Les syndromes myélodysplasiques (SMD) peuvent être conçus comme des conditions pré-leucémiques dans lesquelles l’apoptose avorte les produits de différenciation de cellules souches mutées, potentiellement malignes. Néanmoins, peut-être à cause d’une inhibition progressive de l’apoptose, les SMD se transforment fréquemment en leucémies aiguës myéloïdes (LAM). Nos données indiquent que les SMD à faible risque se caractérisent par l’absence d’activation de NF-κB au sein des cellules portant des altérations cytogénétiques typiques. Par contre, dans les SMD à haut risque de transformation en LAM (ainsi que dans les LAM post-SMD), les cellules souches hématopoïétiques et leurs produits de différenciation montrent une translocation activatrice des sous-unités p50/p65 de NF-κB. L’utilisation d’antagonistes de IKK provoque une inhibition de NF-κB conduisant à une apoptose accélérée, ainsi l’activation de NF-κB serait responsable de la suppression progressive de l’apoptose et donc de la transformation maligne. Ce projet de thèse a consisté à comprendre les mécanismes impliqués dans la dérégulation de l’apoptose dans les SMD/LAM ; ainsi qu’à utiliser des technologies de criblage pour permettre une meilleure compréhension des voies de signalisation impliquées, et à adapter de nouveaux outils d’analyse. Au cours d’une première étude, nous avons montré que les inhibiteurs de méthyltransférase de l’ADN et les inhibiteurs d’histones déacétylases induisent efficacement l’apoptose dans la lignée cellulaire SMD/LAM P39, parallèlement à une inhibition de la translocation de NF-κB du cytoplasme au noyau. Dans une seconde étude, nous avons montré que l’inhibition pharmacologique du récepteur Flt3 induit une inhibition de la voie NF-κB, et pourrait être une cible thérapeutique pertinente. Dans une troisième étude, nous avons montré que l’auto-activation d’ATM chez les patients atteints de SMD/LAM joue un rôle dans l’activation constitutive de NF-κB suggérant qu’ATM serait également une bonne cible thérapeutique dont l’inhibition pourrait réduire le défaut d’apoptose des cellules SMD et LAM. Et enfin, grâce à l’optimisation d’une technique d’analyse d’images à haut débit, nous avons identifié deux composés capables d’induire la mort cellulaire des lignées cellulaires LAM in vitro : le zinc pyrithione et la ouabain. Leurs effets d’inhibition du signal de survie NF-κB, conduisant à une réduction de l’expression de protéines anti-apoptotiques, suggèrent que ces composés pharmaceutiques pourraient être utilisés comme des agents anti-leucémiques. Ce projet de thèse nous a permis de mettre en évidence le potentiel anti-leucémique de différents agents impliqués dans les principales voies de signalisation de l’apoptose dérégulées dans les SMD/LAM, qui pourraient prochainement servir de cibles pour de nouveaux essais thérapeutiques. / Myelodysplastic syndrome (MDS) is a group of hematopoietic stem cell disorders that is characterized by an ineffective hematopoiesis (finaly leading to blood cytopenias) and by a high risk of progression to acute myeloid leukemia (AML). It can therefore be viewed as a preleukemic condition in which apoptosis aborts the differentiation products of potentially malignant mutated (stem) cells. The progression of MDS into AML is associated with progressive inhibition of apoptotsis (by e.g. the expression of antiapoptotic proteins) and a negative prognostic value, suggesting that loss of the apoptotic program could favor the MDS-to-AML transition. Therefore the present project aimed at understanding the mechanisms involved in the deregulation of apoptosis in MDS and AML and the characterization of their underlying signaling pathways by means of standard biochemical and high throughput screening approaches. Our previous work showed that inhibitors of DNA methyltransferases and histone deacetylases effectively induced apoptosis in AML cells in vivo which was associated with an inhibition of NF-κB-dependent transactivation of survival signals. We further found that the pharmacological inhibition of the Flt3 receptor in AML cells decreased NF-κB activation and might therefore constitute a relevant therapeutic target for the treatment of AML. In line with these findings we demonstrated that the constitutive activation of ATM in high-risk MDS and AML patients accounts for the activation of NF-κB suggesting ATM as yet another drugable target for antileukemic therapy. Finally we generated a high throughput image based screening platform, which enabled us to perform large scale drug screening approaches and to identify two compounds with antileukemic properties. Both agent, pyrithione zinc (PZ) and Ouabain (OUA) efficiently induced cell death in AML cells in vitro associated with the inhibition of NF-κB. PZ and OUA exerted significant anticancer effects in vivo, on human AML cells xenografts as well as ex vivo, on CD34+ (but not CD34-) malignant myeloblasts from AML patients. Summarizing this project allowed us to shed some light on the importance of NF-κB during MDS to AML progression and at the same time it helped to identify drugable targets and agents with potential anticancer properties for the treatment of leukemia.

Les syndromes myélodysplasiques (SMD) sont un ensemble d’hémopathies clonales de la cellule souche. Ils touchent les sujets âgés et se caractérisent par une hématopoïèse inefficace, une différenciation anormale et une transformation fréquente en leucémie aiguë myéloblastique (LAM). La prise en charge thérapeutique a considérablement évolué ces dix dernières années, principalement avec l’arrivée de la 5-azacytidine (Aza) dans les SMD de haut risque. Malheureusement, il existe fréquemment un échec ou une perte de réponse rapide au traitement responsable d’une survie médiane globale de seulement quelques mois. La compréhension des mécanismes d’action des agents hypométhylants, la mise en évidence des facteurs biologiques impliqués dans la résistance à l’Aza ou encore l’identification de nouvelles associations de molécules constitue donc un enjeu majeur. Plusieurs équipes, dont la nôtre, ont démontré que l’erlotinib (Erlo) (inhibiteur de l’activité kinase de l’EGFR (Epidermal Growth Factor Receptor)) possède des effets antinéoplasiques dans les SMD/LAM. Compte tenu de sa toxicité modérée, cet inhibiteur de tyrosine kinase est actuellement en essai clinique en France et aux États-Unis dans les SMD en échec d’Aza. Dans ce travail, nous avons tenté de comprendre les mécanismes d’action impliqués dans l’activité de l’Aza et de l’Erlo seuls ou en association. Nous avons observé que l’Aza et la décitabine (un autre agent hypométhylant) induisent la déphosphorylation et la translocation dans le noyau du facteur de transcription FOXO3A où il réactive l’expression de gènes cibles tels que les facteurs pro apoptotiques PUMA et BIM. Cet effet observé rapidement, suggère un effet « off target » non lié à une reprogrammation épigénétique. La phosphorylation constitutive de FOXO3A étant considérée comme un facteur de mauvais pronostic dans les LAM, cette observation soulève l’intérêt potentiel des agents hypométhylants dans