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Mort cellulaire et modulation du clivage de la cadhérine N par un agoniste de PPARβ/δ dans un modèle de cancer de la vessie / Cell death and modulation ofN-cadherin cleavage by a PPARβ/δ agonist in bladder cancer mode!Pechery, Adeline 12 October 2016 (has links)
Le cancer de la vessie est le deuxième cancer urologique après le cancer de la prostate. Le développement de nouveaux agents anticancéreux est nécessaire pour le traitement de cette maladie complexe, car, en dépit d'un large éventail de traitements, aucune augmentation de la survie des patients n'a été observée. - Les effets du GW501516, un agoniste de PPARbeta/delta, n'ont jamais été explorés dans des cellules cancéreuses de la vessie. Nous montrons qu'un traitement par 25 µM de GW501516, pendant 24 h, induit la mort cellulaire par apoptose de cellules dérivées d'un carcinome urothélial invasif mais pas de cellules dérivées d'un cancer urothélial "de bon pronostic". Une stimulation de courte durée par 25 µM de GW501516 induit une augmentation du taux d'espèces réactives de l'oxygène (ROS) qui est associée à une phosphorylation de la protéine de survie Akt. L'apoptose induite par le GW501516 est concomitante à une diminution de l'expression d'une molécule d'adhérence, la cadhérine N qui est une protéine transmembranaire impliquée dans la progression tumorale. Pour la première fois dans un modèle de carcinome, nous montrons que la cadhérine N est la cible d'un clivage protéolytique, libérant des fragments solubles qui peuvent être biologiquement actifs. Le GW501516 module ce clivage à des temps qui précèdent la mort cellulaire. En effet, le GW501516 régule l'expression de protéases telles que ADAMIO à l'origine du clivage de la cadhérine N. - Les fragments de la cadhérine N pourraient intervenir dans les processus de survie ou de mort cellulaires. Par conséquent, cette étude novatrice ouvre le débat quant à la portée thérapeutique du GW501516 dans le traitement du cancer. / Bladder cancer is the most common cancer of the genitourinary tract worldwide and accounts for 5% of ail cancer deaths in human. Despite of a wide range of treatments, no substantial improvement in survival of patients with advanced-stage or metastatic disease has been achieved. The development of nove! effective chemotherapeutic agents is required for the treatment ofthis aggressive disease. Anticancer action of GW501516, an agonist of PPARbeta/delta, has never been investigated in bladder tumor cells. Our results indicated that a 24h treatment by 25 µM of GW501516 induced cell death through both extrinsic and intrinsic apoptotic pathways in T24 cells, derived from an undifferentiated high grade carcinoma but not in RT4 cells, derived from a low grade papillary tumor. GW501516 induced also an early up-regulation of ROS production which was associated with an increase ofphosphorylated Akt level, implicated in cell survival. Apoptosis induced by GW501516 is concomitant with a decrease of N-cadherin expression which is a cell adhesion molecule implicated in tumor progression. For the first time in carcinoma mode!, we showed that N-cadherin was cleaved by proteases, leading to the release of soluble fragments which could be biologically active. Our results indicated that GW501516 modulates N-cadherin cleavage before cell death through the regulation of protease expression such as ADAM l O. N-cadherin fragments could be implicated in cell survival or cell death. By inducing apoptosis of urothelial cancer ce lis and by modulating N-cadherin shedding, GW501516 could be a potential efficient chemotherapeutic drug for bladder cancer through endovesical instillations.
