Metastasierung des Pankreaskarzinoms: Einfluss der hepatischen Mikroumgebung auf das Wachstumsverhalten von Pankreasgangepithelzellen

Pancreatic ductal adenocarcinoma (PDAC) is usually diagnosed when distant metastasis already emerged. These mostly form in the liver whereas recent studies suggest that dissemination of pancreatic ductal epithelial cells (PDECs) may occur prior to primary tumor formation. Yet, it remains widely unclear how the hepatic microenvironment and its condition impact on metastatic outgrowth of disseminated PDECs. This study aimed at elucidating the impact of a physiological liver microenvironment characterized by hepatic stellate cells (HSCs) and an inflammatory hepatic microenvironment featuring a high abundance of hepatic myofibroblasts (HMFs) on growth behavior of premalignant and malignant PDECs. Characterization of liver metastases in PDAC bearing mice unveiled micrometastases with low amounts of proliferating tumor cells in HSCs-rich microenvironments whereas macrometastases with significantly higher quantities of proliferating tumor cells were detected in HMFs-rich areas. In a syngeneic mouse model for which aging was selected as inflammatory stimulus, livers of aged mice exposed significantly higher amounts of proliferating disseminated tumor cells (DTCs) and micrometastases than livers of young mice. Gene expression analysis of liver tissues showed higher expression of HMFs-related genes including Vascular Endothelial Growth Factor (VEGF) in aged mice while young animals showed higher expression of functional homologues of human Interleukin-8 (IL-8). An indirect coculture system in which premalignant H6c7-kras cells or malignant Panc1 cells were cultured in presence of HSCs or HMFs showed that HSCs induce a state of dormancy in PDECs in dependence of IL-8 which is reversed by HMFs in a VEGF-dependent manner. This work shows a striking impact of the hepatic microenvironment and its condition on growth behavior of premalignant and malignant PDECs and identifies HSCs and HMFs as components of a dormancy permissive or restrictive hepatic microenvironment, respectively.Das duktale Adenokarzinom des Pankreas (PDAC) wird meist diagnostiziert, wenn bereits Fernmetastasen entstanden sind. PDAC-Metastasen bilden sich zumeist in der Leber, jedoch ist kaum bekannt, wie die hepatische Mikroumgebung und ihr Zustand das Auswachsen von disseminierten pankreatischen Duktusepithelzellen (PDEZ) beeinflussen können. Diese Studie sollte den Einfluss einer physiologischen Leberumgebung, charakterisiert durch hepatische Sternzellen (HSZ), und einer entzündlichen Mikroumgebung, charakterisiert durch hepatische Myofibroblasten (HMF), auf das Wachstumsverhalten von prämalignen und malignen PDEZ aufklären. Die Charakterisierung von Lebermetastasen in einem endogenen PDAC-Mausmodell zeigte das Aufkommen von Mikrometastasen mit einer geringen Anzahl an proliferierenden Tumorzellen in HSZ-reichen Mikroumgebungen, während Makrometastasen mit einer signifikant höheren Anzahl an proliferierenden Tumorzellen in HMF-reichen Mikroumgebungen festgestellt wurden. In einem syngenen Mausmodell, für welches Altern als inflammatorischer Stimulus gewählt wurde, zeigten Lebern von alten Mäusen eine signifikant höhere Anzahl an proliferierenden disseminierten Tumorzellen (DTZ) und Mikrometastasen als Lebern von jungen Mäusen, bei vergleichbarem Primärtumorwachstum. Genexpressionsanalysen von Lebergeweben zeigten eine deutlich höhere Expression von HMF-assoziierten Genen einschließlich Vascular Endothelial Growth Factor (VEGF) in gealterten Mäusen, während junge Mäuse eine höhere Expression der funktionellen Homologe des humanen Interleukin-8 (IL-8) aufwiesen. Ein indirektes Kokultur-System, in welchem prämaligne H6c7-kras-Zellen oder maligne Panc1-Zellen mit HSZ oder HMF kokultiviert wurden, zeigte, dass HSZ mittels IL-8 einen Dormanzzustand in PDEZ induzieren, welcher durch HMF in Abhängigkeit von VEGF revertiert wird. Diese Arbeit zeigt einen starken Einfluss der hepatischen Mikroumgebung und ihres Zustandes auf das Wachstumsverhalten von prämalignen und malignen PDEZ

Proteinase-activated receptor 2 (PAR2) in hepatic stellate cells – evidence for a role in hepatocellular carcinoma growth in vivo