cette pathologie. Nous avons également identifié deux nouvelles cibles de l’Erlo : les SRC-kinases et la voie mTOR/p70S6K dont l’inhibition par des inhibiteurs biochimiques induit un arrêt du cycle cellulaire en G0/G1 sans apoptose ni différenciation confirmant l’hypothèse d’une action « multikinase » de l’Erlo. Par ailleurs, nous avons mis en évidence une activité synergique sur l’apoptose de l’association Aza et Erlo sur des lignées cellulaires de SMD/LAM et sur des cellules de patients. Cet effet n’a pas été retrouvé avec la décitabine ni les autres inhibiteurs de tyrosine kinase testés. La potentialisation de l’apoptose semble liée à plusieurs mécanismes associant l’augmentation de la concentration intracellulaire d’Aza via l’inhibition des transporteurs ABC, un arrêt de la prolifération, une activation des voies apoptotiques caspases-dépendantes et indépendantes et une activation des dommages à l’ADN. En conclusion, ce travail a permis l’identification de nouvelles cibles de l’Erlo et de l’AZA et a révélé un effet synergique entre ces deux molécules. Ces résultats précliniques encourageants suggèrent que cette association pourrait apporter un potentiel bénéfice chez les patients atteints de SMD/LAM, notamment ceux devenus réfractaires à l’Aza. / Myelodysplasic syndromes (MDS) constitute a diverse group of malignant clonal disorders that typically occur in elderly people. MDS are characterized by ineffective hematopoiesis, refractory cytopenias, morphologic dysplasia and increased potential to transform into acute myeloid leukemia (AML). Treatment of MDS has progressed considerably in recent years with the emergence of new approval agents such as azacytidine (aza)(a hypomethylating agent (HMA)) in higher-risk MDS. However, there are still a significant proportion of patients who do not respond to therapy with aza. Therefore, understanding the mechanisms of action of HMAs, identifying predictive factors for aza resistance and combining HMAs with other active compounds in MDS represent a challenging area to improve MDS/AML treatment. Previous works showed that erlotinib (an inhibitor of the epidermal growth factor receptor (EGFR)) exhibits antineoplastic effects in MDS/AML. Due to its limited toxicity profile, this tyrosine kinase inhibitor is currently being evaluated after failure of aza in two clinical trials. In this project, we aimed at understanding the molecular mechanisms involved in the activity of aza and erlo alone or in combination. We observed that aza and decitabine (another HMA related to aza) induces dephosphorylation and translocation to nucleus of the transcriptional regulator FOXO3A promoting the upregulation of the pro-apoptotic factors PUMA and BIM. This effect could be an “off target” effect and could contribute the bebenfical role of HMA in AML as constitutive phosphorylation of FOXO3A has been shown to be an adverse prognostic factor. We discovered new target for erlo, Src-kinase kinases and mTOR that are implicated in the cell-cycle arrest but not in the induction of apoptosis or differentiation confirming the “multikinase” activity of erlo. We found that the combination of aza and erlo demonstrated synergistic induction of apoptosis in MDS/AML cell lines and in some patient cells. This effect was not observed with decitabine or other tyrosine kinase inhibitors frequently used in onco-hematology. We demonstrated that potentiation of cell death is associated with different mechanisms such as intracellular accumulation of aza (via inhibition of ABC transporters), cell cycle arrest with inhibition of leukemic cells growth, caspase-dependent and -independent induction of apoptosis and DNA damage level. In conclusion, this work identified new targets of aza and erlo and revealed a synergistic induction of apoptosis upon co-treatment suggesting that this drug combination might be promising for SMD/AML treatment SMD/AML, especially the resistant patients.

De nombreuses altérations épigénétiques ont été décrites dans les leucémies aiguës myéloïdes (LAM). Nous avons récemment mis en évidence un enrichissement anormal en la marque histone H3K27me3, située sur 70 kb du cluster HIST1 (6p22) dans 50% des échantillons de patients atteints d'une LAM avec un caryotype normal (CN). Nous étudions dans ce travail, les conséquences cliniques et moléculaires de cette marque. H3K27me3 HIST1high est associé à 1) une meilleure survie des patients en analyse multivariée 2) la sous-expression du mRNA de plusieurs gènes histones (HIST1H1D, HIST1H2BG et HIST1H2BH) 3) un enrichissement fonctionnel en gènes associés à la réponse immunitaire ou inflammatoire, en faveur d’un engagement dans la différenciation granulocytaire, surexprssion confirmée pour trois de ces gènes (CYBB, FCN1 et CLEC4A) par RT-qPCR dans les blastes de patients H3K27me3 HIST1high 4) une diminution de la quantité absolue de protéine histone linker H1d par spectormétrie de masse et par Western blot et 5) une meilleure sensibilité à la différenciation induite par l'acide rétinoïque dans la lignée OCI-AML3 avec un KD de H1d (augmentation de l’expression des marqueurs de différenciation CD11B et CD11C, présence de granules intra-cytoplasmiques et expression des gènes CYBB et ITGAM). En conclusion, le biomarqueur H3K27me3 HIST1high est associé à une meilleure survie dans les LAM-CN NPM1mut, un phénotype plus différencié des blastes et une sous-expression génique et protéique de certains histones incluant le sous-type histone linker H1d. H1d semble être important dans la différenciation des blastes de LAM NPM1mut et pourrait constituer une cible thérapeutique. / The epigenetic machinery is frequently altered in acute myeloid leukemia (AML). We previously described an abnormal histone H3K27me3 repressive enrichment covering 70 kb on the HIST1 cluster (6.p22). In the present work, we further studied the medical significance and the molecular impact of this new epigenetic biomarker. We observed that H3K27me3 HIST1high is associated with 1) a better patients' outcome in multivariate analysis, 2) a lower histone mRNA expression of several histone genes (HIST1H1D, HIST1H2BG and HIST1H2BH), 3) a mature granulocytic gene expression profile including immune or inflammatory responsive genes, (we confirmed the higher expression of three of these genes, CYBB, FCN1 and CLEC4A, using qPCR in the H3K27me3 HIST1high patients' samples), 4) a decrease in histone linker H1d absolute protein abundance by Mass spectrometry and by Western blot analyses and 5) a better retinoic acid sensitization of the H1d KD OCI-AML3 cell line (i.e. increase of CD11B and CD11C expression on cell surface, higher percentage of cytoplasmic granules and mRNA up-expression of two mature granulocytic genes, CYBB and ITGAM). To conclude, this study showed that epigenetic silencing of the HIST1 locus by the H3K27me3 mark is associated with a better outcome, but also a mature gene expression profile in the NPM1mut subgroup of patients. We suggested that H1d has an important role of histone linker expression in AML blast cell differentiation. This protein could constitute a new epigenetic target.

