New chimeric inhibitors targeting the epidermal growth factor (EGFR) and histone deacetylases (HDACs) were synthesized and tested for antineoplastic efficiency in solid cancer (prostate and hepatocellular carcinoma) and leukemia/lymphoma cell models. The most promising compounds, 3BrQuin-SAHA and 3ClQuin-SAHA, showed strong inhibition of tumor cell growth at one-digit micromolar concentrations with IC50 values similar to or lower than those of clinically established reference compounds SAHA and gefitinib. Target-specific EGFR and HDAC inhibition was demonstrated in cell-free kinase assays andWestern blot analyses, while unspecific cytotoxic effects could not be observed in LDH release measurements. Proapoptotic formation of reactive oxygen species and caspase-3 activity induction in PCa and HCC cell lines DU145 and Hep-G2 seem to be further aspects of the modes of action. Antiangiogenic potency was recognized after applying the chimeric inhibitors on strongly vascularized chorioallantoic membranes of fertilized chicken eggs (CAM assay). The novel combination of two drug pharmacophores against the EGFR and HDACs in one single molecule was shown to have pronounced antineoplastic effects on tumor growth in both solid and leukemia/lymphoma cell models. The promising results merit further investigations to further decipher the underlying modes of action of the novel chimeric inhibitors and their suitability for new clinical approaches in tumor treatment.

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Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

Cheung Sao Fong. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves xxiv-xxxvii). / Abstracts in English and Chinese. / Examination Committee List --- p.i / Declaration --- p.ii / Acknowledgements --- p.iii / Abstract --- p.v / Abstract in Chinese --- p.viii / List of Figures and Tables --- p.x / List of Abbreviations --- p.xix / Table of Content --- p.xxiii / Chapter Chapter 1 --- INTRODUCTION --- p.1 / Chapter 1.1 --- Human Liver Cancer --- p.1 / Chapter 1.1.1 --- Incidence of Hepatocellular Carcinoma --- p.1 / Chapter 1.1.2 --- Causes and Symptoms of Hepatocellular Carcinoma --- p.4 / Chapter 1.1.3 --- Treatment Options for Hepatocellular Carcinoma --- p.4 / Chapter 1.1.4 --- Multi-drug Resistance --- p.5 / Chapter 1.1.4.1 --- Mechanisms of Multi-drug Resistance --- p.5 / Chapter 1.2 --- Traditional Chinese Medicine --- p.10 / Chapter 1.2.1 --- Sophora flavescens and Radix Sophorae --- p.10 / Chapter 1.2.2 --- Flavonoid and its Sub-classification --- p.13 / Chapter 1.2.3 --- Flavonoid and Human Health --- p.15 / Chapter 1.3 --- Cell Death --- p.17 / Chapter 1.3.1 --- Necrosis --- p.17 / Chapter 1.3.2 --- Apoptosis --- p.17 / Chapter 1.3.3 --- Signaling Pathways in Apoptosis --- p.18 / Chapter 1.3.3.1 --- Extrinsic (Death Receptor-mediated) Pathway --- p.20 / Chapter 1.3.3.2 --- Intrinsic (Mitochondrial) Pathway --- p.21 / Chapter 1.3.3.3 --- Cysteine Aspartatic Acid Proteases --- p.21 / Chapter 1.4 --- Research Objective (s) --- p.22 / Chapter Chapter 2 --- MATERIALS AND METHODS --- p.23 / Chapter 2.1 --- Materials --- p.23 / Chapter 2.1.1 --- Cell Lines --- p.23 / Chapter 2.1.1.1 --- HepG2 --- p.24 / Chapter 2.1.1.2 --- RHepG2 --- p.24 / Chapter 2.1.1.3 --- WRL-68 --- p.25 / Chapter 2.1.2 --- Culture Media --- p.26 / Chapter 2.1.2.1 --- Rosewell Park Memorial Institute( RPMl) 1640 Medium --- p.26 / Chapter 2.1.2.2 --- Dulbecco's Modified Eagle's Medium (DMEM) --- p.26 / Chapter 2.1.3 --- Animals --- p.27 / Chapter 2.2 --- Traditional Chinese Medicines and Conventional Anti-cancer Drugs --- p.27 / Chapter 2.3 --- Antibodies --- p.29 / Chapter 2.4 --- Chemicals --- p.30 / Chapter 2.5 --- Reagents and Buffers --- p.34 / Chapter 2.5.1 --- Reagents for Silica Gel Column Chromatography --- p.34 / Chapter 2.5.2 --- Buffers for Common Use --- p.34 / Chapter 2.5.3 --- Reagents for Cell Viability Assay --- p.35 / Chapter 2.5.4 --- Reagents