need closer monitoring. For remission induction, a starting dose of 0.4 mg/kg/day for 2 weeks followed by a short taper period seems effective. This study provides no evidence to support more aggressive regimens.

DOTA-Based Plectin-1 Targeted Contrast Agent Enables Detection of Pancreatic Cancer in Human Tissue.

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive and lethal malignancy with extremely poor patient survival rates. A key reason for the poor prognosis is the lack of effective diagnostic tools to detect the disease at curable, premetastatic stages. Tumor surgical resection is PDAC's first-line treatment, however distinguishing between cancerous and healthy tissue with current imaging tools remains a challenge. In this work, we report a DOTA-based fluorescent probe targeting plectin-1 for imaging PDAC with high specificity. To enable heterogeneous functionalization of the DOTA-core with multiple targeting peptide units and the fluorophore, a novel, fully clickable synthetic route that proceeds in one pot was developed. Extensive validation of the probe set the stage for PDAC detection in mice and human tissue. Altogether, these findings may pave the way for improved clinical understanding and early detection of PDAC progression as well as more accurate resection criteria.

Macrophages direct cancer cells through a LOXL2-mediated metastatic cascade in pancreatic ductal adenocarcinoma.

OBJECTIVE: The lysyl oxidase-like protein 2 (LOXL2) contributes to tumour progression and metastasis in different tumour entities, but its role in pancreatic ductal adenocarcinoma (PDAC) has not been evaluated in immunocompetent in vivo PDAC models. DESIGN: Towards this end, we used PDAC patient data sets, patient-derived xenograft in vivo and in vitro models, and four conditional genetically-engineered mouse models (GEMMS) to dissect the role of LOXL2 in PDAC. For GEMM-based studies, K-Ras +/LSL-G12D;Trp53 LSL-R172H;Pdx1-Cre mice (KPC) and the K-Ras +/LSL-G12D;Pdx1-Cre mice (KC) were crossed with Loxl2 allele floxed mice (Loxl2Exon2 fl/fl) or conditional Loxl2 overexpressing mice (R26Loxl2 KI/KI) to generate KPCL2KO or KCL2KO and KPCL2KI or KCL2KI mice, which were used to study overall survival; tumour incidence, burden and differentiation; metastases; epithelial to mesenchymal transition (EMT); stemness and extracellular collagen matrix (ECM) organisation. RESULTS: Using these PDAC mouse models, we show that while Loxl2 ablation had little effect on primary tumour development and growth, its loss significantly decreased metastasis and increased overall survival. We attribute this effect to non-cell autonomous factors, primarily ECM remodelling. Loxl2 overexpression, on the other hand, promoted primary and metastatic tumour growth and decreased overall survival, which could be linked to increased EMT and stemness. We also identified tumour-associated macrophage-secreted oncostatin M (OSM) as an inducer of LOXL2 expression, and show that targeting macrophages in vivo affects Osm and Loxl2 expression and collagen fibre alignment. CONCLUSION: Taken together, our findings establish novel pathophysiological roles and functions for LOXL2 in PDAC, which could be potentially exploited to treat metastatic disease.

Early weight loss is an independent risk factor for shorter survival and increased side effects in patients with metastatic colorectal cancer undergoing first-line treatment within the randomized Phase III trial FIRE-3 (AIO KRK-0306).

