Thesis (M. Sc.)--University of British Columbia, 2005. / Includes bibliographical references (leaves 33-41).

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Malgré le développement de nouvelles thérapeutiques anti-tumorales telles que les anti-tyrosine kinases ou les traitements anti-angiogéniques, la mortalité par cancer reste élevée. Les nouvelles molécules associées aux progrès réalisés en chirurgie, en radiothérapie et en chimiothérapie ont permis d’allonger la durée de vie de ces patients permettant de mieux apprécier le retentissement, à long terme, de ces thérapeutiques sur le système cardiovasculaire. Il apparaît que la prescription de nombreuses chimiothérapies dont les anthracyclines conduisent à une altération de la fonction cardiaque. Les mécanismes physiopathologiques à l’origine de cette dysfonction cardiaque sont complexes, intriqués et restent partiellement méconnus. Afin de limiter cette cardiotoxicité, différentes voies portant sur les modalités d’administration, la galénique et la co-prescription de molécules à visée cardioprotectrice sont explorées. Une meilleure compréhension des phénomènes impliqués dans cette cardiotoxicité est donc nécessaire afin de prévenir son apparition. Il convient, par ailleurs, de préciser l’impact du cancer et des traitements anticancéreux sur le pronostic cardiovasculaire afin que ces patients bénéficient d’un suivi adapté. Dans la partie expérimentale de notre travail, les objectifs étaient d’étudier le stress oxydant plasmatique et tissulaire à court terme et à long terme après l’administration d’anthracyclines ainsi que les modifications de l’expression de certains gènes myocardiques secondaires à cette thérapeutique. Parallèlement, le caractère potentiellement cardioprotecteur des inhibiteurs de l’enzyme de conversion et de l’acide alpha-lipoïque était évalué. En accord avec la littérature, l’administration d’anthracyclines s’est accompagnée d’une augmentation du stress oxydant, aussi bien lors de l’évaluation à court terme qu’à long terme après l’arrêt du traitement. Une perturbation dans l’expression de différents gènes myocardiques a été constatée à distance de l’arrêt du traitement expliquant que la cardiomyopathie toxique induite par les anthracyclines puisse se révéler plusieurs années après l’interruption de cette chimiothérapie. Qu’il s’agisse des inhibiteurs de l’enzyme de conversion ou de l’acide alpha-lipoïque, ces molécules n’ont pas permis de prévenir l’atteinte cardiaque et le déséquilibre, espèces oxydantes/protections antioxydantes, qui accompagnent les effets des anthracyclines. Notre travail souligne la multiplicité et la complexité des mécanismes intervenant dans la cardiotoxicité des anthracyclines ainsi que la nécessité de nouvelles voies de recherche dans cette cardioprotection. La partie clinique de notre travail avait pour objectif de comparer la prise en charge, les caractéristiques et le pronostic de patientes hospitalisées pour un infarctus du myocarde et ayant antécédent de cancer du sein par rapport à des patientes sans antécédent de cancer du sein. Bien que notre étude précise que nos 2 populations étaient comparables en termes de facteurs de risques cardiovasculaires, de type d’infarctus, de technique de revascularisation et de thérapeutiques administrées lors de la phase aiguë, les patientes ayant un antécédent de cancer du sein semblent posséder un moins bon pronostic cardiovasculaire en post-infarctus du myocarde. L’existence d’un antécédent de cancer du sein apparaît comme un facteur indépendant de survenue d’événements cardiovasculaires rythmiques et non-rythmiques durant cette période. Ces nouvelles données doivent être confirmées par des études de plus grande taille mais montrent déjà la nécessité d’un suivi cardiovasculaire étroit de cette population de patients, aussi bien sur la plan ischémique que rythmique. / Despite the development of new anti-cancer drugs such as anti-tyrosine kinases or anti-angiogenic therapy, cancer mortality remains high. These new molecules associated with advances in cancer