A introdução do Mesilato de Imatinibe (MI) como primeiro inibidor específico de BCR-ABL1 na prática clínica revolucionou o tratamento da Leucemia Mieloide Crônica (LMC), tornando-se a terapia padrão para o tratamento desta doença. Porém, cerca de 30% dos pacientes com LMC não respondem à terapia com MI e um número substancial destes casos de resistência não tem causa conhecida. O MI interage com transportadores de membrana ABCG2 e SLCO1A2. Este estudo teve como objetivo investigar a relação da expressão gênica de ABCG2 e de SLCO1A2 com marcadores de resposta ao tratamento com MI, em indivíduos com LMC e avaliar a influência dos polimorfismos ABCG2 c.421C>A e ABCG2 c.-19-99G>A na resposta ao MI. Foram incluídos 118 pacientes com LMC os quais foram classificados em dois grupos: Grupo Respondedor, constituído por 70 pacientes com resposta citogenética completa com a dose padrão de MI (400 mg/dia) por até 18 meses e, Grupo não Respondedor constituído por 48 pacientes sem resposta citogenética completa à dose inicial de 400 mg/dia de MI ou que perderam esta resposta ao longo do tratamento e foram reescalonados para doses de 600 ou 800 mg/dia. A resposta ao tratamento foi avaliada segundo os critérios da European LeukemiaNet. Foram excluídos pacientes com alterações citogenéticas diferentes do cromossomo Ph e mutações no gene BCR-ABL1. Amostras de sangue periférico foram utilizadas para: extração do RNA total para quantificação dos transcritos BCR-ABL1 e expressão gênica de ABCG2 e SLCO1A2; extração de DNA e análise citogenética de banda G. A expressão do gene ABCG2 e SLCO1A2 e as análises dos polimorfismos foram feitas por PCR em tempo real. A expressão de ABCG2 foi maior no grupo de não respondedores ao MI (P=0,028). Este resultado foi influenciado pelos pacientes com resistência primária (N= 34 P=0,029), mas não pelos que apresentaram resistência secundária (N=14 P=0,249) quando comparado com respondedores (N=70). A elevada expressão do gene ABCG2 foi também associada àqueles pacientes que não tiveram resposta molecular maior (número de transcritos BCR-ABL1 ≤ 0,1%) (P=0,027) quando todos os pacientes foram analisados. O gene estudado não foi associado com a resposta molecular completa (número de transcritos BCR-ABL1 ≤ 0,032%). Com relação ao gene SLCO1A2 não foi possível determinar sua expressão devido à baixa concentração do RNA obtido. Os polimorfismos c.421C>A e c.-19-99G>A não foram associados com a expressão do gene ABCG2 e a resposta ao MI. A RMC (no grupo de respondedores) foi associada com o genótipo 421CC e houve tendência a maior frequencia de portadores do genótipo -19-99GG neste mesmo grupo. Portadores do genótipo -19-99AA apresentaram tendência ao risco de ter LMC. Os resultados deste estudo nos permitem concluir que a maior expressão de ABCG2 está associada com a resistência primária ao MI podendo então ser um mediador da resistência ao MI. Os polimorfismos do gene ABCG2 não influenciaram na expressão gênica de ABCG2, mas impactaram na RMC no grupo respondedor ao MI. / The introduction of imatinib mesylate (IM) as the first specific inhibitor of BCR-ABL1 in clinical practice has revolutionized the treatment of chronic myeloid leukemia (CML), becoming the standard therapy for this disease. However, about 20% of CML patients do not respond to therapy with IM and a substantial number of these cases of resistance have no known cause. The MI interacts with membrane transporters ABCG2 and SLCO1A2. The aim of this study was to investigate the relationship of ABCG2 and SLCO1A2 gene expression with markers of response to MI in individuals with CML and evaluate the influence of polymorphisms ABCG2 c.421C> A and c. ABCG2-19-99G> A in response to the MI. One hundred and eighteen patients in chronic phase of CML were studied and classified in two groups: Responder Group comprised 70 patients who had a complete cytogenetic response within 18 months of treatment. The non-responder group comprised 48 patients who did not have a complete cytogenetic response with the initial dose (400 mg/day) of IM or who relapsed during treatment and were submitted to higher doses of 600 or 800 mg/day. Criteria of failed response to treatment were established by European LeukemiaNet. Patients with cytogenetic patterns other than the Philadelphia chromosome and patients with mutations in the BCR-ABL1 gene were excluded from this study. Blood samples were obtained for: total RNA extraction for quantification of BCR-ABL1 and gene expression of ABCG2 and SLCO1A2; genomic DNA extraction and band G cytogenetic analysis. The gene expression and the analysis of the polymorphisms were performed by real time PCR. Expression of ABCG2 in non-responder group was higher than in responder group (P=0.028). This result was influenced by patients with primary resistance (n= 34 P=0.029) but not secondary resistance (n=14 P=0.249) when compared with responders (n=70). The higher expression of ABCG2 gene was also associated with those patients who had major molecular response (number of BCR-ABL1 . 0.1%) (P=0.027) when all patients were analyzed. The studied gene was not associated with the complete molecular response (number of BCR-ABL1 .0.0032). Regarding to the gene SLCO1A2 was not possible to determine its expression due to low concentration of RNA obtained. The c.421C>A e c.-19-99G>A were not associated neither with the ABCG2 gene expression and MI response. CMR in responders group was associated with the 421CC genotype ant there was a trend for higher frequency of carriers of genotype -19-99GG in the same group. Carriers of 19-99AA genotype tended to the risk of having CML. The results of this study allow us to conclude that the higher expression of ABCG2 is associated with primary resistance to IM and may be a mediator of resistance to IM. The ABCG2 polymorphisms did not influence the gene expression of ABCG2 but impacted in CMR of the responders to IM.

L’hématopoïèse regroupe l'ensemble des mécanismes qui assurent le renouvellement continu et régulé des cellules sanguines, à partir des cellules souches hématopoïétiques. La différenciation des cellules souches en cellules matures est un phénomène finement orchestré par divers signaux (facteurs de croissance, hormones, cytokines et microenvironnement médullaire) capables de stimuler la prolifération de cellules quiescentes ainsi que leur engagement dans diverses voies de la maturation hématopoïétique. Ces processus sont généralement régulés via l’activation de facteurs de transcription, mais également par des mécanismes épigénétiques. Le gène RINF/CXXC5 a initialement été décrit comme essentiel pour les processus de différenciation granulocytaire normale. Toutefois, son implication dans d’autres voies de l’hématopoïèse n’avait pas été étudiée. Afin de définir son rôle dans la différenciation et l’engagement vers des lignages hématopoïétiques autres que la voie granulocytaire, notamment érythroïde et monocytaire, sa contribution fonctionnelle dans des lignées hématopoïétiques et dans des cellules primaires CD34+ de moelle osseuse (donneurs sains) a été étudiée par une approche de perte ou gain de fonction. Ces expériences, dans des modèles de la voie granulocytaire (lignée NB4 et HL60 traitées par les rétinoïdes) et de la voie érythroïde (lignées K562 et UT7/GM traitées par l’hémine ou l’EPO) démontrent l’implication de RINF dans la maturation terminale de ces deux lignages. Ces données ont ensuite été validées dans des progéniteurs hématopoïétiques (tests clonogéniques) où l’expression de RINF favorise la différenciation granuleuse et interfère négativement avec la différenciation érythroïde, sans impacter la voie monocytaire. En effet, l’extinction de son expression diminue le nombre des colonies granuleuses et augmente le nombre de colonies érythroïdes. Des dérégulations au niveau de l’expression des facteurs ou co-facteurs de trancription qui régulent l’hématopoïèse peuvent aboutir à des hémopathies, telles que les Leucémies Aiguës Myéloïdes. Ces pathologies sont la résultante de l’association d’une augmentation de la prolifération cellulaire et d’un blocage des processus de différenciation. Au vu de son rôle important au cours de la granulopoïèse et de l’érythropoïèse, l’hypothèse que des dérégulations de RINF pourraient intervenir dans les processus de leucémogenèse a été testée par l’étude de son niveau d’expression dans les différentes Leucémies Aiguës Myéloïdes. Ainsi, il a été démontré que parmi les patients dont le niveau d’expression de RINF est le plus élevé, le pronostic vital est mauvais, associé à une résistance aux traitements chimiothérapeutiques. L’ensemble de ces données a permis d’aboutir à la conclusion que des dérégulations de l’expression de RINF pourraient contribuer au processus de leucémogenèse, et qu’ainsi RINF pourrait être une potentielle cible thérapeutique dans le cadre des LAM. D’un point de vue moléculaire, le mode d’action de la protéine RINF reste à ce jour du domaine de l’hypothèse, mais la présence d’un doigt de zinc de type CXXC lui permettrait d’intervenir dans des mécanismes des régulations épigénétiques, tels que la méthylation de l’ADN. Une meilleure compréhension des mécanismes régulés par la protéine pourrait permettre à terme une meilleure compréhension des