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Innate inflammation promotes tumor development, although the role of innate inflammatory cytokines in established human tumors is unclear. Herein, we report clinical and translational results from a phase Ib trial testing whether IL1β blockade in human pancreatic cancer would alleviate myeloid immunosuppression and reveal antitumor T-cell responses to PD1 blockade. Patients with treatment-naïve advanced pancreatic ductal adenocarcinoma (n = 10) were treated with canakinumab, a high-affinity monoclonal human antiinterleukin-1β (IL1β), the PD1 blocking antibody spartalizumab, and gemcitabine/n(ab)paclitaxel. Analysis of paired peripheral blood from patients in the trial versus patients receiving multiagent chemotherapy showed a modest increase in HLA-DR+CD38+ activated CD8+ T cells and a decrease in circulating monocytic myeloid-derived suppressor cells (MDSC) by flow cytometry for patients in the trial but not in controls. Similarly, we used patient serum to differentiate monocytic MDSCs in vitro and showed that functional inhibition of T-cell proliferation was reduced when using on-treatment serum samples from patients in the trial but not when using serum from patients treated with chemotherapy alone. Within the tumor, we observed few changes in suppressive myeloid-cell populations or activated T cells as assessed by single-cell transcriptional profiling or multiplex immunofluorescence, although increases in CD8+ T cells suggest that improvements in the tumor immune microenvironment might be revealed by a larger study. Overall, the data indicate that exposure to PD1 and IL1β blockade induced a modest reactivation of peripheral CD8+ T cells and decreased circulating monocytic MDSCs; however, these changes did not lead to similarly uniform alterations in the tumor microenvironment., (©2024 The Authors; Published by the American Association for Cancer Research.)

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal malignancy that harbors mutations in homologous recombination-repair (HR-repair) proteins in 20%-25% of cases. Defects in HR impart a specific vulnerability to poly ADP ribose polymerase inhibitors and platinum-containing chemotherapy in tumor cells. However, not all patients who receive these therapies respond, and many who initially respond ultimately develop resistance. Inactivation of the HR pathway is associated with the overexpression of polymerase theta (Polθ, or POLQ). This key enzyme regulates the microhomology-mediated end-joining (MMEJ) pathway of double-strand break (DSB) repair. Using human and murine HR-deficient PDAC models, we found that POLQ knockdown is synthetically lethal in combination with mutations in HR genes such as BRCA1 and BRCA2 and the DNA damage repair gene ATM. Further, POLQ knockdown enhances cytosolic micronuclei formation and activates signaling of cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING), leading to enhanced infiltration of activated CD8+ T cells in BRCA2-deficient PDAC tumors in vivo. Overall, POLQ, a key mediator in the MMEJ pathway, is critical for DSB repair in BRCA2-deficient PDAC. Its inhibition represents a synthetic lethal approach to blocking tumor growth while concurrently activating the cGAS-STING signaling pathway to enhance tumor immune infiltration, highlighting what we believe to be a new role for POLQ in the tumor immune environment.

The tumor microenvironment (TME) in pancreatic ductal adenocarcinoma (PDAC) is a complex ecosystem that drives tumor progression; however, in-depth single cell characterization of the PDAC TME and its role in response to therapy is lacking. Here, we perform single-cell RNA sequencing on freshly collected human PDAC samples either before or after chemotherapy. Overall, we find a heterogeneous mixture of basal and classical cancer cell subtypes, along with distinct cancer-associated fibroblast and macrophage subpopulations. Strikingly, classical and basal-like cancer cells exhibit similar transcriptional responses to chemotherapy and do not demonstrate a shift towards a basal-like transcriptional program among treated samples. We observe decreased ligand-receptor interactions in treated samples, particularly between TIGIT on CD8 + T cells and its receptor on cancer cells, and identify TIGIT as the major inhibitory checkpoint molecule of CD8 + T cells. Our results suggest that chemotherapy profoundly impacts the PDAC TME and may promote resistance to immunotherapy., (© 2023. The Author(s).)

Hepato-pancreatico-biliary (HPB) malignancies are difficult-to-treat and continue to to have a high mortality and significant therapeutic resistance to standard therapies. Immune oncology (IO) therapies have demonstrated efficacy in several solid malignancies when combined with chemotherapy, whereas response rates in pancreatic ductal adenocarcinoma (PDA) are poor. While promising in hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA), there remains an unmet need to fully leverage IO therapies to treat HPB tumors. We therefore defined T cell subsets in the tumor microenvironment of HPB patients utilizing a novel, multiparameter flow cytometry and bioinformatics analysis. Our findings quantify the T cell phenotypic states in relation to checkpoint receptor expression. We demonstrate the presence of CD103 + tissue resident memory T cells (T RM ), CCR7 + central memory T cells, and CD57 + terminally differentiated effector cells across all HPB cancers, while the anti-tumor function was dampened by expression of multiple co-inhibitory checkpoint receptors. Terminally exhausted T cells lacking co-stimulatory receptors were more prevalent in PDA, whereas partially exhausted T cells expressing both co-inhibitory and co-stimulatory receptors were most prevalent in HCC, especially in early stage. HCC patients had significantly higher T RM with a phenotype that could confer restored activation in response to immune checkpoint therapies. Further, we found a lack of robust alteration in T cell activation state or checkpoint expression in response to chemotherapy in PDA patients. These results support that HCC patients might benefit most from combined checkpoint therapies, whereas efforts other than cytotoxic chemotherapy will likely be necessary to increase overall T cell activation in CCA and PDA for future clinical development., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Wan, Zhao, Weissinger, Krantz, Werba, Freeman, Khanna, Siolas, Oberstein, Chattopadhyay, Simeone and Welling.)

