Introdução: Na prática clínica se observa que há diferenças na incidência de efeitos colaterais entre pacientes submetidos ao mesmo esquema terapêutico de radioterapia. Tais diferenças podem ser entendidas como uma radiossensibilidade individual determinada geneticamente. Objetivos: Este estudo teve como objetivo avaliar os efeitos tardios na bexiga em pacientes com câncer do colo uterino tratadas com radioterapia, com ou sem cirurgia, e o valor prognóstico de três polimorfismos genéticos de base única com relação ao desenvolvimento de cistite actínica. Material e métodos: Foi realizada uma análise retrospectiva de 50 pacientes com carcinoma cervical tratadas entre 1999 e 2004, com um mínimo de 6,5 anos de seguimento. A dose de radioterapia na bexiga foi considerada como a soma da dose da radioterapia externa com a dose de braquiterapia no ponto de bexiga definido pelo ICRU 38 (Relato número 38 da Comissão Internacional de Unidades e Medidas em Radiação). Para as correlações entre dose e efeito, foi calculada a dose biológica efetiva (BED) para cada caso. Para a avaliação dos efeitos tardios em bexiga, além dos dados descritos em prontuário, foi feito um questionário específico dirigido aos sintomas urinários, foi realizada cistoscopia em todas as pacientes e a escala LENTSOMA (efeitos tardios no tecido normal/ subjetivo-objetivo tratamento e exames) foi aplicada, utilizando o pior grau do efeito encontrado nos diferentes métodos de avaliação. Variantes genéticas do códon 72 da p53 (Arginina / Prolina), MDM2 SNP309 T/G e ATMex39 5557 G>A foram identificadas usando o método de genotipagem de SNP ABI SNaPshot e os resultados foram correlacionados com a incidência e grau de cistite actínica. Resultados: Complicações clínicas tardias da bexiga foram registradas em 17 (34%) pacientes usando dados coletados dos prontuários e em 41 (82%) pacientes pelo questionário de existência e gravidade dos efeitos tardios da irradiação. Essas complicações foram diretamente correlacionadas com a BED. Vinte e oito pacientes (56%) desenvolveram cistite diagnosticada por cistoscopia (16% Grau 2-4). MDM2 SNP309 TT associado a TP53 (P72R) GG foram relacionados com o aumento da incidência de cistite. Conclusões: Cistite actínica, em grau 2 ou maior, foi elevada nessa população e apresentou uma maior incidência quando realizado um questionário específico para tal. Houve associação com maior dose de radioterapia (BED Gy3 > 100 Gy) e com MDM2 SNP309 TT associado a TP53 (P72R) GG. / Introduction: In clinical practice it is observed that there are differences in the incidence of side effects among patients undergoing the same regimen of radiotherapy. Such differences can be understood as a genetically determined individual radiosensitivity. Purposes: This study aimed to evaluate urinary bladder late effects in patients with uterine cervix cancer treated with radiotherapy with or without surgery and the prognostic value of three single nucleotide polymorphisms (SNPs) related to radiation cystitis. Material and methods: retrospective analysis of 50 patients with cervical carcinoma treated between 1999 and 2004 with a minimum of 6.5 years of follow-up was performed. The radiation dose in the bladder was considered as the dose delivered by external beam irradiation plus the brachytherapy dose in the ICRU Report 38 (International Commission of Radiation Units and Measurements report number 38) bladder point. For dose-effect correlations the biological effective dose (BED) was calculated for each case. For evaluation of bladder late effects, besides the data collected from the charts review, a specific query directed to urinary symptoms was applied to the patients and also a cystoscopy was performed in all of them. The LENTSOMA (late effects of normal tissues/subjective-objective management analytic) scale for bladder late effects was applied. Genetic variants of p53 codon72 (arginine/proline) polymorphism, MDM2 SNP309 T/G and ATMex39 5557G>A were identified by using ABI SNaPshot SNP genotyping method. And the results were correlated with the incidence and grade of radiation cystitis. Results: Clinical late bladder complications were recorded in 17 (34%) patients using data collected from the charts and in 41 (82%) patients by the questionnaire for the existence and severity of late irradiation effects. These complications were directly related with the BED. Twenty eight patients (56%) developed cystitis diagnosed by cystoscopy (16% Grade 2-4). MDM2 SNP309 TT associated with TP53 (P72R) GG was related with increased incidence of cystitis. Conclusions: Late radiation cystitis grade 2 or greater were high in this population and presented a higher incidence when a specific questionnaire was used. Higher radiation dose (BED Gy3 > 100 Gy) and MDM2 SNP309 TT associated with TP53 (P72R) GG were correlated with bladder late effects