Background Previous studies have established that proteinase-activated receptor 2 (PAR2) promotes migration and invasion of hepatocellular carcinoma (HCC) cells, suggesting a role in HCC progression. Here, we assessed the impact of PAR2 in HCC stromal cells on HCC growth using LX-2 hepatic stellate cells (HSCs) and Hep3B cells as model. Methods PAR2 expression and function in LX-2 cells was analysed by RT-PCR, confocal immunofluorescence, electron microscopy, and [Ca2+]i measurements, respectively. The impact of LX-2-expressed PAR2 on tumour growth in vivo was monitored using HCC xenotransplantation experiments in SCID mice, in which HCC-like tumours were induced by coinjection of LX-2 cells and Hep3B cells. To characterise the effects of PAR2 activation in LX-2 cells, various signalling pathways were analysed by immunoblotting and proteome profiler arrays. Results Following verification of functional PAR2 expression in LX-2 cells, in vivo studies showed that these cells promoted tumour growth and angiogenesis of HCC xenografts in mice. These effects were significantly reduced when F2RL1 (encoding PAR2) was downregulated by RNA interference (RNAi). In vitro studies confirmed these results demonstrating RNAi mediated inhibition of PAR2 attenuated Smad2/3 activation in response to TGF-β1 stimulation in LX-2 cells and blocked the pro-mitotic effect of LX-2 derived conditioned medium on Hep3B cells. Furthermore, PAR2 stimulation with trypsin or a PAR2-selective activating peptide (PAR2-AP) led to activation of different intracellular signalling pathways, an increased secretion of pro-angiogenic and pro-mitotic factors and proteinases, and an enhanced migration rate across a collagen- coated membrane barrier. Silencing F2RL1 by RNAi or pharmacological inhibition of Src, hepatocyte growth factor receptor (Met), platelet-derived growth factor receptor (PDGFR), p42/p44 mitogen activated protein kinase (MAPK) or matrix-metalloproteinases (MMPs) blocked PAR2-AP-induced migration. Conclusion PAR2 in HSCs plays a crucial role in promoting HCC growth presumably by mediating migration and secretion of pro-angiogenic and pro-mitotic factors. Therefore, PAR2 in stromal HSCs may have relevance as a therapeutic target of HCC

IL7R is associated with CNS infiltration and relapse in pediatric B-cell precursor acute lymphoblastic leukemia

No abstract available

Venetoclax enhances the efficacy of therapeutic antibodies in B-cell malignancies by augmenting tumor cell phagocytosis

Immunotherapy has evolved as a powerful tool for the treatment of B-cell malignancies, and patient outcomes have improved by combining therapeutic antibodies with conventional chemotherapy. Overexpression of antiapoptotic B-cell lymphoma 2 (Bcl-2) is associated with a poor prognosis, and increased levels have been described in patients with "double-hit" diffuse large B-cell lymphoma, a subgroup of Burkitt's lymphoma, and patients with pediatric acute lymphoblastic leukemia harboring a t(17;19) translocation. Here, we show that the addition of venetoclax (VEN), a specific Bcl-2 inhibitor, potently enhanced the efficacy of the therapeutic anti-CD20 antibody rituximab, anti-CD38 daratumumab, and anti-CD19-DE, a proprietary version of tafasitamab. This was because of an increase in antibody-dependent cellular phagocytosis by macrophages as shown in vitro and in vivo in cell lines and patient-derived xenograft models. Mechanistically, double-hit lymphoma cells subjected to VEN triggered phagocytosis in an apoptosis-independent manner. Our study identifies the combination of VEN and therapeutic antibodies as a promising novel strategy for the treatment of B-cell malignancies

Epithelial RNase H2 Maintains Genome Integrity and Prevents Intestinal Tumorigenesis in Mice