Body weight loss is frequently regarded as negatively related to outcomes in patients with malignancies. This retrospective analysis of the FIRE-3 study evaluated the evolution of body weight in patients with metastatic colorectal cancer (mCRC). FIRE-3 evaluated first-line FOLFIRI (folinic acid, fluorouracil and irinotecan) plus cetuximab or bevacizumab in mCRC patients with RAS-WT tumors (ie, wild-type in KRAS and NRAS exons 2-4). The prognostic and predictive relevance of early weight loss (EWL) regarding patient outcomes and treatment side effects were evaluated. Retrospective data on body weight during first 6 months of treatment were evaluated (N = 326). To correlate with efficacy endpoints and treatment side effects, patients were grouped according to clinically significant EWL ≥5% and <5% at Month 3. Age constituted the only significant predictor of EWL following a linear relationship with the corresponding log odds ratio (P = .016). EWL was significantly associated with the incident frequencies of diarrhea, edema, fatigue, nausea and vomiting. Further, a multivariate analysis revealed EWL to be an independent negative prognostic factor for overall survival (32.4 vs 21.1 months; hazard ratio [HR]: 1.64; 95% confidence interval [CI] = 1.13-2.38; P = .0098) and progression-free survival (11.8 vs 9.0 months; HR: 1.72; 95% CI = 1.18-2.5; P = .0048). In conclusion, EWL during systemic treatment against mCRC is significantly associated with patient age. Patients exhibiting EWL had worse survival and higher frequencies of adverse events. Early preventative measures targeted at weight maintenance should be evaluated, especially in elderly patients being at highest risk of EWL.

Maintenance Olaparib for Germline BRCA-Mutated Metastatic Pancreatic Cancer.

BACKGROUND: Patients with a germline BRCA1 or BRCA2 mutation make up a small subgroup of those with metastatic pancreatic cancer. The poly(adenosine diphosphate-ribose) polymerase (PARP) inhibitor olaparib has had antitumor activity in this population. METHODS: We conducted a randomized, double-blind, placebo-controlled, phase 3 trial to evaluate the efficacy of olaparib as maintenance therapy in patients who had a germline BRCA1 or BRCA2 mutation and metastatic pancreatic cancer and disease that had not progressed during first-line platinum-based chemotherapy. Patients were randomly assigned, in a 3:2 ratio, to receive maintenance olaparib tablets (300 mg twice daily) or placebo. The primary end point was progression-free survival, which was assessed by blinded independent central review. RESULTS: Of the 3315 patients who underwent screening, 154 underwent randomization and were assigned to a trial intervention (92 to receive olaparib and 62 to receive placebo). The median progression-free survival was significantly longer in the olaparib group than in the placebo group (7.4 months vs. 3.8 months; hazard ratio for disease progression or death, 0.53; 95% confidence interval [CI], 0.35 to 0.82; P = 0.004). An interim analysis of overall survival, at a data maturity of 46%, showed no difference between the olaparib and placebo groups (median, 18.9 months vs. 18.1 months; hazard ratio for death, 0.91; 95% CI, 0.56 to 1.46; P = 0.68). There was no significant between-group difference in health-related quality of life, as indicated by the overall change from baseline in the global quality-of-life score (on a 100-point scale, with higher scores indicating better quality of life) based on the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (between-group difference, -2.47 points; 95% CI, -7.27 to 2.33). The incidence of grade 3 or higher adverse events was 40% in the olaparib group and 23% in the placebo group (between-group difference, 16 percentage points; 95% CI, -0.02 to 31); 5% and 2% of the patients, respectively, discontinued the trial intervention because of an adverse event. CONCLUSIONS: Among patients with a germline BRCA mutation and metastatic pancreatic cancer, progression-free survival was longer with maintenance olaparib than with placebo. (Funded by AstraZeneca and others; POLO ClinicalTrials.gov number, NCT02184195.).

AGR2-Dependent Nuclear Import of RNA Polymerase II Constitutes a Specific Target of Pancreatic Ductal Adenocarcinoma in the Context of Wild-Type p53.