régulations de l’hématopoïèse, voire des processus de leucémogenèse. / During hematopoiesis, hematopoietic stem cells (HSC) differentiation is orchestred by different signals, able to stimulate cell proliferation of quiescent cells, and their commitment in the different hematopoietic lineages. These process are regulated by transcription factors activation, as well by epigenetic mecanisms. By a microarray approach, we have identified a novel retinoid-responsive gene (CXXC5) encoding a Retinoid-Inducible Nuclear Factor (RINF) that plays an essential role during in vitro human hematopoiesis. Indeed, expression studies and gene silencing experiments both demonstrate RINF requirement during in vitro terminal differentiation of myeloid leukemia cells (NB4, HL60), but also during normal myelopoiesis of bone marrow progenitors (CD34+ HSPC cells in presence of cytokines). In the present study, we demonstrate that in cell lines, RINF overexpression provokes an earlier myeloid differentiation under retinoids treatement and slow-downs erythroid maturation induced by hemin whereas its down-regulation accelerates erythroid terminal differentiation. In normal CD34+ HSCP, we demonstrated that RINF down regulation (1) promotes differentiation in erythroid lineage at the expense of granulocyte lineage, and (2) accelerates terminal erythroid differentiation. Overexpression, contribute to promote myeloid pathway even though cells are in erythroid conditions. Because of its role during hematopoiesis regulation and its gene localization in 5q31.2, we investigated CXXC5/RINF expression in primary human acute myeloid leukemia (AML) cells derived from 594 patients. A wide variation in CXXC5/RINF mRNA levels was observed in the immature leukemic myeloblasts. Furthermore, patients with low-risk cytogenetic abnormalities showed significantly lower levels compared to patients with high-risk abnormalities, and high RINF/CXXC5/ mRNA levels were associated with decreased overall survival for patients receiving intensive chemotherapy for newly diagnosed AML. CXXC5/RINF knockdown in AML cell lines caused increased susceptibility to chemotherapy-induced apoptosis, and regulation of apoptosis also seemed to differ between primary human AML cells with high and low RINF expression. The association with adverse prognosis together with the antiapoptotic effect of CXXC5/RINF suggests that targeting of CXXC5/RINF should be considered as a possible therapeutic strategy, especially in high-risk patients who show increased expression in AML cells compared with normal hematopoietic cells.

A Leucemia Mielóide Crônica (LMC) é uma doença rara. No entanto, os avanços nas pesquisas básica e clínica nos últimos anos, colocaram a LMC em evidência sendo hoje uma neoplasia maligna potencialmente curável. O diagnóstico e tratamento desta doença são, no entanto, extremamente caros. Não havendo dados sistemáticos nem registros de incidência da LMC no Rio Grande do Sul ou no Brasil, o levantamento de dados baseado em registros dos centros de referência se justifica também para planejar ações em saúde. Entre 1996 e 2000, 276 casos foram diagnosticados. A estimativa de casos novos anuais foi de aproximadamente 0,6:100.000 habitantes, e a idade média no momento do diagnóstico foi 42 anos e 4 meses (±16 anos e 2 meses). Quanto ao tratamento e evolução destes pacientes, dos 257 avaliados, 56 (21,8%) foram submetidos ao transplante alogênico de medula óssea, com taxa de sobrevida em 5 anos de 75% e 27% para as fases crônica e acelerada/blástica, respectivamente. O tempo médio de sobrevida para os 257 pacientes foi de 47,7 meses (IC 43,3 - 52,1). Comparando ao relatado na literatura, encontramos um menor número anual de novos casos e também uma média de idade no diagnóstico mais baixa. Isto poderia ser explicado pela menor referência de idosos a serviços terciários de saúde. Para os pacientes transplantados, os resultados foram semelhantes aos relatados na literatura. / Although rare, the advances made in basic and clinical research throughout the last years have thrown a spotlight on CML. Diagnosis and treatment of CML is of high cost. Since there is no systematic data or information about the incidence of CML in Rio Grande do Sul or Brazil, the data obtained from reference centers serve to estimate the number of CML cases in our state to better plan health actions. Between 1996 and 2000, 276 cases were diagnosed. The annual estimate of new cases was approximately of 0,6:100,000 inhabitants, and the median age at diagnosis was 42 years and 4 months (±16 years and 2 months). The mean overall survival time for the 257 patients was 47,7 months (CI 43,3-52,1). That could be explained by the lack of referral for older patients. Regarding treatment and evolution, of the 257 valuable patients, 56 (21,8%) were submitted to allogeneic BMT with a five-year survival of 75% and 27% for chronic and accelerated/blastic phases, respectively. In conclusion, we found a lower estimated incidence and a lower median age at diagnosis. For the transplanted patients the results were similar to those reported in the literature.

Les leucémies aiguë myéloïde (LAM) sont un groupe d’hémopathies malignes, dont le traitement est généralement composé de deux génotoxiques : la cytarabine (Ara-C) et la daunorubicine (DNR). Nous avons montré que l’Ara-C et la DNR induisent la déconjugaison rapide de SUMO (Small Ubiquitin-related Modifier) de ses protéines cibles. Cette deSUMOylation est dûe à l'inactivation des enzymes E1 et E2 de SUMOylation par les espèces réactives de l'oxygène (ROS) produites par l’Ara-C et la DNR et est impliquée dans l'activation de l'apoptose. En outre, cet axe ROS/SUMO est anergisé dans les LAM chimiorésistantes. Cependant, il peut être réactivé par des pro-oxydants ou par inhibition de la voie SUMO par l'acide anacardique. Pour identifier les protéines contrôlées par l’axe ROS/SUMO nous avons effectué une approche de spectrométrie de masse quantitative (SILAC). Parmi les 1000 protéines SUMOylées identifiées, la plupart des 114 protéines qui perdent leur SUMOylation lors du traitement sont impliquées dans la régulation de l'expression des gènes. De plus, un ChIP-Seq avec des anticorps anti SUMO-2 a permis de montrer que les génotoxiques, en particulier la DNR, induisent une diminution massive de la présence de protéines SUMOylées sur la chromatine. La recherche de motifs au sein des séquences fixant SUMO a permis d’identifier le motif de liaison de CTCF à l’ADN. De plus, CTCF a été trouvé dans la SILAC comme l’une des protéines déSUMOylées par les traitements. En utilisant des données publiques de Chip-Seq pour CTCF, nous avons identifié 55 gènes qui fixent à la fois CTCF et SUMO et dont l’expression est régulée par les traitements. Dans la dernière partie de ce travail, nous avons étudié le groupe de 19 protéines dont la SUMOylation augmente suite aux traitements génotoxiques. Parmi ces protéines, nous avons trouvé diverses protéines centromériques, y compris CENP-B et CENP-C. En utilisant le PLA (Proximity Ligation Assay) nous avons pu montrer que CENP-B et CENP-C colocalisent avec SUMO et yH2AX après traitement. Cela suggère que la SUMOylation des protéines centromériques se produit sur les sites de cassure et pourrait jouer un rôle dans la réparation des dommages de l'ADN. / Acute Myeloid Leukemias (AML) are a group a severe hematological malignancies, which treatment is generally composed of two genotoxics: Cytarabine (Ara-C) and Daunorubicin (DNR). We have shown that these drugs induce the rapid deconjugation of the Small Ubiquitin-related Modifier (SUMO) from its target protein. This is due to the inactivation of SUMO E1 and E2 enzymes by Reactive oxygen species (ROS). This deSUMOylation participated in the activation of specific genes and is involved the induction of apoptosis. In addition, this ROS/SUMO axis is anergized in chemoresistant AMLs. However, it can be reactivated by pro-oxidants or inhibition of the SUMO pathway with anacardic acid, an inhibitor of the SUMO E1. To identify which proteins are regulated by this ROS/SUMO axis, we performed a quantitative mass spectrometry approach. Among the 1000 identified SUMO targets, most of the 114 proteins, which SUMOylation decrease upon treatment, are involved in the regulation of gene expression. In addition, we showed by ChIP-Seq with SUMO-2 antibodies that genotoxics, in particular DNR, induce a massive decrease of the presence of SUMOylated proteins on the chromatin. Motif search analysis of the SUMO binding sequences in these genes identified CTCF binding motif. Interestingly, CTCF was found in the SILAC as deSUMOylated by the drugs. Using publicly available ChIP-Seq data for CTCF, we found 55 genes which are occupied by both SUMO-2 and CTCF and which expression is regulated by the drugs. In the last part of this work, we got interested in the 19 proteins that get up-SUMOylated upon treatment. Among them, we found centromeric proteins, including CENP-B and CENP-C. Using Proximity Ligation Assay, we could show that CENP-B and CENP-C colocalize with both SUMO and yH2AX upon DNR treatment. Altogether, this suggests that centromeric protein up-SUMOylation occurs at sites of DNA damage and might play a role in DNA damage repair.