surgery, radiotherapy and chemotherapy have succeeded in improving life expectancy in these patients. It has also allowed a long-term evaluation of the cardiovascular impact of these therapies. Many chemotherapy drugs, such as anthracyclines, lead to impaired cardiac function. The pathophysiological mechanisms of this cardiac dysfunction are complex, intricate and remain partially unknown. To reduce this cardiotoxicity, different pathways concerning administration modalities, drug presentation and the co-prescription of cardioprotective molecules are being explored. Better understanding of the mechanisms involved in this cardiotoxicity is necessary to prevent its onset. Furthermore the impact of cancer and cancer treatment on cardiovascular outcomes must be clarified in order to ensure appropriate follow-up in these patients. In the experimental part of our work, the objectives were to study plasma and tissue oxidative stress in the short and long term after anthracycline administration and also changes in myocardial gene expression induced by this therapy. At the same time, the potential cardioprotective effect of angiotensin converting enzyme inhibitors and alpha-lipoic acid was evaluated. Consistent with the literature, the administration of anthracyclines induced an increase in oxidative stress, in both the short and long-term after the end of the treatment. A disturbance in myocardial gene expression was found a long time after the end of the treatment, which explains why anthracycline cardiomyopathy may appear years after discontinuation of the chemotherapy. Neither angiotensin converting enzyme inhibitors nor alpha-lipoic acid was able to prevent the imbalance in cardiac oxidant / antioxidant species. Our work highlights the many facets and complexity of anthracycline cardiotoxicity and the need for new research to prevent it. As for the clinical part, among female patients hospitalized for myocardial infarction, we compared the management, the characteristics and the prognosis in patients with a history of breast cancer with those in patients without a history of breast cancer. Although our populations were comparable in terms of cardiovascular risk factors, type of infarction, revascularization technique and treatment administered during the acute phase, patients with a history of breast cancer seemed to have a worse cardiovascular prognosis following the myocardial infarction. A history of breast cancer appears to be an independent factor of rhythm-related and non-rhythm-related cardiovascular adverse events during this period. These new data should be confirmed by larger studies, but they already show that patients treated with anthracyclines need specific cardiovascular monitoring for both ischemic and rhythm-related adverse events.

Diss. (sammanfattning) Stockholm : Karol. inst., 2004. / Härtill 6 uppsatser.

Les Anthracyclines (ex : Doxorubicine (Dox)) fréquemment utilisées en chimiothérapie anticancéreuse peuvent conduire à une cardiotoxicité aboutissant à de l’insuffisance cardiaque et à une cardiomyopathie dilatée. Au niveau cellulaire, la Dox est connue pour générer un stress oxydant fort, s’intercaler directement entre les brins d’ADN, inhiber les Topoisomérase II (TopII) ou encore provoquer une détresse énergétique conduisant à la mort aussi bien des cellules tumorales que des cardiomyocytes. Néanmoins, les voies de signalisations/mécanismes moléculaires complets ne sont pas identifiés à ce jour. L’objectif de ce travail de thèse consiste donc à mieux comprendre les mécanismes de la cardiotoxicité de la Dox et à identifier de nouvelles cibles cellulaires cardio-protectrices limitant les effets cardiaques délétères de cette Anthracycline. Dans ce but, nous focalisons nos recherches sur le rôle de la protéine EPAC1, un facteur d’échange pour les petites protéines G directement activé par l’AMPc, dans la réponse des cellules cardiaques à la Dox. EPAC1 est une protéine centrale de la voie de signalisation AMPc dans le cardiomyocyte en réponse à une stimulation β-adrénergique. Or, plusieurs études