Metabolic Reprogramming Is an Initial Step in Pancreatic Carcinogenesis That Can Be Targeted to Inhibit Acinar-to-Ductal Metaplasia.

Metabolic reprogramming is a hallmark of cancer and is crucial for cancer progression, making it an attractive therapeutic target. Understanding the role of metabolic reprogramming in cancer initiation could help identify prevention strategies. To address this, we investigated metabolism during acinar-to-ductal metaplasia (ADM), the first step of pancreatic carcinogenesis. Glycolytic markers were elevated in ADM lesions compared with normal tissue from human samples. Comprehensive metabolic assessment in three mouse models with pancreas-specific activation of KRAS, PI3K, or MEK1 using Seahorse measurements, nuclear magnetic resonance metabolome analysis, mass spectrometry, isotope tracing, and RNA sequencing analysis revealed a switch from oxidative phosphorylation to glycolysis in ADM. Blocking the metabolic switch attenuated ADM formation. Furthermore, mitochondrial metabolism was required for de novo synthesis of serine and glutathione (GSH) but not for ATP production. MYC mediated the increase in GSH intermediates in ADM, and inhibition of GSH synthesis suppressed ADM development. This study thus identifies metabolic changes and vulnerabilities in the early stages of pancreatic carcinogenesis. Significance: Metabolic reprogramming from oxidative phosphorylation to glycolysis mediated by MYC plays a crucial role in the development of pancreatic cancer, revealing a mechanism driving tumorigenesis and potential therapeutic targets. See related commentary by Storz, p. 2225.

Carcinoid syndrome caused by a pulmonary carcinoid mimics intestinal manifestations of ulcerative colitis: A case report.

BACKGROUND: Pulmonary carcinoids are rare, low-grade malignant tumors characterized by neuroendocrine differentiation and relatively indolent clinical behavior. Most cases present as a slow-growing polypoidal mass in the major bronchi leading to hemoptysis and pulmonary infection due to blockage of the distal bronchi. Carcinoid syndrome is a paraneoplastic syndrome caused by the systemic release of vasoactive substances that presents in 5% of patients with neuroendocrine tumors. Due to such nonspecific presentation, most patients are misdiagnosed or diagnosed late and may receive several courses of antibiotics to treat recurrent pneumonia before the tumor is diagnosed. CASE SUMMARY: We report the case of a 48-year-old male who presented with cough, dyspnea, a history of recurrent pneumonitis, and therapy-refractory ulcerative colitis that completely subsided after the resection of a pulmonary carcinoid. CONCLUSION: We report and emphasize pulmonary carcinoid as a differential diagnosis in patients with nonresponding inflammatory bowel diseases and recurrent pneumonia.

An Eschar-like souvenir from a journey to Colombia: Ecthyma gangrenosum as a differential diagnosis of tropical diseases in immunocompromised patients - a case report.

BACKGROUND: Ecthyma gangrenosum (EG) is a cutaneous infectious disease characterized by eschar-like skin ulcers typically caused by Pseudomonas aeruginosa. Here, we report a case of relapsing EG in a patient who had returned from a trip to Colombia, thus establishing EG as an important differential diagnosis of tropical diseases, and demonstrating that even long-term antibiotic treatment can result in only partial remission of EG. CASE PRESENTATION: A 77-year-old man with underlying chronic lymphocytic leukemia (CLL) on ibrutinib treatment was admitted because of a superinfected mosquito bite on the left ear and multiple partially necrotic skin lesions disseminated all over the entire body five days after returning from a trip to Colombia. The initial clinical suspicion of a tropical disease (leishmaniosis, systemic mycosis, or others) could not be confirmed. During the diagnostic workup, microbiological cultures of the skin biopsies and bronchoalveolar lavage revealed Pseudomonas aeruginosa, leading to a diagnosis of EG. Initial antibiotic treatment resulted in partial remission. However, the patient had to be re-admitted due to a relapse 3-4 weeks after the first episode. Finally, the patient was successfully treated with a combined approach consisting of antibiotics, recurrent surgical incisions, and administration of immunoglobulins. CONCLUSIONS: In conclusion, EG should be considered as a differential diagnosis in immunosuppressed patients presenting with eschar-like skin ulcers. A combined treatment approach seems to be the best choice to achieve clinical cure and avoid relapse.

