Jens T. Siveke

Nanoliposomal irinotecan with fluorouracil and folinic acid in metastatic pancreatic cancer after previous gemcitabine-based therapy (NAPOLI-1): a global, randomised, open-label, phase 3 trial

BACKGROUND Nanoliposomal irinotecan showed activity in a phase 2 study in patients with metastatic pancreatic ductal adenocarcinoma previously treated with gemcitabine-based therapies. We assessed the effect of nanoliposomal irinotecan alone or combined with fluorouracil and folinic acid in a phase 3 trial in this population. METHODS We did a global, phase 3, randomised, open-label trial at 76 sites in 14 countries. Eligible patients with metastatic pancreatic ductal adenocarcinoma previously treated with gemcitabine-based therapy were randomly assigned (1:1) using an interactive web response system at a central location to receive either nanoliposomal irinotecan monotherapy (120 mg/m(2) every 3 weeks, equivalent to 100 mg/m(2) of irinotecan base) or fluorouracil and folinic acid. A third arm consisting of nanoliposomal irinotecan (80 mg/m(2), equivalent to 70 mg/m(2) of irinotecan base) with fluorouracil and folinic acid every 2 weeks was added later (1:1:1), in a protocol amendment. Randomisation was stratified by baseline albumin, Karnofsky performance status, and ethnic origin. Treatment was continued until disease progression or intolerable toxic effects. The primary endpoint was overall survival, assessed in the intention-to-treat population. The primary analysis was planned after 305 events. Safety was assessed in all patients who had received study drug. This trial is registered at ClinicalTrials.gov, number NCT01494506. FINDINGS Between Jan 11, 2012, and Sept 11, 2013, 417 patients were randomly assigned either nanoliposomal irinotecan plus fluorouracil and folinic acid (n=117), nanoliposomal irinotecan monotherapy (n=151), or fluorouracil and folinic acid (n=149). After 313 events, median overall survival in patients assigned nanoliposomal irinotecan plus fluorouracil and folinic acid was 6.1 months (95% CI 4.8-8.9) vs 4.2 months (3.3-5.3) with fluorouracil and folinic acid (hazard ratio 0.67, 95% CI 0.49-0.92; p=0.012). Median overall survival did not differ between patients assigned nanoliposomal irinotecan monotherapy and those allocated fluorouracil and folinic acid (4.9 months [4.2-5.6] vs 4.2 months [3.6-4.9]; 0.99, 0.77-1.28; p=0.94). The grade 3 or 4 adverse events that occurred most frequently in the 117 patients assigned nanoliposomal irinotecan plus fluorouracil and folinic acid were neutropenia (32 [27%]), diarrhoea (15 [13%]), vomiting (13 [11%]), and fatigue (16 [14%]). INTERPRETATION Nanoliposomal irinotecan in combination with fluorouracil and folinic acid extends survival with a manageable safety profile in patients with metastatic pancreatic ductal adenocarcinoma who previously received gemcitabine-based therapy. This agent represents a new treatment option for this population. FUNDING Merrimack Pharmaceuticals.

Liver-specific inactivation of Notch2, but not Notch1, compromises intrahepatic bile duct development in mice.

The Notch pathway is an evolutionary conserved, intercellular signaling pathway that plays an important role in cell fate specification and the embryonic development of many organs, including the liver. In humans, mutations in the Notch receptor ligand Jagged1 gene result in defective intrahepatic bile duct (IHBD) development in Alagille syndrome. Developmental abnormalities of IHBD in mice doubly heterozygous for Jagged1 and Notch2 mutations propose that interactions of Jagged1 and its receptor Notch2 are crucial for normal IHBD development. Because different cell types in the liver are involved in IHBD development and morphogenesis, the cell‐specific role of Notch signaling is not entirely understood. We investigated the effect of combined or single targeted disruption of Notch1 and Notch2 specifically in hepatoblasts and hepatoblast‐derived lineage cells on liver development using AlbCre transgenic mice. Hepatocyte differentiation and homeostasis were not impaired in mice after combined deletion of Notch1 and Notch2 (N1N2F/FAlbCre). However, we detected irregular ductal plate structures in N1N2F/FAlbCre newborns, and further postnatal development of IHBD was severely impaired characterized by disorganized ductular structures accompanied by portal inflammation, portal fibrosis, and foci of hepatocyte feathery degeneration in adulthood. Further characterization of mutant mice with single deletion of Notch1 (N1F/FAlbCre) or Notch2 (N2F/FAlbCre) showed that Notch2 but not Notch1 is indispensable for normal perinatal and postnatal IHBD development. Further reduction of Notch2 gene dosage in Notch2 conditional/mutant (N2F/LacZAlbCre) animals further enhanced IHBD abnormalities and concomitant liver pathology. Conclusion: Notch2 is required for proper IHBD development and morphogenesis. (HEPATOLOGY 2008;48:607–616.)

