The purpose of this study was to assess the prognostic significance and clinical correlations of cyclooxgenase-2 expression (COX) in a cohort of patients treated with radiation (RT) for post-mastectomy chest wall relapse (PMCWR). Between 1975 and 1999, 113 patients were treated for isolated PMCWR. All patients were treated with biopsy and/or excision of the CWR followed by RT. Median follow-up was 10 years. All clinical data including demographics, pathology, staging, receptor status, HER-2/neu status, and adjuvant therapy were entered into a computerized database. Paraffin-embedded CWR specimens were retrieved from 42 patients, of which 38 were evaluated, created into a tissue microarray, stained by immunohistochemical methods for COX, and graded 0-3+. A score of 2-3+ was considered positive. Overall survival from original diagnosis for the entire cohort was 44% at 10 years. Survival rate after chest wall recurrence was 28% at 10 years. The distant metastasis-free survival rate after CWR was 40% at 10 years. Local-regional control of disease was achieved in 79% at 10 years after CWR. COX was considered positive in 13 of 38 cases. COX was inversely correlated with ER (p= .045) and PR (p = .028), and positively correlated with HER-2/neu (p =.003). COX was also associated with a shorter time to PMCWR. The distant metastasis-free rate for COX negative patients was 70% at 10 years, compared with 31% at 10 years for COX-2 positive patients (p = 0.029). COX positive had a poorer local-regional progression-free rate of 19% at 10 years, compared with 81% at 10 years for COX negative (p = 0.003). Outcome following RT for PMCWR is relatively poor. Positive COX correlated with other markers of poor outcome including a shorter time to local relapse, negative ER/PR and positive Her-2/neu status. Positive COX correlated with higher distant metastasis and lower local-regional control of disease. If confirmed with larger studies, these data have implications with respect to the concurrent use of COX-2 inhibitors and radiation for PMCWR.

Currently, opioids are extensively used in clinical practices in order to treat pain in patients. However, prolonged administration of opioids are not feasible due to the development of side effects especially tolerance, constipation, addiction and dependence. Our drug design is mainly aimed to reduce opioid induce side effects such as development of tolerance. The first strategy examined involves design and synthesis of peptide based single molecules that have a mu agonist and delta agonist pharmacophore in combination with a COX2 inhibitory pharmacophore. A new molecule, 3-17 having good delta agonist activity, partial COX2 inhibitory activity and weak mu agonist activity was produced. Moreover, Investigation of the bioactivities of the synthesized ligands including 3-17 in terms of their ligand receptor interactions were probed using NMR conformational analysis along with docking analysis to the respective homology modeled mu and delta opioid receptors as well as the COX2 enzyme. As a further continuation of this work, instead of peptide based mu agonist and delta agonist type pharmacophore, the highly mu selective fentanyl pharmacophore was used in combination with a pyrazole based and a pyrazolone based COX pharmacophore. Based on the SAR study and docking analysis of synthesized ligands to the homology modeled mu opioid receptor, an ideal tolerant position without significant loss of mu opioid agonist activity for fentanyl were found. The second strategy involves design and synthesis of a peptide based single molecule that has a mu agonist and a delta antagonist pharmacophore in combination with a NK1 antagonist pharmacophore. A novel molecule (4-2) containing delta antagonist activity, weak mu agonist activity and NK1 antagonist activity was identified. Its homology modeled mu opioid receptor bound conformation was compared with that of reference ligands. Docking analysis of modified 4-2 to the homology modeled mu opioid receptor revealed that it can be further modified to obtain better mu agonist activity. 4-2 showed antinociception for 45 min period of time after injection in tail flick assay. In addition to studies that were directed to avoid tolerance development due to opioid administration, peptide based potential analgesics such as biphalin was modified by introducing more peptidomimetic character in order to enhance its blood brain barrier permeability and proteolytic stability. The novel molecule (6-7) was produced in this study and its antinociception lasted for 30 min period of time after injection in the tail flick assay.