Response to cancer immunotherapy in primary versus metastatic disease has not been well-studied. We found primary pancreatic ductal adenocarcinoma (PDA) is responsive to diverse immunotherapies whereas liver metastases are resistant. We discovered divergent immune landscapes in each compartment. Compared to primary tumor, liver metastases in both mice and humans are infiltrated by highly anergic T cells and MHCII lo IL10 + macrophages that are unable to present tumor-antigen. Moreover, a distinctive population of CD24 + CD44 - CD40 - B cells dominate liver metastases. These B cells are recruited to the metastatic milieu by Muc1 hi IL18 hi tumor cells, which are enriched >10-fold in liver metastases. Recruited B cells drive macrophage-mediated adaptive immune-tolerance via CD200 and BTLA. Depleting B cells or targeting CD200/BTLA enhanced macrophage and T-cell immunogenicity and enabled immunotherapeutic efficacy of liver metastases. Our data detail the mechanistic underpinnings for compartment-specific immunotherapy-responsiveness and suggest that primary PDA models are poor surrogates for evaluating immunity in advanced disease., (© 2022. The Author(s), under exclusive licence to Springer Nature Limited.)

Transcriptional heterogeneity among malignant cells of a tumor has been studied in individual cancer types and shown to be organized into cancer cell states; however, it remains unclear to what extent these states span tumor types, constituting general features of cancer. Here, we perform a pan-cancer single-cell RNA-sequencing analysis across 15 cancer types and identify a catalog of gene modules whose expression defines recurrent cancer cell states including 'stress', 'interferon response', 'epithelial-mesenchymal transition', 'metal response', 'basal' and 'ciliated'. Spatial transcriptomic analysis linked the interferon response in cancer cells to T cells and macrophages in the tumor microenvironment. Using mouse models, we further found that induction of the interferon response module varies by tumor location and is diminished upon elimination of lymphocytes. Our work provides a framework for studying how cancer cell states interact with the tumor microenvironment to form organized systems capable of immune evasion, drug resistance and metastasis., (© 2022. The Author(s), under exclusive licence to Springer Nature America, Inc.)

Background: Historically, robotic surgery incurs longer operative times, higher costs, and nonsuperior outcomes compared with laparoscopic surgery. However, in areas of limited visibility and decreased accessibility such as the gastroesophageal junction, robotic platforms may improve visualization and facilitate dissection. This study compares 30-day outcomes between robotic-assisted foregut surgery (RAF) and laparoscopic-assisted foregut surgery in the Veterans Health Administration., Study Design: This is a retrospective review of the Veterans Affairs Quality Improvement Program database. Patients undergoing laparoscopic-assisted foregut surgery and RAF were identified using CPT codes 43280, 43281, 43282, and robotic modifier S2900. Multivariable logistic regression and multivariable generalized linear models were used to analyze the independent association between surgical approach and outcomes of interest., Results: A total of 9,355 veterans underwent minimally invasive fundoplication from 2008 to 2019. RAF was used in 5,392 cases (57.6%): 1.63% of cases in 2008 to 83.41% of cases in 2019. After adjusting for confounding covariates, relative to laparoscopic-assisted foregut surgery, RAF was significantly associated with decreased adjusted odds of pulmonary complications (adjusted odds ratio [aOR] 0.44, p < 0.001), acute renal failure (aOR 0.14, p = 0.046), venous thromboembolism (aOR 0.44, p = 0.009) and increased odds of infectious complications (aOR 1.60, p = 0.017). RAF was associated with an adjusted mean ± SD of 29 ± 2-minute shorter operative time (332 minutes vs 361 minutes; p < 0.001)., Conclusions: Veterans undergoing RAF ascertained shorter operative times and reduced complications vs laparoscopy. As surgeons use the robotic platform, clinical outcomes and operative times continue to improve, particularly in operations where extra articulation in confined spaces is required., (Copyright © 2022 by the American College of Surgeons. Published by Wolters Kluwer Health, Inc. All rights reserved.)

Background: Video-assisted thoracoscopic surgery (VATS) offers reduced morbidity compared with open thoracotomy (OT) for pulmonary surgery. The use of VATS over time has increased, but at a modest rate in civilian populations. This study examines temporal trends in VATS use and compares outcomes between VATS and OT in the Veterans Health Administration (VHA)., Methods: Patients who underwent pulmonary surgery (wedge or segmental resection, lobectomy, or pneumonectomy) at Veterans Affairs centers from 2008 to 2018 were retrospectively identified using the Veterans Affairs Surgical Quality Improvement Project database. The cohort was divided into OT and VATS and propensity score matched, taking into account the type of pulmonary resection, preoperative diagnosis, and comorbidities. Thirty-day postoperative outcomes were compared. The prevalence of VATS use and respective complications over time was also analyzed., Results: A total of 16,895 patients were identified, with 5,748 per group after propensity matching. VATS had significantly lower rates of morbidity and a 2-day reduction in hospital stay. Whereas 76% of lung resections were performed open in 2008, nearly 70% of procedures were performed using VATS in 2018. While VATS was associated with an 8% lower rate of major complications compared with thoracotomy in 2008, patients undergoing VATS lung resection in 2018 had a 58% lower rate of complications ( p  < 0.001)., Conclusions: VATS utilization at VHA centers has become the predominant technique used for pulmonary surgeries over time. OT patients had more complications and longer hospital stays compared with VATS. Over the study period, VATS patients had increasingly lower complication rates compared with open surgery., Competing Interests: No financial or competing conflicts of interest to disclose., (Thieme. All rights reserved.)

