Whilst progress has been made in reducing mortality in some cancers, mortality rates remain high in many cancers and there is a need to develop novel therapeutic strategies. In this thesis, various pharmacological strategies designed to enhance the activity of existing therapeutic drugs were evaluated. Cancer cells are dependent upon aerobic glycolysis (the Warburg effect) and glutamine uptake. Using clinically approved tyrosine kinase inhibitors and Bortezomib, significant enhancement of chemosensitivity was observed when used in combination with inhibitors of lactate dehydrogenase (Gossypol) and pyruvate kinase dehydrogenase (Dichloroacetate). In contrast, depletion of glutamine from media had to be extensive in order to induce cell death and cell death only occurred after prolonged exposure to glutamine-deprived conditions. This suggests that glutamine depletion strategies alone are unlikely to be successful but may be useful in combination with other agents targeting glutamine addiction in cancer cells. Finally, Temozolomide (TMZ) is an important drug in the treatment of glioblastomas but its activity is reduced by resistance mechanisms including O6 methyl guanine methyltransferase (MGMT) and mismatch repair (MMR). This thesis has identified analogues of TMZ (EA02-45, EA02-59, EA02-64 and EA02-65) that are MGMT and MMR independent in terms of inducing cell kill in vitro. These compounds are promising leads for future development. In conclusion, this thesis has demonstrated that interfering with the metabolic phenotype of cancer can enhance the activity of existing drugs and identified novel analogues of TMZ that circumvent drug resistance mechanisms that hamper the efficacy of TMZ.

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Le sarcome de Ewing est la seconde tumeur pédiatrique de l’os la plus fréquente. Elle est caractérisée par une translocation chromosomique résultant à la fusion de EWSR1 avec un membre de la famille ETS. Chez 85% des patients, cette fusion conduit à l’expression de la protéine chimérique EWS-FLI1 qui est l’oncogène majeur de ce sarcome. Ce dernier agit principalement par son action transcriptionelle sur des cibles qui lui sont propres. Au niveau thérapeutique, le sarcome d’Ewing est traité par chimiothérapie, chirurgie locale et par radiothérapie. La survie à long terme des patients est de l’ordre de 70%, mais beaucoup plus basse pour les patients métastatiques et quasi nulle lors d’une récidive. Parmi maintes caractéristiques, certains cancers présentent une dérégulation énergétique. L’influence d’EWS-FLI1 sur cet aspect n’a fait l’objet d’aucune étude dans le contexte du sarcome d’Ewing. Nous avons donc étudié par profilage métabolomique des cellules de sarcome d’Ewing en présence ou en absence d’EWS-FLI1. En comparant ces deux conditions, des modulations du profil énergétique relatif au cycle de Krebs, des précurseurs de le glycosylation ainsi que des métabolites de la voie de la méthionine et du tryptophane ont été observés. En parallèle, grâce à un crible de banque de shRNAs réalisé dans des conditions expérimentales similaires à l’étude métabolomique (lignée d’Ewing avec ou sans EWS-FLI1), nous avons pu identifier des gènes présentant des caractéristiques « synthétique létales », c'est-à-dire tuant uniquement les cellules du sarcome d’Ewing en présence de son oncogène. / Ewing sarcoma, the second most commonly occurring pediatric bone tumor, is most often characterized by a chromosomal translocation between EWSR1 and FLI1. The gene fusion EWS-FLI1 accounts for 85% of all Ewing sarcoma and is considered the major oncogene and master regulator of Ewing sarcoma. EWS-FLI1 is a transcriptional modulator of targets, both directly and indirectly. Ewing sarcoma is aggressively treated with chemotherapy, localized surgery and radiation and has an overall survival of about 70%, however, survival for metastasis or relapsed cases remains low. One of the cancer hallmarks, metabolic deregulation, is most likely partly dependent on EWS-FLI1 in Ewing sarcoma cells. In order to get a better understanding of Ewing sarcoma biology and oncogenesis, it might be of high interest to investigate the influence of EWS-FLI1 in Ewing sarcoma cells. We therefore performed a global metabolic profiling of Ewing sarcoma cells with or without inhibition of EWS-FLI1. Several changes in the energy metabolism were observed throughout this study; the observed changes were consistent with an energy profile that moved from a cancer cell energy metabolism towards the energy metabolism of a more normal cell upon EWS-FLI1 inhibition, primarily based on the TCA cycle. Levels of TCA intermediates, glycosylation precursors, methionine pathway metabolites and amino acids, especially changes in the tryptophan metabolic pathway, were altered upon EWS-FLI1 inhibition. Parallel to this study, we performed a high-throughput synthetic lethality screen, in order to not only identify essential genes for cell survival and proliferation, but also to identify new synthetic lethal targets that could specifically target Ewing sarcoma cells carrying the EWS-FLI1 fusion gene.