Made available in DSpace on 2016-05-02T13:54:42Z (GMT). No. of bitstreams: 1 DISSERTACAO COMPLETA ERICA SILVA BIANCHETTI.pdf: 401322 bytes, checksum: d859a5d12a9b16ecd28ee0fecfa86d09 (MD5) Previous issue date: 2006-06-01 / Conselho Nacional de Desenvolvimento Cientifico e Tecnologico / Etoricoxib is a new medicine expected to lead the next generation of selective inhibitors of COX-2 Presently the focus of many clinical assays it is a potent fast-action second generation coxib and the most selective of all The purpose of this study was to evaluate the interference of different nutritional diets in the anti-inflammatory and analgesic actions of etoricoxib and also the interactions of this NSAID plus different diets and their gastric and hematological side effects The following assays were carried out a) paw edema induced by carrageenin b) granuloma test c) dermatitis induced by croton oil d) vascular permeability in rats e) writhing test in mice f) formalin test g) gastric ulcers by stress and h) evaluation of the hematological parameters after sub-chronic treatment With regard to edema by carrageenin the etoricoxib-treated group showed a maximum peak of edema 49.04% (1.061 +- 0.1886) the other groups showed the following percentages of inhibiton etoricoxib + hyperproteic diet 30.2% (1.4537 +- 0.0955) etoricoxib + hyperlipidic diet 35.96% (64.04 +- 0.0578) etoricoxib + hyperglicidic diet 35.35% (1.346 +-0.0423) etoricoxib + standardized diet 33% (1.2968+-0.047) all of them in relation to the control group (2.0825+-0.1886) and the results were statistically significant (p < 0.01) However when the groups treated with etoricoxib associated to different diets were compared there was no statistically significant difference In the granuloma test the daily oral administration of 1 mg/kg of etoricoxib during 6 days significantly (p < 0.01) inhibited the formation of granulomatous tissue 57.02% (153.2 +- 21.908) the other groups showed the following percentages of inhibition etoricoxib + hyperlipidic diet 59% (144.98 +- 9.632) etoricoxib + hyperproteic diet 47.5% (185.575 +- 26.043) etoricoxib + hyperglicidic diet 38.5% (217.4 +- 21.318) etoricoxib + standardized diet 47.13% (166.583 2 +- 2.229) all of them in relation to the control group (353.475 +- 37.692) In the croton oil-induced dermatitis the edema of the control group had 10.33 mg The treatment with etoricoxib (1 mg/kg) associated with different nutritional diets showed inhibition of the edema but not significantly when compared to the control group The inhibition percentages were etoricoxib-treated group 7.86% (9.525 +- 1.345) etoricoxib + hyperproteic diet 31.43% (7.0875 +- 1.160) etoricoxib + hyperlipidic diet 35.6% (6.6625 +- 1.523) etoricoxib + hyperglicidic diet 39.5% (6.2571 +- 1.362) etoricoxib + standardized diet 30.7% (7.1875 +- 1.130) *p < 0.05 (Student s t test) when compared to the control group (10.3375 +- 1.462) In the vascular permeability by histamine etoricoxib (1 mg/kg) etoricoxib + hyperproteic diet etoricoxib + hyperlipidic diet etoricoxib + hyperglicidic diet and etoricoxib + standardized diet exhibited the following inhibition percentages 5.29% -31.4% -31.3% 4.05% and 15.82 respectively These results were not significant when compared to the control group (527.862 +- 66.869) In the writhing test the administration of etoricoxib (1mg/kg) inhibited the algogenic process in 9.32% (49.86 +- 4.166) When associated with different nutritional diets the inhibition percentages were hyperproteic diet 29.27% (38.9 +- 6.166) hyperlipidic diet 11.36% (48.75 +- 5.384) hyperglicidic diet 9.81% (49.6 +- 6.775) standardized diet -7.3% (59 +- 4.946) In the formalin test both in the acute and late phase all the treatments caused significant (p < 0.05) inhibitions of the hyperalgesic process etoricoxib (1mg/kg) 47.74% (62.71 +- 8.462) etoricoxib + hyperproteic diet 74.64% (30.428 +- 5.163) etoricoxib + hyperglicidic diet 68.61% (37.67 +- 5.308) etoricoxib + hyperlipidic diet 46.46% (64.25 +- 5.662) etoricoxib + standardized diet 68.2% (38.17 +- 5.528) when compared to the control group (120 +- 5.021) In the late phase the percentages of inhibition were 84.4% (10.142 +- 2.98) for etoricoxib 82.65% (11.28 +- 2.705) for etoricoxib + hyperproteic diet 66.16% (22 +- 11.781) for etoricoxib + hyperlipidic diet 98.72% (0.18 +- 0.0) for etoricoxib + hyperglicidic diet and 99.74% (0.16 +- 0.1667) for etoricoxib + standardized diet in comparison with the control group (65 +- 4.167) In the test of stress-induced ulcer the animals treated with etoricoxib (1mg/kg) + standardized diet showed the highest lesion index when compared to the other groups The lowest lesion index was shown by the group treated with etoricoxib + hyperlipidic diet whose significance was p < 0.01 (Student s t test) when compared to the control group The hematological parameters in the groups treated with etoricoxib (1mg/kg) + hyperlipidic diet (19.637 +- 3.879) and etoricoxib + hyperglicidic diet (19.3 +- 4.562) showed statistically significant differences in the hematocrit (HCT) in relation to the group treated only with etoricoxib (40.5375 +- 2.410) for p < 0.01 (Student s t test) There was a significant difference in the group treated with etoricoxib + hyperglicidic diet (8.9 +- 1.940) in relation to the group treated with etoricoxib (19.9 +- 2.134) (Student s t test) In the erythrocyte dosage the group etoricoxib + hyperglicidic diet (3.82125 +- 0.893) showed a significant difference when compared to the group treated with etoricoxib (9.4037 +- 1.027) (p < 0.01 Student s t test) No statistically significant differences were observed in the other hematological parameters The evaluation of the ponderal development of the animals treated with etoricoxib (1mg/kg) and etoricoxib assiciated with different kinds of nutritional diets showed no significant differences between the treated and control groups however the group treated with etoricoxib + hyperglicidic diet revealed lower ponderal development than the other groups With regard to diuresis there were variations in all the groups For water and feed consumption variations were practically similar in all the experimental groups The weight of the organs from different groups of animals treated with etoricoxib (1mg/kg) and etoricoxib associated with different nutritional diets showed no significant differences when compared to the control group The mean weight of the organs are within the normal parameters for rats The results suggest that a) the association of etoricoxib to different kinds of diets did not change the anti-inflammatory effect in the present assays b) the association of different types of diets potentialized the analgesic effect mainly when associated to hyperproteic diet for peripheral pain and hyperglicidic diet for central pain c) the association of etoricoxib to hyperglicidic diet decreases the gastric lesion index d) the use of etoricoxib alone did not interfere with the hematological parameters e) the association of etoricoxib to hyperglicidic diet interfered with the hemoglobin and erythrocyte index f) the treatment of the sub-chronic phase (30 days) with etoricoxib alone and etoricoxib associated to different nutritional diets caused no changes on the ponderal development diuresis and water and feed consumption / O etoricoxib (Arcóxia®) um medicamento novo posicionado para liderar a próxima geração de inibidores seletivos de COX-2 é um coxib de segunda geração potente e de ação rápida sendo motivo atualmente de muitos ensaios clínicos É o mais seletivo de COX-2 de todos os coxibs O objetivo deste estudo foi estudar em modelos in vivo a interferência sobre a atividade antiinflamatória e