Loss of Wasl improves pancreatic cancer outcome.

Several studies have suggested an oncogenic role for the neural Wiskott-Aldrich syndrome protein (N-WASP, encoded by the Wasl gene), but thus far, little is known about its function in pancreatic ductal adenocarcinoma (PDAC). In this study, we performed in silico analysis of WASL expression in PDAC patients and found a correlation between low WASL expression and prolonged survival. To clarify the role of Wasl in pancreatic carcinogenesis, we used 2 oncogenic Kras-based PDAC mouse models with pancreas-specific Wasl deletion. In line with human data, both mouse models had an increased survival benefit due to either impaired tumor development in the presence of the tumor suppressor Trp53 or the delayed tumor progression and senescent phenotype upon genetic ablation of Trp53. Mechanistically, loss of Wasl resulted in cell-autonomous senescence through displacement of the N-WASP binding partners WASP-interacting protein (WIP) and p120ctn; vesicular accumulation of GSK3ß, as well as YAP1 and phosphorylated ß-catenin, which are components of the destruction complex; and upregulation of Cdkn1a(p21), a master regulator of senescence. Our findings, thus, indicate that Wasl functions in an oncogenic manner in PDAC by promoting the deregulation of the p120-catenin/ß-catenin/p21 pathway. Therefore, strategies to reduce N-WASP activity might improve the survival outcomes of PDAC patients.

Prognostic factors in hepatocellular carcinoma patients undergoing transarterial chemoembolization and radioembolization: a retrospective study.

OBJECTIVE: Most patients with hepatocellular carcinoma are diagnosed at intermediate or advanced stages (BCLC B or C) and undergo palliative local treatments such as transarterial chemoembolization or selective internal radiation therapy, also called radioembolization. In terms of liver function and tumor extent, stages BCLC B and C comprise a wide spectrum of tumor manifestations. Predictors of survival in these patients undergoing transarterial chemoembolization and selective internal radiation therapy might help stratification into different prognostic groups and help to select the optimal treatment modality. METHODS: In this retrospective study, all patients with hepatocellular carcinoma who underwent transarterial chemoembolization between January 2010 and December 2014 and all hepatocellular carcinoma patients who underwent selective internal radiation therapy between August 2012 and December 2016 were recruited. The prognostic value of pretherapeutic clinical and laboratory parameters for the prediction of overall survival was analyzed using uni- and multi-variable Cox regression models. RESULTS: We enrolled 129 patients in the transarterial chemoembolization group and 34 patients in the selective internal radiation therapy group. The predictive value of the albumin-bilirubin grade was validated for both the transarterial chemoembolization and the selective internal radiation therapy group. Multivariable analysis identified albumin-bilirubin grade and tumor size as independent predictors for the transarterial chemoembolization group and tumor size, serum albumin and serum sodium as independent predictors for the selective internal radiation therapy group. CONCLUSION: While measures of liver dysfunction predicted survival similarly in both cohorts, we found tumor size to predict survival differently in transarterial chemoembolization- and selective internal radiation therapy-treated patients. Tumor size might help to select the most appropriate treatment in hepatocellular carcinoma patients, although this finding has to be validated in further studies.

High-Fat Diet Accelerates Carcinogenesis in a Mouse Model of Barrett's Esophagus via Interleukin 8 and Alterations to the Gut Microbiome.