The gut microbiome shapes local and systemic immunity. The liver is presumed to be a protected sterile site. As such, a hepatic microbiome has not been examined. Here, we showed a liver microbiome in mice and humans that is distinct from that of the gut and is enriched in Proteobacteria. It undergoes dynamic alterations with age and is influenced by the environment and host physiology. Fecal microbial transfer experiments revealed that the liver microbiome is populated from the gut in a highly selective manner. Hepatic immunity is dependent on the microbiome, specifically the bacteroidetes species. Targeting bacteroidetes with oral antibiotics reduced hepatic immune cells by approximately 90%, prevented antigen-presenting cell (APC) maturation, and mitigated adaptive immunity. Mechanistically, our findings are consistent with presentation of bacteroidetes-derived glycosphingolipids to NKT cells promoting CCL5 signaling, which drives hepatic leukocyte expansion and activation, among other possible host-microbe interactions. Collectively, we reveal a microbial/glycosphingolipid/NKT/CCL5 axis that underlies hepatic immunity.

Background: Preoperative biliary drainage (PBD) has been advocated to address the plethora of physiologic derangements associated with cholestasis. However, available literature reports mixed outcomes and is based on largely outdated and/or single-institution studies., Methods: Patients undergoing PBD prior to pancreaticoduodenectomy (PD) for periampullary malignancy between 2014-2018 were identified in the ACS-NSQIP pancreatectomy dataset. Patients with PBD were propensity-score-matched to those without PBD and 30-day outcomes compared., Results: 8,970 patients met our inclusion criteria. 4,473 with obstruction and PBD were matched to 829 with no preoperative drainage procedure. In the non-jaundiced cohort, 711 stented patients were matched to 2,957 without prior intervention. PBD did not influence 30-day mortality (2.2% versus 2.4%) or major morbidity (19.8% versus 20%) in patients with obstructive jaundice. Superficial surgical site infections (SSIs) were more common with PBD (6.8% versus 9.2%), however, no differences in deep or organ-space SSIs were found. Patients without obstruction prior to PBD exhibited a 3-fold increase in wound dehiscence (0.5% versus 1.5%) additionally to increased superficial SSIs., Conclusion: PBD was not associated with an increase in 30-day mortality or major morbidity but increased superficial SSIs. PBD should be limited to symptomatic, profoundly jaundiced patients or those with a delay prior to PD., (Copyright © 2021 International Hepato-Pancreato-Biliary Association Inc. Published by Elsevier Ltd. All rights reserved.)

Objective: Mediastinal masses are commonly encountered by the thoracic surgeon. Few studies have reported on the frequency and characteristics of symptoms at presentation. The primary objective of this study is to determine how often patients present with symptoms from a mediastinal mass. The secondary objective is to determine if the presence of symptoms has an effect on outcomes after surgery., Methods: A retrospective review of an institutional database was performed. All patients who underwent surgical resection of a mediastinal mass from 2013 to 2019 were included in the analysis. Medical records were reviewed for the presence or absence of symptoms preoperatively, and these cohorts were compared. Multivariable analysis was performed, adjusting for clinical variables to assess for differences between these cohorts., Results: 70 patients underwent surgery for a mediastinal mass. The average age was 49.2 years, and 46 patients (65.7%) presented with symptoms. There were no significant differences in demographics between the symptomatic and asymptomatic groups. The most common symptom was dyspnea in 18 patients (22%), followed by chest pain (15 patients, 19%) and dysphagia (8 patients, 10%). When comparing symptomatic and asymptomatic patients, symptomatic patients had a larger tumor size (5.8 cm vs 3.8 cm, P = .04) and a longer length of stay (2.0 days vs 1.2 days, P = .02)., Conclusions: The majority of patients with mediastinal masses present with symptoms, with the most common symptom being dyspnea. Symptomatic patients are more likely to have a larger tumor and tend to have a longer length of hospital stay postoperatively compared to asymptomatic patients.

Background: Morbidity after Pancreaticoduodenectomy (PD) has remained unchanged over the past decade. Delayed Gastric Emptying (DGE) is a major contributor with significant impact on healthcare-costs, quality of life and, for malignancies, even survival. We sought to develop a scoring system to aid in easy preoperative identification of patients at risk for DGE., Methods: The ACS-NSQIP dataset from 2014 to 2018 was queried for patients undergoing PD with Whipple or pylorus preserving reconstruction. 15,154 patients were analyzed using multivariable logistic regression to identify risk factors for DGE, which were incorporated into a prediction model. Subgroup analysis of patients without SSI or fistula (primary DGE) was performed., Results: We identified 9 factors independently associated with DGE to compile the PrEDICT-DGE score: Procedures (Concurrent adhesiolysis, feeding jejunostomy, vascular reconstruction with vein graft), Elderly (Age>70), Ductal stent (Lack of biliary stent), Invagination (Pancreatic reconstruction technique), COPD, Tobacco use, Disease, systemic (ASA>2), Gender (Male) and Erythrocytes (preoperative RBC-transfusion). PrEDICT-DGE scoring strongly correlated with actual DGE rates (R 2  = 0.95) and predicted patients at low, intermediate, and high risk. Subgroup analysis of patients with primary DGE, retained all predictive factors, except for age>70 (p = 0.07) and ASA(p = 0.30)., Conclusion: PrEDICT-DGE scoring accurately identifies patients at high risk for DGE and can help guide perioperative management., (Copyright © 2021 International Hepato-Pancreato-Biliary Association Inc. Published by Elsevier Ltd. All rights reserved.)

