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  • 1
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    German Medical Science; Düsseldorf, Köln
    In:  27. Deutscher Krebskongress; 20060322-20060326; Berlin; DOCPO269 /20060320/
    Publication Date: 2006-04-21
    Keywords: ddc: 610
    Language: English
    Type: conferenceObject
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  • 2
    Keywords: SYSTEM ; CANCER ; APOPTOSIS ; THERAPY ; INDUCTION ; treatment ; CANCER-THERAPY ; TRAIL ; function ; CANCER-TREATMENT ; cancer therapy
    Type of Publication: Book chapter
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  • 3
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    Keywords: DISEASE ; DISEASES ; TARGET
    Type of Publication: Patent
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  • 4
    Keywords: RECEPTOR ; APOPTOSIS ; CELLS ; AGENTS ; human ; KINASE ; DISEASE ; LONG-TERM ; GENE ; GENES ; PROTEIN ; DRUG ; PATIENT ; ACTIVATION ; primary ; TRANSPLANTATION ; INDUCTION ; T-CELLS ; BINDING ; protein kinase ; TARGET ; CELL-DEATH ; INDUCED APOPTOSIS ; MODULATION ; LYMPHOCYTES ; CROHNS-DISEASE ; INFLAMMATORY-BOWEL-DISEASE ; 6- MERCAPTOPURINE ; CD28 ; COLITIS IN-VIVO ; GTPASE
    Abstract: Azathioprine and its metabolite 6-mercaptopurine (6-MP) are immunosuppressive drugs that are used in organ transplantation and autoimmune and chronic inflammatory diseases such as Crohn disease. However, their molecular mechanism of action is unknown. In the present study, we have identified a unique and unexpected role for azathioprine and its metabolites in the control of T cell apoptosis by modulation of Rac1 activation upon CD28 costimulation. We found that azathioprine and its metabolites induced apoptosis of T cells from patients with Crohn disease and control patients. Apoptosis induction required costimulation with CD28 and was mediated by specific blockade of Rac1 activation through binding of azathioprine- generated 6-thioguanine triphosphate (6-Thio-GTP) to Rac1 instead of GTP. The activation of Rac1 target genes such as mitogen-activated protein kinase kinase (MEK), NF-kappaB, and bcl-x(L), was suppressed by azathioprine, leading to a mitochondrial pathway of apoptosis. Azathioprine thus converts a costimulatory signal into an apoptotic signal by modulating Rac1 activity. These findings explain the immunosuppressive effects of azathioprine and suggest that 6-Thio-GTP derivates may be useful as potent immunosuppressive agents in autoimmune diseases and organ transplantation
    Type of Publication: Journal article published
    PubMed ID: 12697733
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  • 5
    Keywords: RECEPTOR ; APOPTOSIS ; CELLS ; EXPRESSION ; tumor ; TUMOR-CELLS ; carcinoma ; CELL ; human ; SYSTEM ; NEW-YORK ; PROTEIN ; MONOCLONAL-ANTIBODY ; DEATH DOMAIN ; NF-KAPPA-B ; LIGAND ; INDUCTION ; ANTIGEN ; BINDING ; treatment ; ANTITUMOR-ACTIVITY ; antibodies ; antibody ; FORM ; TARGET ; REQUIREMENTS ; FUSION ; SURFACE ; CARCINOMAS ; NETHERLANDS ; RECEPTORS ; BEHAVIOR ; CYTOTOXIC LIGAND TRAIL ; AFFINITY ; GM-CSF ; COLORECTAL-CARCINOMA ; EP-CAM ; MR 34,000 ; single-chain variable fragment,TNF-related apoptosis-inducing ligand,targeting,apoptosis,epithelial ; SURFACE GLYCOPROTEIN
    Abstract: The apparent tumor selective apoptosis-inducing activity of recombinant soluble TNF-related apoptosis-inducing ligand (TRAIL) has aroused much interest for use in clinical application. However, to exploit fully its therapeutic potential, the characteristics of both the TRAIL receptor system and soluble TRAIL (sTRAIL) should be taken into account: first, the widespread expression of the various TRAIL receptors throughout the human body; second, the differential binding affinities and crosslinking requirements of the agonistic receptors TRAIL-RI and TRAIL-R2; and third, the solution behavior of particular sTRAIL preparations. Therefore, we constructed a novel TRAIL fusion protein, designated scFvC54:sTRAIL, comprising the human scFv antibody fragment C54 genetically linked to the N-terminus of human sTRAIL. The scFvCS4:sTRAIL fusion protein was designed to induce apoptosis by crosslinking