Introdução: Na prática clínica se observa que há diferenças na incidência de efeitos colaterais entre pacientes submetidos ao mesmo esquema terapêutico de radioterapia. Tais diferenças podem ser entendidas como uma radiossensibilidade individual determinada geneticamente. Objetivos: Este estudo teve como objetivo avaliar os efeitos tardios na bexiga em pacientes com câncer do colo uterino tratadas com radioterapia, com ou sem cirurgia, e o valor prognóstico de três polimorfismos genéticos de base única com relação ao desenvolvimento de cistite actínica. Material e métodos: Foi realizada uma análise retrospectiva de 50 pacientes com carcinoma cervical tratadas entre 1999 e 2004, com um mínimo de 6,5 anos de seguimento. A dose de radioterapia na bexiga foi considerada como a soma da dose da radioterapia externa com a dose de braquiterapia no ponto de bexiga definido pelo ICRU 38 (Relato número 38 da Comissão Internacional de Unidades e Medidas em Radiação). Para as correlações entre dose e efeito, foi calculada a dose biológica efetiva (BED) para cada caso. Para a avaliação dos efeitos tardios em bexiga, além dos dados descritos em prontuário, foi feito um questionário específico dirigido aos sintomas urinários, foi realizada cistoscopia em todas as pacientes e a escala LENTSOMA (efeitos tardios no tecido normal/ subjetivo-objetivo tratamento e exames) foi aplicada, utilizando o pior grau do efeito encontrado nos diferentes métodos de avaliação. Variantes genéticas do códon 72 da p53 (Arginina / Prolina), MDM2 SNP309 T/G e ATMex39 5557 G>A foram identificadas usando o método de genotipagem de SNP ABI SNaPshot e os resultados foram correlacionados com a incidência e grau de cistite actínica. Resultados: Complicações clínicas tardias da bexiga foram registradas em 17 (34%) pacientes usando dados coletados dos prontuários e em 41 (82%) pacientes pelo questionário de existência e gravidade dos efeitos tardios da irradiação. Essas complicações foram diretamente correlacionadas com a BED. Vinte e oito pacientes (56%) desenvolveram cistite diagnosticada por cistoscopia (16% Grau 2-4). MDM2 SNP309 TT associado a TP53 (P72R) GG foram relacionados com o aumento da incidência de cistite. Conclusões: Cistite actínica, em grau 2 ou maior, foi elevada nessa população e apresentou uma maior incidência quando realizado um questionário específico para tal. Houve associação com maior dose de radioterapia (BED Gy3 > 100 Gy) e com MDM2 SNP309 TT associado a TP53 (P72R) GG. / Introduction: In clinical practice it is observed that there are differences in the incidence of side effects among patients undergoing the same regimen of radiotherapy. Such differences can be understood as a genetically determined individual radiosensitivity. Purposes: This study aimed to evaluate urinary bladder late effects in patients with uterine cervix cancer treated with radiotherapy with or without surgery and the prognostic value of three single nucleotide polymorphisms (SNPs) related to radiation cystitis. Material and methods: retrospective analysis of 50 patients with cervical carcinoma treated between 1999 and 2004 with a minimum of 6.5 years of follow-up was performed. The radiation dose in the bladder was considered as the dose delivered by external beam irradiation plus the brachytherapy dose in the ICRU Report 38 (International Commission of Radiation Units and Measurements report number 38) bladder point. For dose-effect correlations the biological effective dose (BED) was calculated for each case. For evaluation of bladder late effects, besides the data collected from the charts review, a specific query directed to urinary symptoms was applied to the patients and also a cystoscopy was performed in all of them. The LENTSOMA (late effects of normal tissues/subjective-objective management analytic) scale for bladder late effects was applied. Genetic variants of p53 codon72 (arginine/proline) polymorphism, MDM2 SNP309 T/G and ATMex39 5557G>A were identified by using ABI SNaPshot SNP genotyping method. And the results were correlated with the incidence and grade of radiation cystitis. Results: Clinical late bladder complications were recorded in 17 (34%) patients using data collected from the charts and in 41 (82%) patients by the questionnaire for the existence and severity of late irradiation effects. These complications were directly related with the BED. Twenty eight patients (56%) developed cystitis diagnosed by cystoscopy (16% Grade 2-4). MDM2 SNP309 TT associated with TP53 (P72R) GG was related with increased incidence of cystitis. Conclusions: Late radiation cystitis grade 2 or greater were high in this population and presented a higher incidence when a specific questionnaire was used. Higher radiation dose (BED Gy3 > 100 Gy) and MDM2 SNP309 TT associated with TP53 (P72R) GG were correlated with bladder late effects