Background: Previous literature in other surgical disciplines regarding the impact of resident and fellow involvement on operative time and outcomes has yielded mixed results. The impact of trainee involvement on minimally invasive thoracic surgery is unknown. This study compared risk-adjusted differences in operative time and outcomes of video-assisted thoracoscopic lobectomy for cancer between cases performed with and without residents and fellows involved., Methods: All patients undergoing elective video-assisted thoracoscopic lobectomy for cancer between 2008 and 2018 were identified in the Veterans Affairs Surgical Quality Improvement Program database. Patients were stratified into 2 cohorts: cases with residents and fellows involved, and cases performed only by attending surgeons. Primary outcomes included operative time, postoperative hospital length of stay, and composite 30-day morbidity and mortality. Secondary outcomes included factors associated with high and low trainee operative autonomy., Results: A total of 3678 patients met study inclusion criteria. In all, 1780 cases were performed with residents and fellows involved (median postgraduate year, 5; interquartile range, 4-7). Multivariate analysis showed that operative time was significantly shorter in resident- and fellow-involved cases compared with attending-only cases (mean [SD], 3.6 [1.4] versus 3.8 [1.6] hours; P < .001). There were no significant differences in composite 30-day morbidity and mortality (16.0% versus 17.1%; adjusted odds ratio = 0.93; 95% confidence interval, 0.77-1.11; P = .40) or length of stay. Substratification of trainees by postgraduate year resulted in similar findings. Cases performed in July through October and those in the Northeastern United States were associated with low autonomy., Conclusions: Current training paradigms in thoracic surgery are safe, and the involvement of motivated and skilled trainees with appropriate supervision may benefit operative duration., (Copyright © 2021 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Pancreatic ductal adenocarcinoma (PDAC) is a leading cause of cancer-related mortality in the United States and has only recently achieved a 5-yr survival rate of 10%. This dismal prognosis reflects the remarkable capacity of PDAC to effectively adapt to and resist therapeutic intervention. In this review, we discuss recent advances in our understanding of the biological underpinnings of PDAC and their implications as targetable vulnerabilities in this highly lethal disease., (© 2021 Beatty et al.; Published by Cold Spring Harbor Laboratory Press.)

Pancreatic ductal adenocarcinoma (PDAC) features a hostile tumor microenvironment (TME) that renders it remarkably resistant to most therapeutic interventions. Consequently, survival remains among the poorest compared with other gastrointestinal cancers. Concerted efforts are underway to decipher the complex PDAC TME, break down barriers to efficacious therapies and identify novel treatment strategies. In the recent Clinical Science, Li and colleagues identify the long noncoding RNA KLHDC7B-DT as a crucial epigenetic regulator of IL-6 transcription in PDAC and illustrate its potent influences on the pancreatic TME. In this commentary, we introduce epigenetics in pancreatic cancer and put the findings by Li et al. in context with current knowledge., (© 2021 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.)

Piezo1 is a mechanosensitive ion channel that has gained recognition for its role in regulating diverse physiological processes. However, the influence of Piezo1 in inflammatory disease, including infection and tumor immunity, is not well studied. We postulated that Piezo1 links physical forces to immune regulation in myeloid cells. We found signal transduction via Piezo1 in myeloid cells and established this channel as the primary sensor of mechanical stress in these cells. Global inhibition of Piezo1 with a peptide inhibitor was protective against both cancer and septic shock and resulted in a diminution in suppressive myeloid cells. Moreover, deletion of Piezo1 in myeloid cells protected against cancer and increased survival in polymicrobial sepsis. Mechanistically, we show that mechanical stimulation promotes Piezo1-dependent myeloid cell expansion by suppressing the retinoblastoma gene Rb1 We further show that Piezo1-mediated silencing of Rb1 is regulated via up-regulation of histone deacetylase 2. Collectively, our work uncovers Piezo1 as a targetable immune checkpoint that drives immunosuppressive myelopoiesis in cancer and infectious disease., (Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

Programmed cell death protein 1 (PD-1) ligation delimits immunogenic responses in T cells. However, the consequences of programmed cell death 1 ligand 1 (PD-L1) ligation in T cells are uncertain. We found that T cell expression of PD-L1 in cancer was regulated by tumor antigen and sterile inflammatory cues. PD-L1 + T cells exerted tumor-promoting tolerance via three distinct mechanisms: (1) binding of PD-L1 induced STAT3-dependent 'back-signaling' in CD4 + T cells, which prevented activation, reduced T H 1-polarization and directed T H 17-differentiation. PD-L1 signaling also induced an anergic T-bet - IFN-γ - phenotype in CD8 + T cells and was equally suppressive compared to PD-1 signaling; (2) PD-L1 + T cells restrained effector T cells via the canonical PD-L1-PD-1 axis and were sufficient to accelerate tumorigenesis, even in the absence of endogenous PD-L1; (3) PD-L1 + T cells engaged PD-1 + macrophages, inducing an alternative M2-like program, which had crippling effects on adaptive antitumor immunity. Collectively, we demonstrate that PD-L1 + T cells have diverse tolerogenic effects on tumor immunity.