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.

Notch Signaling Is Required for Exocrine Regeneration After Acute Pancreatitis

BACKGROUND & AIMS The mechanisms for tissue regeneration and renewal after acute pancreatitis are not well understood but may involve activation of Notch signaling. To study the effect of Notch signaling ablation during acute experimental pancreatitis, we used a chemical and genetic approach to ablate Notch signaling in cerulein-induced pancreatitis in mice. METHODS Acute pancreatitis was induced by cerulein treatment in mice treated with the gamma-secretase inhibitor dibenzazepine or in conditional Notch1 knockout mice. Mice were characterized using immunohistologic, biochemical, and molecular methods. To investigate Notch and beta-catenin interaction, acinar 266-6 cells were analyzed using transfection and biochemical assays. RESULTS Loss of Notch signaling results in impaired regeneration after acute pancreatitis with fewer mature acinar cells in dibenzazepine-treated and Notch1-deficient mice in the regenerative phase 3 days after induction. beta-catenin expression was increased and prolonged during exocrine regeneration. Crosstalk between Notch and beta-catenin-mediated signaling was identified, with Notch1-IC inhibiting beta-catenin-mediated transcriptional activity. This inhibition was dependent on a functional RAM domain. CONCLUSIONS Inhibition of Notch signaling in vivo leads to impaired regeneration of the exocrine pancreas after acute pancreatitis. Our results suggest an interaction of Notch and Wnt signaling in pancreatic acinar cells, providing evidence for a role of these pathways in the regulation of the maturation process of acinar cells.

Chemokine Receptor CCR1 But Not CCR5 Mediates Leukocyte Recruitment and Subsequent Renal Fibrosis after Unilateral Ureteral Obstruction

As chemokine receptor CCR1 and CCR5 expression on circulating leukocytes is thought to contribute to leukocyte recruitment during renal fibrosis, the authors examined the effects of unilateral ureteral obstruction (UUO) in mice deficient for CCR1 or CCR5. Analysis of UUO kidneys from CCR1-deficient mice revealed a reduction of interstitial macrophages and lymphocytes (35% and 55%, respectively) compared with wild-type controls. CCR1-deficient mice had reduced CCR5 mRNA levels in UUO kidneys, which correlated with a reduction of CCR5+ T cell infiltrate as determined by flow cytometry. Interstitial fibroblasts, renal TGF-beta1 mRNA expression, interstitial volume, and collagen I deposits were all significantly reduced in CCR1-deficient mice. In contrast, renal leukocytes and fibrosis were unaffected in CCR5-deficient mice with UUO. However, if treated with the CCR1 antagonist BX471, CCR5-deficient mice showed a similar reduction of renal leukocytes and fibrosis as CCR1-deficient mice. To determine the underlying mechanism labeled macrophages and T cells isolated from either wild-type, CCR1-deficient, or CCR5-deficient mice were injected into wild-type mice with UUO. Three hours later, renal cell recruitment was reduced for CCR1-deficient cells or cells pretreated with BX471 compared with CCR5-deficient or wild-type cells. Thus, CCR1 but not CCR5 is required for leukocyte recruitment and fibrosis after UUO in mice. Therefore, CCR1 is a promising target for therapeutic intervention in leukocyte-mediated fibrotic tissue injury, e.g. progressive renal fibrosis.

Early Requirement of Rac1 in a Mouse Model of Pancreatic Cancer

BACKGROUND & AIMS Pancreatic ductal adenocarcinoma (PDAC) is a fatal disease without effective chemopreventive or therapeutic approaches. Although the role of oncogenic Kras in initiating development of PDAC is well established, downstream targets of aberrant Ras signaling are poorly understood. Acinar-ductal metaplasia (ADM) appears to be an important prerequisite for development of pancreatic intraepithelial neoplasia (PanIN), a common precursor to PDAC. RAS-related C3 botulinum substrate 1 (Rac1), which controls actin reorganization, can be activated by Ras, is up-regulated in several human cancers, and is required for cerulein-induced morphologic changes in acini. We investigated effects of loss of Rac1 in Kras-induced pancreatic carcinogenesis in mice. METHODS Using a Cre/lox approach, we deleted Rac1 from pancreatic progenitor cells in different mouse models of PDAC and in mice with cerulein-induced acute pancreatitis. Acinar epithelial explants of mutant mice were used to investigate the role of Rac1 in vitro. RESULTS Rac1 expression increased in mouse and human pancreatic tumors, particularly in the stroma. Deletion of Rac1 in Kras(G12D)-induced PDAC in mice reduced formation of ADM, PanIN, and tumors and significantly prolonged survival. Pancreatic epithelial metaplasia was accompanied by apical-basolateral redistribution of F-actin, along with basal expression of Rac1. Acinar epithelial explants that lacked Rac1 or that were incubated with inhibitors of actin polymerization had a reduced ability to undergo ADM in 3-dimensional cultures. CONCLUSIONS In mice, Rac1 is required for early metaplastic changes and neoplasia-associated actin rearrangements in development of pancreatic cancer. Rac1 might be developed as a diagnostic marker or therapeutic target for PDAC.