Nous avons étudié les relations entre les différentes voies du métabolisme énergétique lors de la mise en place des effets Crabtree et Warburg. L’effet du glucose sur le métabolisme énergétique de S. cerevisiae se traduit dans un premier temps par une inhibition cinétique du métabolisme oxydatif (effet Crabtree). Après l’ajout de glucose aux cellules, nous avons mis en évidence l’accumulation d’un intermédiaire de la glycolyse, le F1,6bP. Ceci induit une diminution drastique du rapport G6P/F1,6bP. Or, il a été montré que le G6P stimule et le F1,6bP inhibe l’activité de la chaine respiratoire mitochondriale « in-situ ». L’utilisation de mutants et la modulation de ce rapport nous a permis de montrer que l’induction de l’effet Crabtree chez la levure Saccharomyces cerevisiae est dû à une diminution du rapport G6P/F1,6bP. Parallèlement, le glucose induit un réarrangement génétique qui à terme conduit à un effet Warburg. Nous avons mis en évidence une diminution, au cours du temps du contenu mitochondrial par effet de dilution, suite à un arrêt de la biogenèse mitochondriale (répression de HAP4). Nous avons pu montrer que cette diminution quantitative des OXPHOS est sans effet sur la synthèse d’ATP cellulaire. Ceci est dû à une augmentation du flux de synthèse d’ATP glycolytique. L’utilisation de mutants HAP4", nous a permis de montrer qu’il n’y a pas de lien simple entre prolifération et répression des OXPHOS. Bien que le flux glycolytique diminue dans les conditions de maintien des OXPHOS, ceci est sans effet notoire sur la vitesse de prolifération. Ceci est un rare exemple d’une situation biologique ou l’on observe un découplage entre métabolisme énergétique et prolifération. / We used the yeast Crabtree (+) model to study the relationships between the energy metabolism pathways during the implementation of the Warburg effect. The effect of glucose on S. cerevisiae energetic metabolism results initially in a kinetic inhibition of the oxidative metabolism (Crabtree effect). Rapidly after the addition of glucose, we found an accumulation of F1, 6bP. This induces a drastic reduction in the ratio G6P / F1,6bP. Moreover, it has been shown that G6P stimulates and F1,6bP inhibits the activity of the respiratory chain "in-vitro". Mutants and the modulation of this ratio allowed us to show that the induction of the Crabtree effect is due to a decrease in the G6P / F1,6bP ratio. In parallel with the implementation of the Crabtree effect, glucose induces a genetic rearrangement that leads to a Warburg effect. We showed a decrease over time of mitochondrial enzymatic equipment by dilution effect, due to a halt of mitochondrial biogenesis (transcriptional repression of HAP4). We have been able to show that this decrease in respiratory capacity has no effect on the cellular capacity for ATP synthesis. This is due to the increase in glycolytic ATP synthesis flux. Furthermore, the use of mutants where there is no repression of mitochondrial metabolism upon glucose addition allowed us to show that there is no simple link between OXPHOS activity and cell proliferation. i.e. Mitochondrial metabolism repression/high glycolytic flux is not mandatory to allow a rapid cell proliferation. This is a rare example where energetic metabolism and cell proliferation are uncoupled.