Background: Vascular reconstruction during pancreaticoduodenectomy is increasingly utilized to improve pancreatic cancer resectability. However, few multi-institutional studies have evaluated the morbidity and mortality of arterial and venous reconstruction during this procedure., Methods: A retrospective analysis was performed utilizing the targeted pancreas module of the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) for pancreaticoduodenectomy from 2014 to 2015. Demographics, comorbidities, and 30-day outcomes for patients who underwent venous or arterial reconstruction and both were compared to no reconstruction., Results: A total of 3002 patients were included in our study: 384 with venous reconstruction, 52 with arterial, 81 with both, and 2566 without. Compared to patients without reconstruction, those who underwent venous reconstruction had more congestive heart failure (1.8% vs 0.2%, P < 0.01), those with arterial reconstruction had higher rates of pulmonary disease (11.5% vs. 4.5%, P = 0.02), and neoadjuvant chemotherapy was more common in both venous (34% vs 12%, P < 0.01) and arterial reconstruction (21% vs 12%, P = 0.04). In multivariable analysis, there was no increase in morbidity or mortality following venous reconstruction. However, arterial reconstruction was associated with increased 30-day mortality with an odds ratio (OR): 6.7, 95%; confidence interval (CI): 1.8-25. Morbidity was increased as represented with return to the operating room (OR: 4.5, 95%; CI: 1.5-15), pancreatic fistula (OR: 4.4, 95%; CI: 1.7-11), and reintubation (OR: 3.9, 95%; CI: 1.1-14)., Conclusions: Venous reconstruction during pancreaticoduodenectomy does not increase perioperative morbidity or mortality and should be considered for patients previously considered to be unresectable or those where R0 resection would otherwise not be possible due to venous involvement. Careful consideration should be made prior to arterial reconstruction given the significant increase in perioperative complications and death within 30 days.

Background: Large burn injuries induce a systemic response in affected patients. Soluble ST2 (sST2) acts as a decoy receptor for interleukin-33 (IL-33) and has immunosuppressive effects. sST2 has been described previously as a prognostic serum marker. Our aim was to evaluate serum concentrations of sST2 and IL-33 after thermal injury and elucidate whether sST2 is associated with mortality in these patients., Methods: We included 32 burn patients (total body surface area [TBSA] >10%) admitted to our burn intensive care unit and compared them to eight healthy probands. Serum concentrations of sST2 and IL-33 were measured serially using an enzyme-linked immunosorbent assay (ELISA) technique., Results: The mean TBSA was 32.5%±19.6%. Six patients (18.8%) died during the hospital stay. Serum analyses showed significantly increased concentrations of sST2 and reduced concentrations of IL-33 in burn patients compared to healthy controls. In our study cohort, higher serum concentrations of sST2 were a strong independent predictor of mortality., Conclusions: Burn injuries cause an increment of sST2 serum concentrations with a concomitant reduction of IL-33. Higher concentrations of sST2 are associated with increased in-hospital mortality in burn patients.

We found that the cancerous pancreas harbors a markedly more abundant microbiome compared with normal pancreas in both mice and humans, and select bacteria are differentially increased in the tumorous pancreas compared with gut. Ablation of the microbiome protects against preinvasive and invasive pancreatic ductal adenocarcinoma (PDA), whereas transfer of bacteria from PDA-bearing hosts, but not controls, reverses tumor protection. Bacterial ablation was associated with immunogenic reprogramming of the PDA tumor microenvironment, including a reduction in myeloid-derived suppressor cells and an increase in M1 macrophage differentiation, promoting TH1 differentiation of CD4 + T cells and CD8 + T-cell activation. Bacterial ablation also enabled efficacy for checkpoint-targeted immunotherapy by upregulating PD-1 expression. Mechanistically, the PDA microbiome generated a tolerogenic immune program by differentially activating select Toll-like receptors in monocytic cells. These data suggest that endogenous microbiota promote the crippling immune-suppression characteristic of PDA and that the microbiome has potential as a therapeutic target in the modulation of disease progression. Significance: We found that a distinct and abundant microbiome drives suppressive monocytic cellular differentiation in pancreatic cancer via selective Toll-like receptor ligation leading to T-cell anergy. Targeting the microbiome protects against oncogenesis, reverses intratumoral immune tolerance, and enables efficacy for checkpoint-based immunotherapy. These data have implications for understanding immune suppression in pancreatic cancer and its reversal in the clinic. Cancer Discov; 8(4); 403-16. ©2018 AACR. See related commentary by Riquelme et al., p. 386 This article is highlighted in the In This Issue feature, p. 371 ., (©2018 American Association for Cancer Research.)

The tumor microenvironment (TME) in pancreatic ductal adenocarcinoma (PDA) is characterized by immune tolerance, which enables disease to progress unabated by adaptive immunity. However, the drivers of this tolerogenic program are incompletely defined. In this study, we found that NLRP3 promotes expansion of immune-suppressive macrophages in PDA. NLRP3 signaling in macrophages drives the differentiation of CD4 + T cells into tumor-promoting T helper type 2 cell (Th2 cell), Th17 cell, and regulatory T cell populations while suppressing Th1 cell polarization and cytotoxic CD8 + T cell activation. The suppressive effects of NLRP3 signaling were IL-10 dependent. Pharmacological inhibition or deletion of NLRP3, ASC (apoptosis-associated speck-like protein containing a CARD complex), or caspase-1 protected against PDA and was associated with immunogenic reprogramming of innate and adaptive immunity within the TME. Similarly, transfer of PDA-entrained macrophages or T cells from NLRP3 -/- hosts was protective. These data suggest that targeting NLRP3 holds the promise for the immunotherapy of PDA., (© 2017 Daley et al.)