of agonistic TRAIL receptors only after specific binding of scFvCS4:sTRAIL to the abundantly expressed carcinoma-associated cell surface antigen EGP2 (alias EpCAM). Target antigen-restricted apoptosis induction was demonstrated for various EGP2-positive tumor cells and could be inhibited by an EGP2 competing antibody. Target antigen binding converted soluble scFvCS4: sTRAIL into a membrane-bound form of TRAIL that was capable of signaling apoptosis not only through TRAIL-R1 but also through TRAIL-R2. Size-exclusion fast protein liquid chromatography (FPLC) indicated that scFvCS4:sTRAIL was produced as stable and homogeneous trimers in the absence of detectable TRAIL aggregates. The favorable characteristics of the scFvCS4:sTRAIL fusion protein potentially reduce the amount of sTRAIL required for antitumor activity and may be of value for the treatment of various human carcinomas. (C) 2003 Wiley-Liss, Inc
    Type of Publication: Journal article published
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  • 6
    Keywords: RECEPTOR ; APOPTOSIS ; CELLS ; INHIBITOR ; tumor ; TUMOR-CELLS ; carcinoma ; Germany ; human ; IN-VIVO ; INHIBITION ; DEATH ; HEPATOCELLULAR-CARCINOMA ; PROTEIN ; PROTEINS ; RNA ; LINES ; MICE ; TRANSDUCTION ; NF-KAPPA-B ; COMPLEX ; COMPLEXES ; MECHANISM ; CONTRAST ; hepatocytes ; CELL-LINES ; signal transduction ; SUPPRESSION ; 5-FLUOROURACIL ; ALPHA ; hepatocellular carcinoma ; resistance ; CARCINOMA CELLS ; EFFICACY ; SIGNAL-TRANSDUCTION ; LINE ; CANCER-CELLS ; CARCINOMA-CELLS ; KAPPA-B ; RECEPTORS ; FLOW-CYTOMETRY ; cell lines ; PROTEASOME ; TRAIL ; SIGNALING COMPLEX ; HUMAN HEPATOCYTES ; TRAIL-INDUCED APOPTOSIS ; APOPTOSIS-INDUCING LIGAND ; CASPASE-8 ACTIVATION ; INHIBITORS ; signaling ; RE ; INTERFERENCE ; CASPASE-8 ; MEDIATED APOPTOSIS ; TUMORICIDAL ACTIVITY ; interaction ; SIGNALING COMPLEXES ; CLINICAL-RELEVANCE ; carcinoma cell ; death receptor
    Abstract: TRAIL exhibits potent anti-tumor activity on systemic administration in mice. Because of its proven in vivo efficacy, TRAIL may serve as a novel anti-neoplastic drug. However, approximately half of the tumor cell lines tested so far are TRAIL resistant, and potential toxic side effects of certain recombinant forms of TRAIL on human hepatocytes have been described. Pretreatment with the proteasome inhibitor MG132 and PS-341 rendered TRAIL-resistant hepatocellular carcinoma (HCC) cell lines but not primary human hepatocytes sensitive for TRAIL-induced apoptosis. We investigated the different levels of possible MG132-induced interference with resistance to apoptotic signal transduction. Although proteasome inhibition efficiently suppressed nuclear factor-kappaB (NF-kappa B) activity, specific suppression of NF-kappa B by mut kappa B alpha failed to sensitize TRAIL-resistant cell lines for TRAIL-induced apoptosis. In contrast to the previously reported mechanism of sensitization by 5-fluorouracil (5-FU), cellular FLICE-inhibitory protein (cFLIP)(L) and cFLIP(S) were markedly upregulated in the TRAIL death inducing signaling complex (DISC) by proteasome inhibitor pretreatment. Compared with 5-FU pretreatment, caspase-8 was more efficiently recruited to the DISC in MG132 pretreated cells despite the presence of fewer death receptors and more cFLIP in the DISC., But downregulation of cFLIP by short interference RNA (siRNA) further sensitized the HCC cell lines. In conclusion, these results show that otherwise chemotherapy-resistant tumor cells can be sensitized for TRAIL-induced apoptosis at the DISC level in the presence of high levels of cFLIP, which suggests the existence of an additional factor that modulates the interaction of FADD and the TRAIL death receptors. Of clinical relevance, proteasome inhibitors sensitize HCC cells but not primary human hepatocytes for TRAIL-induced apoptosis
    Type of Publication: Journal article published
    PubMed ID: 16037944
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  • 7