Le cancer du rein papillaire de type 2 (PRCC2) est un cancer très agressif avec un potentiel métastatique élevé et pour lequel il n’y a pas de traitement efficace. La forme héréditaire de PRCC2 est associée au syndrome rare de la léiomyomatose cutanéo-utérine héréditaire (HLRCC). HLRCC est due à une mutation germinale hétérozygote du gène Fumarate Hydratase (FH) qui code l'enzyme du cycle de Krebs, la Fumarase. Le déficit en fumarase induit l’accumulation de fumarate et active les voies de signalisation du facteur de transcription inductible par l’hypoxie (HIF) et des espèces réactives de l’oxygène (ROS). Néanmoins, aucune mutation du gène FH n’a été rapportée dans les cas de PRCC2 sporadiques. Le projet de recherche porte sur la caractérisation moléculaire des PRCC2 héréditaires et sporadiques. Notre analyse du transcriptome a identifié des différences entre les signatures moléculaires des PRCC2 héréditaires et sporadiques. Cependant, l’étude d’immunohistochimie n'a pas révélé de biomarqueurs potentiels. Les analyses bio-informatiques de profils d’expression génique ont révélé que les tumeurs PRCC2 héréditaires et sporadiques partagent une dérégulation de la voie principale NRF2/KEAP1. Il a été montré que la surexpression de AKR1B10 (Aldo-Keto Reductase Family 1 Membre B10) est la conséquence directe de l’activation de l'élément de réponse antioxydant (ARE). Finalement, nous avons établi un nouveau modèle in vitro de lignée cellulaire, NCCFH1 (FH-/-), issue d’un patient HLRCC. NCCFH1 représente une plateforme idéale pour les études fonctionnelles, métaboliques et thérapeutiques. Bortézomib pourrait être la meilleure alternative thérapeutique pour les patients avec PRCC2. / Papillary Renal Cell Carcinoma type 2 (PRCC2) is known to be a very aggressive type of kidney cancer with a high metastatic potential, poor outcome and absence of effective therapy. Hereditary form of PRCC2 is associated with rare hereditary leiomyomatosis and renal cell carcinoma (HLRCC). HLRCC is characterized by germline heterozygous mutations in the Fumarate Hydratase (FH) gene that encodes an enzyme of the Krebs cycle, Fumarase. It has been shown that the accumulation of fumarate induces activation of Hypoxia Inducible Factor (HIF) and ROS (Reactive Oxygen Species) pathways. Nevertheless, no FH gene mutation has been reported in sporadic PRCC2 tumors. The goal of this study is to better characterize hereditary and sporadic PRCC2. Our transcriptome analysis identified the set of genes that are differentially expressed between the two types of PRCC2. Subsequent immunohistochemistry screening did not reveal any potential diagnostics biomarkers. Further, the comprehensive computational analysis of gene profiling data revealed that hereditary and sporadic PRCC2 share the similar molecular signature with NRF2-KEAP1 axis deregulation as one of the major pathway in both forms. We demonstrated that over expression of Aldo-keto reductase family 1 member B10 (AKR1B10) is the direct consequence of the antioxidant response element (ARE) activation shared in hereditary and sporadic tumors. Finally, we have established FH-deficient cell line (NCCFH1) a new preclinical model of hereditary PRCC2. It presents the perfect platform for studying the metabolic features and testing new therapies for hereditary PRCC2, while bortezomib appears to be a potential efficient therapeutic option.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / O carcinoma epidermoide de esôfago (CEE) representa 90% dos casos de câncer de esôfago no Brasil. O CEE tem detecção tardia, um comportamento extremamente agressivo e baixa sobrevida, sendo, portanto, um alvo interessante para o estudo dos mecanismos envolvidos em sua carcinogênese, a fim de se identificar possíveis alvos terapêuticos ou marcadores moleculares que ajudem na prática clínica. Mudanças no metabolismo energético da célula tumoral parecem ter papel de destaque na transformação maligna. Sabe-se que células tumorais consomem glicose avidamente produzindo ácido lático, mesmo em condições de normóxia. Dentre os fatores que podem contribuir para o estímulo da glicólise em