The progression of pancreatic oncogenesis requires immune-suppressive inflammation in cooperation with oncogenic mutations. However, the drivers of intratumoral immune tolerance are uncertain. Dectin 1 is an innate immune receptor crucial for anti-fungal immunity, but its role in sterile inflammation and oncogenesis has not been well defined. Furthermore, non-pathogen-derived ligands for dectin 1 have not been characterized. We found that dectin 1 is highly expressed on macrophages in pancreatic ductal adenocarcinoma (PDA). Dectin 1 ligation accelerated the progression of PDA in mice, whereas deletion of Clec7a-the gene encoding dectin 1-or blockade of dectin 1 downstream signaling was protective. We found that dectin 1 can ligate the lectin galectin 9 in mouse and human PDA, which results in tolerogenic macrophage programming and adaptive immune suppression. Upon disruption of the dectin 1-galectin 9 axis, CD4 + and CD8 + T cells, which are dispensable for PDA progression in hosts with an intact signaling axis, become reprogrammed into indispensable mediators of anti-tumor immunity. These data suggest that targeting dectin 1 signaling is an attractive strategy for developing an immunotherapy for PDA.

Inflammation is paramount in pancreatic oncogenesis. We identified a uniquely activated γδT cell population, which constituted ∼40% of tumor-infiltrating T cells in human pancreatic ductal adenocarcinoma (PDA). Recruitment and activation of γδT cells was contingent on diverse chemokine signals. Deletion, depletion, or blockade of γδT cell recruitment was protective against PDA and resulted in increased infiltration, activation, and Th1 polarization of αβT cells. Although αβT cells were dispensable to outcome in PDA, they became indispensable mediators of tumor protection upon γδT cell ablation. PDA-infiltrating γδT cells expressed high levels of exhaustion ligands and thereby negated adaptive anti-tumor immunity. Blockade of PD-L1 in γδT cells enhanced CD4(+) and CD8(+) T cell infiltration and immunogenicity and induced tumor protection suggesting that γδT cells are critical sources of immune-suppressive checkpoint ligands in PDA. We describe γδT cells as central regulators of effector T cell activation in cancer via novel cross-talk., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Background & Aims: The role of radiation therapy in the treatment of patients with pancreatic ductal adenocarcinoma (PDA) is controversial. Randomized controlled trials investigating the efficacy of radiation therapy in patients with locally advanced unresectable PDA have reported mixed results, with effects ranging from modest benefit to worse outcomes compared with control therapies. We investigated whether radiation causes inflammatory cells to acquire an immune-suppressive phenotype that limits the therapeutic effects of radiation on invasive PDAs and accelerates progression of preinvasive foci., Methods: We investigated the effects of radiation therapy in p48(Cre);LSL-Kras(G12D) (KC) and p48(Cre);LSLKras(G12D);LSL-Trp53(R172H) (KPC) mice, as well as in C57BL/6 mice with orthotopic tumors grown from FC1242 cells derived from KPC mice. Some mice were given neutralizing antibodies against macrophage colony-stimulating factor 1 (CSF1 or MCSF) or F4/80. Pancreata were exposed to doses of radiation ranging from 2 to 12 Gy and analyzed by flow cytometry., Results: Pancreata of KC mice exposed to radiation had a higher frequency of advanced pancreatic intraepithelial lesions and more foci of invasive cancer than pancreata of unexposed mice (controls); radiation reduced survival time by more than 6 months. A greater proportion of macrophages from radiation treated invasive and preinvasive pancreatic tumors had an immune-suppressive, M2-like phenotype compared with control mice. Pancreata from mice exposed to radiation had fewer CD8(+) T cells than controls, and greater numbers of CD4(+) T cells of T-helper 2 and T-regulatory cell phenotypes. Adoptive transfer of T cells from irradiated PDA to tumors of control mice accelerated tumor growth. Radiation induced production of MCSF by PDA cells. A neutralizing antibody against MCSF prevented radiation from altering the phenotype of macrophages in tumors, increasing the anti-tumor T-cell response and slowing tumor growth., Conclusions: Radiation treatment causes macrophages murine PDA to acquire an immune-suppressive phenotype and disabled T-cell-mediated anti-tumor responses. MCSF blockade negates this effect, allowing radiation to have increased efficacy in slowing tumor growth., (Copyright © 2016 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Neoplastic pancreatic epithelial cells are believed to die through caspase 8-dependent apoptotic cell death, and chemotherapy is thought to promote tumour apoptosis. Conversely, cancer cells often disrupt apoptosis to survive. Another type of programmed cell death is necroptosis (programmed necrosis), but its role in pancreatic ductal adenocarcinoma (PDA) is unclear. There are many potential inducers of necroptosis in PDA, including ligation of tumour necrosis factor receptor 1 (TNFR1), CD95, TNF-related apoptosis-inducing ligand (TRAIL) receptors, Toll-like receptors, reactive oxygen species, and chemotherapeutic drugs. Here we report that the principal components of the necrosome, receptor-interacting protein (RIP)1 and RIP3, are highly expressed in PDA and are further upregulated by the chemotherapy drug gemcitabine. Blockade of the necrosome in vitro promoted cancer cell proliferation and induced an aggressive oncogenic phenotype. By contrast, in vivo deletion of RIP3 or inhibition of RIP1 protected against oncogenic progression in mice and was associated with the development of a highly immunogenic myeloid and T cell infiltrate. The immune-suppressive tumour microenvironment associated with intact RIP1/RIP3 signalling depended in part on necroptosis-induced expression of the chemokine attractant CXCL1, and CXCL1 blockade protected against PDA. Moreover, cytoplasmic SAP130 (a subunit of the histone deacetylase complex) was expressed in PDA in a RIP1/RIP3-dependent manner, and Mincle--its cognate receptor--was upregulated in tumour-infiltrating myeloid cells. Ligation of Mincle by SAP130 promoted oncogenesis, whereas deletion of Mincle protected against oncogenesis and phenocopied the immunogenic reprogramming of the tumour microenvironment that was induced by RIP3 deletion. Cellular depletion suggested that whereas inhibitory macrophages promote tumorigenesis in PDA, they lose their immune-suppressive effects when RIP3 or Mincle is deleted. Accordingly, T cells, which are not protective against PDA progression in mice with intact RIP3 or Mincle signalling, are reprogrammed into indispensable mediators of anti-tumour immunity in the absence of RIP3 or Mincle. Our work describes parallel networks of necroptosis-induced CXCL1 and Mincle signalling that promote macrophage-induced adaptive immune suppression and thereby enable PDA progression.