BACKGROUND & AIMS: Promoted by pancreatitis, oncogenic KrasG12D triggers acinar cells' neoplastic transformation through acinar-to-ductal metaplasia (ADM) and pancreatic intraepithelial neoplasia. Anterior gradient 2 (Agr2), a known inhibitor of p53, is detected at early stage of pancreatic ductal adenocarcinoma (PDAC) development. RNA polymerase II (RNAPII) is a key nuclear enzyme; regulation of its nuclear localization in mammalian cells represents a potential therapeutic target. METHODS: A mouse model of inflammation-accelerated KrasG12D-driven ADM and pancreatic intraepithelial neoplasia development was used. Pancreas-specific Agr2 ablation was performed to access its role in pancreatic carcinogenesis. Hydrophobic hexapeptides loaded in liposomes were developed to disrupt Agr2-RNAPII complex. RESULTS: We found that Agr2 is up-regulated in ADM-to-pancreatic intraepithelial neoplasia transition in inflammation and KrasG12D-driven early pancreatic carcinogenesis. Genetic ablation of Agr2 specifically blocks this metaplastic-to-neoplastic process. Mechanistically, Agr2 directs the nuclear import of RNAPII via its C-terminal nuclear localization signal, undermining the ATR-dependent p53 activation in ADM lesions. Because Agr2 binds to the largest subunit of RNAPII in a peptide motif-dependent manner, we developed a hexapeptide to interfere with the nuclear import of RNAPII by competitively disrupting the Agr2-RNAPII complex. This novel hexapeptide leads to dysfunction of RNAPII with concomitant activation of DNA damage response in early neoplastic lesions; hence, it dramatically compromises PDAC initiation in vivo. Moreover, the hexapeptide sensitizes PDAC cells and patient-derived organoids harboring wild-type p53 to RNAPII inhibitors and first-line chemotherapeutic agents in vivo. Of note, this therapeutic effect is efficient across various cancer types. CONCLUSIONS: Agr2 is identified as a novel adaptor protein for nuclear import of RNAPII in mammalian cells. Also, we provide genetic evidence defining Agr2-dependent nuclear import of RNAPII as a pharmaceutically accessible target for prevention and treatment in PDAC in the context of wild-type p53.

Bcl3 Couples Cancer Stem Cell Enrichment With Pancreatic Cancer Molecular Subtypes.

BACKGROUND & AIMS: The existence of different subtypes of pancreatic ductal adenocarcinoma (PDAC) and their correlation with patient outcome have shifted the emphasis on patient classification for better decision-making algorithms and personalized therapy. The contribution of mechanisms regulating the cancer stem cell (CSC) population in different subtypes remains unknown. METHODS: Using RNA-seq, we identified B-cell CLL/lymphoma 3 (BCL3), an atypical nf-κb signaling member, as differing in pancreatic CSCs. To determine the biological consequences of BCL3 silencing in vivo and in vitro, we generated bcl3-deficient preclinical mouse models as well as murine cell lines and correlated our findings with human cell lines, PDX models, and 2 independent patient cohorts. We assessed the correlation of bcl3 expression pattern with clinical parameters and subtypes. RESULTS: Bcl3 was significantly down-regulated in human CSCs. Recapitulating this phenotype in preclinical mouse models of PDAC via BCL3 genetic knockout enhanced tumor burden, metastasis, epithelial to mesenchymal transition, and reduced overall survival. Fluorescence-activated cell sorting analyses, together with oxygen consumption, sphere formation, and tumorigenicity assays, all indicated that BCL3 loss resulted in CSC compartment expansion promoting cellular dedifferentiation. Overexpression of BCL3 in human PDXs diminished tumor growth by significantly reducing the CSC population and promoting differentiation. Human PDACs with low BCL3 expression correlated with increased metastasis, and BCL3-negative tumors correlated with lower survival and nonclassical subtypes. CONCLUSIONS: We demonstrate that bcl3 impacts pancreatic carcinogenesis by restraining CSC expansion and by curtailing an aggressive and metastatic tumor burden in PDAC across species. Levels of BCL3 expression are a useful stratification marker for predicting subtype characterization in PDAC, thereby allowing for personalized therapeutic approaches.

Green Tea Extract to Prevent Colorectal Adenomas, Results of a Randomized, Placebo-Controlled Clinical Trial.