La sénescence est un processus caractérisé par un arrêt stable du cycle cellulaire. Ce mécanisme peut être induit en réponse à de nombreux stress, comme l’activation d’un oncogène, le raccourcissement des télomères ou bien le traitement avec des composés génotoxiques. Cette réponse cellulaire est considérée comme une barrière antitumorale limitant la prolifération des cellules exposées au risque de transformation. La mise en place de la sénescence dépend de profonds changements au niveau moléculaire, dont l’activation d’un programme de dégradation sélective des protéines. Cette dégradation de protéines associée à la sénescence (SAPD) peut expliquer plusieurs caractéristiques des cellules sénescentes, notamment la présence de défauts dans la voie de synthèse des ribosomes (SARD). Ces derniers sont liés à un stress nucléolaire qui mène à l’accumulation de certaines protéines ribosomiques dans le noyau, où elles peuvent effectuer des fonctions indépendantes de leur rôle structurale dans les ribosomes. Parmi ces protéines ribosomiques, RPS14/uS11 peut s’accumuler dans le nucléoplasme et réguler le cycle cellulaire en inhibant CDK4. Ces mécanismes de régulation post-traductionnelle -le SAPD ainsi que les conséquences des SARD- contribuent de manière importante au phénotype sénescent. Nous avons émis l’hypothèse que la caractérisation des effecteurs dans ces voies pourrait mener à l’identification de nouvelles protéines importantes pour la sénescence et la suppression tumorale. Dans un premier temps, nous avons évalué le rôle de la protéine ribosomique RPL22/eL22 dans le cycle cellulaire et la sénescence. Tout comme RPS14, RPL22 a été identifié dans l’analyse de l’interactome de CDK4 lors de la sénescence induite par la perte du facteur de la ribogenèse RSL1D1. Nous avons pensé que RPL22 pourrait agir de manière similaire à RPS14 et ainsi effectuer des fonctions extra-ribosomiques impliquées dans la régulation du cycle cellulaire. Dans le premier article présenté dans cette thèse, nous montrons que la surexpression de RPL22 dans des fibroblastes humains induit un phénotype sénescent et que RPL22 peut lier et inhiber CDK4 afin d’activer la voie de RB. Ensemble, ces données indiquent un rôle suppressif de RPL22 dans le cycle cellulaire. En second lieu, nous nous sommes penchés sur la caractérisation des effecteurs du programme de dégradation sélective de protéines associé à la sénescence. Ce programme est mené à terme par le système ubiquitine-protéasome, un mécanisme finement régulé par différents types de protéines. Parmi celles-ci, les E3 ubiquitine ligases définissent la spécificité de ce système en interagissant avec les substrats à dégrader. Nous avons donc pensé que certaines E3 ubiquitine ligases spécifiques pourraient être importantes pour le mécanisme de dégradation protéique associé à la sénescence. Afin d’identifier celles-ci, nous avons effectué un criblage de shARN ciblant des gènes d’E3 ubiquitine ligases dans le contexte de la sénescence induite par les oncogènes. Ceci a mené à l’identification d’ASB14 comme un acteur important de la sénescence. Dans le deuxième article de cette thèse, nous montrons que la perte d’ASB14 produit un contournement de la sénescence induite par l’oncogène RAS dans plusieurs modèles cellulaires. ASB14 est une protéine peu caractérisée et nous avons généré des anticorps afin d’analyser son expression. Nous montrons ensuite qu’ASB14 s’exprime fortement dans le pancréas sain, tandis que ses niveaux diminuent dans les tumeurs pancréatiques. Enfin, nous avons identifié les partenaires d’interaction d’ASB14 dans le contexte de la sénescence induite par l’oncogène RAS. Globalement, les travaux présentés dans cette thèse nous ont permis d’identifier deux nouvelles protéines impliquées dans la sénescence cellulaire : la protéine ribosomique RPL22 et l’E3 ubiquitine ligase ASB14. Ces deux protéines contribuent à la régulation post-traductionnelle du phénotype sénescent. D’un côté, RPL22 peut inhiber l’activité de CDK4 afin