analgésica do etoricoxib antiinflamatório inibidor seletivo de COX-2 associado a diferentes tipos de dietas nutricionais observando as possíveis interações entre este AINE com as dietas empregadas e observar possíveis efeitos adversos ao nível gástrico e hematológico com o uso da associação do etoricoxib com as dietas nutricionais Para tanto foram utilizados os seguintes ensaios a) edema de pata por carragenina b) teste do granuloma c) dermatite induzida por óleo de croton d) permeabilidade vascular em ratos e) contorções em camundongos f) teste da formalina g) úlcera por estresse e h) avaliação dos parâmetros hematológicos após tratamento sub-crônico No edema por carragenina o grupo tratado com etoricoxib produziu inibição no pico máximo do edema de 49,04% (1.061 +- 0.1886) no tratado com etoricoxib + dieta hiperprotéica a inibição foi de 30,2% (1.4537 +- 0.0955) no tratado com etoricoxib + dieta hiperlipídica a inibição foi de 35,96% (64.04 +- 0.0578) no tratado com etoricoxib + dieta hiperglicidica a inibição foi de 35,36% (1.346 +- 0.0423) e no grupo tratado com etoricoxib + dieta padrão a inibição foi de 33% (1.3968 +- 0.047) todos em relação ao grupo controle (2.0825 +- 0.1886) apresentando resultados significativos estatisticamente (p < 0,01) Entretanto quando comparados entre si os grupos tratados com etoricoxib associado às diferentes dietas não houve diferença estatística significativa No teste do granuloma a administração diária de 1 mg/kg/v.o de etoricoxib durante 6 dias inibiu de forma significativa a formação do tecido granulomatoso (p < 0,01) em 57,02% (153.2 +- 21.908) e 59% (144.98 +- 9.632) pelo grupo tratado com etoricoxib + dieta hiperlipídica respectivamente no grupo tratado com etoricoxib + dieta hiperprotéica a inibição foi de 47,5% (185.575 +- 26.043) no tratado com etoricoxib + dieta hiperglicídica a inibição foi de 38,5% (217.4 +- 21.318) e no tratado com etoricoxib + dieta padrão foi 47,13% (166.583 2 +- 2.229) todas em relação ao grupo controle (353.475 +- 37.692) Na dermatite por óleo de cróton o edema no grupo controle foi de 10,33 mg Neste experimento observou-se que o tratamento dos animais com etoricoxib (1mg/kg) associado aos diferentes tipos de dietas nutricionais apresentou inibição do processo edematogênico mas não de forma significativa quando comparado com o grupo controle Para o grupo tratado com etoricoxib a inibição foi de 7,86% (9.525 +- 1.354) etoricoxib + dieta hiperprotéica foi de 31,43% (7.0875 +- 1.160) etoricoxib + dieta hiperlipídica foi de 35,6% (6.6625 +- 1.523) etoricoxib + dieta hiperglicídica foi de 39,5% (6.2571 +- 1.362) e etoricoxib + dieta padrão foi de 30.7% (7.1875 +- 1.130) *p < 0.05 ( teste t de Student) quando comparado ao grupo controle (10.3375 +- 1.462) Na permeabilidade vascular por histamina o etoricoxib (1mg/kg) etoricoxib + dieta hiperprotéica etoricoxib + dieta hiperlipídica etoricoxib + dieta hiperglicídica e etoricoxib + dieta padrão apresentaram inibições de 5,29% -18.4% -31.3% 4,05% e 15,82% respectivamente não sendo significativas quando comparados ao grupo controle (527.862 +- 66.869) No teste de contorções a administração de etoricoxib (1mg/kg) produziu 9,32% (49.86 +- 4.166) de inibição do processo algogênico e quando associado as diferentes dietas nutricionais a inibição foi de dieta hiperprotéica 29,27% (38.9 +- 6.166) dieta hiperlipídica 11,36% (48.75 +- 5.384) hiperglicídica 9,81% (49.6 +- 6.775) e dieta padrão 7,3% (59 +- 4.946) No teste da formalina tanto na fase aguda quanto na fase tardia todos os tratamentos produziram inibições significativas do processo hiperalgésico (p < 0.05) cujas percentagens de inibições foram de 47,74% para etoricoxib (1mg/kg) (62.71 +- 8.462) 74,64% para etoricoxib (1mg/kg) + dieta hiperprotéica (30.428 +- 5.163) 68,61% para etoricoxib (1mg/kg) + dieta hiperglicídica (37.67 +- 