Chan, Hoi Ling. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 206-220). / Abstracts in English and Chinese. / ACKNOWLEDGEMENTS --- p.i / ABBREVIATIONS --- p.ii / ABSTRACT --- p.viii / 撮要 --- p.xii / PUBLICATIONS --- p.xiv / TABLE OF CONTENTS --- p.xv / Chapter CHAPTER 1: --- GENERAL INTRODUCTION / Chapter 1.1 --- Hematopoiesis & Leukemia --- p.1 / Chapter 1.1.1 --- An Overview on Hematopoiesis Development --- p.1 / Chapter 1.1.2 --- Leukemia --- p.6 / Chapter 1.1.2.1 --- General Symptoms of Leukemia --- p.7 / Chapter 1.1.2.2 --- Classification of Leukemia --- p.8 / Chapter 1.1.2.3 --- Conventional Treatment against Leukemia --- p.15 / Chapter 1.1.2.4 --- Novel Approaches --- p.19 / Chapter 1.2 --- The Chinese Medicinal Herb-Banlangen (板藍根） --- p.24 / Chapter 1.2.1 --- An Overview on Natural Indigo Compounds Derived from Banlangen --- p.24 / Chapter 1.2.2 --- Tryptanthrin --- p.29 / Chapter 1.2.2.1 --- Anti-bacterial Activity of Tryptanthrin --- p.29 / Chapter 1.2.2.2 --- Anti-tumor Activity of Tryptanthrin --- p.31 / Chapter 1.2.2.3 --- Anti-inflammatory Activity of Tryptanthrin --- p.33 / Chapter 1.2.2.4 --- Cutting Edges of Tryptanthrin as a Drug --- p.34 / Chapter 1.2.2.5 --- Metabolism of Tryptanthrin --- p.35 / Chapter 1.3 --- Aims and Scopes of This Investigation --- p.37 / Chapter CHAPTER 2: --- MATERIALS AND METHODS / Chapter 2.1 --- Materials --- p.39 / Chapter 2.1.1 --- Animals --- p.39 / Chapter 2.1.2 --- Cell Lines --- p.39 / Chapter 2.1.3 --- "Cell Culture Medium, Buffers and Other Reagents" --- p.41 / Chapter 2.1.4 --- Reagents for 3H-Thymidine Incorporation Assay --- p.45 / Chapter 2.1.5 --- Reagents and Buffers for Flow Cytometry --- p.46 / Chapter 2.1.6 --- Reagents for DNA Extraction --- p.49 / Chapter 2.1.7 --- Reagents for Measuring Caspase Activity --- p.50 / Chapter 2.1.8 --- Reagents for Total RNA Isolation --- p.53 / Chapter 2.1.9 --- Reagents and Buffers for Reversed Transcription-PCR --- p.54 / Chapter 2.1.10 --- Reagents and Buffers for Real Time-PCR --- p.59 / Chapter 2.1.11 --- Reagents and Buffers for Gel Electrophoresis of Nucleic Acids --- p.59 / Chapter 2.1.12 --- "Reagents, Buffers and Materials for Western Blot Analysis" --- p.61 / Chapter 2.2 --- Methods --- p.70 / Chapter 2.2.1 --- Culture of the Tumor Cell Lines --- p.70 / Chapter 2.2.2 --- "Isolation, Preparation and Culture of Mouse Peritoneal Macrophages" --- p.70 / Chapter 2.2.3 --- Determination of Cell Viability --- p.71 / Chapter 2.2.4 --- Determination of Cell Proliferation by [3H]-TdR Incorporation Assay --- p.72 / Chapter 2.2.5 --- Determination of Anti-leukemia Activity In Vivo --- p.73 / Chapter 2.2.6 --- Analysis of Cell Cycle Profile/DNA Content by Flow Cytometry --- p.74 / Chapter 2.2.7 --- Measurement of Apoptosis --- p.75 / Chapter 2.2.8 --- Determination of the Mitochondrial Membrane Potential --- p.77 / Chapter 2.2.9 --- Measurement of Caspase Activity --- p.78 / Chapter 2.2.10 --- Study of Intracellular Accumulation of Reactive Oxygen Species --- p.79 / Chapter 2.2.11 --- Gene Expression Study --- p.80 / Chapter 2.2.12 --- Protein Expression Study --- p.83 / Chapter 2.2.13 --- Measurement of Cell Differentiation --- p.87 / Chapter CHAPTER 3: --- STUDIES ON THE ANTI-PROLIFERATIVE EFFECT OF TRYPTANTHRIN AND INDIRUBIN-3'-OXIME ON MYELOID LEUKEMIA CELLS / Chapter 3.1 --- Introduction --- p.90 / Chapter 3.2 --- Results --- p.94 / Chapter 3.2.1 --- Effects of Indirubin-3'-oxime and Tryptanthrin on the Proliferation of Myeloid Leukemia Cell Lines of Human and Murine Origins In Vitro --- p.94 / Chapter 3.2.2 --- Kinetic and Reversibility Studies of the Anti-proliferative Effect of Tryptanthrin on Murine Myelomonocytic Leukemia WEHI-3B JCS Cells In Vitro --- p.108 / Chapter 3.2.3 --- Cytotoxic Effect of Tryptanthrin on Murine Myelomonocytic Leukemia WEHI-3B JCS Cells In Vitro --- p.113 / Chapter 3.2.4 --- Cytotoxicity of Tryptanthrin on Non-Cancer Cell Line and Primary Myeloid Cells In Vitro --- p.115 / Chapter 3.2.5 --- Effects of Tryptanthrin on the Cell Cycle Profile of the Murine Myelomonocytic Leukemia WEHI-3B JCS Cells In Vitro --- p.118 / Chapter 3.2.6 --- Effects of Tryptanthrin on the Expression of Cell Cycle Related Genes in Murine Myelomonocytic Leukemia WEHI-3B JCS Cells In Vitro --- p.123 / Chapter 3.2.7 --- Expression of CDK-inhibitors in Tryptanthrin-treated Murine Myeloid Leukemia WEHI-3B JCS Cells --- p.126 / Chapter 3.2.8 --- Effects of Tryptanthrin on the In Vivo Tumorigenicity of the Murine Myelomonocytic Leukemia WEHI-3B JCS Cells --- p.128 / Chapter 3.2.9 --- In Vivo Anti-tumor Effect of Tryptanthrin on Murine Myelomonocytic Leukemia WEHI-3B JCS Cells --- p.130 / Chapter 3.3 --- Discussion --- p.132 / Chapter CHAPTER 4: --- STUDIES ON THE APOPTOSIS-INDUCING EFFECT OF TRYPTANTHRIN ON MURINE MYELOMONOCYTIC LEUKEMIA WEHI-3B JCS CELLS / Chapter 4.1 --- Introduction --- p.139 / Chapter 4.2 --- Results --- p.143 / Chapter 4.2.1 --- Induction of DNA Fragmentation by Tryptanthrin in the Murine Myelomonocytic Leukemia WEHI-3B Cells In Vitro --- p.143 / Chapter 4.2.2 --- Induction of Phosphatidylserine Externalization by Tryptanthrin in Murine Myelomonocytic Leukemia WEHI-3B JCS Cells --- p.145 / Chapter 4.2.3 --- Change of Mitochondrial Membrane Potential of Tryptanthrin- treated Murine Myelomonocytic Leukemia WEHI-3B JCS Cells --- p.147 / Chapter 4.2.4 --- Induction of Caspase Activity in Tryptanthrin-treated Murine Myelomonocytic Leukemia WEHI-3B JCS cells --- p.150 / Chapter 4.2.5 --- Induction of Reactive Oxygen Species in Tryptanthrin-treated Murine Myelomonocytic Leukemia WEHI-3B JCS cells --- p.155 / Chapter 4.2.6 --- Expression of Bcl-2 Family Proteins in the Tryptanthrin-treated Murine Myelomonocytic Leukemia WEHI-3B JCS cells --- p.160 / Chapter 4.2.7 --- Effects of Tryptanthrin on the mRNA Expression of Bcl-2 Family Proteins in Murine Myelomonocytic Leukemia WEHI-3B JCS Cells --- p.163 / Chapter 4.2.8 --- Expression of Fas and Fas Ligand Proteins in Tryptanthrin-treated Murine Myelomonocytic Leukemia WEHI-3B JCS cells --- p.167 / Chapter 4.2.9 --- Expression of Pro-Apoptotic Protein in Tryptanthrin- treated Murine Myelomonocytic Leukemia WEHI-3B JCS cells --- p.170 / Chapter 4.2 --- Discussion --- p.173 / Chapter CHAPTER 5: --- STUDIES ON THE DIFFERENTIATION-INDUCING ABILITY OF TRYPTANTHRIN ON MURINE MYELOMONOCYTIC LEUKEMIA WEHI-3B JCS CELLS / Chapter 5.1 --- Introduction --- p.184 / Chapter 5.2 --- Results --- p.186 / Chapter 5.2.1 --- Morphological Studies on Tryptanthrin-treated Murine Myelomonocytic Leukemia WEHI-3B JCS Cells --- p.186 / Chapter 5.2.2 --- Effects of Tryptanthrin on the Cell Size and Granularity of the Murine Myelomonocytic Leukemia WEHI-3B JCS Cells --- p.189 / Chapter 5.2.3 --- Effects of Tryptanthrin on Induction of NBT-reducing Activity in the Murine Myelomonocytic Leukemia WEHI-3B JCS Cells --- p.191 / Chapter 5.3 --- Discussion --- p.195 / Chapter CHAPTER 6: --- CONCLUSIONS AND FUTURE PERSPECTIVES --- p.198 / REFERENCES --- p.206

Yip, Wai Ki. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 203-228). / Abstracts in English and Chinese. / ACKNOWLEDGMENTS --- p.i / ABBREVIATIONS --- p.iii / ABSTRACT --- p.x / 撮要 --- p.xiv / TABLE OF CONTENTS --- p.xvii / Chapter CHAPTER 1: --- GENERAL INTRODUCTION / Chapter 1.1 --- Hematopoiesis and Leukemia / Chapter 1.1.1 --- An Overview on Hematopoiesis Development --- p.1 / Chapter 1.1.1.1 --- Hematopoietic Growth Factors --- p.4 / Chapter 1.1.1.2 --- Site Switching of Hematopoiesis --- p.5 / Chapter 1.1.2 --- An Overview on Leukemia --- p.7 / Chapter 1.1.2.1 --- Classification of Leukemia --- p.7 / Chapter 1.1.2.2 --- Conventional Therapy of Leukemia --- p.10 / Chapter 1.1.2.3 --- Novel Approaches to Leukemia Therapy: Apoptosis and Differentiation Induction --- p.13 / Chapter 1.2 --- Polysaturated Fatty Acids / Chapter 1.2.1 --- An Overview on Polyunsaturated Fatty Acids --- p.16 / Chapter 1.2.2 --- An Overview on Essential Fatty Acids --- p.17 / Chapter 1.2.2.1 --- Alpha Linolenic Acids (ALA) --- p.17 / Chapter 1.2.2.2 --- Gamma Linolenic Acid (GLA) --- p.18 / Chapter 1.2.3 --- "An Overview on Conjugated Fatty Acids: Conjugated Linoleic Acid (CLA), Conjugated EPA and Conjugated DHA" --- p.20 / Chapter 1.2.4 --- Conjugated Linolenic Acid (CLN) --- p.24 / Chapter 1.2.4.1 --- Identification and Production of CLN --- p.28 / Chapter 1.2.4.2. --- Metabolism of CLN --- p.29 / Chapter 1.2.4.3 --- Anti-Obese and Hypolipidemic Effect of CLN --- p.30 / Chapter 1.2.4.4 --- Anti-Proliferative Effect of CLN --- p.30 / Chapter 1.2.4.5 --- Other Novel Effects of CLN --- p.32 / Chapter 1.3 --- Aims and Scopes of This Investigation --- p.34 / Chapter CHAPTER 2: --- MATERIALS AND METHODS / Chapter 2.1 --- Materials --- p.36 / Chapter 2.1.1 --- Animals --- p.36 / Chapter 2.1.2 --- Human Cell Lines --- p.36 / Chapter 2.1.3 --- "Cell Culture Medium, Buffers and Other Reagents" --- p.38 / Chapter 2.1.4 --- Reagents and Buffer for Flow Cytometry --- p.44 / Chapter 2.1.5 --- Reagents for DNA Extraction --- p.47 / Chapter 2.1.6 --- Cell Death Detection ELISApLus --- p.48 / Chapter 2.1.7 --- Reagents for Measuring Caspase Activity --- p.50 / Chapter 2.1.8 --- Reagents for FACE´ёØ ELISA Kit --- p.53 / Chapter 2.1.9 --- Reagents for Western Blotting --- p.55 / Chapter 2.2 --- Methods --- p.65 / Chapter 2.2.1 --- Culturing the Tumor Cell Lines --- p.65 / Chapter 2.2.2 --- "Isolation, Preparation and Culturing of Murine Peritoneal Macrophages and Bone Marrow Cells" --- p.66 / Chapter 2.2.3 --- Anti-proliferation Assays --- p.67 / Chapter 2.2.4 --- Cell Viability Determination --- p.68 / Chapter 2.2.5 --- Determination of Anti-leukemia Activity In Vivo (In Vivo Tumorigenicity Assay) --- p.69 / Chapter 2.2.6 --- Cell Cycle Analysis by Flow Cytometry --- p.69 / Chapter 2.2.7 --- Detection of Apoptosis --- p.70 / Chapter 2.2.8 --- Assessment of Differentiation-associated Characteristics --- p.74 / Chapter 2.2.9 --- Measurement of Caspase Activities --- p.76 / Chapter 2.2.10 --- Protein Expression Study --- p.78 / Chapter 2.2.11 --- Detection of Phosphorylation of JNK by FACE´ёØ JNK ELISA Kit --- p.83 / Chapter 2.2.12 --- Detection of Phosphorylation of NF-kB by FACE´ёØ NF-kB p65 Profiler --- p.85 / Chapter 2.2.13 --- Statistical Analysis --- p.85 / Chapter CHAPTER 3: --- STUDIES ON THE ANTI PROLIFERATIVE EFFECTS OF CONJUGATED LINOLENIC ACIDS ON THE HUMAN MYELOID LEUKEMIA CELLS / Chapter 3.1 --- Introduction --- p.86 / Chapter 3.2 --- Results / Chapter 3.2.1 --- Anti-proliferative Activity of CLN Isomers on Various Myeloid Leukemia and Lymphoma Cell Lines In Vitro --- p.88 / Chapter 3.2.2 --- Direct Cytotoxic Effect of Jacaric Acid on HL-60 Cells In Vitro --- p.95 / Chapter 3.2.3 --- Cytotoxic Effect of Jacaric Acid on Primary Murine Cells and Human Normal Cell Lines In Vitro --- p.98 / Chapter 3.2.4 --- Kinetics and Reversibility Studies of the Anti-proliferative Effect of Four CLN Isomers on the Human Promyelocytic Leukemia HL-60 Cells --- p.101 / Chapter 3.2.5 --- Synergistic Anti-proliferative Effect of Jacaric Acid with Vitamin D3 and All Trans-Retinoic Acid (ATRA) on the Human Promyelocytic Leukemia HL-60 Cells In Vitro --- p.114 / Chapter 3.2.6 --- Effect