d’activer la voie de RB et ainsi réguler le cycle cellulaire. D’une autre part, ASB14 est importante pour le maintien du phénotype sénescent et semble avoir un rôle dans la suppression tumorale du pancréas. Nos résultats suggèrent que RPL22 et ASB14 sont importants pour la sénescence et la suppression tumorale. / Cellular senescence is characterized by a stable cell cycle arrest. This process can be induced by a variety of cellular stresses, including oncogene activation, telomere shortening and genotoxic treatments. In fact, senescence is considered an antitumor barrier that prevents cellular transformation. Senescence is associated with widespread molecular changes, including the activation of a selective protein degradation program. This senescence-associated protein degradation (SAPD) could regulate some senescence-associated phenotypes, including the senescence-associated ribosome biogenesis defects (SARD). Senescence-associated ribosome biogenesis defects are linked to a nuclear accumulation of some ribosomal proteins such as RPS14/uS11 capable of carrying out extra-ribosomal functions. In particular, RPS14 can inhibit CDK4 and mediate senescence. Thus, we hypothesize that the proteins implicated in these pathways -SAPD and SARD- could be important for senescence and tumor suppression. First, we evaluated the ability of the ribosomal protein L22 (RPL22/eL22) to regulate cellular senescence and cell cycle progression. RPL22, as RPS14, was identified as a binding partner for CDK4 in senescent cells induced by depleting the ribosome biogenesis factor RSL1D1. Hence, we though that RPL22 could act in a manner similar to RPS14. In chapter two, we show that RPL22 overexpression induces a senescent phenotype in human fibroblasts. In addition, we show that RPL22 can interact with CDK4 inhibiting its activity and stimulating the RB tumor suppressor pathway. Taken together, these results indicate a suppressive role of RPL22 in cell cycle progression. Next, we focused on the characterization of SAPD effectors. This mechanism is mediated by the ubiquitin-proteasome system which is tightly regulated by E3 ubiquitin ligases. Thus, we thought that specific E3 ubiquitin ligases could be important for SAPD and for senescence. In order to discover E3 ubiquitin ligases that contribute to senescence, we performed an unbiased screening using shRNA libraries in Ras-induced senescent cells. This led to the identification of ASB14 as an important mediator of senescence. In chapter three, we show that ASB14 depletion leads to a bypass of Ras-induced senescence. ASB14 is a poorly characterized E3 ligase, and we generated antibodies in order to analyze its expression levels. We show that ASB14 is highly expressed in the normal pancreas whereas its expression is reduced in pancreatic cancer tissues. Finally, we uncovered the interactome of ASB14 in Ras-induced senescent cells. Overall, we have discovered two new senescence mediators: ribosomal protein L22 and E3 ubiquitin ligase ASB14. These proteins are implicated in the post-translational regulation of the senescent phenotype. RPL22 acts as a CDK4 inhibitor to activate RB pathway and regulate cell cycle arrest and ASB14 is an important mediator of senescence maintenance. Taken together, our results suggest that RPL22 and ASB14 are important for cellular senescence and tumor suppression.

The Cbl family of E3 ubiquitin ligases are important negative regulators of multiple receptor and cytoplasmic tyrosine kinases, and participate in a wide variety of cellular processes. Uncoupling of Cbl-mediated negative regulation allows activated receptor tyrosine kinases such as the Met receptor to escape degradation, enhancing their oncogenic potential in vitro and in vivo. Despite the consequences of loss of Cbl-mediated negative regulation for human disease, little is known about the mechanisms regulating Cbl protein levels themselves. / In this thesis work, I demonstrate a differential regulation of c-Cbl and Cbl-b downstream of the Met receptor tyrosine kinase. Cbl-b protein levels decrease in response to Met kinase activity, whereas c-Cbl levels remain stable. Cbl-b is partially degraded in a proteasome-dependant manner. This requires Cbl-b ubiquitin ligase activity and a carboxy terminal domain region located between the RING and UBA domains. I conclude that the regulation of c-Cbl and Cbl-b differs downstream of Met, and propose that negative regulation of Cbl-b by a dysregulated Met receptor may contribute to tumourigenesis.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 5 uppsatser.