ont récemment montré l’implication de certains acteurs de cette voie (Rac, RhoA) dans la cardiotoxicité induite par la Dox faisant d’EPAC1 une cible thérapeutique potentielle. Nous avons donc étudié in vitro (cultures primaires de cardiomyocytes de rat nouveau-nés (Dox 1µM)) et in vivo (souris sauvages ou invalidées pour EPAC1 (Dox, iv, 12mg/kg total)) les effets de la Dox sur l’expression et l’activité d’EPAC1 et sur les voies de signalisation qu’il régule. In vivo, les souris sauvages traitées à la Dox développent une cardiomyopathie dilatée associée à une altération de l’homéostasie calcique 15 semaines après traitement. In vitro, la Dox induit des modifications de l’expression/activité d’EPAC1 et de l’homéostasie calcique, la formation de complexes TopIIβ/ADN conduisant à des dommages à l’ADN, une dérégulation de la biogénèse et de l’activité de la chaîne respiratoire mitochondriale et finalement à l’apoptose des cardiomyocytes. L’inhibition pharmacologique (Ce3F4, Esi09) ou génétique d’EPAC1 réduit l’ensemble des dommages cellulaires in vitro et empêche le développement de la cardiomyopathie dilatée in vivo. De manière importante, nous montrons que contrairement à ce qui est observé dans les cellules cardiaques, l’inhibition d’EPAC1 augmente la toxicité de la Dox envers les cellules tumorales et en particulier envers les cellules MCF-7 issues de cancer mammaire métastatique, principale indication de la Dox. Nos résultats suggèrent donc que l’inhibition d’EPAC1 semble être une stratégie thérapeutique prometteuse dans la prévention de la cardiomyopathie induite par les traitements anticancéreux à base d’Anthracyclines. / Doxorubicin (Dox) is an Anthracycline commonly used to treat many types of cancer; unfortunately this chemotherapeutic agent often induces side effects such as cardiotoxicity leading to cardiomyocyte death and dilated cardiomyopathy (DCM). This cardiotoxicity has been related to reactive oxygen species generation, DNA intercalation, topoisomerase II inhibition and bioenergetics alterations resulting in DNA damages and ultimately in cardiomyocyte death. Nevertheless, complete molecular mechanisms are not yet identified. Therefore, there is a need for new treatment options and strategies aiming at reducing Dox side effects in the heart. Among these mechanisms, EPAC1 (Exchange Protein directly Activated by cAMP) signaling could be worth investigating as EPAC1 indirectly activates small G proteins (Rac1 and Rho A), which are known to be involved in Dox-induced cardiotoxicity. Therefore, we have investigated the effect of Dox on EPAC1 signaling in both in vivo mice model (C57BL/6 vs EPAC1 KO mice, iv injections, 12mg/kg) and in vitro model (primary culture of neonatal rat cardiomyocytes (NRVM), Dox 1μM). In vivo, Dox-treated mice developed a DCM associated with Ca2+ homeostasis dysfunction. In vitro, Dox induced DNA damages and cell death associated with huge mitochondrial disorders, characterized by a decrease in mitochondrial biogenesis and respiratory chain activity. This cell death is associated with apoptotic features including mitochondrial membrane permeabilization, caspase activation, cell size reduction and relative plasma membrane integrity. We also observed that Dox led to a modification of the protein level and the activity of EPAC1 in the same manner to the cAMP level. By contrast, the inhibition of EPAC1, prevented DNA/TopIIβ complexes, decreased Dox-induced DNA damages, loss of mitochondrial membrane potential, apoptosis and finally cardiomyocyte death. Mitochondrial biogenesis and respiratory chain activity operated normally when EPAC1 was inhibited. These results were confirmed in vivo since Dox-induced cardiotoxicity was prevented in EPAC1 KO mice as evidenced by unaltered cardiac function (no DCM) at 15 weeks post-treatment. Interestingly, the protection conferred by EPAC1 inhibition was not transferred in human cancer cell lines treated by Dox. Inhibition of EPAC1 could thus be a valuable therapeutic strategy to limit Dox-induced cardiomyopathy during cancer chemotherapy.