BACKGROUND & AIMS: Barrett's esophagus (BE) is a precursor to esophageal adenocarcinoma (EAC). Progression from BE to cancer is associated with obesity, possibly due to increased abdominal pressure and gastroesophageal reflux disease, although this pathogenic mechanism has not been proven. We investigated whether environmental or dietary factors associated with obesity contribute to the progression of BE to EAC in mice. METHODS: Tg(ED-L2-IL1RN/IL1B)#Tcw mice (a model of BE, called L2-IL1B mice) were fed a chow (control) or high-fat diet (HFD) or were crossbred with mice that express human interleukin (IL) 8 (L2-IL1B/IL8 mice). Esophageal tissues were collected and analyzed for gene expression profiles and by quantitative polymerase chain reaction, immunohistochemistry, and flow cytometry. Organoids were established from BE tissue of mice and cultured with serum from lean or obese individuals or with neutrophils from L2-IL1B mice. Feces from mice were analyzed by 16s ribosomal RNA sequencing and compared to 16s sequencing data from patients with dysplasia or BE. L2-IL1B were mice raised in germ-free conditions. RESULTS: L2-IL1B mice fed an HFD developed esophageal dysplasia and tumors more rapidly than mice fed the control diet; the speed of tumor development was independent of body weight. The acceleration of dysplasia by the HFD in the L2-IL1B mice was associated with a shift in the gut microbiota and an increased ratio of neutrophils to natural killer cells in esophageal tissues compared with mice fed a control diet. We observed similar differences in the microbiomes from patients with BE that progressed to EAC vs patients with BE that did not develop into cancer. Tissues from dysplasias of L2-IL1B mice fed the HFD contained increased levels of cytokines that are produced in response to CXCL1 (the functional mouse homolog of IL8, also called KC). Serum from obese patients caused organoids from L2-IL1B/IL8 mice to produce IL8. BE tissues from L2-IL1B mice fed the HFD and from L2-IL1B/IL8 mice contained increased numbers of myeloid cells and cells expressing Cxcr2 and Lgr5 messenger RNAs (epithelial progenitors) compared with mice fed control diets. BE tissues from L2-IL1B mice raised in germ-free housing had fewer progenitor cells and developed less dysplasia than in L2-IL1 mice raised under standard conditions; exposure of fecal microbiota from L2-IL1B mice fed the HFD to L2-IL1B mice fed the control diet accelerated tumor development. CONCLUSIONS: In a mouse model of BE, we found that an HFD promoted dysplasia by altering the esophageal microenvironment and gut microbiome, thereby inducing inflammation and stem cell expansion, independent of obesity.

Current Concepts of Pharmacotherapy in Crohn's Disease.

BACKGROUND: The incidence of Crohn's disease (CD) is rising, and still many patients have to undergo repeated surgery due to failure of pharmacologic therapy. RESULTS: While the introduction of anti-TNF agents started biologic therapy for CD and revolutionized the management of patients, the number of patients who do not respond to this treatment or lose their initial response to this treatment is still substantial. Therefore, the recent introduction of new therapeutic options with anti-integrins and new anti-cytokines was an important step to provide more effective treatment for our patients. Yet, next to new drugs also new treatment strategies have been proposed. CONCLUSION: In this article, we will review these new aspects of pharmacologic therapy for CD -patients.

Longer observation time increases adenoma detection in the proximal colon - a prospective study.

BACKGROUND AND STUDY AIMS: Longer observation times are associated with increased adenoma detection rates (ADR) in the entire colon. However, adenomas in the proximal colon are at risk of being missed during colonoscopy. The aim of this study was to investigate the impact of observation time on detection of adenomatous polyps in the proximal colon. PATIENTS AND METHODS: This was a prospective study at a university hospital in Germany. Colonoscopies were conducted using magnetic endoscope imaging (MEI) in order to determine the exact position of the scope. Exact observation times spent for the detection of polyps in the proximal and distal colon segments were assessed. The primary outcome was adenoma detection in the proximal colon. ROC curves were generated in order to test the correlation between observation time and adenoma detection. Logistic regression analysis was used to check for interfering factors. RESULTS: A total 480 procedures with 538 polyps were available for analysis. The overall adenoma detection rate was 38.5 %. ADR in the proximal colon was 28.0 %. There was a significant association between observation time in the proximal colon and the detection of proximal adenomas ( P  < 0.001). The impact of the time factor on ADR was stronger in the proximal compared to the distal colon ( P  = 0.030). A net period of 4 min 7 sec was found to be the minimum time span for sufficient adenoma detection in the proximal colon. CONCLUSION: Observation time is significant in terms of adenoma detection in the proximal colon. The impact of observation time on ADR is stronger in the proximal compared to the distal colon. In the proximal colon a minimum time span of 4 minutes should be spent in order to ensure adequate adenoma detection.