Thesis (Ph.D.) -- University of Texas Southwestern Medical Center at Dallas, 2005. / Not embargoed. Vita. Bibliography: 155-182.

No description available.

Dilated (DCM) and ischemic cardiomyopathies (ICM) are associated with cardiac remodeling, where the ubiquitin–proteasome system (UPS) holds a central role. Little is known about the UPS and its alterations in patients suffering from DCM or ICM. The aim of this study is to characterize the UPS activity in human heart tissue from cardiomyopathy patients. Myocardial tissue from ICM (n = 23), DCM (n = 28), and control (n = 14) patients were used to quantify ubiquitinylated proteins, E3-ubiquitin-ligases muscle-atrophy-F-box (MAFbx)/atrogin-1, muscle-RING-finger-1 (MuRF1), and eukaryotic-translation-initiation-factor-4E (eIF4E), by Western blot. Furthermore, the proteasomal chymotrypsin-like and trypsin-like peptidase activities were determined fluorometrically. Enzyme activity of NAD(P)H oxidase was assessed as an index of reactive oxygen species production. The chymotrypsin- (p = 0.71) and caspase-like proteasomal activity (p = 0.93) was similar between the groups. Trypsin-like proteasomal activity was lower in ICM (0.78 ± 0.11 µU/mg) compared to DCM (1.06 ± 0.08 µU/mg) and control (1.00 ± 0.06 µU/mg; p = 0.06) samples. Decreased ubiquitin expression in both cardiomyopathy groups (ICM vs. control: p < 0.001; DCM vs. control: p < 0.001), as well as less ubiquitin-positive deposits in ICM-damaged tissue (ICM: 4.19% ± 0.60%, control: 6.28% ± 0.40%, p = 0.022), were detected. E3-ligase MuRF1 protein expression (p = 0.62), NADPH-oxidase activity (p = 0.63), and AIF-positive cells (p = 0.50). Statistical trends were detected for reduced MAFbx protein expression in the DCM-group (p = 0.07). Different levels of UPS components, E3 ligases, and UPS activation markers were observed in myocardial tissue from patients affected by DCM and ICM, suggesting differential involvement of the UPS in the underlying pathologies.

Die Herzinsuffizienz ist aufgrund ihrer weltweit ansteigenden Prävalenz und den damit einhergehenden beträchtlichen Kosten im stationären sowie ambulanten Sektor von großer Relevanz für die globalen Gesundheitssysteme. Trotz multipler Möglichkeiten der pharmakologischen und chirurgischen Therapie ist die Mortalität weiterhin hoch. Die Etablierung neuer medikamentöser Behandlungsansätze ist daher von enormer Bedeutung und bedarf der Erweiterung des Verständnisses der pathophysiologischen Grundlagen der Erkrankung. Kardiomyopathien zählen zu den häufigsten Ursachen der Herzinsuffizienz. Dysfunktionen des Ubiquitin-Proteasom-Systems (UPS) wurden bereits in der Progression der Herzinsuffizienz bei Kardiomyopathien diskutiert und setzten einen potentiellen Fokus auf die E3-Ligasen. Diese Hypothese aufgreifend hatte die vorliegende Arbeit das Ziel, erstmalig den kompletten Myostatin/AKT/forkhead box protein (FOXO)-Signalweg und dessen Auswirkungen auf die E3-Ligasen muscle atrophy F-box gene (MAFbx) und muscle ring-finger protein-1 (MuRF1) im fortgeschrittenen humanen Kardiomyopathie-Stadium zu charakterisieren und mögliche neue Ansatzpunkte für die pharmakologische Therapie verschiedener Formen der Kardiomyopathie zu ermitteln. Zu diesem Zweck wurden Myokardproben von 26 Patienten mit ischämischer Kardiomyopathie (ICM), 23 Patienten mit dilatativer Kardiomyopathie (DCM) und 17 Kontrollpatienten molekularbiologisch, proteinbiochemisch und immunhistochemisch analysiert, um Veränderungen der Komponenten der Myostatin/AKT/FOXO-Signalkaskade und der E3-Ligasen MAFbx