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Análise da expressão das metaloproteinases 2 e 9 e seus reguladores no câncer de bexiga / Expression of metalloproteinases 2 and 9 and their regulator genes in bladder cancerPiovesan, Luís Felipe 20 January 2012 (has links)
Introdução: O Carcinoma Urotelial de Bexiga (CUB) é o segundo tumor urológico mais prevalente no Brasil. Devido ao elevado custo médico no processo que envolve seu diagnóstico, tratamento e seguimento, o CUB é um dos tipos de tumores mais caros para os sistemas de saúde. Embora existam fatores prognósticos definidos, como o estadiamento patológico, a diferenciação histológica e a presença de invasão angiolinfática (IAL), os mesmos demonstram-se insuficientes para uma acurada definição de comportamento da doença. Com a evolução da pesquisa molecular um grande número de potenciais novos marcadores de agressividade tem surgido. As Metaloproteinases da matriz (MMP) sao proteínas teciduais, pertencentes à família das endoproteinases, que degradam vários componentes da matriz extracelular. A expressão de diversas MMPs, especialmente MMP-2 e MMP-9 (gelatinases), bem como seus ativadores e inibidores, tem sido estudada como potencial marcador de comportamento tumoral em várias neoplasias. Objetivos: Avaliarmos os níveis de expressão dos genes das gelatinases MMP-2 e MMP-9 no CUB, assim como proteínas envolvidas em suas vias de ativação e inibição (MMP-14, IL-8, TIMP-1, TIMP-2, RECK e TGF-! ). Material e Método: Estudamos pela técnica de qRT-PCR a expressão dos 8 genes em amostras de CUB de 40 pacientes submetidos a RTUb, tendo como grupo controle amostras de urotélio sem câncer de 6 pacientes submetidos a prostatectomia aberta por HPB, bem como sua relação com marcadores prognósticos clássicos (estádio, grau e IAL). Resultados: Houve uma superexpressão de MMP-9 na maioria das amostras de CUB, bem como subexpressão de MMP-2, TIMP-1, TIMP-2, MMP-14, IL-8, TGF-! e RECK. Comparando os níveis de expressão dos genes com o estádio patológico, houve uma superexpressão de MMP-9 nos tumores pT1-2, quando comparados com pTa (p=0,026), bem como maior expressão de IL-8 nos tumores pT1 e pT2 (p=0,015 e p=0,048, respectivamente). Embora estatisticamente nao significativa, houve uma superexpressão de MMP-14 nos tumores pT2, quando comparados aos demais (p=0,087). Com relação ao grau histológico, também identificamos superexpressão de MMP-9 nos tumores de alto grau, quando comparados aos de baixo grau (p=0,012), assim como maior expressão de IL-8 nos tumores de alto grau (p=0,003). Conclusão: Houve uma superexpressão de MMP-9 e uma subexpressão de MMP-2, TIMP-1, TIMP-2, MMP-14, RECK, IL-8 e TGF-! no CUB, quando comparado com o grupo controle. Também identificamos uma superexpressão de MMP-9 e IL-8 em tumores pT1-2 quando comparados com pTa e de alto grau quando comparados com baixo grau. A subexpressão dos principais inibidores da MMP-9 (TIMP-1 e RECK) pode explicar sua superexpressão no CUB, assim como a superexpressão de IL-8 nos tumores invasivos e de alto grau pode agir como fator ativador da MMP-9 nestes mesmos tumores / Introduction: Bladder cancer (BC) is the second most common urological tumor in Brazil. Because its high cost on diagnosis, treatment and follow-up, BC is one of the most expensive malignancies for health care providers. Although we have well-known prognostic factors, like pathological stage, histologic grade and lymphovascular invasion, they are insufficient to figure more accurate tumor aggressiveness. Recent molecular biology helped us to discover a huge amount of potential markers. Matrix metalloproteinases (MMP) are tissue endopeptidases that degrade components of extracellular matrix. Expression of several MMP, specially MMP-2 and MMP-9 (gelatinases), and their activators and inhibitors, are investigated as potential behavior markers in many neoplasms. Objectives: The aim of this study was to evaluate expression levels of gelatinases MMP-2 and MMP-9 genes by quantitative real-time polymerase chain reaction (qRT-PCR) in BC, as well as other proteins evolved in the activation and inhibition pathways (MMP-14, IL-8, TIMP-1, TIMP-2, RECK e TGF-b). Material and Method: Present study analyzed tissue expression of 8 genes in BC samples of transutethral resection of 40 patients by qRT-PCR, as well as their relation with current prognostic factors (stage, grade and LVI). The control group was composed of utothelial tissue from 6 patients with benign prostatic hyperplasia (BPH) treated surgically with retropubic prostatectomy. Results: In the tumor samples, MMP-9 presented an overexpression and MMP-2, TIMP-1, TIMP-2, MMP-14, RECK, IL-8, and TGF-b were underexpressed in BC tissue compared to control. Comparing gene level expression to pathologic stage, there was MMP-9 overexpression in pT1-2 tumors compared to pTa (p=0.026), as wall as IL-8 overexpression in pT1 and pT2 tumors (p=0.015 e p=0.048, respectively). Although not statiscally significant, there was MMP-14 overexpression in pT2 tumors in comparison to pTa-1 (p=0.087). About grade, there was MMP-9 overexpression in high-grade tumors compared to low-grade (p=0.012), as well as IL-8 overexpression in high-grade tumors (p=0.003). There was not relation of any gene expression to LVI. Conclusions: We found overexpression of MMP-9 and underexpression of MMP-2, TIMP-1, TIMP-2, MMP-14, RECK, TGF-b and IL-8 in BC compared with the control group. According to the prognostic factors we found increased levels of MMP-9 and IL-8 gene expression in pT1-2 compared to pTa tumors and high-grade compared to low-grade tumors. Underexpression of major MMP-9 inhibitors (TIMP-1 and RECK) could explain MMP-9 overexpression in BC, as well as IL-8 overexpression in high-grade and stage tumors could act as activation factor of MMP-9 in these tumors
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Engenharia de tecidos em bexiga urinária modelo em coelhos /Piovesana, Tadeu Ravazi January 2020 (has links)
Orientador: Matheus Bertanha / Resumo: Introdução: Diversas doenças congênitas ou adquiridas promovem alterações anatômicas ou funcionais, dificultando ou impossibilitando a função de reservatório da bexiga, ou até mesmo necessitando sua remoção cirúrgica. Quando as terapias conservadoras não são eficazes, algumas técnicas cirúrgicas podem ser empregadas para o aumento ou reconstrução da bexiga e por fim, o desvio urinário pode ser a única alternativa terapêutica. No entanto, todas as técnicas cirúrgicas atuais podem levar a complicações. A substituição de tecidos da bexiga por equivalentes criados em laboratório poderia melhorar o resultado da cirurgia reconstrutiva. Objetivos: Propor um modelo de remendo de bexiga urinária produzido com uso de veias descelularizadas e semeadas com células-tronco mesenquimais em modelo animal em coelhos. Material e Métodos: Foram constituídos dois grupos de 5 coelhos fêmeas não prenhas. Os dois grupos de animais foram submetidos a anestesia inalatória e foi realizada uma cirurgia para retirada de um fragmento de 1 cm2 de bexiga para implantação do produto de teste. Grupo 1: Controle – foi implantado um segmento de 1cm2 de veia cava de coelho descelularizada com pontos contínuos de Vicryl 7.0; Grupo 2: Experimento – foi implantado um segmento de veia cava descelularizada semeada com células tronco autólogas, também fixado por pontos cirúrgicos de Vicryl 7.0 com pontos contínuos. Para o grupo 2, foram coletadas células-tronco mesenquimais autólogas derivadas de tecido adiposo que f... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Background: Several congenital or acquired diseases promote anatomical or functional changes, making it difficult or impossible for the bladder reservoir function, or even requiring its surgical removal. When conservative therapies are ineffective, some surgical techniques may be used to increase or reconstruct the bladder, and ultimately, urinary diversion may be the only therapeutic alternative. However, all current surgical techniques can lead to complications. Replacement of bladder tissues with laboratory-created equivalents could improve the outcome of reconstructive surgery. Recent research involving stem cells and cell engineering points to a promising future based on regenerative and tissue replacement therapy. Objectives: To propose a model of urinary bladder patch produced with the use of decellularized veins and seeded with mesenchymal stem cells in an animal model in rabbits. To evaluate the biointegration of the graft implanted in the urinary bladder of rabbits after 21 days by histomorphological study of the explant. Methods: Two groups of 5 non-pregnant female rabbits were formed. Both groups of animals underwent inhalation anesthesia and surgery was performed to remove a 1 cm2 bladder fragment for implantation of the test product. Group 1: Control - a 1cm2 segment of decellularized rabbit vena cava with continuous Vicryl 7.0 stitches was implanted; Group 2: Experiment - a decellularized vena cava segment seeded with autologous stem cells was implanted, also f... (Complete abstract click electronic access below) / Mestre