RelA regulates CXCL1/CXCR2-dependent oncogene-induced senescence in murine Kras-driven pancreatic carcinogenesis.

Tumor suppression that is mediated by oncogene-induced senescence (OIS) is considered to function as a safeguard during development of pancreatic ductal adenocarcinoma (PDAC). However, the mechanisms that regulate OIS in PDAC are poorly understood. Here, we have determined that nuclear RelA reinforces OIS to inhibit carcinogenesis in the Kras mouse model of PDAC. Inactivation of RelA accelerated pancreatic lesion formation in Kras mice by abrogating the senescence-associated secretory phenotype (SASP) gene transcription signature. Using genetic and pharmacological tools, we determined that RelA activation promotes OIS via elevation of the SASP factor CXCL1 (also known as KC), which activates CXCR2, during pancreatic carcinogenesis. In Kras mice, pancreas-specific inactivation of CXCR2 prevented OIS and was correlated with increased tumor proliferation and decreased survival. Moreover, reductions in CXCR2 levels were associated with advanced neoplastic lesions in tissue from human pancreatic specimens. Genetically disabling OIS in Kras mice caused RelA to promote tumor proliferation, suggesting a dual role for RelA signaling in pancreatic carcinogenesis. Taken together, our data suggest a pivotal role for RelA in regulating OIS in preneoplastic lesions and implicate the RelA/CXCL1/CXCR2 axis as an essential mechanism of tumor surveillance in PDAC.

Magnetic endoscope imaging for routine colonoscopy: impact on propofol dosage and patient safety - a randomized trial.

BACKGROUND AND STUDY AIM: The use of magnetic endoscope imaging (MEI) has been previously shown to facilitate colonoscopy procedures. We aimed to evaluate the benefits of MEI in terms of reduction in propofol dosage in patients undergoing routine colonoscopy. METHODS: We conducted a randomized prospective trial in a university hospital in Germany. Endoscopists were randomly assigned 1:1 to use MEI during colonoscopy (MEI arm) or to conduct colonoscopy without the use of MEI (standard arm). The desired level of sedation was conscious sedation as assessed using the Observer's Assessment of Alertness and Sedation scores. After complete recovery, patient satisfaction was assessed using a numeric rating scale (NRS) ranging from 1 to 10 points. The primary outcome was total propofol dosage. Secondary outcome measures were patient satisfaction, patients' cooperation, and complication rates, as well as cecal intubation time and adenoma detection. RESULTS: Among 334 randomized patients, no severe adverse events were observed. Median propofol dosage was significantly lower in the MEI arm compared with the standard arm (150 mg vs. 180 mg; P = 0.04). Deep sedation was observed in 7.8 % of patients in the MEI group and 3.6 % in the standard arm (P = 0.10). Patient satisfaction scores were higher in the MEI arm compared with standard procedures (9.0 vs. 8.5; P = 0.04). No significant differences in patients' cooperation, cecal intubation time, and adenoma detection were observed between the study arms. CONCLUSION: The use of MEI may be useful in reducing propofol dosage for colonoscopy and improving patient satisfaction.ClinicalTrials.gov identifier: NCT02121704.

Narrow-band imaging vs. high definition white light for optical diagnosis of small colorectal polyps: a randomized multicenter trial.