    Keywords: RECEPTOR ; APOPTOSIS ; CANCER CELLS ; CELLS ; EXPRESSION ; GROWTH ; tumor ; TUMOR-CELLS ; carcinoma ; Germany ; human ; INHIBITION ; PATHWAY ; PATHWAYS ; DEATH ; HEPATOCELLULAR-CARCINOMA ; PROTEINS ; RNA ; DRUG ; MONOCLONAL-ANTIBODY ; TUMORS ; RELEASE ; TUMOR-NECROSIS-FACTOR ; ACTIVATION ; LIGAND ; MECHANISM ; FAMILY ; DOMAIN ; INDUCTION ; mechanisms ; DOWN-REGULATION ; CYTOCHROME-C ; MITOCHONDRIA ; UNITED-STATES ; RECEPTORS ; OVEREXPRESSION ; TUMOR CELLS ; Bcl-2 ; HUMAN HEPATOCYTES ; TRAIL-INDUCED APOPTOSIS ; APOPTOSIS-INDUCING LIGAND ; CD95 ; CASPASE ; INHIBITORS ; signaling ; FAMILIES ; SOLID TUMORS ; CYCLOOXYGENASE-2 ; TUMOR-CELL ; death receptor ; downregulation ; function ; caspases ; DRUGS ; cyclooxygenase ; RELEVANCE ; NECROSIS ; MCL-1 ; CELECOXIB-INDUCED APOPTOSIS ; PRIMARY HUMAN HEPATOCYTES
    Abstract: Inhibition of cyclooxygenase (COX)-2 elicits chemopreventive and therapeutic effects in solid tumors that are coupled with the induction of apoptosis in tumor cells. We investigated the mechanisms by which COX-2 inhibition induces apoptosis in hepatocellular carcinoma (HCC) cells. COX-2 inhibition triggered expression of the CD95, tumor necrosis factor (TNIF)-R, and TNF-related apoptosis-inducing ligand (TRAIL)-R1 and TRAIL-R2 death receptors. Addition of the respective specific ligands further increased apoptosis, indicating that COX-2 inhibition induced the expression of functional death receptors. Overexpression of a dominant-negative Fas-associated death domain mutant reduced COX-2 inhibitor-mediated apoptosis. Furthermore, our findings showed a link between COX-2 inhibition and the mitochondrial apoptosis pathway. COX-2 inhibition led to a rapid down-regulation of myeloid cc leukemia-1 (Mcl-1), an antiapoptotic member of the Bcl-2 family, followed by translocation of Bax to mitochondria and cytochrome c release front mitochondria. Consequently, overexpression of Mcl-1 led to inhibition of COX-2 inhibitor-mediated apoptosis. Furthermore, blocking endogenous Mcl-1 function using a small - interfering RNA approach enhanced COX-2 inhibitor-mediated apoptosis. It is of clinical importance that celecoxib acted synergistically with chemotherapeutic drugs in the induction of apoptosis in HCC cells. The clinical relevance of these results is further substantiated by the finding that COX-2 inhibitors did not sensitize primary human hepatocytes toward chemotherapy-induced apoptosis. In conclusion, COX-2 inhibition engages different apoptosis pathways in HCC cells stimulating death receptor signaling, activation of caspases, and apoptosis originating from mitochondria
    Type of Publication: Journal article published
    PubMed ID: 16849551
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  • 8
    Keywords: APOPTOSIS ; EXPRESSION ; Germany ; DEATH ; GENE ; GENES ; ACTIVATION ; IDENTIFICATION ; PLASMA ; MUTATION ; PLASMA-MEMBRANE ; MORPHOLOGY ; SELECTION ; RE ; ACCELERATOR
    Abstract: A sophisticated hunt for genes differentially expressed during early T-cell development has led to the identification of Gimap4, a gene with a promising expression profile during T-cell development, However, gene-knockout reveals that Gimap4 does not play a role in T-cell development, selection, and activation, but that instead it acts as an accelerator of T-cell death during the final transition from a cell with apoptotic morphology to one with a disintegrated plasma membrane
    Type of Publication: Journal article published
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  • 9
    Keywords: RECEPTOR ; APOPTOSIS ; CELLS ; EXPRESSION ; carcinoma ; CELL ; Germany ; IN-VIVO ; INHIBITION ; PATHWAY ; DEATH ; GENE ; PROTEIN ; LINES ; ACTIVATION ; LIGAND ; DNA ; INFECTION ; REDUCTION ; DOMAIN ; CARCINOGENESIS ; INDUCTION ; T cells ; T-CELLS ; CELL-LINES ; CELL-LINE ; LYMPHOCYTES ; MITOCHONDRIA ; STOMACH ; RECEPTORS ; TRAIL ; REGULATOR ; inflammation ; FAS ; methods ; IMMUNE PRIVILEGE ; leukaemia ; death receptor ; INHIBIT ; Helicobacter pylori ; GASTRIC EPITHELIAL APOPTOSIS ; INFILTRATING MUCOSAL LYMPHOCYTES ; VACUOLATING CYTOTOXIN