und MuRF1 zu identifizieren. Aus diesen Untersuchungen resultierten umfangreiche Alterationen des Signalwegs vor allem in DCM-Patienten. In dieser Gruppe war die Gen- und Proteinexpression der E3-Ligase MAFbx und des Transkriptionsfaktors FOXO1 gegenüber der Kontrollgruppe verringert. Weiterhin zeigte sich eine Reduktion von AKT auf der Genexpressionsebene und von Myostatin auf der Proteinebene in der DCM-Gruppe. Die ICM-Patienten wiesen mit Reduktionen der Genexpression von AKT und MAFbx sowie einem verringerten Anteil MuRF1-positiver Zellen in den immunhistochemischen Analysen nur geringe Unterschiede gegenüber der Kontrollgruppe auf. Die limitierten Veränderungen des Myostatin/AKT/FOXO-Signalwegs und der E3-Ligasen MAFbx und MuRF1 in ICM-Patienten lassen auf eine eher begrenzte Relevanz der Signalkaskade in der Pathophysiologie dieser Erkrankung schließen. Im Kontrast dazu stehen die detektierten Alterationen der analysierten Zielmoleküle in der DCM-Gruppe. Diese Divergenzen zeigen Unterschiede in der Pathogenese von ICM und DCM auf der Ebene des UPS. Daher unterstützt diese Arbeit die Hypothese, dass eine Therapieoptimierung dieser beiden Kardiomyopathien durch pharmakologische Adressierung verschiedener molekularer Ansatzpunkte erreicht werden könnte. In dieser Arbeit konnte die simultane Reduktion von MAFbx und FOXO1 in DCM-Patienten gezeigt werden. Durch die Validierung dieser synergistischen Regulation könnte FOXO1 einen potentiellen Angriffspunkt neuer medikamentöser Therapien der DCM darstellen. Unklar bleibt, ob die beobachtete Reduktion von MAFbx Ausdruck eines kardialen Schutzmechanismus oder der Progression des pathologischen Remodelings ist. Daher müssen weiterführende Studien klären, ob die E3-Ligase MAFbx über die therapeutische Beeinflussung des Transkriptionsfaktors FOXO1 herauf- oder herabreguliert werden sollte. Die Ergebnisse der vorliegenden Arbeit geben zudem einen Hinweis darauf, dass die Regulation von FOXO1 und MAFbx in DCM-Patienten nicht allein von Myostatin und AKT abhängig ist. Die Betrachtung weiterer Einflussfaktoren von MAFbx und FOXO1 in humanem Herzmuskelgewebe könnte somit ebenfalls Gegenstand zukünftiger Forschungsvorhaben sein. / Disturbances in the ubiquitin proteasome system, and especially changes of the E3 ligases, are subjects of interest when searching for causes and therapies for cardiomyopathies. The aim of this study was to clarify whether the myostatin/AKT/forkhead box O (FOXO) pathway, which regulates the expression of the E3 ligases muscle atrophy F-box gene (MAFbx) and muscle ring-finger protein-1 (MuRF1), is changed in dilated cardiomyopathy of ischemic origin (IDCM) and dilated cardiomyopathy of non-ischemic origin (NIDCM). The mRNA and protein expression of myostatin, AKT, FOXO1, FOXO3, MAFbx and MuRF1 were quantified by real-time polymerase chain reaction and ELISA, respectively, in myocardial tissue from 26 IDCM and 23 NIDCM patients. Septal tissue from 17 patients undergoing Morrow resection served as a control. MAFbx and FOXO1 mRNA and protein expression (all p < 0.05), AKT mRNA (p < 0.01) and myostatin protein expression (p = 0.02) were decreased in NIDCM patients compared to the control group. Apart from decreases of AKT and MAFbx mRNA expression (both p < 0.01), no significant differences were detected in IDCM patients compared to the control group. Our results demonstrate that the myostatin/AKT/FOXO pathway is altered in NIDCM but not in IDCM patients. FOXO1 seems to be an important drug target for regulating the expression of MAFbx in NIDCM patients.