and Buffers for Typical Apoptosis Experiments --- p.35 / Chapter 2.5.4.1 --- Cell Cycle Analysis --- p.35 / Chapter 2.5.4.2 --- Terminal Deoxynucleotidyl Transferase-mediated dUTP Nick End Labeling (TUNEL) Assay --- p.35 / Chapter 2.5.4.3 --- DNA Fragmentation Detection --- p.35 / Chapter 2.5.5 --- Reagents and Buffers for Western Blot Study --- p.36 / Chapter 2.5.5.1 --- Whole-cell Protein Extraction --- p.38 / Chapter 2.5.5.2 --- Mitochondrial and Cytosolic Fraction Protein Extraction --- p.38 / Chapter 2.5.6 --- Reagents and Buffers for Mitochondrial Transmembrane Potential Depolarization Measurement --- p.39 / Chapter 2.5.7 --- Reagents and Buffers for in vivo Animal Study --- p.39 / Chapter 2.5.8 --- Reagents and Buffers for Two-Dimensional Gel Electrophoresis --- p.40 / Chapter 2.5.8.1 --- Sample Preparation --- p.40 / Chapter 2.5.8.2 --- First Dimension Gel Electrophoresis - Isoelectric Focusing (IEF) --- p.40 / Chapter 2.5.8.3 --- Second Dimension Gel 日ectrophoresis - SDS-Polyacrylamide Gel Electrophoresis (SDS-PAGE) --- p.40 / Chapter 2.5.8.4 --- Silver Staining --- p.41 / Chapter 2.5.9 --- Reagents for Mass Spectrometry Preparation --- p.42 / Chapter 2.5.9.1 --- Destaining --- p.42 / Chapter 2.5.9.2 --- Trypsin Digestion --- p.42 / Chapter 2.5.9.3 --- Desalting of Peptide Mixture --- p.43 / Chapter 2.5.10 --- Reagents and Buffers for Real-Time PCR --- p.43 / Chapter 2.6 --- Methods --- p.44 / Chapter 2.6.1 --- Isolation of Bioactive Constituents by Silica Gel Column Chromatography --- p.44 / Chapter 2.6.2 --- Cell Viability Assay --- p.45 / Chapter 2.6.3 --- Typical Apoptosis Experiments --- p.45 / Chapter 2.6.3.1 --- Cell Cycle Analysis --- p.46 / Chapter 2.6.3.2 --- Annexin V-FITC/ PI Staining Experiment --- p.47 / Chapter 2.6.3.3 --- Terminal Deoxynucleotidyl Transferase-mediated dUTP Nick End Labeling (TUNEL) Assay --- p.48 / Chapter 2.6.3.4 --- DNA Fragmentation Reaction --- p.48 / Chapter 2.6.4 --- Western Blot Study --- p.49 / Chapter 2.6.4.1 --- Whole-cell Protein Extraction --- p.49 / Chapter 2.6.4.2 --- Mitochondrial and Cytosolic Fraction Protein Extraction --- p.50 / Chapter 2.6.5 --- Caspase Activity Determination --- p.54 / Chapter 2.6.6 --- Mitochondrial Transmembrane Potential Depolarization Measurement --- p.55 / Chapter 2.6.7 --- in vivo Animal Study --- p.56 / Chapter 2.6.8 --- Two-Dimensional Gel Electrophoresis --- p.58 / Chapter 2.6.8.1 --- Sample Preparation --- p.58 / Chapter 2.6.8.2 --- First Dimension Electrophoresis - Isoelectric Focusing (IEF) --- p.59 / Chapter 2.6.8.3 --- Second Dimension Electrophoresis - SDS-Polyacrylamide Gel Electrophoresis (SDS-PAGE) --- p.60 / Chapter 2.6.8.4 --- Silver Staining --- p.61 / Chapter 2.6.9 --- Mass Spectrometry Preparation --- p.63 / Chapter 2.6.9.1 --- Destaining and Trypsin Digestion --- p.63 / Chapter 2.6.9.2 --- Peptide Extraction --- p.63 / Chapter 2.6.9.3 --- Desalting of Peptide Mixture --- p.64 / Chapter 2.6.10 --- Real-Time PCR --- p.65 / Chapter 2.6.11 --- Cellular Glutathione Level Detection --- p.69 / Chapter 2.7 --- Statistical Analysis --- p.70 / Chapter Chapter 3 --- RESULTS AND DISCUSSIONS - CYTOTOXICITY OF FLAVONOIDS ISOLATED FROM RADIX SOPHORAE --- p.72 / Chapter 3.1 --- Screening of Cytotoxic Flavonoids from Radix Sophorae --- p.72 / Chapter 3.2 --- Cytotoxicity of Leachianone A on Human Hepatoma Cell Lines --- p.74 / Chapter 3.3 --- Cytotoxicity of Leachianone A on Human Normal Liver Cell Line --- p.77 / Chapter 3.4 --- Cytotoxicity of Sophoraflavone J on Human Hepatoma Cell Line --- p.79 / Chapter 3.5 --- Cytotoxicity of Sophoraflavone J on Human Normal Liver Cell Line --- p.79 / Chapter 3.6 --- Cytotoxicities of Cisplatin and Taxol on Human Hepatoma as well as Normal Liver Cell Lines --- p.81 / Chapter 3.7 --- Conclusion --- p.86 / Chapter Chapter 4 --- "RESULTS AND DISCUSSIONS - MECHANISTIC STUDY OF LEACHIANONE A-INDUCED CELL DEATH IN HEPATOMA CELLS, HepG2 and RHepG2" --- p.88 / Chapter 