Prior studies have demonstrated the effect of diazoxide in protecting against apoptosis via mitochondrial KATP channel opening in vitro. The current investigations are designed to determine if sildenafil, a phosphodiesterase-5 inhibitor and known mitochondrial KATP channel opener, would protect against chronic doxorubicin cardiomyopathy both in vivo and in vitro.Male ICR mice were randomized to 1 of 4 treatments: saline, sildenafil (0.7 mg/kg IP), doxorubicin (5 mg/kg IP), and sildenafil (0.7 mg/kg IP)+doxorubicin. Apoptosis was determined using the terminal deoxynucleotidyl transferase mediated dUTP nick-end labeling and in situ oligo ligation methods. Desmin distribution was determined via immunofluorescence. Bcl-2 was analyzed by Western blot. Left ventricular function was measured in Langendorff mode. Electrocardiographical analysis measured changes indicative of doxorubicin cardiotoxicity (ST-prolongation). In vitro studies using adult ventricular cardiomyocytes were exposed to doxorubicin (1 μM), sildenafil (1 μM) with or without NG-nitro-L-arginine methyl ester (L-NAME; 100 μM), or 5-hydroxydecanoate (5-HD; 100 μM) 1 hour before doxorubicin and incubated for 18 hours. Doxorubicin-treated mice demonstrated increased apoptosis and desmin disruption, which was attenuated in the sildenafil+doxorubicin group. Bcl-2 decreased in the doxorubicin group but was maintained at basal levels in the sildenafil+doxorubicin group. Left ventricular developed pressure and rate pressure product were significantly depressed in the doxorubicin group but attenuated in the sildenafil+doxorubicin group. ST-interval significantly increased in the doxorubicin group over 8 weeks. In the sildenafil+doxorubicin group, ST-interval remained unchanged from baseline. Doxorubicin significantly increased apoptosis, caspase-3 activation, and disruption of mitochondrial membrane potential in vitro,. In contrast, sildenafil significantly protected against doxorubicin cardiotoxicity; however, protection was abolished by both L-NAME and 5-HD. Cell viability studies using spectrophotometer and flow cytometric techniques demonstrated that sildenafil did not affect the antitumor efficacy of doxorubicin in PC-3 cells in vitro. In fact, flow cytometry data indicate that sildenafil, when combined with doxorubicin, was synergistic in the antineoplastic action of doxorubicin. Prophylactic treatment with sildenafil prevented apoptosis and left ventricular dysfunction in a chronic model of doxorubicin-induced cardiomyopathy. Moreover, these studies provide relevant clinical data on the safety and efficacy of sildenafil, leading the way for clinical trials in humans receiving doxorubicin chemotherapy.

Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Biochemical Sciences Candidate: Lucie Gavurová Supervisor: PharmDr. Anna Jirkovská, PhD. Title of diploma thesis: Antiproliferative and cardioprotective activity of novel dexrazoxane analogues Anthracycline antibiotics (such as daunorubicin, doxorubicin or epirubicin) forms the basis of anticancer therapy in many hematological malignancies and solid tumors. However, their clinical use is limited by adverse effects. The most serious of these effects is chronic form of anthracycline-induced cardiotoxicity. Dexrazoxane is the only one clinically approved cardioprotective agent against anthracycline cardiotoxicity so far. Despite its well-evidenced cardioprotective effects, dexrazoxane use is very limited due to its possible adverse effects. The the synthesis of novel analogs of might contribute to understanding of the relationship between structure and effects of dexrazoxane. Finally, this approach could lead to the synthesis of structure with better pharmacological properties. The aim of this diploma thesis was to assess the antiproliferative activity of novel analogues of dexrazoxane (JR-281B, JR-311, JR-306A, JR-306B, JR-232 and JR-312B), and the study of the influence on the antiproliferative effect of anthracyclines....

Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Biochemical Sciences Candidate: Jana Kroupová Supervisor: PharmDr. Anna Jirkovská, Ph.D. Title of diploma thesis: The effect of the proteasome inhibition of the antiproliferative effect of anthracycline antibiotics Anthracycline antibiotics (daunorubicin, doxorubicin) belong to the most effective antitumor drugs. In current clinical practice they are used mostly in the combinations with either "classical" or new targeted antitumor drugs. The proteasome inhibitors (bortezomib and carfilzomib) are also viewed as a part of new "targeted" antitumor drugs. The proteasome is a multienzyme complex in eukaryotic cells which is responsible for intracellular degradation of proteins. The proteasome inhibitors have been largely used in the therapy of multiple myeloma, but their potential has been also studied in the case of other malignancies. Their use in the combination with anthracyclines could be a possible alternative in the therapy of some tumor illnesses, but the effect of combination of anthracyclines and proteasome inhibitors on tumor cells have not been sufficiently explained. The anthracycline therapy is also accompanied by serious adverse side effect - the cardiotoxicity, which potential could be influenced by the...