INTRODUCTION: Preclinical, epidemiological, and small clinical studies suggest that green tea extract (GTE) and its major active component epigallocatechingallate (EGCG) exhibit antineoplastic effects in the colorectum. METHODS: A randomized, double-blind trial of GTE standardized to 150 mg of EGCG b.i.d. vs placebo over 3 years was conducted to prevent colorectal adenomas (n = 1,001 with colon adenomas enrolled, 40 German centers). Randomization (1:1, n = 879) was performed after a 4-week run-in with GTE for safety assessment. The primary end point was the presence of adenoma/colorectal cancer at the follow-up colonoscopy 3 years after randomization. RESULTS: The safety profile of GTE was favorable with no major differences in adverse events between the 2 well-balanced groups. Adenoma rate in the modified intention-to-treat set (all randomized participants [intention-to-treat population] and a follow-up colonoscopy 26-44 months after randomization; n = 632) was 55.7% in the placebo and 51.1% in the GTE groups. This 4.6% difference was not statistically significant (adjusted relative risk 0.905; P = 0.1613). The respective figures for the per-protocol population were 54.3% (151/278) in the placebo group and 48.3% (129/267) in the GTE group, indicating a slightly lower adenoma rate in the GTE group, which was not significant (adjusted relative risk 0.883; P = 0.1169). DISCUSSION: GTE was well tolerated, but there was no statistically significant difference in the adenoma rate between the GTE and the placebo groups in the whole study population.

Functional biomarkers derived from computed tomography and magnetic resonance imaging differentiate PDAC subgroups and reveal gemcitabine-induced hypo-vascularization.

PURPOSE: Pancreatic ductal adenocarcinoma (PDAC) is a molecularly heterogeneous tumor entity with no clinically established imaging biomarkers. We hypothesize that tumor morphology and physiology, including vascularity and perfusion, show variations that can be detected by differences in contrast agent (CA) accumulation measured non-invasively. This work seeks to establish imaging biomarkers for tumor stratification and therapy response monitoring in PDAC, based on this hypothesis. METHODS AND MATERIALS: Regional CA accumulation in PDAC was correlated with tumor vascularization, stroma content, and tumor cellularity in murine and human subjects. Changes in CA distribution in response to gemcitabine (GEM) were monitored longitudinally with computed tomography (CT) Hounsfield Units ratio (HUr) of tumor to the aorta or with magnetic resonance imaging (MRI) ΔR1 area under the curve at 60 s tumor-to-muscle ratio (AUC60r). Tissue analyses were performed on co-registered samples, including endothelial cell proliferation and cisplatin tissue deposition as a surrogate of chemotherapy delivery. RESULTS: Tumor cell poor, stroma-rich regions exhibited high CA accumulation both in human (meanHUr 0.64 vs. 0.34, p < 0.001) and mouse PDAC (meanAUC60r 2.0 vs. 1.1, p < 0.001). Compared to the baseline, in vivo CA accumulation decreased specifically in response to GEM treatment in a subset of human (HUr -18%) and mouse (AUC60r -36%) tumors. Ex vivo analyses of mPDAC showed reduced cisplatin delivery (GEM: 0.92 ± 0.5 mg/g, vs. vehicle: 3.1 ± 1.5 mg/g, p = 0.004) and diminished endothelial cell proliferation (GEM: 22.3% vs. vehicle: 30.9%, p = 0.002) upon GEM administration. CONCLUSION: In PDAC, CA accumulation, which is related to tumor vascularization and perfusion, inversely correlates with tumor cellularity. The standard of care GEM treatment results in decreased CA accumulation, which impedes drug delivery. Further investigation is warranted into potentially detrimental effects of GEM in combinatorial therapy regimens.

Influence of extracorporeal cytokine adsorption on hemodynamics in severe acute pancreatitis: Results of the matched cohort pancreatitis cytosorbents inflammatory cytokine removal (PACIFIC) study.