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In-Hospital Outcomes after Radical Cystectomy for Bladder Cancer: Comparing National Trends in the United States and Germany from 2006 to 2014Groeben, Christer, Koch, Rainer, Baunacke, Martin, Borkowetz, Angelika, Wirth, Manfred P., Huber, Johannes 07 August 2020 (has links)
Background: Radical cystectomy (RC) still poses a significant risk for mortality and morbidity. Objectives: We compared in-hospital outcomes after RC in the United States and Germany using population-based data. Methods: We compared data from the US Nationwide Inpatient Sample to the German hospital billing database. Mortality and transfusion during hospital stay and length of stay (LOS) were evaluated. Results: In all, 17,711 (the United States) and 60,447 (Germany) cases were included. The share of robot-assisted RC increased to 20.5% in the United States vs. 2.3% in Germany (p < 0.001). In-hospital mortality was 1.9% (the United States) vs. 4.6% (Germany), transfusion rates were 34.2% (the United States) vs. 58.7% (Germany), and LOS was 10.7 (the United States) vs. 25.1 days (Germany; all p < 0.001). On multivariate analysis, higher patient age and lower annual hospital caseload were associated with increased mortality and longer LOS. Minimalinvasive surgery was associated with less blood transfusion and shorter LOS in the United States vs. hospital caseload and choice of urinary diversion in Germany. Conclusions: Healthcare systems might exert a relevant impact on outcomes of oncologic surgery. Increased in-hospital mortality rates in Germany seem to be partly explained by much longer LOS compared to those in the United States. Annual caseload seems to be influential on in-hospital outcomes raising the question of centralization of RC.
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Perineurální šíření pánevních nádorů: mechanismus a diagnostika / Perineural spread of pelvic tumors: mechanism and diagnosisČapek, Štěpán January 2021 (has links)
Perineural spread of pelvic tumors mechanism and diagnosis Abstract Neoplastic lumbosacral plexopathies are infrequent affections of the lumbosacral plexus. Cases with minimal or non-specific finding on imaging can be particularly puzzling to diagnose. We describe a series of patients with perineural spread from the site of the primary tumor along the visceral autonomous nerves to the lumbosacral plexus and further proximally to the spinal nerves and even intradurally and also distally to the sciatic nerve. On series of 17 patients diagnosed with perineural spread of pelvic malignancy we describe characteristic clinical presentation and imaging finding. In many of these cases a tissue biopsy is necessary to finalize the diagnosis. We describe operative technique of targeted fascicular biopsy of the sciatic nerve and our experience with this procedure. On series of 117 patients, we report the outcome and complication: diagnostic yield was 84.8% and complication rate was 2.7 %. If a tissue sample is needed to conclude the diagnosis, targeted fascicular biopsy does increase the yield at an acceptable complication rate. Perineural spread of pelvic cancer is a new clinical-pathological entity with an unknown natural history or ideal treatment strategy. Based on the imaging finding in this group we present a...
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Stend pro analýzu rekuperace energie v experimentálním vozidle / Test bench for analysis of energy recovery in experimental vehicleIndruch, Jiří January 2010 (has links)
The diploma thesis deals with design of an experimental test bench for recovery energy simulation at machines with hydrostatic energy transmission. This work describes choice of connection and selection of hydrostatic and other components. A first part of the thesis deals with calculation and design of the flywheel whose is its rotational kinetic energy corresponds in a certain scale to translational kinetic energy of the experimental vehicle. The thesis outlines the efficiency of transformation of rotational kinetic energy to pressure energy its accumulation and subsequent conversion back to rotational kinetic energy. Precise determination of the effectiveness of hydrostatic recovery is one of the objectives of experiments that will be implemented at the test bench. The task of the measurement and physical-technical analysis to be conducted at the manufactured test bench is primarily to obtain data at for the precise control of the hydrostatic energy recovery system to maximize its efficiency.