5.308) 46,46% para etoricoxib (1mg/kg) + dieta hiperlipídica (64.25 +- 5.662) e 68,2% para etoricoxib (1mg/kg) + dieta padrão (38.17 +- 5.528) quando comparados ao grupo controle (120 +- 5.021) Na fase tardia as percentagens de inibições foram de 84,4% (10.142 +- 2.98) para etoricoxib 82,65% (11.28 +- 2.705) para etoricoxib + dieta hiperprotéica 66,16% (22 +- 11.781) para etoricoxib + dieta hiperlipídica 98,72% (0,18 +- 0.0) para etoricoxib + dieta hiperglicídica e 99,74% (0.16 +- 0.1667) para etoricoxib + dieta padrão em comparação com o grupo controle (65 +- 4.167) No teste de úlcera por estresse observou-se que o tratamento dos animais com etoricoxib (1mg/kg) + dieta padrão foi o grupo que apresentou maior índice de lesão comparado aos outros grupos de tratamentos Já o grupo tratado com etoricoxib (1mg/kg) + dieta hiperglicídica foi o que apresentou menor índice de lesão cuja significância quando comparado ao grupo controle foi de p < 0.01 (teste t de Student) Os parâmetros hematológicos nos grupos tratados com etoricoxib (1mg/kg) + dieta hiperlipídica (19.637 +- 3.879) e etoricoxib + dieta hiperglicídica (19.3 +- 4.562) apresentaram diferenças estatisticamente significativas para o hematócrito (HCT) em relação ao grupo tratado apenas com etoricoxib (40.5375 +- 2.410) para p < 0.01 (teste t de student) Quanto à hemoglobina (HGB) foi significativa a diferença para o grupo tratado com etoricoxib + dieta hiperglicídica (8.9 +- 1.940) em relação ao grupo tratado com etoricoxib (19.9 +- 2.134) (p < 0.05, teste t de Student) Na dosagem de hemácias o grupo etoricoxib + dieta hiperglicídica (3.82125+- 0.893) apresentou diferença significativa quando comparada com o grupo tratado com etoricoxib (9.4037 +- 1.027) (p < 0.01, teste t de Student) Em relação aos outros parâmetros hematológicos não foram observadas diferenças significativas estatisticamente Na avaliação do desenvolvimento ponderal dos animais tratados com etoricoxib (1mg/kg) e etoricoxib associado aos diferentes tipos de dietas nutricionais não foram observadas diferenças significativas entre os grupos tratados e o controle entretanto o grupo tratado com etoricoxib + dieta hiperglicidica apresentou desenvolvimento ponderal menor que os outros grupos Em relação à diurese pôde-se observar ocorrência de variações em todos os grupos Para os consumos de água e ração houve variações praticamente semelhantes em todos os grupos experimentais Quanto ao peso dos órgãos dos diferentes grupos de animais tratados com etoricoxib (1mg/kg) e etoricoxib associado a diferentes dietas nutricionais não apresentaram diferenças significativas quando comparados ao grupo controle O peso médio dos órgãos encontram-se dentro dos parâmetros normais para a espécie animal (ratos) A partir dos resultados obtidos pode-se sugerir que a) A associação do etoricoxib aos diferentes tipos de dietas empregadas não alterou o efeito antiinflamatório nos ensaios empregados b) A associação do etoricoxib aos diferentes tipos de dietas empregadas potencializou o efeito analgésico principalmente quando associado à dieta hiperprotéica para dor periférica e dieta hiperglicídica para dor central c) A associação do etoricoxib à dieta hiperglicídica diminui o índice de lesão gástrica d) O tratamento com etoricoxib isolado não interferiu sobre os parâmetros hematológicos avaliados e) A associação do etoricoxib à dieta hiperglicídica provocou interferência sobre a taxa de hemoglobina e hemácias f) O tratamento em fase sub-crônica (30 dias) com etoricoxib e etoricoxib associado às diferentes dietas nutricionais não produziu alterações sobre o desenvolvimento ponderal diurese consumo de água e ração