BACKGROUND: Outcome of severe acute pancreatitis (SAP) highly depends on the degree of systemic inflammation and organ failure. Although treatment approaches targeting the inflammatory cascade have failed in pancreatitis, recent studies suggest that extracorporeal cytokine adsorption effectively reduces concentrations of pro-inflammatory cytokines and potentially improves the outcome of sepsis. METHODS: Sixteen patients with SAP, presenting within 7 days upon onset of pain, an APACHE-II score of ≥10 and ≥1 marker of poor prognosis, received 2 consecutive 24-h treatments with CytoSorb® extracorporeal cytokine adsorption (intervention group). Hemodynamics, organ failure, and mortality were compared with an APACHE-II score-matched retrospective control group of 32 patients. RESULTS: The primary objective (20% decrease in the vasopressor dependency index or 20% increase in the cardiac index) was reached in 68.8% of the intervention and 28.1% of the control patients (p = 0.007), respectively. The cytokine adsorption significantly reduced IL-6 (-1998 pg/ml, p = 0.005) serum levels and resulted in stable CRP (p = 0.101) and decreased PCT (p = 0.003) levels in contrast to increased CRP (p = 0.014) and stable PCT levels (p = 0.695) in the control group. While mortality and improvement of respiratory failure were similar in both groups, renal failure significantly improved (change of KDIGO classification 72 h postcytokine adsorption [-1 vs. 0, p = 0.005]) and the SOFA score significantly decreased (day 5: -1.8 ± 2.0 vs. 1 ± 3.8, p = 0.013) in the intervention group. CONCLUSION: Cytokine adsorption might be an effective treatment option to stabilize hemodynamics in SAP. It decreases levels of the pro-inflammatory marker IL-6 and stabilizes organ function according to serial SOFA score assessments.

Variants That Affect Function of Calcium Channel TRPV6 Are Associated With Early-Onset Chronic Pancreatitis.

BACKGROUND & AIMS: Changes in pancreatic calcium levels affect secretion and might be involved in development of chronic pancreatitis (CP). We investigated the association of CP with the transient receptor potential cation channel subfamily V member 6 gene (TRPV6), which encodes a Ca2+-selective ion channel, in an international cohort of patients and in mice. METHODS: We performed whole-exome DNA sequencing from a patient with idiopathic CP and from his parents, who did not have CP. We validated our findings by sequencing DNA from 300 patients with CP (not associated with alcohol consumption) and 1070 persons from the general population in Japan (control individuals). In replication studies, we sequenced DNA from patients with early-onset CP (20 years or younger) not associated with alcohol consumption from France (n = 470) and Germany (n = 410). We expressed TRPV6 variants in HEK293 cells and measured their activity using Ca2+ imaging assays. CP was induced by repeated injections of cerulein in TRPV6mut/mut mice. RESULTS: We identified the variants c.629C>T (p.A210V) and c.970G>A (p.D324N) in TRPV6 in the index patient. Variants that affected function of the TRPV6 product were found in 13 of 300 patients (4.3%) and 1 of 1070 control individuals (0.1%) from Japan (odds ratio [OR], 48.4; 95% confidence interval [CI], 6.3-371.7; P = 2.4 × 10-8). Twelve of 124 patients (9.7%) with early-onset CP had such variants. In the replication set from Europe, 18 patients with CP (2.0%) carried variants that affected the function of the TRPV6 product compared with 0 control individuals (P = 6.2 × 10-8). Variants that did not affect the function of the TRPV6 product (p.I223T and p.D324N) were overrepresented in Japanese patients vs control individuals (OR, 10.9; 95% CI, 4.5-25.9; P = 7.4 × 10-9 for p.I223T and P = .01 for p.D324N), whereas the p.L299Q was overrepresented in European patients vs control individuals (OR, 3.0; 95% CI, 1.9-4.8; P = 1.2 × 10-5). TRPV6mut/mut mice given cerulein developed more severe pancreatitis than control mice, as shown by increased levels of pancreatic enzymes, histologic alterations, and pancreatic fibrosis. CONCLUSIONS: We found that patients with early-onset CP not associated with alcohol consumption carry variants in TRPV6 that affect the function of its product, perhaps by altering Ca2+ balance in pancreatic cells. TRPV6 regulates Ca2+ homeostasis and pancreatic inflammation.