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Úloha buněčného metabolismu v karcinogenezi. Molekulární patofyziologie chemorezistence karcinomu močového měchýře / The Role of Cellular Metabolism in Carcinogenesis. Molecular Pathophysiology of Bladder Cancer ChemoresistanceKripnerová, Michaela January 2019 (has links)
Therapeutic resistance of tumours represents an important clinical issue. We can classify the therapeutic tumour resistance in two ways. According to the clinical course, tumours can behave either as primary resistant, i.e. from the very beginning not responsive, or they can display a secondary (also called acquired) resistance, whereby an initial clinical response is lost and the tumour develops into chemo-, radio- or immunoresistant disease. An alternative classification distinguishes cell autonomous resistance mechanisms from resistance that relies on complex interactions within the context of tumour microenvironment. From the research perspective, modelling therapeutic resistance frequently involves experimental treatment of sensitive cancer cells and selection of daughter resistant cell lines. The Ph.D. thesis includes derivation of two unique models of urothelial bladder carcinoma therapeutic resistance. The first model involves newly established urothelial carcinoma cell lines BC44 and BC44DoxoR, which resulted from a prolonged doxorubicin exposure of the mother cell line. The daughter chemoresistant cell line exhibits multidrug resistant phenotype, which extends beyond the selecting drug - doxorubicin - to four additional chemotherapeutic drugs (cisplatin, methotrexate, vinblastine, and...
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Bladder Tumor Recurrence after Primary Surgery for Transitional Cell Carcinoma of the Upper Urinary TractOehlschläger, Sven, Baldauf, Anka, Wiessner, Diana, Gellrich, Jörg, Hakenberg, Oliver W., Wirth, Manfred P. January 2004 (has links)
Objective: Primary transitional cell carcinoma (TCC) of the upper urinary tract represents 6–8% of all TCC cases. Nephroureterectomy with removal of a bladder cuff is the treatment of choice. The rates of TCC recurrence in the bladder after primary upper urinary tract surgery described in the literature range between 12.5 and 37.5%. In a retrospective analysis we examined the occurrence of TCC after nephroureterectomy for upper tract TCC in patients without a previous history of bladder TCC at the time of surgery.
Methods: Between 1990 and 2002, 29 patients underwent primary nephroureterectomy for upper tract TCC. The mean age of the patients was 69.5 years. In 5 cases upper urinary tract tumors were multilocular, in the remaining cases unilocular in the renal pelvis (n = 12) or the ureter (n = 12). The follow-up was available for 29 patients with a mean follow-up of 3.37 (0.1–11.2) years.
Results: 11/29 (37.9%) patients had TCC recurrence with 9/11 patients having bladder TCC diagnosed within 2.5 years (0.9–6.0) after nephroureterectomy. 13/29 patients are alive without TCC recurrence, 3/29 patients died due to systemic TCC progression and 5/29 died of unrelated causes without evidence of TCC recurrence.