BACKGROUND AND STUDY AIM: The aim of the study was to compare the latest narrow-band imaging (NBI) device with high-definition white light (HDWL) endoscopy for accuracy of real-time optical diagnosis of small colorectal polyps. PATIENTS AND METHODS: We conducted a randomized, prospective, multicenter trial at three study sites in Germany. In the NBI arm, endoscopists used NBI for the prediction of polyp pathology on the basis of the NBI International Colorectal Endoscopic classification. In the HDWL arm, NBI was not used for optical classification of polyp histology. The primary outcome was accuracy of optical diagnoses (neoplastic vs. non-neoplastic) in small polyps measuring < 10 mm. Secondary end points included sensitivity and negative predictive value (NPV). RESULTS: A total of 380 patients were randomized 1:1 to either the NBI or HDWL arm. A total of 421 polyps measuring < 10 mm were detected (55.8 % neoplastic, 44.2 % non-neoplastic). Accuracy, sensitivity, and NPV were 73.7 %, 82.4 %, and 75.5 %, respectively, in the NBI arm and 79.2 %, 79.8 %, and 73.4 %, respectively, in the HDWL arm (P = 0.225, P = 0.667, P = 0.765). More polyps were assessed with high confidence in the HDWL arm (82.6 %) than in the NBI arm (73.7 %; P = 0.038). The NPV of the prediction of neoplastic histology in diminutive polyps (≤ 5 mm) rated with high confidence was 90.3 % in the NBI arm. We detected significant differences between the participating study sites in the performance data of predictions. CONCLUSION: The levels of accuracy for real-time prediction of polyp histology (< 10 mm) did not differ between NBI and HDWL for optical diagnosis. Variation in the performance of optical diagnosis was apparent between study centers. TRIAL REGISTRATION: ClinicalTrials.gov (NCT02009774).

Polarization of the vacuolar adenosine triphosphatase delineates a transition to high-grade pancreatic intraepithelial neoplasm lesions.

OBJECTIVES: A functional vacuolar adenosine triphosphatase (v-ATPase) complex regulates canonical Wnt/ß-catenin signaling. The goal of this study was to identify the distribution of the v-ATPase in human and murine models of pancreatic intraepithelial neoplasms (PanINs) and assess its role in Wnt/ß-catenin signaling. METHODS: We evaluated the immunolabeling pattern of the v-ATPase in human PanIN specimens and murine PanIN-1 and PanIN-2 lesions obtained from Ptf1a(Cre/+); LSL-Kras(G12D) mice. Wnt/ß-catenin signaling was interrogated in primary PanIN cells by examining the phosphorylated levels of its surface coreceptor, low-density lipoprotein receptor-related protein-6 (LRP6), and its intracellular effector, nonphosphorylated ß-catenin. The response of primary PanIN cells to epidermal growth factor (EGF) was assessed in the absence and presence of the v-ATPase inhibitor, concanamycin. RESULTS: In advanced (PanIN-2), but not early (PanIN-1), lesions, the v-ATPase assumed a polarized phenotype. Blocking the v-ATPase disrupted Wnt/ß-catenin signaling in primary PanIN cells despite significantly higher levels of the total and activated Wnt cell surface coreceptor, LRP6. Vacuolar adenosine triphosphatase blockade significantly decreased the total and activated levels of EGF receptor, a determinant of PanIN progression. The activation of EGF receptor and its intracellular mediator, p44/42 mitogen-activated protein kinase, was also reduced by v-ATPase blockade. This led to diminished proliferation in response to EGF ligand. CONCLUSIONS: The v-ATPase regulates Wnt/ß-catenin and EGF receptor signaling in PanINs.

Deficiency of caveolin-1 in Apc(min/+) mice promotes colorectal tumorigenesis.