INTRODUÇÃO: Cardiotoxicidade é frequentemente associada ao uso crônico de doxorubicina (DOX) podendo levar a cardiomiopatia e insuficiência cardíaca. A identificação de miRNAs cardiotoxicidade-específicos e seu potencial como biomarcadores poderia fornecer uma ferramenta prognostica valiosa e uma potencial área de intervenção. METODOLOGIA: Este é um sub-estudo do ensaio clínico prospectivo \"Efeito do Carvedilol na Prevenção da Cardiotoxicidade Induzida por Quimioterapia\" (ensaio CECCY) no qual incluiu 56 pacientes do sexo feminino (idade 49.9±3.3) provenientes do braço placebo. Os pacientes incluídos foram submetidos à quimioterapia com DOX seguido por taxanos. Troponina cardiaca I (cTnI), fração de ejeção do ventrículo esquerdo (FEVE) e microRNAs foram mensurados periodicamente. RESULTADOS: Os níveis circulantes de miR-1, -133b, -146a e -423-5p aumentaram significativamente durante o tratamento (18.6, 11.5, 10.6 e 12.1-vezes respectivamente; p < 0.001) enquanto miR-208a e -208b foram indetectáveis. cTnI aumentou de 6.6 ± 0.3 para 46.7 ± 5.5 pg/ml (p < 0.001) enquanto FEVE tendeu a diminuir de 65.3±0.5 para 63.8±0.9 (p=0.053) após 12 meses; deis pacientes (17.9%) desenvolveram cardiotoxicidade. miR-1 foi associado a mudanças na FEVE (r2=0.363, p < 0.001) enquanto miR-1 e -133b foram associados a cTnI (r2 = 0.675 e 0.758; p < 0.001). Além disso, miR-1 antecipou a cardiotoxicidade e mostrou uma area sobre a curva maior que cTnI para discriminar pacientes que desenvolveram cardiotoxicidade daqueles que não desenvolveram (AUC = 0.849 e 456, p<0.001 e 0.663, respectivamente). CONCLUSÃO: Nossos dados sugerem miR-1 como um potencial novo biomarcador de cardiotoxicidade induzida por DOX em pacientes com câncer de mama. Estes resultados podem levar a novas estratégias de detecção precoce do risco de lesão cardíaca induzida por DOX bem como a introdução de uma nova área para intervenção / INTRODUCTION: Cardiotoxicity is frequently associated with the chronic use of doxorubicin (DOX) and may lead to cardiomyopathy and heart failure. Identification of cardiotoxicity-specific miRNA biomarkers could provide clinicians with a valuable prognosis tool and a potential area for intervention. METHODS: This is an ancillary study from the prospective trial \"Carvedilol Effect in Preventing Chemotherapy-Induced Cardiotoxicity.\" (CECCY trial) which included 56 female patients (49.9±3.3 age) from placebo arm. Enrolled patients were treated with DOX followed by taxanes. Cardiac troponin I (cTnI), left ventricle ejection fraction (LVEF) and miRNAs were measured periodically. RESULTS: Circulating levels of miR-1, -133b, -146a and -423-5p increased along the treatment (18.6, 11.5, 10.6 and 12.1-fold respectively; p < 0.001); miR-208a and -208b were undetectable. cTnI increased from 6.6±0.3 to 46.7 ± 5.5 pg/ml (p < 0.001) while LVEF tended to decrease from 65.3±0.5 to 63.8±0.9 (p=0.053) over 12 months; ten patients (17.9%) developed cardiotoxicity. miR-1 was associated to changes in LVEF (r2=0.363, p < 0.001) while miR-1 and -133b were associated to cTnI (r2 = 0.675 and 0.758; p < 0.001). Furthermore, miR-1 anticipated cardiotoxicity and showed greater area under the curve than cTnI to discriminate between patients who did and did not developed cardiotoxicity (AUC = 0.849 and 456, p < 0.001 and 0.663, respectively). CONCLUSION: Our data suggest circulating miR-1 as a potential new biomarker of DOX-induced cardiotoxicity in breast cancer patients. These results may lead to new earlier strategies to detect drug-induced cardiac injury risk before it develops to an irreversible stage or introduce new area for intervention