Dectin-1 is a C-type lectin receptor critical in anti-fungal immunity, but Dectin-1 has not been linked to regulation of sterile inflammation or oncogenesis. We found that Dectin-1 expression is upregulated in hepatic fibrosis and liver cancer. However, Dectin-1 deletion exacerbates liver fibro-inflammatory disease and accelerates hepatocarcinogenesis. Mechanistically, we found that Dectin-1 protects against chronic liver disease by suppressing TLR4 signaling in hepatic inflammatory and stellate cells. Accordingly, Dectin-1(-/-) mice exhibited augmented cytokine production and reduced survival in lipopolysaccharide (LPS)-mediated sepsis, whereas Dectin-1 activation was protective. We showed that Dectin-1 inhibits TLR4 signaling by mitigating TLR4 and CD14 expression, which are regulated by Dectin-1-dependent macrophage colony stimulating factor (M-CSF) expression. Our study suggests that Dectin-1 is an attractive target for experimental therapeutics in hepatic fibrosis and neoplastic transformation. More broadly, our work deciphers critical cross-talk between pattern recognition receptors and implicates a role for Dectin-1 in suppression of sterile inflammation, inflammation-induced oncogenesis, and LPS-mediated sepsis., (Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.)

Activation of signal-transcriptional factor signal transducer and activator of transcription 3 (STAT3) is associated with more aggressive behaviour in a variety of human malignancies. As selective STAT3 inhibitors exist, this protein might represent a novel therapeutic target. Although STAT3 seems to play an important role in progression of pancreatic ductal carcinoma (PDAC), only few data on this subject exist. The aim of our study was the investigation of STAT3 activation and its correlation with its possible regulator HER2. Expression of tyrosine-705 phosphorylated STAT3 (pSTAT3) was determined immunohistochemically in 79 PDACs. HER2 status assessed by immunohistochemistry and double colour silver in situ hybridization was available from a previous study. PSTAT3 expression was seen in 33 (41.8%) patients. Six patients were scored as HER2 positive having strong correlation with pSTAT3 expression (p = 0.004, Fisher's exact test). No association of pSTAT3 expression with patients' age, tumour staging and grading, perineural invasion of tumour cells or survival time was seen. pSTAT3 is frequently expressed in PDAC. Nevertheless, its immediate clinical relevance seems to be low. However, further research needs to determine whether STAT3 status in PDAC is predictive for the response to novel targeting therapies., (© 2013 APMIS. Published by John Wiley & Sons Ltd.)

Background: We report the results of a phase II trial of adding the anti-ascular endothelial growth factor (VEGF) bevacizumab to gemcitabine neoadjuvant chemotherapy for patients with borderline and unresectable non-metastatic pancreatic cancer., Patients and Methods: Patients were assigned to one of the two treatment arms. Both groups received 1,000 mg/m(2) gemcitabine on days 1, 8, and 15 of a 4-week cycle for a total of four cycles. Group 1 received 5 mg/kg bevacizumab for six weeks (three doses), every second week, starting at week 6 of gemcitabine therapy. Group 2 received 5 mg/kg bevacizumab for 12 weeks (six doses), every second week, starting at week 1 of gemcitabine therapy. The objective of the present study was to assess the rate of complete radical resection and overall survival., Results: A total of 30 patients were enrolled: 19 patients had unresectable and 11 patients had borderline-resectable pancreatic cancer. Eleven patients (37%) underwent resection. The median overall survival of patients who underwent tumor resection was 13 months (95% confidence interval=11-15 months)., Conclusion: In general, adding bevacizumab to neoadjuvant gemcitabine does not improve outcomes for patients with locally advanced pancreatic cancer. However, in individual cases, surgery is consequently possible and prolonged survival may be observed.

Background: Despite advances in combination therapies, the prognosis of pancreatic ductal adenocarcinoma (PDAC) remains extremely poor. Blocking of overexpressed HER2 oncogene improves survival in breast and gastroesophageal cancer and might be also a therapeutic option in PDAC. The purpose of this study was to evaluate HER2 gene amplification and protein expression in PDAC., Methods: HER2 protein expression was investigated using a FDA-approved antibody in 87 formalin-fixed and paraffin-embedded cases of PDAC with complete follow-up. HER2 gene amplification was assessed on tissue microarrays using dual color silver in situ hybridization (DISH)., Results: Generally, HER2 immunostaining showed considerable heterogeneity. In 19 cases, ≥10 of tumor cells showed some positive reaction. In no case, complete membranous staining was observed. Using the scoring system developed for assessment of HER2 status in gastroesophageal cancer, 9 cases showed positive immunohistologic staining (score 2+ to 3+). After performing DISH, 6 (7%) immunohistochemically 2+ or 3+ cases were found to have HER2 gene amplification, whereas none of these cases showed polyploidy. No association of HER2 status and clinicopathologic parameters or survival was observed (P>0.05)., Conclusions: HER2 is overexpressed in a subset of PDACs, identifying them as possible candidates for a targeted therapy. For assessment of HER2 status in PDAC, the scoring system originally developed for gastric cancer is recommend.