Caveolin-1 (Cav1), a scaffold protein of membrane caveolae and coactivator of peroxisome proliferator-activated receptor gamma (PPARg), inhibits oncogenic signaling through Ras and wingless. However, the in vivo role of Cav1 in colorectal cancer (CRC) remained unknown. To test whether loss of Cav1 accelerates tumorigenesis, we generated a novel mouse model of CRC by crossing C57BL/6 Apc(min/+) with B6129 Cav1 knockout (Cav1-/-) mice. Apc(min/+) Cav1-/- mice developed large, microinvasive and vascularized intraepithelial adenocarcinomas in the distal colon and rectum with higher incidence than Apc(min/+) Cav1+/- and Apc(min/+) Cav1+/+ littermates. Intratumoral gene signatures related to Ras and wingless signaling were elevated, nuclear localization of PPARg protein and expression of PPARg-target genes were reduced independently of Cav1. The PPARg-agonist rosiglitazone prevented tumor formation in mice irrespectively of the Cav1 status and upregulated expression of the Ras-inhibitory protein docking protein-1. Thus, codeficiency of Cav1 and adenomatous polyposis coli facilitated formation of CRC, and activation of PPARg may offer novel strategies for treatment of CRC.

Deletion of IκBα activates RelA to reduce acute pancreatitis in mice through up-regulation of Spi2A.

BACKGROUND & AIMS: The transcription factor nuclear factor-κB (NF-κB) (a heterodimer of NF-κB1p50 and RelA) is activated rapidly in acute pancreatitis (AP). However, it is not clear whether NF-κB promotes or protects against AP. We used the NF-κB inhibitor protein, inhibitor of κB (IκB)α, to study the roles of NF-κB in the development of AP in mice. METHODS: IκBα or the combination of IκBα and RelA selectively were deleted from pancreas of mice using the Cre/locus of cross-over P strategy; cerulein or L-arginine were used to induce AP. We performed microarray analyses of the IκBα- and RelA-deficient pancreata. DNA from healthy individuals and patients with acute or chronic pancreatitis were analyzed for variants in coding regions of alpha-1-antichymotrypsin. RESULTS: Mice with pancreas-specific deletion of IκBα had constitutive activation of RelA and a gene expression profile consistent with NF-κB activation; development of AP in these mice was attenuated and trypsin activation was impaired. However, AP was fully induced in mice with pancreas-specific deletion of IκBα and RelA. By using genome-wide expression analysis, we identified a cluster of NF-κB-regulated genes that might protect against the development of AP. The serine protease inhibitor 2A (Spi2a) was highly up-regulated in IκBα-deficient mice. Lentiviral-mediated expression of Spi2A reduced the development of AP in C57BL/6 and RelA-deficient mice. However, we did not correlate any variants of alpha-1-antichymotrypsin, the human homologue of Spi2a, with acute or chronic pancreatitis. CONCLUSIONS: Pancreas-specific deletion of IκBα results in nuclear translocation of RelA and reduces AP induction and trypsin activation in mice after administration of cerulein or L-arginine. Constitutive activation of RelA up-regulates Spi2A, which protects mice against the development of AP.

Transjugular intrahepatic porto-systemic stent-shunt for therapy of bleeding esophageal varices due to extramedullary hematopoiesis in primary myelofibrosis: a case report.

BACKGROUND: Primary myelofibrosis belongs to the group of myeloproliferative syndromes. Extramedullary hematopoiesis in the liver can lead to portal hypertension. PATIENT AND METHODS: We report a case of a patient with life-threatening, endoscopically not treatable bleeding from esophageal varices due to extramedullary hematopoiesis of the liver that was successfully treated with placement of a transjugular intrahepatic porto-systemic stent-shunt (TIPS). RESULTS: Therapy of variceal bleeding by TIPS insertion was successful. During a 29-month follow-up, no hepatic failure, hepatic encephalopathy, or further variceal bleeding episode occurred. CONCLUSION: TIPS placement is a well-established procedure for the treatment of complications due to portal hypertension mainly due to liver cirrhosis. This report illustrates that TIPS placement can also be a promising treatment option in patients with primary myelofibrosis and portal hypertension due to extramedullary hematopoiesis.

Pan-histone deacetylase inhibitor panobinostat sensitizes gastric cancer cells to anthracyclines via induction of CITED2.