    Abstract: Background Chronic infection with Helicobacter pylori is related to the pathogenesis of the noncardia carcinoma of the stomach. In this study we investigated the mechanisms of H. pylori-induced apoptosis in T lymphocytes, which could explain a mechanism of immune evasion facilitating chronic inflammation of the mucosa and gastric carcinogenesis. Materials and methods The supernatant of H. pylori culture was used to study the mechanism of apoptosis induction in human leukaemia T cell lines Jurkat and CEM and in primary T cells. The cytotoxin associated gene A (CagA) and vacuolating cytotoxin A (Vac A) positive bacterial strain H. pylori 60190 (CagA+, VacA+) and as a control the less toxic H. pylori strain Tx30a (CagA-, VacA-) were used to produce the supernatant. Cell death was determined by DNA fragmentation and protein expression by Western blot. Results H. pylori 60190-induced apoptosis was neither blocked by inhibition of the death ligands TRAIL (TNF-related apoptosis-inducing ligand), CD95L/FasL and TNF-alpha (tumour necrosis factor-a) in wild type Jurkat cells nor in FADD(def) (Fas-associated death domain protein) and caspase-8(def) subclones of the Jurkat cell line. Yet, the pancaspase inhibitor zVAD-fmk could inhibit up to 90% of H. pylori-induced apoptosis. Stable transfection of Jurkat wild type cells with Bcl-x(L and) Bcl-2 resulted in marked reduction of H. pylori-induced apoptosis, showing that the mitochondrial pathway is the key regulator. This is supported by the finding that surviving primary human lymphocytes upregulate Bcl-2 when exposed to H. pylori supernatant. Conclusions H. pylori-induced apoptosis of T cells is mediated by the mitochondrial pathway and could create a local environment that facilitates life-long infection by immune evasion
    Type of Publication: Journal article published
    PubMed ID: 17217377
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  • 10
    Keywords: RECEPTOR ; APOPTOSIS ; CELLS ; EXPRESSION ; CELL ; Germany ; human ; DEATH ; CLONING ; GENE-EXPRESSION ; PROTEIN ; SAMPLE ; SAMPLES ; DIFFERENTIATION ; LIGAND ; MECHANISM ; CONTRAST ; mechanisms ; IN-SITU ; NEOPLASIA ; CELL-DEATH ; DECREASE ; RECEPTORS ; SMALL-INTESTINE ; TRAIL ; protein expression ; LACKING ; molecular ; RECOMBINANT ; MOLECULAR-MECHANISM ; VARIANT ; INCREASE ; CELL-SURFACE EXPRESSION ; PH ; regulation ; development ; MOLECULAR-MECHANISMS ; methods ; cell death ; CELIAC-DISEASE ; death receptor ; USA ; LIGAND TRAIL ; HOMEOSTASIS ; INCREASES ; apoptotic ; MUCOSAL ; ACYL-COA-SYNTHETASE-5 ; HUMAN SMALL-INTESTINE ; IMPAIRED EXPRESSION
    Abstract: Background & Aims: The constant renewal of enterocytes along the crypt-villus axis (CVA) of human small intestine is due to cell-inherent changes resulting in the apoptotic cell death of senescent enterocytes. The aim of the present study was to examine underlying molecular mechanisms of the cell death at the villus tip. Methods: Characterization of human acyl-coenzyme A (CoA) synthetase 5 (ACSL5) was performed by cloning, recombinant protein expression, biochemical approaches, and several functional and in situ analyses. Results: Our data show that different amounts of acyl-CoA synthetase 5-full length (ACSL5-fl) and a so far unknown splice variant lacking exon 20 (ACSL5-Delta 20) are found in human enterocytes. In contrast with the splice variant ACSL5-Delta 20, recombinant and purified ACSL5-fl protein is active at a highly alkaline pH. Over expression of ACSL5-fl protein is associated with a decrease of the anti-apoptotic FLIP protein in a ceramide-dependent manner and an increased cell-surface expression of the death receptor TRAIL-RI. Expression analyses revealed that the ACSL5-fl/ACSL5-Delta 20 ratio increases along the CVA, thereby sensitizing ACSL5-fl-dominated cells at the villus tip to the death ligand TRAIL, which is corroborated by functional studies with human small intestinal mucosal samples and an immortalized human small intestinal cell fine. Conclusions: Our results suggest an ACSL5-dependent regulatory mechanism that contributes to the cellular renewal along the CVA in human small intestine. Deregulation of the ACSL5-fl/ACSL5-Delta 20 homeostasis in the maturation and shedding of cells along the CVA might also be of relevance for the development of intestinal neoplasia
    Type of Publication: Journal article published
    PubMed ID: 17681178
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