Conclusion: Our data indicate a high incidence of bladder TCC after nephroureterectomy for primary upper tract TCC of up to 6 years after primary surgery. Because of the high incidence of bladder TCC within the first 3 years of surgery, careful follow-up is needed over at least this period. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
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The Value of Conventional Urine Cytology in the Diagnosis of Residual Tumour after Transurethral Resection of Bladder CarcinomasHakenberg, Oliver W., Franke, P., Fröhner, Michael, Manseck, Andreas, Wirth, Manfred January 2000 (has links)
Background: Transurethral resection leads to characteristic histological changes of tissue repair (’TUR cystitis‘), which also cause non-specific cytological changes. The aim of this study was to investigate the diagnostic sensitivity and specificity of conventional exfoliative urinary cytology in diagnosing residual urothelial carcinoma after differential transurethral resection. Patients and Methods: 417 urinary cytology specimens of all 374 patients undergoing primary (n = 326) or secondary (n = 91) transurethral resection of urothelial carcinoma of the bladder at our institution between June 1996 and December 1997 were examined. The cytology specimens were stained according to Papanicolaou’s method. The sensitivity and specificity of the cytologic diagnosis and of the tumour grading were compared with histological findings. Results: The overall sensitivity of urine cytology in tumour detection was 77.6% for primary lesions and 74.5% in the detection of residual carcinoma after transurethral resection. The diagnostic specificity was 77% and 84.3% respectively. The degree of sensitivity was dependent on tumour grade and was lower for well differentiated tumours. After transurethral resection, the sensitivity for grade 1 residual tumours was 11%, whereas it was 54% for grade 1 tumours before primary transurethral resection. Conclusions: The inflammatory changes following transurethral resection of primary bladder carcinoma cause reactive cytologic changes that make the diagnosis of well differentiated residual carcinoma more difficult. However, urinary cytology after transurethral resection has the same diagnostic accuracy for medium and poorly differentiated tumours as before primary resection and thus remains a very useful diagnostic tool. / Hintergrund: Transurethrale Resektionen von Blasentumoren führen zu histologischen Veränderungen («TUR Zystitis») im Sinne regenerativer Veränderungen, welche urinzytologisch zu diagnostischen Fehleinschätzungen führen können. Das Ziel unserer Untersuchung war der Vergleich der diagnostischen Sensitivität und Spezifität der Urinzytologie vor transurethraler Resektion mit der bei der Diagnose von Residualtumoren nach transurethraler Resektion. Patienten und Methoden: Untersucht wurden 417 urinzytologische Präparate von allen 374 Patienten, die in unserer Einrichtung zwischen Juni 1996 und Dezember 1997 einer primären (n = 326) oder sekundären (n = 91) transurethralen Resektion von Urothelkarzinomen der Harnblase unterzogen wurden. Die zytologischen Präparate wurden nach Papanicolaou gefärbt. Sensitivität und Spezifität der zytologischen Diagnostik und des Tumorgradings wurden mit den histologischen Befunden verglichen. Ergebnisse: Die Sensitivität der Urinzytologie in der primären Tumorerkennung lag bei 77,6% und die für die Diagnose von Residualtumoren nach transurethraler Resektion bei 74,5%. Die diagnostische Spezifität lag bei 77% bzw. 84,3%. Die Sensitivität war abhängig vom Differenzierungsgrad der Urothelkarzinome und war bei gut differenzierten Tumoren am niedrigsten. Nach transurethraler Resektion betrug die Sensitivität der zytologischen Diagnose für G1-Residualtumore lediglich 11%, während sie für G1-Primärtumore bei 54% lag. Schlußfolgerungen: Die entzündlichenVeränderungen nach transurethraler Resektion verursachen Veränderungen exfoliierter Urothelzellen, welche die zytologische Diagnose von residualen G1-Tumoren erschweren. Die Diagnose mäßig und schlecht differenzierter residualer Urothelkarzinome nach transurethraler Resektion hat dagegen die gleiche Sensitivität und Spezifität wie die bei primärer Untersuchung, so daß die Urinzytologie auch bei der Diagnose von Residualtumoren ein wertvolles diagnostisches Verfahren darstellt. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
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Small interfering RNA-vermittelte Hemmung der Apoptoseinhibitoren BCL2, BCL-XL, XIAP und Survivin in Zellkultur- und Mausmodellen des humanen HarnblasenkarzinomsKunze, Doreen 02 November 2011 (has links)
Das Harnblasenkarzinom (BCa) stellt in Deutschland die vierthäufigste Tumorneuerkrankung und die zehnthäufigste krebsbedingte Todesursache bei Männern dar. Nichtmuskelinvasive BCa werden organerhaltend aus der Blasenwand entfernt und zur Rezidiv- und Progressionsprophylaxe mittels intravesikaler Chemo- oder Immuntherapien behandelt. Trotz dieser adjuvanten Therapien, die mit starken Nebenwirkungen verbunden sein können, ist nur eine bedingte Minimierung des Rezidivrisikos möglich. Besonders im fortgeschrittenen Stadium weisen Harnblasenkarzinome eine schlechte Prognose auf. Obwohl das BCa eine chemosensitive Erkrankung darstellt, wird das Ansprechen auf lokale oder systemische Chemotherapien häufig durch auftretende Resistenzmechanismen limitiert. Daher stehen sowohl die Verbesserung konventioneller Chemotherapien als auch die Suche nach neuartigen Behandlungsstrategien im Fokus der experimentellen BCa-Forschung.