BACKGROUND & AIMS: Chemotherapy modestly prolongs survival of patients with advanced gastric cancer, but strategies are needed to increase its efficacy. Histone deacetylase (HDAC) inhibitors modify chromatin and can block cancer cell proliferation and promote apoptosis. METHODS: Gastric cancer cell lines were incubated with the HDAC inhibitor LBH589 (Panobinostat, Novartis, Germany); levels of proliferation, apoptosis, histone acetylation, and gene expression were determined. We identified factors downstream of HDAC that regulated chemoresistance. The effects of combination chemotherapy of HDAC inhibitors and anthracyclines were studied in CEA424/SV40 T-antigen (CEA/Tag) transgenic mice, which develop gastric tumors. We analyzed gastric tumor samples from patients using immunohistochemistry. RESULTS: HDAC2 was expressed in human gastric cancer cell lines and tumor samples, as well as in gastric tumors from CEA/Tag mice, compared with non-neoplastic gastric tissue. LBH589 inhibited proliferation of cancer cells in vitro. LBH589 down-regulated expression of genes that mediate anthracycline resistance by activating expression of Cbp/p300-interacting transactivator, with Glu/Asp-rich carboxy-terminal domain 2 (CITED2), a gene that mediates sensitivity to chemotherapeutics. Pre-incubation of cells with an HDAC inhibitor and overexpression of CITED2-sensitized gastric cell lines to anthracycline-mediated cell death. In CEA/Tag mice, LBH589 induced tumor-cell expression of CITED2 and increased the efficacy of anthracycline to reduce tumor growth. Levels of CITED2 were increased in gastric tumor samples from patients who had complete responses to epirubicin. CONCLUSIONS: The HDAC inhibitor LBH589 can overcome the resistance of mouse gastric cancer cells to anthracyclines by inducing expression of CITED2. Levels of CITED2 in gastric tumors correlate with patients' response to epirubicin. LBH589 might be used to increase the response of patients to anthracyclines.

Myeloid, but not pancreatic, RelA/p65 is required for fibrosis in a mouse model of chronic pancreatitis.

BACKGROUND & AIMS: Little is known about how transcription factors might regulate pathogenesis of chronic pancreatitis (CP). We analyzed the in vivo role of RelA/p65, a component of the transcription factor nuclear factor (NF)-κB, in different cell types during development of CP in mice. METHODS: RelA/p65 was functionally inactivated in the pancreas (relaΔpanc), in myeloid cells (relaΔmye), or both (relaΔpanc,Δmye) compartments using the Cre-loxP strategy. Experimental CP was induced with repetitive injections of cerulein over 6 weeks. Pancreata were investigated histologically and biochemically. We created an in vitro coculture assay of pancreatic stellate cells (PSC) and macrophages and performed gene arrays from pancreata and macrophages with functionally inactivated RelA/p65. Tissue samples from patients with CP were analyzed for matrix metalloproteinase (MMP) 10 expression. RESULTS: In contrast to their relaF/F littermates, relaΔpanc displayed typical signs of CP after long-term stimulation with cerulein. Numerous macrophages and activated α-smooth muscle actin (SMA)-positive PSCs were detected. Additional inactivation of RelA/p65 in myeloid cells (relaΔpanc,Δmye) attenuated fibrosis. In vitro, RelA/p65-deficient, lipopolysaccharide (LPS)-stimulated macrophages degraded fibronectin in cocultured PSCs. Using gene expression analysis, MMP-10 was identified as a candidate for this process. Recombinant MMP-10 degraded fibronectin in LPS-stimulated PSCs. In tissue samples from patients with CP, MMP-10 was up-regulated in myeloid cells. CONCLUSIONS: RelA/p65 functions in myeloid cells to promote pathogenesis of CP. In acinar cells, RelA/p65 protects against chronic inflammation, whereas myeloid RelA/p65 promotes fibrogenesis. In macrophage, MMP-10 functions as a RelA/p65-dependent, potentially antifibrogenic factor during progression of CP.