[Pathogenesis of acute pancreatitis]. / Pathogenese der akuten Pankreatitis.

Acute pancreatitis is characterized by the autodigestion of the pancreas by its own digestive enzymes. The pathophysiological onset of the disease occurs in the acinar cells. The normally inactive precursors of secreted proteases are prematurely activated and as a result digest the cells from within. The activation of trypsinogen to trypsin represents the key event as active trypsin activates further digestive enzymes and can therefore initiate the activation of the complete protease cascade. This premature activation of proteases results in the cell death of acinar cells and in the induction of a strong proinflammatory immune response. Cells of the innate immune system migrate into the damaged organ and potentiate the local damage again via the release of inflammatory cytokines, such as tumor necrosis factor alpha and reactive oxygen species. Concomitant to the local immune reaction, a systemic activation of the immune system also occurs, which can develop into a systemic inflammatory response syndrome (SIRS). In the course of the SIRS severe complications such as organ failure can occur. The consequence of this pronounced SIRS in the later course of the disease is a strong immunological counter-regulation, the so-called compensatory anti-inflammatory reaction syndrome (CARS). In the course of this immunosuppression commensal bacteria from the intestines can colonize the pancreatic necrosis. The outcome of the SIRS/CARS balance is decisive for the course and the prognosis of the patient.

Levels of the Autophagy-Related 5 Protein Affect Progression and Metastasis of Pancreatic Tumors in Mice.

BACKGROUND AND AIMS: Cells in pancreatic ductal adenocarcinoma (PDAC) undergo autophagy, but its effects vary with tumor stage and genetic factors. We investigated the consequences of varying levels of the autophagy related 5 (Atg5) protein on pancreatic tumor formation and progression. METHODS: We generated mice that express oncogenic Kras in primary pancreatic cancer cells and have homozygous disruption of Atg5 (A5;Kras) or heterozygous disruption of Atg5 (A5+/-;Kras), and compared them with mice with only oncogenic Kras (controls). Pancreata were analyzed by histology and immunohistochemistry. Primary tumor cells were isolated and used to perform transcriptome, metabolome, intracellular calcium, extracellular cathepsin activity, and cell migration and invasion analyses. The cells were injected into wild-type littermates, and orthotopic tumor growth and metastasis were monitored. Atg5 was knocked down in pancreatic cancer cell lines using small hairpin RNAs; cell migration and invasion were measured, and cells were injected into wild-type littermates. PDAC samples were obtained from independent cohorts of patients and protein levels were measured on immunoblot and immunohistochemistry; we tested the correlation of protein levels with metastasis and patient survival times. RESULTS: A5+/-;Kras mice, with reduced Atg5 levels, developed more tumors and metastases, than control mice, whereas A5;Kras mice did not develop any tumors. Cultured A5+/-;Kras primary tumor cells were resistant to induction and inhibition of autophagy, had altered mitochondrial morphology, compromised mitochondrial function, changes in intracellular Ca2+ oscillations, and increased activity of extracellular cathepsin L and D. The tumors that formed in A5+/-;Kras mice contained greater numbers of type 2 macrophages than control mice, and primary A5+/-;Kras tumor cells had up-regulated expression of cytokines that regulate macrophage chemoattraction and differentiation into M2 macrophage. Knockdown of Atg5 in pancreatic cancer cell lines increased their migratory and invasive capabilities, and formation of metastases following injection into mice. In human PDAC samples, lower levels of ATG5 associated with tumor metastasis and shorter survival time. CONCLUSIONS: In mice that express oncogenic Kras in pancreatic cells, heterozygous disruption of Atg5 and reduced protein levels promotes tumor development, whereas homozygous disruption of Atg5 blocks tumorigenesis. Therapeutic strategies to alter autophagy in PDAC should consider the effects of ATG5 levels to avoid the expansion of resistant and highly aggressive cells.

CD36-triggered cell invasion and persistent tissue colonization by tumor microvesicles during metastasis.