of Jacaric Acid on the Cell Cycle Profile of the HL-60 Cells In Vitro --- p.116 / Chapter 3.2.7 --- Effect of Jacaric Acid on the In Vivo Tumorigenicity of the HL-60 Cells --- p.119 / Chapter 3.3 --- Discussion --- p.121 / Chapter CHAPTER 4: --- STUDIES ON THE APOPTOSIS-INDUCING AND DIFFERENTIATION-INDUCING EFFECTS OF CONJUGATED LINOLENIC ACIDS ON THE HUMAN MYELOID LEUKEMIA CELLS / Chapter 4.1.1 --- Introduction --- p.128 / Chapter 4.2 --- Results / Chapter 4.2.1 --- Induction of Apoptosis in the Human Promyelocytic Leukemia HL-60 Cells by Jacaric Acid --- p.134 / Chapter 4.2.2 --- Apoptosis-Inducing Effect of Jacaric Acid on the Human Promyelocytic Leukemia HL-60 Cells as Detected by Annexin V-GFP PI Double Staining Method --- p.138 / Chapter 4.2.3 --- Effect of Jacaric Acid on the Mitochondrial Membrane Potential in the Human Promyelocytic Leukemia HL-60 Cells --- p.140 / Chapter 4.2.4 --- Effects of Jacaric Acid on the Caspase Activities in the Human Promyelocytic Leukemia HL-60 Cells --- p.142 / Chapter 4.2.5 --- Effects of Jacaric Acid and Antioxidants on the ROS Induction in the Human Promyelocyic Leukemia hl-6 Cells --- p.147 / Chapter 4.2.6 --- Effect of N-acetyl-L-Cysteine on the Apoptosis-Inducing Activity of Jacaric Acid in the Human Promyelocytic Leukemia HL-60 Cells --- p.149 / Chapter 4.2.7 --- Morphological Studies on the Jacaric Acid-treated Human Promyelocytic Leukemia HL-60 Cells --- p.151 / Chapter 4.2.8 --- Cell Size and Granularity of the Human Promyelocytic Leukemia HL-60 Cells after Treatment with Different CLN Isomers --- p.153 / Chapter 4.2.9 --- Expression of Differentiation-Related Cell Surface Markers in the Human Promyelocytic Leukemia HL-60 Cells after Treatment with Jacaric Acid --- p.155 / Chapter 4.3 --- Discussion --- p.158 / Chapter CHAPTER 5: --- STUDIES ON THE APOPTOSIS-ASSOCIATED PROTEINS AND SIGNALING PATHWAYS IN CONJUGATED LINOLENIC ACID-INDUCED APOPTOSIS OF THE HUMAN MYELOID LEUKEMIA CELLS / Chapter 5.1 --- Introduction --- p.165 / Chapter 5.2 --- Results / Chapter 5.2.1 --- Expression of Fas and Fas Ligand Proteins in the Jacaric Acid- treated Human Promyelocytic Leukemia HL-60 Cells --- p.171 / Chapter 5.2.2 --- Expression of Bcl-2 Family Member Proteins in the Jacaric Acid- treated Human Promyelocytic Leukemia HL-60 Cells --- p.173 / Chapter 5.2.3 --- Cytochrome c Release in the Jacaric Acid-treated Human Promyelocytic Leukemia HL-60 Cells --- p.175 / Chapter 5.2.4 --- Cleavage of Poly(ADP-ribose) Polymerase (PARP) in the Jacaric Acid-treated Human Promyelocytic Leukemia HL-60 Cells --- p.177 / Chapter 5.2.5 --- Phosphorylation of ERK in the Jacaric Acid-treated Human Promyelocytic Leukemia HL-60 Cells --- p.179 / Chapter 5.2.6 --- Phosphorylation of JNK in the Jacaric Acid-treated Human Promyelocytic Leukemia HL-60 Cells --- p.181 / Chapter 5.2.7 --- Phosphorylation of NF-kB Protein in the Jacaric Acid-treated Human Promyelocytic Leukemia HL-60 Cells --- p.183 / Chapter 5.3 --- Discussion --- p.185 / Chapter CHAPTER 6: --- CONCLUSIONS AND FUTURE PERSPECTIVES --- p.195 / REFERENCES --- p.203

A leucemia mieloide crônica (LMC) é uma expansão clonal da célula tronco hematopoética, traduzindo-se por hiperplasia mieloide, leucocitose, neutrofilia, basofilia e esplenomegalia. O cromossomo Filadélfia é característico da doença, sendo produto da translocação t(9:22)(q34;q11), resultando na fusão dos genes ABL e BCR. Esta fusão gera um gene híbrido que codifica uma proteína com elevada atividade tirosinoquinase e tem um papel central na patogenia da LMC. O mesilato de imatinibe (MI) é um derivado da fenilaminopirimidina que inibe a proteína tirosinoquinase BCR-ABL1 in vitro e in vivo. O MI interage com transportadores de membrana de influxo, como o organic carion solute carrier 22 ,member 1 (SLC22A1,hOCT1); e de efluxo, como ATP binding cassette B1 (ABCB1, MDR1, P-gp). Os polimorfismos ABCB1 c.1236C>T, C.3435C>T e c.2677G>T/A têm sido associados com a alteração da função da P-gp. Este estudo teve por objetivo investigar a relação da expressão do RNAm de ABCB1 e SLC22A1 com marcadores de resposta ao tratamento com MI e avaliar a atividade funcional da P-gp em células mononucleares de pacientes com diferentes haplótipos para os polimorfismos ABCB1 c.1236C>T, c.3435C>T e c.2677G>T/A. Foram incluídos 118 pacientes com LMC para o estudo da expressão do RNAm de SLC22A1 e ABCB1 e para o estudo da atividade da P-gp foram selecionados 28 pacientes de acordo com os haplótipos dos polimorfismos ABCB1 c.1236C>T, c.3435C>T e c.2677G>T/A. Para o estudo da expressão do RNAm de SLC22A1 e ABCB1 foram constituídos dois grupos: Grupo 1 com 70 pacientes com resposta citogenética completa com a dose padrão de MI (400 mg/dia de MI) em até 18 meses e, Grupo 2 com 48 pacientes sem resposta citogenética completa com a dose inicial de 400 mg/dia de MI ou que perderam esta resposta ao longo do tratamento. Para o estudo da atividade funcional da P-gp, dos 118 pacientes incluídos, foram selecionados 10 pacientes que apresentaram o haplótipo 1236CC/3435CC/2677GG, 10 pacientes que apresentaram o haplótipo 1236CT/3435CT/2677GT e 8 pacientes que apresentaram o haplótipo 1236TT/3435TT/2677TT. A resposta ao tratamento foi avaliada segundo os critérios da European LeukemiaNet. Amostras de sangue foram obtidas para: quantificação de BCR-ABL1, extração do RNAm total, análise citogenética de banda G, dosagem da concentração plasmática de MI e análise da atividade e expressão da P-gp. A análise da expressão dos genes ABCB1 e SLC22A1 foi feita por PCR em tempo real, a análise da atividade e expressão da P-gp foram