The Ras inhibitors caveolin-1 and docking protein 1 activate peroxisome proliferator-activated receptor γ through spatial relocalization at helix 7 of its ligand-binding domain.

Peroxisome proliferator-activated receptor γ (PPARγ) is a transcription factor that promotes differentiation and cell survival in the stomach. PPARγ upregulates and interacts with caveolin-1 (Cav1), a scaffold protein of Ras/mitogen-activated protein kinases (MAPKs). The cytoplasmic-to-nuclear localization of PPARγ is altered in gastric cancer (GC) patients, suggesting a so-far-unknown role for Cav1 in spatial regulation of PPARγ signaling. We show here that loss of Cav1 accelerated proliferation of normal stomach and GC cells in vitro and in vivo. Downregulation of Cav1 increased Ras/MAPK-dependent phosphorylation of serine 84 in PPARγ and enhanced nuclear translocation and ligand-independent transcription of PPARγ target genes. In contrast, Cav1 overexpression sequestered PPARγ in the cytosol through interaction of the Cav1 scaffolding domain (CSD) with a conserved hydrophobic motif in helix 7 of PPARγ's ligand-binding domain. Cav1 cooperated with the endogenous Ras/MAPK inhibitor docking protein 1 (Dok1) to promote the ligand-dependent transcriptional activity of PPARγ and to inhibit cell proliferation. Ligand-activated PPARγ also reduced tumor growth and upregulated the Ras/MAPK inhibitors Cav1 and Dok1 in a murine model of GC. These results suggest a novel mechanism of PPARγ regulation by which Ras/MAPK inhibitors act as scaffold proteins that sequester and sensitize PPARγ to ligands, limiting proliferation of gastric epithelial cells.

Identification of CCR9- murine plasmacytoid DC precursors with plasticity to differentiate into conventional DCs.

Whereas the final differentiation of conventional dendritic cells (CDCs) from committed precursors occurs locally in secondary lymphoid or peripheral tissues, plasmacytoid dendritic cells (PDCs) are thought to fully develop in the bone marrow from common DC progenitors before migrating to the periphery. In our study, we define, for the first time, a subpopulation of CCR9(-) major histocompatibility complex class II(low) PDCs in murine bone marrow, which express E2-2 and are immediate precursors of CCR9(+) fully differentiated PDCs. However, CCR9(-) PDCs have the plasticity to acquire the phenotype and function of CD11b(+) CD8α(-) major histocompatibility complex class II(high) CDC-like cells under the influence of soluble factors produced by intestinal epithelial cells or recombinant GM-CSF. This deviation from the PDC lineage commitment is regulated on the level of transcription factors reflected by down-regulation of E2-2 and up-regulation of ID2, PU.1, and BATF3. Thus, CCR9(-) PDCs are immediate PDC precursors that can be reprogrammed to differentiate into CDC-like cells with higher antigen-presenting and cytokine-producing capacity under the influence of the local tissue microenvironment.

Notch2 is required for progression of pancreatic intraepithelial neoplasia and development of pancreatic ductal adenocarcinoma.

Pancreatic cancer is one of the most fatal malignancies lacking effective therapies. Notch signaling is a key regulator of cell fate specification and pancreatic cancer development; however, the role of individual Notch receptors and downstream signaling is largely unknown. Here, we show that Notch2 is predominantly expressed in ductal cells and pancreatic intraepithelial neoplasia (PanIN) lesions. Using genetically engineered mice, we demonstrate the effect of conditional Notch receptor ablation in KrasG12D-driven pancreatic carcinogenesis. Deficiency of Notch2 but not Notch1 stops PanIN progression, prolongs survival, and leads to a phenotypical switch toward anaplastic pancreatic cancer with epithelial-mesenchymal transition. By expression profiling, we identified increased Myc signaling regulated by Notch2 during tumor development, placing Notch2 as a central regulator of PanIN progression and malignant transformation. Our study supports the concept of distinctive roles of individual Notch receptors in cancer development.