HINTERGRUND: Gastrointestinale Nebenwirkungen unter NSAR, ASS und Phenprocoumon spielen eine bedeutende Rolle im klinischen Alltag. Im Rahmen der Einführung der COX-2 Inhibitoren sollten relevanten Ursachen für Ulcera und Blutungen im Bereich des oberen Gastrointestinaltraktes dargestellt und die Behandlungsstrategien verschieden ausgerichteter Krankenhäuser im klinischen Alltag verglichen werden. METHODEN: Es wurden stationär gastroduodenoskopierte Patienten einer Rheumaklinik und von Krankenhäusern der Grund- und Regelversorgung unter der Therapie mit NSAR, ASS, Phenprocoumon, Glukokortikoiden und COX-2 Inhibitoren im Rahmen einer offenen, multizentrischen Fallkontrollstudie verglichen. Des Weiteren wurden alle Patienten mit einer oberen gastrointestinalen Blutung oder einem Ulcus im Bereich des oberen Gastrointestinaltraktes in die Studie eingeschlossen. Der Einfluss einer Helicobacter pylori Infektion und einer Magenschutzprophylaxe wurde überprüft. ERGEBNISSE: Die höchsten Ulcusraten traten unter der Kombinationstherapie von NSAR und ASS auf. Patienten mit NSAR oder ASS hatten eine Ulcusrate von 35% bzw. 31%. Die Blutungsrate der Patienten mit ASS lag jedoch um 15% höher. Die COX-2 Inhibitoren zeigten mit einer Ulcusrate von 10% deutlich bessere Ergebnisse. Patienten mit einer Helicobacter pylori Besiedlung hatten eine signifikant erhöhte Ulcusrate (48% zu 34%), zeigten aber keine Unterschiede in der Blutungsrate. Der Anteil der Patienten mit einer Magenschutzprophylaxe betrug nur 17%. Die Blutungsrate der Patienten ohne Magenschutz lag bei 87%. SCHLUSSFOLGERUNGEN: Im klinischen Alltag einer rheumatologischen Fachklinik treten gehäuft Ulcera unter NSAR auf. Unter den COX-2 Inhibitoren zeigte sich eine geringere Ulcusrate. Im Unterschied dazu haben in den Krankenhäusern der Regel -und Grundversorgung die Patienten mit einem Ulcus an erster Stelle eine Therapie mit ASS. Eine konsequent durchgeführte Magenschutzprophylaxe mit Protonenpumpeninhibitoren verhindert das Auftreten von gastrointestinalen Ulcera und Blutungen. / BACKGROUND: Gastrointestinal side effects under NSAR, ASS and Phenprocoumon play an important role in the clinical everyday life. In the context of the introduction of the COX-2 inhibitors relevant causes for ulcera and bleedings within the range of the upper gastrointestinal section should be represented and the treatment strategies of differently aligned hospitals in the clinical everyday life be compared. METHODS: Gastro duodenal syncopated in-patients of a hospital for rheumatic diseases and from state hospitals under the therapy with NSAR, ASS, Phenprocoumon, Glukokortikoiden and COX-2 inhibitors were compared within the context of an open, multi-centric drop control study. All patients with an upper gastrointestinal bleeding or an ulcus were included in the area of the upper gastrointestinal section of the study. The influence of a Helicobacter pylori infection and a stomach protection prophylaxis was examined. RESULTS: The highest ulcus rate arose under the combination therapy of NSAR and ASS. Patients with NSAR or ASS had a ulcus rate of 35% and 31% respectively. The bleeding rate of the patients with ASS was however around 15% higher. The COX-2 inhibitors showed clearly better results with an ulcus rate of 10 percent. Patients with a Helicobacter pylori colonization had a significantly increased ulcus rate (48% to 34%), however they showed no differences in the bleeding rate. The proportion of the patients with a stomach protection prophylaxis amounted to only 17 percent. The bleeding rate of the patients without stomach protection was 87%. CONCLUSIONS: In the clinical everyday life of a rheumatological specialized clinic ulcera under NSAR arise. Under the COX-2 inhibitors a smaller ulcus rate shows itself. In contrast to it, patients with an ulcus receive a therapy with ASS in the state hospitals. A consistently implemented stomach protection prophylaxis with proton pump inhibitors prevented the appearance of gastrointestinal ulcera and bleedings.