Die Apoptose, eine Form des programmierten Zelltodes, ist ein essenzieller, streng regulierter biologischer Prozess, welcher der Aufrechterhaltung der Gewebshomöostase und der gezielten, entzündungsfreien Eliminierung geschädigter Zellen dient. Fehlregulationen in den Apoptosesignalwegen stellen ein zentrales Ereignis in der Tumorgenese dar und tragen außerdem zur Entstehung von Chemo- und Radiotherapieresistenzen bei. Eine wichtige Rolle in der Apoptoseregulation spielen die Mitglieder der BCL2- und der Inhibitor of Apoptosis Protein (IAP)-Familien, deren wichtigste antiapoptotische Vertreter BCL2, BCL-XL, XIAP und Survivin häufig in Tumoren, einschließlich des BCa, überexprimiert sind.
Unter Verwendung von small interfering RNAs (siRNAs), synthetischen Nukleinsäurekonstrukten zur selektiven Geninhibition, wurde im Rahmen der Arbeit in vitro und in vivo untersucht, ob die Hemmung der Apoptoseinhibitoren BCL2, BCL-XL, XIAP und Survivin – allein und in Kombination mit Chemotherapie – eine Therapieoption zur Behandlung des BCa darstellen könnte. Da zur Tumorentstehung und -progression eine Vielzahl von genetischen Veränderungen beitragen, erscheint der Angriff eines einzelnen Zielgens unzureichend für eine effektive Tumortherapie. Aufgrund dessen wurde untersucht, ob durch simultane Reduktion der ausgewählten Apoptoseinhibitoren in BCa-Zellen stärkere wachstumsinhibitorische Effekte erzielt werden können.
In der vorliegenden Arbeit wurde gezeigt, dass insbesondere die siRNA-vermittelte Hemmung von BCL-XL und Survivin in den BCa-Zelllinien EJ28 und J82 antiproliferative Effekte hervorruft und diese Tumorzellen gegenüber einer nachgeschalteten Chemotherapie mit Mitomycin C oder Cisplatin sensitiviert. Hingegen bewirkte sowohl die transiente als auch die stabile RNAi-induzierte Hemmung von BCL2 und XIAP in den untersuchten BCa-Monolayerzellkulturen, möglicherweise infolge kontinuierlicher Versorgung der Tumorzellen mit Sauerstoff und Nährstoffen, keine Reduktion des Tumorwachstums.
Eine gegenüber den Einzelbehandlungen deutliche Verstärkung der antitumoralen und insbesondere der chemosensitivierenden Effekte in den BCa-Zelllinien wurde durch simultane Hemmung von BCL-XL und Survivin erzielt. Beispielsweise stieg der Anteil apoptotischer Zellen von 64 % nach Survivin-siRNA+Cisplatin-Behandlung auf 94 % nach gleichzeitiger BCL-XL+Survivin-Inhibition in Kombination mit Cisplatin. Folglich stellt die simultane Inhibition von BCL-XL und Survivin in Kombination mit Chemotherapeutika eine äußert viel versprechende BCa-Therapieoption dar. Tierexperimentelle Studien belegen die wachstumsinhibitorische Wirkung der Survivin-Reduktion und der kombinierten BCL-XL-siRNA+Chemotherapie-Behandlung, so wurde das Tumorendvolumen im Vergleich zur Kontrollbehandlung um 43 % bzw. um 48 % reduziert.
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