Volume assessment in patients with necrotizing pancreatitis: a comparison of intrathoracic blood volume index, central venous pressure, and hematocrit, and their correlation to cardiac index and extravascular lung water index.

Objective:Volume depletion and/or increased hematocrit are associated with poor prognosis in necrotizing pancreatitis. Several studies suggest that intrathoracic blood volume index (ITBI) might be superior to central venous pressure (CVP) with regard to preload assessment. Therefore, the aim of our study was to evaluate the predictive value of CVP and hematocrit with regard to ITBI, and to correlate these parameters to cardiac index (CI). Design:Prospective study. Setting:Medical intensive care unit, university hospital. Patients and Interventions:Within 24 hrs of intensive care unit-admission, 96 hemodynamic measurements using the PiCCO system were performed in 24 patients with necrotizing pancreatitis. Main Results:Mean CVP (12.11 ± 5.97 mm Hg; median 11.5 normal: 1–9 mm Hg) was elevated, whereas mean ITBI (822.8 ± 157.0 mL/m2; median 836 mL/m2; normal: 850–1000 mL/m2) was decreased. Fifty-one of 96 ITBI values were decreased (prevalence of hypovolemia of 53%). No CVP value was decreased. Fifty-three CVP measurements were elevated despite simultaneous ITBI levels indicating a normal or decreased preload. Sensitivity, specificity, positive predictive value, and negative predictive value of CVP with regard to volume depletion (ITBI <850 mL/m2), were 0%, 100%, 0%, and 47%, respectively. An increase in hematocrit (hematocrit >40% [female] or >44% [male]) was found in 11 of 51 measurements with decreased ITBI. Sensitivity, specificity, positive predictive value, and negative predictive value of an increase in hematocrit with regard to volume depletion according to ITBI were 22%, 82%, 58%, and 48%, respectively. ITBI and &Dgr;-ITBI significantly correlated to CI and &Dgr;-CI (r = .566, p < 0.001; r = .603, p < 0.001), respectively. CVP and &Dgr;-CVP did not correlate to CI and &Dgr;-CI, respectively. There was a significant correlation between ITBI and extravascular lung water index (r = .392; p < 0.001), but no correlation between CVP and extravascular lung water index (r = .074; p = 0.473). Conclusions:Volume depletion according to ITBI was found in more than half the patients. The predictive values of CVP and hematocrit with regard to volume depletion were low. ITBI and its changes significantly correlated to CI and its changes, which was not observed for CVP and &Dgr;-CVP. Therefore, ITBI appears to be more appropriate for volume management in necrotizing pancreatitis than CVP or hematocrit.

IKKα controls p52/RelB at the skp2 gene promoter to regulate G1‐ to S‐phase progression

The IκB‐inducing kinase (IKK) is composed of two catalytic subunits, IKKα and IKKβ, and a regulatory subunit, IKKγ. IKK‐regulated signaling pathways are believed to promote the proliferation of normal cells as well as the aberrant proliferation of cancer cells. The molecular mechanisms linking the IKK signaling pathway components to the cell cycle machinery are not entirely understood. To study the function(s) of the catalytic subunits of the IKK complex, we used pancreatic cancer cells, with constitutive IKK activity. We show that the G1 phase of the cell cycle is specifically regulated by the IKKα subunit, which regulates the stability of the cyclin‐dependent kinase inhibitor p27Kip1. Increased p27Kip1 protein levels following the transfection of IKKα‐specific siRNAs are a result of the downregulation of the F‐box protein S‐phase kinase‐associated protein 2 (skp2). Additionally, we demonstrate that IKKα signaling regulates the transcription of the skp2 gene by controlling the composition of a RelB‐containing NF‐κB complex. Together, this work defines a novel IKKα‐regulated growth pathway involving the p52/RelB‐dependent transcriptional regulation of the skp2 gene.

Origin of pancreatic ductal adenocarcinoma from atypical flat lesions: a comparative study in transgenic mice and human tissues†

Pancreatic ductal adenocarcinoma (PDAC) and its precursor lesions, pancreatic intraepithelial neoplasia (PanIN), display a ductal phenotype. However, there is evidence in genetically defined mouse models for PDAC harbouring a mutated kras under the control of a pancreas‐specific promoter that ductal cancer might arise in the centroacinar‐acinar region, possibly through a process of acinar‐ductal metaplasia (ADM). In order to further elucidate this model of PDAC development, an extensive expression analysis and molecular characterization of the putative and already established (PanIN) precursor lesions were performed in the Kras

Genetically engineered mouse models of pancreatic cancer: unravelling tumour biology and progressing translational oncology

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