Mehrere Studien haben gezeigt, daß die Cyclooxygenase-2 (COX-2) eine bedeutende Rolle sowohl bei Entstehung als auch Progression maligner Tumoren spielt. COX-2-Inhibitoren werden bereits in klinischen Studien zur Krebstherapie getestet. COX-2 ist die induzierbare Isoform der Cyclooxygenase - dem Schlüsselenzym der Synthese von Prostaglandinen und anderen Eicosanoiden. Im Tier- und Zellkulturmodell konnten COX-Hemmer anti-Tumor-Effekte hervorrufen. Es ist jedoch unklar, ob diese Effekte durch Hemmung des COX-Enzyms oder durch COX-unabhängige Mechanismen vermittelt werden. Wir untersuchten daher die Auswirkung der COX-Inhibition zum einen durch den selektiven COX-2-Hemmer NS-398 sowie zum anderen durch COX-Isoform-spezifische RNA-Interferenz (RNAi) in zwei humanen Ovarialkarzinomzellinien (OVCAR-3 und SKOV-3). OVCAR-3 zeigte eine konstitutive COX-1-Expression und eine durch IL-1beta induzierbare COX-2-Expression. SKOV-3 war COX-1- und COX-2-negativ. IL-1beta führte bei OVCAR-3 zu einer vermehrten Produktion von Prostaglandin E2 (PGE2), die durch eine gegen die COX-2 gerichtete siRNA gehemmt werden konnte, wohingegen COX-1-siRNA keinen Effekt hatte. Das deutet darauf hin, daß die COX-2 die Hauptquelle von PGE2 in OVCAR-3 ist. 1mikroM NS-398 waren ausreichend, um die PGE2-Produktion und somit auch die COX-2 in OVCAR-3 zu inhibieren. Höhere Konzentrationen NS-398 (>10mikroM) hatten einen antiproliferativen Effekt. Auch in der COX-2-negativen Zellinie SKOV-3 trat diese Wachstumshemmung auf; sie war nicht durch exogene Zufuhr von PGE2 (10mikroM) reversibel. Durchflußzytometrische Zellzyklusanalyse ergab, daß der Wachstumshemmung in beiden Zellinien ein G0/G1-Zellzyklusarrest zugrunde liegt. Dagegen führten weder COX-1- noch COX-2-Ausschaltung durch RNAi zu ähnlichen Auswirkungen auf Proliferation bzw. Zellzyklus. Diese Ergebnisse zeigen, dass ein COX-2-unabhängiger Mechanismus für den durch NS-398 induzierten G0/G1-Arrest verantwortlich ist. / Several studies have provided evidence that the enzyme Cyclooxygenase-2 (COX-2) plays an important role in tumor development and progression. COX-2-inhibitors are already evaluated in clinical trials as cancer therapeutics. COX-2 is the inducible isoform of cyclooxygenase - the rate-limiting enzyme in the synthesis of prostaglandins and other eicosanoids. COX-inhibitors cause antitumor effects in animal models and in cell culture experiments. However, it is not clear, whether these effects are due to inhibition of the COX-enzyme or mediated via a COX-independent mechanism. We therefore investigated the effects of COX inhibition by the selective COX-2-inhibitor NS-398, as well as by COX-isoform specific RNA interference (RNAi) in the human ovarian carcinoma cell lines OVCAR-3 and SKOV-3. OVCAR-3 cells showed a constitutive expression of COX-1, and an inducible COX-2 expression. COX-2 was induced through stimulation with Interleukin-1beta, leading to production of high levels of Prostaglandin E2 (PGE2). SKOV-3 cells were negative for both COX isoforms. Selective COX-2-suppression by RNAi reduced PGE2 production in OVCAR-3, whereas COX-1-siRNA had no effect on PGE2 synthesis. Thus, COX-2 is the main source of PGE2 in OVCAR-3 cells. In these cells, 1microM NS-398 was sufficient to completely inhibit PGE2-synthesis - and thus the activity of the COX-2 enzyme. Increasing amounts of NS-398 (>10microM) had an antiproliferative effect. This growth inhibition was also observed in the COX-negative cell line SKOV-3, it could not be reverted by exogenous addition of PGE2 (10microM). Flowcytometric analysis of the cell cycle revealed that this growth inhibition was based on a G0/G1-cell-cycle-arrest. In contrast, suppression of COX-1 or COX-2 by RNAi had no effect on proliferation or cell cycle progression. These results suggest that a COX-independent mechanism is responsible for the G0/G1-arrest induced by NS-398.