Non-healing skin ulcers are often resistant to most common therapies. Treatment with growth factors has been demonstrated to improve closure of chronic wounds. Here we investigate whether lyophilized culture supernatant of freshly isolated peripheral blood mononuclear cells (PBMC) is able to enhance wound healing. PBMC from healthy human individuals were prepared and cultured for 24 hours. Supernatants were collected, dialyzed and lyophilized (SEC(PBMC)). Six mm punch biopsy wounds were set on the backs of C57BL/6J-mice and SEC(PBMC) containing emulsion or controls were applied daily for three days. Morphology and neo-angiogenesis were analyzed by H&E-staining and CD31 immuno-staining, respectively. In vitro effects on diverse skin cells were investigated by migration assays, cell cycle analysis, and tube formation assay. Signaling pathways were analyzed by Western blot analysis. Application of SEC(PBMC) on 6 mm punch biopsy wounds significantly enhanced wound closure. H&E staining of the wounds after 6 days revealed that wound healing was more advanced after application of SEC(PBMC) containing emulsion. Furthermore, there was a massive increase in CD31 positive cells, indicating enhanced neo-angiogenesis. In primary human fibroblasts (FB) and keratinocytes (KC) migration but not proliferation was induced. In endothelial cells (EC) SEC(PBMC) induced proliferation and tube-formation in a matrigel-assay. In addition, SEC(PBMC) treatment of skin cells led to the induction of multiple signaling pathways involved in cell migration, proliferation and survival. In summary, we could show that emulsions containing the secretome of PBMC derived from healthy individuals accelerates wound healing in a mouse model and induce wound healing associated mechanisms in human primary skin cells. The formulation and use of such emulsions might therefore represent a possible novel option for the treatment of non-healing skin ulcers.

Rationale: Acute myocardial infarction (AMI) followed by ventricular remodeling is the major cause of congestive heart failure and death in western world countries., Objective: Of relevance are reports showing that infusion of apoptotic leucocytes or anti-lymphocyte serum after AMI reduces myocardial necrosis and preserves cardiac function. In order to corroborate this therapeutic mechanism, the utilization of an immunosuppressive agent with a comparable mechanism, such as anti-thymocyte globulin (ATG) was evaluated in this study., Methods and Results: AMI was induced in rats by ligation of the left anterior descending artery. Initially after the onset of ischemia, rabbit ATG (10 mg/rat) was injected intravenously. In vitro and in vivo experiments showed that ATG induced a pronounced release of pro-angiogenic and chemotactic factors. Moreover, paracrine factors released from ATG co-incubated cell cultures conferred a down-regulation of p53 in cardiac myocytes. Rats that were injected with ATG evidenced higher numbers of CD68+ macrophages in the ischemic myocardium. Animals injected with ATG evidenced less myocardial necrosis, showed a significant reduction of infarct dimension and an improvement of post-AMI remodeling after six weeks (infarct dimension 24.9% vs. 11.4%, p<0.01). Moreover, a higher vessel density in the peri-infarct region indicated a better collateralization in rats that were injected with ATG., Conclusions: These data indicate that ATG, a therapeutic agent successfully applied in clinical transplant immunology, triggered cardioprotective effects after AMI that salvaged ischemic myocardium by down-regulation of p53. This might have raised the resistance against apoptotic cell death during ischemia. The combination of these mechanisms seems to be causative for improved cardiac function and less ventricular remodeling after experimental AMI.

Congestive heart failure developing after acute myocardial infarction (AMI) is a major cause of morbidity and mortality. Clinical trials of cell-based therapy after AMI evidenced only a moderate benefit. We could show previously that suspensions of apoptotic peripheral blood mononuclear cells (PBMC) are able to reduce myocardial damage in a rat model of AMI. Here we experimentally examined the biochemical mechanisms involved in preventing ventricular remodelling and preserving cardiac function after AMI. Cell suspensions of apoptotic cells were injected intravenously or intramyocardially after experimental AMI induced by coronary artery ligation in rats. Administration of cell culture medium or viable PBMC served as controls. Immunohistological analysis was performed to analyse the cellular infiltrate in the ischaemic myocardium. Cardiac function was quantified by echocardiography. Planimetry of the infarcted hearts showed a significant reduction of infarction size and an improvement of post AMI remodelling in rats treated with suspensions of apoptotic PBMC (injected either intravenously or intramoycardially). Moreover, these hearts evidenced enhanced homing of macrophages and cells staining positive for c-kit, FLK-1, IGF-I and FGF-2 as compared to controls. A major finding in this study further was that the ratio of elastic and collagenous fibres within the scar tissue was altered in a favourable fashion in rats injected with apoptotic cells. Intravenous or intramyocardial injection of apoptotic cell suspensions results in attenuation of myocardial remodelling after experimental AMI, preserves left ventricular function, increases homing of regenerative cells and alters the composition of cardiac scar tissue. The higher expression of elastic fibres provides passive energy to the cardiac scar tissue and results in prevention of ventricular remodelling.