feitas por citometria de fluxo e a dosagem da concentração plasmática de MI foi realizada por eletroforese capilar. Resultados: A expressão de ABCB1 e SLC22A1 foi analisada nos 118 pacientes incluídos e foi similar entre os grupos de resposta. A elevada expressão do gene SLC22A1 foi associada àqueles pacientes que alcançaram a resposta molecular maior (RMM) no grupo respondedor (P=0,009). Não houve associação entre a expressão de ABCB1 e a resposta ao MI. Nenhum dos genes foi associado à resposta molecular completa (RMC). No estudo da atividade da P-gp foi observada uma maior atividade nos pacientes que apresentavam o haplótipo 1236CC/3435CC/2677GG quando comparado àqueles que possuíam o haplótipo com alelo mutado. Não houve diferença na expressão do RNAm dos genes SLC22A1 e ABCB1, expressão da P-gp e concentração plasmástica de MI entre os grupos de haplótipos. Os pacientes que não alcançaram a RMM apresentaram uma maior taxa de efluxo mediado pela P-gp quando comparado aos indivíduos que alcançaram esta resposta (64,7% vs. 45,7%; P=0,001). Os indivíduos que alcançaram a RMM e RMC apresentaram maior mediana de expressão do gene SLC22A1. Os pacientes sem RMM apresentaram menor concentração plasmática de MI quando comparados aos que alcançaram esta resposta (0,51 µg/mL vs. 1,42 µg/mL; P=0,001). Não foi observada associação entre a concentração plasmática de MI e a RMC. Em conclusão os pacientes respondedores a dose padrão de 400mg/dia de MI e que alcançaram a RMM apresentam maior expressão de RNAm de SLC22A1 e os portadores dos haplótipos 1236CT/3435CT/2677GT e 1236TT/3435TT/2677TT exibem menor efluxo mediado pela P-gp apresentando maior frequência de RMM. / Chronic myeloid leukemia (CML) is a clonal expansion of hematopoietic stem cell, translating into myeloid hyperplasia, leukocytosis, neutrophilia, basophilia and splenomegaly. The Philadelphia chromosome is characteristic of the disease, being the product of the translocation t(9:22)( q34,q11), resulting in the fusion of the BCR and ABL genes. This fusion generates a hybrid gene that encodes a protein with elevated tyrosine kinase activity and plays a central role in the pathogenesis of CML. Imatinib mesylate (IM) is a derivative of fenilaminopirimidine that inhibits BCR-ABL1 fusion protein tyrosine kinase in vitro and in vivo. IM interacts with uptake membrane transporters, such as cation organic solute carrier 22, member 1 (SLC22A1, hOCT1) and efflux as ATP binding cassette B1 (ABCB1, MDR1,P-gp). ABCB1 polymorphisms c.1236C>T,c.3435C>T and c.2677G>T/A have been associated with altered function of P-gp. This study aimed to investigate the relationship between mRNA expression of ABCB1 and SLC22A1 with markers of response to treatment with IM and evaluate the functional activity of P-gp in mononuclear cells of patients with different haplotypes for ABCB1 c.1236C>T, c.3435C>T and c.2677G>T/A polymorphisms. This study included 118 patients with CML to study the mRNA expression of SLC22A1 and ABCB1 and to study the P-gp activity, 28 patients were selected according to the haplotypes of ABCB1 c.1236C>T, c.3435C>T and c.2677G>T/A polymorphisms. To study the mRNA expression of SLC22A1 and ABCB1, two groups were constituted: Group 1 with 70 patients with a complete cytogenetic response with standard-dose IM (400 mg/day) in 18 months, and group 2 with 48 patients without complete cytogenetic response with the initial dose of IM (400 mg/day) or have lost this response during treatment. To study the P-gp functional activity, 10 patients with haplotype 1236CC/3435CC/2677GG, 10 patients with haplotype 1236CT/3435CT/2677GT and 8 patients with haplotype 1236TT/3435TT/2677TT were enrolled. Treatment response was assessed according to European LeukemiaNet criteria. Blood samples were obtained for: quantification of BCR-ABL1, mRNA extraction, G band cytogenetic analysis, measurement of IM plasma levels and P-gp activity and expression. The ABCB1 and SLC22A1 gene expression analysis was made by real-time PCR, analysis of P-gp activity and protein expression were performed by flow cytometry and determination of plasma Levels of IM was performed by capillary electrophoresis. Results: Expression of ABCB1 and SLC22A1 were analyzed in 118 patients included and was similar between the response groups. Higher expression of the SLC22A1 gene was associated with those patients who achieved a major molecular response (MMR) in the responder group (P=0.009). There was no association between ABCB1 expression and IM response. None of the studied genes was associated with complete molecular response (CMR). In the study of P-gp activity we observed greater activity mediated by P-gp in patients with 1236CC/3435CC/2677GG haplotype when compared to those with the mutated allele. There was no difference in mRNA expression of SLC22A1 and ABCB1 genes, P-gp expression and IM plasma levels between haplotypes groups. Patients who did not achieve MMR showed a higher rate of efflux mediated by P-gp compared to individuals who did achieve this response (64.7% vs. 45.7%, P=0.001). Individuals who achieved MMR and CMR had higher median of SLC22A1 expression. Patients without MMR had lower IM plasma levels compared with those who achieved this response (0.51 µg/mL vs. 1.42 µg/mL, P=0.001). No association was observed between IM plasma levels and CMR. In conclusion patients responders to standard dose of IM (400 mg/day) and who achieved MMR have higher SLC22A1 mRNA expression and the carriers of 1236CT/3435CT/2677GT 1236TT/3435TT/2677TT haplotypes exhibit lower efflux mediated by P-gp with higher frequency of MMR.