Tumor microvesicles are a peculiar type of extracellular vesicles that circulate in the blood of patients with metastatic cancer. The itineraries and immune cell interactions of tumor microvesicles during the intravascular and extravascular stages of metastasis are largely unknown. We found that the lipid receptor CD36 is a major mediator of the engulfment of pancreatic tumor microvesicles by myeloid immune cells in vitro and critically samples circulating tumor microvesicles by resident liver macrophages in mice in vivo. Direct nanoscopic imaging of individual tumor microvesicles shows that the microvesicles rapidly decay during engulfment whereby their cargo is targeted concomitantly to the plasma membrane and the cytoplasm excluding lysosomal compartments. CD36 also promotes internalization of blood cell (nontumor) microvesicles, which involves endolysosomal pathways. A portion of tumor microvesicles circulating in the liver microcirculation traverses the vessel wall in a CD36-dependent way. Extravasated microvesicles colonize distinct perivascular Ly6C- macrophages for at least 2 wk. Thus, the microvesicles are increasingly integrated into CD36-induced premetastatic cell clusters and enhance development of liver metastasis. Hence, promotion of metastasis by pancreatic tumor microvesicles is associated with CD36-regulated immune cell invasion and extravasation of microvesicles and persistent infiltration of specific tissue macrophages by microvesicle cargo.-Pfeiler, S., Thakur, M., Grünauer, P., Megens, R. T. A., Joshi, U., Coletti, R., Samara, V., Müller-Stoy, G., Ishikawa-Ankerhold, H., Stark, K., Klingl, A., Fröhlich, T., Arnold, G. J., Wörmann, S., Bruns, C. J., Algül, H., Weber, C., Massberg, S., Engelmann, B. CD36-triggered cell invasion and persistent tissue colonization by tumor microvesicles during metastasis.

New wine into old wineskins: PGC-1α and NF-κB in obesity and acute pancreatitis.

Obesity and acute pancreatitis are both proinflammatory conditions. Importantly, obesity increases severity in acute pancreatitis by enhancing inflammation. In a recent issue of The Journal of Pathology, Pérez and Ruiz-Pérez et al connected obesity and pancreatitis for the first time, through the transcriptional regulator PPARγ coactivator 1α (PGC-1α). Obesity reduces pancreatic PGC-1α levels and potentiates not only oxidative but also IL-6-mediated inflammatory damage during acute pancreatitis by relieving the binding of PGC-1α to the NF-κB subunit p65. Blockade of the IL-6 receptor subunit gp130 ameliorated tissue injury, substantiating the importance of deregulated PGC-1α/p65/IL-6 signaling in obesity and acute pancreatitis. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Early pancreatic cancer lesions suppress pain through CXCL12-mediated chemoattraction of Schwann cells.

Pancreatic ductal adenocarcinoma (PDAC) cells (PCC) have an exceptional propensity to metastasize early into intratumoral, chemokine-secreting nerves. However, we hypothesized the opposite process, that precancerous pancreatic cells secrete chemokines that chemoattract Schwann cells (SC) of nerves and thus induce ready-to-use routes of dissemination in early carcinogenesis. Here we show a peculiar role for the chemokine CXCL12 secreted in early PDAC and for its receptors CXCR4/CXCR7 on SC in the initiation of neural invasion in the cancer precursor stage and the resulting delay in the onset of PDAC-associated pain. SC exhibited cancer- or hypoxia-induced CXCR4/CXCR7 expression in vivo and in vitro and migrated toward CXCL12-expressing PCC. Glia-specific depletion of CXCR4/CXCR7 in mice abrogated the chemoattraction of SC to PCC. PDAC mice with pancreas-specific CXCL12 depletion exhibited diminished SC chemoattraction to pancreatic intraepithelial neoplasia and increased abdominal hypersensitivity caused by augmented spinal astroglial and microglial activity. In PDAC patients, reduced CXCR4/CXCR7 expression in nerves correlated with increased pain. Mechanistically, upon CXCL12 exposure, SC down-regulated the expression of several pain-associated targets. Therefore, PDAC-derived CXCL12 seems to induce tumor infiltration by SC during early carcinogenesis and to attenuate pain, possibly resulting in delayed diagnosis in PDAC.