BACKGROUND & AIMS: RNase H2 is a holoenzyme, composed of 3 subunits (ribonuclease H2 subunits A, B, and C), that cleaves RNA:DNA hybrids and removes mis-incorporated ribonucleotides from genomic DNA through ribonucleotide excision repair. Ribonucleotide incorporation by eukaryotic DNA polymerases occurs during every round of genome duplication and produces the most frequent type of naturally occurring DNA lesion. We investigated whether intestinal epithelial proliferation requires RNase H2 function and whether RNase H2 activity is disrupted during intestinal carcinogenesis. METHODS: We generated mice with epithelial-specific deletion of ribonuclease H2 subunit B (H2bΔIEC) and mice that also had deletion of tumor-suppressor protein p53 (H2b/p53ΔIEC); we compared phenotypes with those of littermate H2bfl/fl or H2b/p53fl/fl (control) mice at young and old ages. Intestinal tissues were collected and analyzed by histology. We isolated epithelial cells, generated intestinal organoids, and performed RNA sequence analyses. Mutation signatures of spontaneous tumors from H2b/p53ΔIEC mice were characterized by exome sequencing. We collected colorectal tumor specimens from 467 patients, measured levels of ribonuclease H2 subunit B, and associated these with patient survival times and transcriptome data. RESULTS: The H2bΔIEC mice had DNA damage to intestinal epithelial cells and proliferative exhaustion of the intestinal stem cell compartment compared with controls and H2b/p53ΔIEC mice. However, H2b/p53ΔIEC mice spontaneously developed small intestine and colon carcinomas. DNA from these tumors contained T>G base substitutions at GTG trinucleotides. Analyses of transcriptomes of human colorectal tumors associated lower levels of RNase H2 with shorter survival times. CONCLUSIONS: In analyses of mice with disruption of the ribonuclease H2 subunit B gene and colorectal tumors from patients, we provide evidence that RNase H2 functions as a colorectal tumor suppressor. H2b/p53ΔIEC mice can be used to study the roles of RNase H2 in tissue-specific carcinogenesis

Involvement of the central nervous system in acute lymphoblastic leukemia: opinions on molecular mechanisms and clinical implications based on recent data

Acute lymphoblastic leukemia (ALL) is the most common childhood cancer. One of the major clinical challenges is adequate diagnosis and treatment of central nervous system (CNS) involvement in this disease. Intriguingly, there is little solid evidence on the mechanisms sustaining CNS disease in ALL. Here, we present and discuss recent data on this topic, which are mainly derived from preclinical model systems. We thereby highlight sites and routes of leukemic CNS infiltration, cellular features promoting infiltration and survival of leukemic cells in a presumably hostile niche, and dormancy as a potential mechanism of survival and relapse in CNS leukemia. We also focus on the impact of ALL cytogenetic subtypes on features associated with a particular CNS tropism. Finally, we speculate on new perspectives in the treatment of ALL in the CNS, including ideas on the impact of novel immunotherapies

The Hepatic Microenvironment and TRAIL-R2 Impact Outgrowth of Liver Metastases in Pancreatic Cancer after Surgical Resection

Most patients with pancreatic ductal adenocarcinoma (PDAC) undergoing curative resection relapse within months, often with liver metastases. The hepatic microenvironment determines induction and reversal of dormancy during metastasis. Both tumor growth and metastasis depend on the Tumor necrosis factor (TNF)-related apoptosis-inducing ligand-receptor 2 (TRAIL-R2). This study investigated the interplay of TRAIL-R2 and the hepatic microenvironment in liver metastases formation and the impact of surgical resection. Although TRAIL-R2-knockdown (PancTu-I shTR2) decreased local relapses and number of macroscopic liver metastases after primary tumor resection in an orthotopic PDAC model, the number of micrometastases was increased. Moreover, abdominal surgery induced liver inflammation involving activation of hepatic stellate cells (HSCs) into hepatic myofibroblasts (HMFs). In coculture with HSCs, proliferation of PancTu-I shTR2 cells was significantly lower compared to PancTu-I shCtrl cells, an effect still observed after switching coculture from HSC to HMF, mimicking surgery-mediated liver inflammation and enhancing cell proliferation. CXCL-8/IL-8 blockade diminished HSC-mediated growth inhibition in PancTu-I shTR2 cells, while Vascular Endothelial Growth Factor (VEGF) neutralization decreased HMF-mediated proliferation. Overall, this study points to an important role of TRAIL-R2 in PDAC cells in the interplay with the hepatic microenvironment during metastasis. Resection of primary PDAC seems to induce liver inflammation, which might contribute to outgrowth of liver metastases

Rilke's Novel Die Aufzeichungen des Malte Laurids Brigge in Czech Translations

The diploma thesis deals with two translations of Rilke's novel Die Aufzeichnungen des Malte Laurids Brigge. Each translation is not only conceived as a final product, but also as a communication process, influenced by a number of cultural and socio-political factors. The thesis therefore attempts to capture changes in Rilke's reception in relation to the literary paradigm and - with regards to the political situation - to the contemporary publisher policy, because during the period of socialism Rilke's work, which was highly valued in the thirties, came back into general awareness quite slowly in connection with the gradual liberation of cultural and political situation. The goal of the thesis is to map the problems of the translations' genesis with regards to the period and cultural environment and to the translators' poetic style. Part of the thesis addresses a translatological analysis, which is the base for defining both of the translators' methods