Nierenzellkarzinome (RCC) gehören zu den häufigsten malignen Tumoren weltweit. Aufgrund der alarmierend hohen Inzidenz- und Sterberate besteht ein dringender Bedarf an neuen therapeutischen Targets zur Behandlung von RCCs. Punktmutationen in der Codesequenz von Proteinen führen zu einer Anhäufung von fehlgefalteten Proteinen in Tumorzellen und erfordern eine stärkere Kontrolle der Proteinqualität. Das Ubiquitin-Proteasome-System (UPS) bietet daher ein ideales therapeutisches Target für die RCC Therapie. Aktuelle Veröffentlichungen deuten auf eine Deregulation des COP9 Signalosome (CSN)-Cullin-RING-Ubiquitin-Ligase-(CRL)-Signalweges hin, einem Bestandteil des UPS. In der vorliegenden Arbeit wurden ausgewählte Komponenten des CSN-CRL Signalweges im RCC Gewebe und in vier RCC Zelllinien untersucht. In immunohistochemischen Studien am klarzelligen RCC-Gewebe konnte keine Hochregulierung einer einzelnen CSN-Untereinheit gezeigt werden. Höchstwahrscheinlich ist der gesamte CSN-Komplex im klarzelligen Nierenkarzinom im Vergleich zu nicht-malignem Nierengewebe stärker exprimiert. Die Untersuchung von vier RCC-Zelllinien zeigte eine interessante Deregulierung der CAND1-Skp2-p27 Achse in einer der Zelllinien. 786-O Zellen wiesen zwei p27Kip1 (p27) Varianten (p27V109G und p27I119T), eine Erhöhung des Skp2 und eine Reduktion des CAND1 Levels auf. Die Expression und Lokalisation von CAND1 wurde weiter in einer größeren RCC-Kohorte untersucht. Dabei zeigte sich eine negative Korrelation zwischen einer hohen zytosolischen CAND1 Expression und dem Gesamtüberleben von Patienten mit klarzelligen renalen Tumoren. Beide p27 Varianten werden durch das UPS abgebaut und binden an das CSN, Skp2, Cdks sowie an Cyclin E. Interessanterweise zeigte die p27 Mutanten beinhaltende Zelllinie 786-O eine höhere Proliferationsrate als die p27-Wildtyp-Zelllinie A498. In einem im Rahmen dieser Arbeit entwickelten Genotypisierungs-Assay konnte eine große RCC-Kohorte nach den beiden p27-Mutanten untersucht werden. In 42,5% der RCC Patienten konnte die Mutante p27V109G heterozygot nachgewiesen werden. Die Präsenz der beiden Mutanten p27V109 und p27I119T im RCC-Gewebe sowie die veränderte Expression von Skp2 und CAND1 machen den CSN-CRL Signalweg zu einem attraktiven therapeutischen Target für die Behandlung von Patienten mit Nierenzellkarzinom. / Renal cell carcinomas (RCC) belong to the most common malignant tumors worldwide. Alarming high incidence and mortality rates elucidate the urgent need for new therapeutic targets in RCCs. Point mutations in protein coding sequences lead to numerous unfolded proteins in cancer cells, requiring effective protein quality control. Therefore, components of the ubiquitin proteasome system (UPS) might be a promising new approach for RCC therapy. Recent publications in renal cancers point to a deregulated COP9 signalosome (CSN)-Cullin-RING Ubiquitin Ligase (CRL) pathway, a segment of the UPS. In the present thesis, selected components of the CSN-CRL pathway were studied in RCC tissues and four RCC cell lines. Immunohistochemistry results did not show an overexpression of a single CSN subunit in clear cell RCC tissues (ccRCC). However, it seems that the CSN holo complex is upregulated in analyzed ccRCCs. Examination of four RCC cell lines revealed a deregulation of the CAND1-Skp2-p27 axis in 786-O cells. These cells harbor two p27Kip1 (p27) mutants (p27V109G and p27I119T), high Skp2 and decreased CAND1 levels. Expression and localization of CAND1 was studied in a larger cohort of RCC tissues and revealed high cytosolic levels of CAND1 to be negatively correlated with overall survival in ccRCC patients. Both p27 variants were found to be degraded by the UPS and bound to the CSN, Skp2, Cdks and cyclin E. Interestingly, 786-O cells appear to grow 3-fold faster than A496 cells expressing p27wt. Further, a large cohort of RCC was screened for both p27 variants using a genotyping assay, specifically designed within the present thesis. 42.5% of the RCC patients harbor p27V109G heterozygously. The occurrence of p27V109G and p27I119T in RCC tissues as well as changed expression of Skp2 and CAND1 make the CSN-CRL pathway an attractive therapeutic target for the treatment of patients with RCC.