4.1 --- Promotion of Cell Cycle Arrest --- p.88 / Chapter 4.2 --- Induction of Apoptosis as Evidenced by Phosphatidylserine Externalization and DNA Fragmentation --- p.93 / Chapter 4.2.1 --- Occurrence of Phosphatidylserine Externalization --- p.94 / Chapter 4.2.2 --- DNA Fragmentation Detection --- p.99 / Chapter 4.2.2.1 --- Terminal Deoxynucleotidyl Transferase(TdT)-mediated dUTP Nick End Labeling (TUNEL) Assay --- p.99 / Chapter 4.2.2.2 --- DNA Laddering Pattern in Agarose Gel Electrophoresis --- p.103 / Chapter 4.3 --- Recruitment of Multiple Signaling Pathways in Leachianone A-induced Apoptosis --- p.105 / Chapter 4.3.1 --- "Activation of Caspases-3, -8, and -9" --- p.105 / Chapter 4.3.2 --- Altered Expressions of Bcl-2 Family Proteins --- p.112 / Chapter 4.3.3 --- Loss of Mitochondrial Membrane Potential --- p.115 / Chapter 4.4 --- in vivo Tumor Growth Inhibition in HepG2-bearing Nude Mice --- p.121 / Chapter 4.5 --- Conclusion --- p.127 / Chapter Chapter 5 --- RESULTS AND DISCUSSIONS - MECHANISTIC STUDY OF SOPHORAFLAVONE J-INDUCED CELL DEATH IN HEPATOMA CELLS HepG2 --- p.132 / Chapter 5.1 --- Execution of Cellular Apoptosis --- p.133 / Chapter 5.2 --- Involvement of Multiple Signaling Pathways in Sophoraflavone J-induced Apoptosis --- p.138 / Chapter 5.3 --- Differential Proteomes of Control and Sophoraflavone J-treated HepG2 Cells --- p.148 / Chapter 5.4 --- Conclusion --- p.167 / Chapter Chapter 6 --- OVERALL CONCLUSION AND FUTURE PERSPECTIVES --- p.169 / References --- p.xxiv

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

Obwohl der Wildtyp des Hepatitis-B-Virus (HBV) nicht zytopathogen und die Pathogenese der Hepatitis B generell immunvermittelt ist, können in immunsupprimierten Nierentransplantatempfängern mit chronischer Hepatitis B schwere Leberschäden bis hin zu Leberzirrhose und Leberversagen entstehen. Die Entwicklung von Leberzirrhose in den Nierentransplantierten ist assoziiert mit der Akkumulation und Persistenz von komplexen HBV-Varianten mit Mutationen im Core-Promotor / X-Gen, Deletionen im Core (C)-Gen und teilweise zusätzlichen Deletionen im präS-Bereich. Dies lässt eine Rolle der Varianten in der speziellen Pathogenese bei Immunsupprimierten vermuten. In der vorliegenden Arbeit wurden funktionelle Analysen der komplexen Varianten im Vergleich zu Referenz-Wildtypgenomen und Wildtyp-ähnlichen Genomen der Patienten aus der frühen Infektionsphase durchgeführt, um Hinweise auf den potentiellen Beitrag der Varianten zur Pathogenese zu erlangen. Die Analysen erfolgten durch transiente Transfektion der humanen Hepatomazelllinie HuH7 mit repräsentativen HBV-Gesamtgenomen, die aus 2 Patienten während des Krankheitsverlaufs von einer asymptomatischen Infektion hin zur Leberzirrhose isoliert und kloniert worden waren. Trotz einiger Unterschiede im Detail wiesen die komplexen Varianten einen gemeinsamen, drastisch vom Wildtyp abweichenden Phänotyp auf. Dieser war gekennzeichnet durch eine veränderte Transkription mit reduzierten präC- und Oberflächen-mRNAs und verstärkter Expression der prägenomischen RNA, eine starke Reduktion des häufigsten Spleißprodukts der prägenomischen RNA, SP1, eine extrem reduzierte oder fehlende Expression und/oder Sekretion aller Oberflächenproteine und des HBeAg, ein verändertes intrazelluläres Verteilungsmuster des schwach exprimierten Core-Proteins und teilweise der Oberflächenproteine sowie eine erhöhte Replikation und Anreicherung gegenüber Wildtyp-HBV aufgrund einer verstärkten reversen Transkription der prägenomischen RNA. Dieser Phänotyp basierte zum Teil auf den Mutationen in Core-Promotor und C-Gen, wurde jedoch deutlich durch zusätzliche Mutationen in den übrigen Genomabschnitten beeinflusst. Die vielfältigen Veränderungen der Varianten unterstützen ihren vermuteten Beitrag zur Pathogenese. / Although wild-type hepatitis B virus is not cytopathogenic and the pathogenesis of hepatitis B is generally immune mediated, also