Distinct Pathogenesis of Pancreatic Cancer Microvesicle-Associated Venous Thrombosis Identifies New Antithrombotic Targets In Vivo.

OBJECTIVE: Cancer patients are at high risk of developing deep venous thrombosis (DVT) and venous thromboembolism, a leading cause of mortality in this population. However, it is largely unclear how malignant tumors drive the prothrombotic cascade culminating in DVT. APPROACH AND RESULTS: Here, we addressed the pathophysiology of malignant DVT compared with nonmalignant DVT and focused on the role of tumor microvesicles as potential targets to prevent cancer-associated DVT. We show that microvesicles released by pancreatic adenocarcinoma cells (pancreatic tumor-derived microvesicles [pcMV]) boost thrombus formation in a model of flow restriction of the mouse vena cava. This depends on the synergistic activation of coagulation by pcMV and host tissue factor. Unlike nonmalignant DVT, which is initiated and propagated by innate immune cells, thrombosis triggered by pcMV was largely independent of myeloid leukocytes or platelets. Instead, we identified externalization of the phospholipid phosphatidylethanolamine as a major mechanism controlling the prothrombotic activity of pcMV. Disrupting phosphatidylethanolamine-dependent activation of factor X suppressed pcMV-induced DVT without causing changes in hemostasis. CONCLUSIONS: Together, we show here that the pathophysiology of pcMV-associated experimental DVT differs markedly from innate immune cell-promoted nonmalignant DVT and is therefore amenable to distinct antithrombotic strategies. Targeting phosphatidylethanolamine on tumor microvesicles could be a new strategy for prevention of cancer-associated DVT without causing bleeding complications.

Changes in pathogen spectrum and antimicrobial resistance development in the time-course of acute necrotizing pancreatitis.

BACKGROUND AND AIM: In contrast to the first peak of multi-organ failure in acute pancreatitis, the second peak is mostly triggered by septic complications. Our aim was to analyze the spectrum of pathogens and antimicrobial resistance development in relation to the time-course of the disease and its clinical outcome. METHODS: One hundred twenty-two patients with acute necrotizing pancreatitis undergoing pancreas puncture at two tertiary academic medical centers in Germany were retrospectively analyzed. RESULTS: At species level, there was a change in spectrum from Enterococcus faecalis (∆d150 - d1 = 14.6% - 16.7% = -2.1%) to Enterococcus faecium (∆d150 - d1 = 93.1% - 16.3% = 76.8%) (P < 0.001) and from Candida albicans (∆d150 - d1 = 39.7% - 23.6% = 16.1%) to non-albicans Candida spp. (∆d150 - d1 = 43.5% - 6.4% = 37.1%) (P = 0.005). Time-to-event analysis of acquired antimicrobial resistance showed that the overall number of patients with Enterobacteriaceae presented an antimicrobial susceptibility decrease by 59.7% (∆d1 - d100 = 87.0% - 27.3% = 59.7%). The cumulative incidence of multi-resistant bacteria increased with length of hospital stay (∆d150 - d1 = 49.1% - 3.1% = 46.0%) (P = 0.004). Multivariable logistic regression analysis in relation to the pathogen spectrum and antimicrobial resistance development showed a significantly higher mortality for non-albicans Candida spp. (P = 0.039, odds ratio [OR] = 3.32 [95% confidence interval [CI]: 1.07-10.35]), E. faecium (P = 0.009, OR = 3.73 [95% CI: 1.38-10.05]), and multi-resistant bacteria (P = 0.007, OR = 5.08 [95% CI: 1.55-16.66]). CONCLUSIONS: Antimicrobial treatment of infected pancreatic necrosis becomes more challenging over time, owing to a change in spectrum favoring difficult-to-treat pathogens and an increase in multi-resistant bacteria associated with worse clinical outcomes (World Health Organization trial registration number: DRKS00014785).