células tumorais destacam-se as alterações em enzimas da via glicolítica tais como: as piruvato-cinases M1 e M2 (PKM1 e PKM2), a hexocinase II (HKII), isofoma 1 do transportador de glicose, GLUT-1, e o fator de transcrição induzido por hipóxia (HIF1α), responsável pela transcrição das proteínas citadas. O objetivo do estudo é avaliar a relação entre a expressão de HIF1α, HK2, PKM2, PKM1 e GLUT-1 e dados clínico-patológicos no CEE. Para tal, foram avaliados tumores conservados em parafina de 44 pacientes com CEE matriculados no INCA e no Hospital das Clínicas de Porto Alegre. Além disso, foram coletadas amostras de biópsia de esôfago em 67 pacientes sem doença esofágica, que foram submetidos à endoscopia no Hospital Universitário Pedro Ernesto (HUPE). A expressão das proteínas foi avaliada nos tecidos por imuno-histoquímica, enquanto que a expressão do mRNA de GLUT-1 também foi avaliada nas amostras controle. Foi observado que as amostras controle expressam HK2, PKM1, PKM2, HIF1α nas camadas do epitélio esofágico. Já GLUT-1 e Ki-67 são vistos apenas na camada basal. Além disso, a expressão do mRNA de GLUT-1 não teve correlação com fatores etiológicos da doença. Em CEE a expressão de HK2, PKM2 e GLUT-1 foi vista em todos os tumores, já a expressão de HIF1α e PKM1 foi variável. Além disso, observou-se que maior expressão de HIF-1α apresenta correlação com invasão linfonodal e diferenciação, enquanto que a expressão de HK2 tem relação com sobrevida e PKM1 com diferenciação. As correlações clínicas encontradas sugerem que alterações no metabolismo energético é um alvo de estudo interessante para desenvolvimento de marcadores moleculares que auxiliem a prática clínica. / The esophageal squamous cell carcinoma (ESCC) represents 90% of cases of esophageal cancer in Brazil. The ESCC has late diagnosis, highly aggressive behavior and poor survival. ESCC is an interesting target to the study of mechanism involved in its carcinogenesis, in order to identify potential drug targets or biomarkers to help clinical practice. Changes in tumor cell energy metabolism appear to have a prominent role in malignant transformation. Tumor cells consume glucose avidly and produce lactic acid, even under normoxia. Among the factors that may contribute to the stimulation of glycolysis in tumor cells, there are changes in the glycolytic pathway enzymes such as: pyruvate kinase M1 and M2 (PKM2 and PKM1), hexokinase II (HKII), glucose transporter isoform 1, GLUT-1, and transcription factor induced by hypoxia (HIF1α), responsible for the transcription of proteins cited. The goal of the study is to evaluate the relationship between the expression of HIF1α, HK2, PKM2, PKM1 and GLUT-1 and clinicopathological data in ESCC. Biopsy of the esophagus in patients without esophageal disease were collected, who underwent endoscopy at University Hospital Pedro Ernesto (HUPE). Tissue samples were collected from 44 patients with a histologically confirmed diagnosis of ESCC recruted from Hospital Universitário Pedro Ernesto (HUPE-UERJ), and Instituto Nacional de Câncer (INCA). Tissue samples from healthy individuals submitted to endoscopic routine examination, not related to cancer or esophageal disorders, at HUPE-UERJ were also included in this study. The expression of proteins in tissues was evaluated by immunohistochemistry, while mRNA expression of GLUT-1 was also evaluated in the control samples. It was observed that the control samples express HK2, PKM1, PKM2, HIF1α layers of the esophageal epithelium. GLUT-1 and Ki-67 are seen only in the basal layer. Furthermore, expression of GLUT-1 mRNA did not correlate with disease etiological factors. In ESCC expression of HK2, PKM2 and GLUT-1 was seen in all tumors, and the expression of HIF1α and PKM1 was variable. We found that increased expression of HIF-1α correlates with lymph node invasion and differentiation, whereas the expression of HK2 is related to survival, and differentiation with PKM1. The clinical correlations found suggest that alterations in energy metabolism are an interesting subject of study for development of biomarkers that help clinical practice.