immuno-suppressed patients, such as renal transplant recipients, with chronic hepatitis B may develop liver cirrhosis and end-stage liver disease. In renal transplant recipients, the development of liver cirrhosis is associated with the accumulation and persistence of complex HBV variants with mutations in core promoter / X gene, deletions in core (C) gene and sometimes additional deletions in the preS region. This suggests a role of these variants in the special pathogenesis in immuno-suppressed patients. In the present work, the complex variants were functionally analyzed in comparison to reference wild-type genomes and wild-type-like HBV genomes from the early asymptomatic phase of infection. For the analyses, representative cloned full-length HBV genomes isolated from 2 patients before and during liver cirrhosis were transiently transfected into the human hepatoma cell line HuH7. In spite of some variations, the complex variants showed a common phenotype, which was drastically altered compared to wild-type. It was characterized by reduced preC and surface mRNAs and increased expression of pregenomic RNA, by a strong reduction of the major spliced pregenomic RNA, SP1, by a partial or complete defect in expression and/or secretion of surface proteins and HBeAg, by an aberrant intracellular localization of the weakly expressed core protein and in some cases of the surface proteins, and by an enhanced replication and enrichment over wild-type HBV due to an enhanced reverse transcription of variant pregenomic RNA. The phenotypic alterations were often based on the mutations in core promoter and C gene but were considerably influenced by the additional mutations in other genomic regions. The multiple functional changes of the variants support their assumed contribution to pathogenesis.

Humans have two plasminogen activators (PAs), tissue-type plasminogen activator (tPA) and urokinase-type plasminogen activator (uPA), which generate plasmin to breakdown fibrin and other barriers to cell migration. Both PAs are used as pharmaceuticals but their efficacies are limited by their rapid clearance from the circulation, predominantly by parenchymal cells of the liver. At the commencement of the work presented here, the hepatic receptors responsible for mediating the catabolism of the PAs were little understood. tPA degradation by hepatic cell lines was known to depend on the formation of binary complexes with the major PA inhibitor, plasminogen activator inhibitor type-1 (PAI-1). Initial studies presented here established that uPA was catabolised in a fashion similar to tPA by the hepatoma cell line, HepG2. Other laboratories around this time found that the major receptor mediating the binding and endocytosis of the PAs is Low Density Lipoprotein Receptor-related Protein (LRP1). LRP1 is a giant 600 kDa protein that binds a range of structurally and functionally diverse ligands including, activated α2 macroglobulin, apolipoproteins, β amyloid precursor protein, and a number of serpin-enzymes complexes, including PA??PAI-1 complexes. Further studies for the work presented here centred on this receptor. By using radiolabelled binding assays, ligand blots, and Western blots on cultured cells, the major findings are that: (1) basal LRP1 expression on HepG2 is low compared to a clone termed, HepG2a16, but appears to increase in long term culture; (2) a soluble form of LRP1, which retains ligand-binding capacity, is present in human circulation; (3) soluble LRP1 is also present in cerebral spinal fluid where its role in neurological disorders such as Alzheimer??s disease is a developing area of interest; and (4) the release of LRP1 is a mechanism conserved in evolution, possibly as distantly as molluscs. The discovery, identification, and characterisation of soluble LRP1 introduces this protein in the human circulation, and presents a possible further level of regulation for its associated receptor system.