Les leucémies myéloïdes aigües résultent d’un dérèglement du processus de l’hématopoïèse et regroupent des maladies hétérogènes qui présentent des profils cliniques et génétiques variés. La compréhension des processus cellulaires responsables de l’initiation et du maintien de ces cancers permettrait de développer des outils thérapeutiques efficaces et ciblés. Au cours des dernières années, une quantité croissante d’anomalies génétiques reliées au développement de leucémies ont été corrélées à une expression anormale des gènes HOX et de leurs cofacteurs MEIS et PBX. Des modèles expérimentaux murins ont confirmé le rôle direct joué par ces protéines dans le développement de leucémies. En effet, la protéine MEIS1 collabore avec HOXA9 dans la leucémogenèse et requiert pour ce faire trois domaines distincts. Deux de ces domaines sont conservés chez PREP1, un membre de la même classe d’homéoprotéine que MEIS1. En utilisant une approche de gain-de-fonction, j’ai confirmé l’importance du rôle joué par le domaine C-terminal de MEIS1 dans l’accélération des leucémies induites par HOXA9. J’ai également montré que l’activité de ce domaine était corrélée avec une signature transcriptionnelle associée à la prolifération cellulaire. J’ai ensuite réalisé un criblage à haut débit afin d’identifier des antagonistes de l’interaction MEIS-PBX, également essentielle à l’accélération des leucémies HOX. À cette fin, j’ai développé un essai de transfert d’énergie de résonance de bioluminescence (BRET) permettant de détecter la dimérisation MEIS-PBX dans les cellules vivantes. Plus de 115 000 composés chimiques ont été testés et suite à une confirmation par un essai orthogonal, une vingtaine de molécules ont été identifiées comme inhibiteurs potentiels. Ces composés pourront être rapidement testés sur la prolifération de cellules leucémiques primaires dans un contexte d’étude préclinique. Finalement, deux approches protéomiques complémentaires ont permis d’identifier des partenaires potentiels de MEIS1 et PREP1. La catégorisation fonctionnelle de ces candidats suggère un nouveau rôle pour ces homéoprotéines dans l’épissage de l’ARN et dans la reconnaissance de l’ADN méthylé. / Acute myeloid leukemias are the result of a perturbed hematopoietic process and regroup heterogeneous diseases with distinct clinical and genetic profiles. Identifying and understanding the faulty cellular processes would allow the development of targeted and efficient therapeutic tools. Over the last 15 years, a growing number of disease-linked genetic anomalies have been correlated with abnormal expression levels of HOX genes and their cofactors MEIS and PBX. Mouse model experimentations revealed a direct role for these proteins in leukemogenesis. Indeed, the protein MEIS1 collaborates with HOXA9 in the acceleration of leukemia development. This specific function requires the presence of three different domains, two of which are highly conserved in PREP1, another member of the MEIS class of homeoproteins. Using a gain-of-function approach, I confirmed the importance of the C-terminal domain of MEIS1 in the acceleration of HOXA9-induced leukemias. I also correlated the activity of this domain with a transcriptional signature related to cell proliferation. Furthermore, I performed a high-throughput screen to identify antagonists of the MEIS-PBX interaction, also required for acceleration of HOX-induced leukemogenesis. In this regard I developed an assay that exploits bioluminescence resonance energy transfer (BRET) to monitor the MEIS-PBX dimerization in living cells. More than 115 000 compounds were tested and upon confirmation of their activity using an orthogonal assay, 20 small molecules were identified as potential inhibitors. These compounds will be rapidly tested on proliferation of primary leukemic cells in a preclinical setting. Finally two complementary proteomic approaches allowed the identification of new potential partners of MEIS1 and PREP1. The functional clustering of these candidates suggests a new role for homeoproteins in mRNA splicing and methylated DNA recognition.

Le protéasome (CP) contrôle la majorité des fonctions cellulaires par la dégradation des protéines intracellulaires. En plus d’exprimer le CP, les vertébrés expriment également l’immunoprotéasome (IP), caractérisé par des préférences de dégradation distinctes. Le rôle le mieux caractérisé pour l’IP est la génération d’antigènes adaptés pour la liaison au complexe majeur d’histocomptabilité de classe I (CMH-I). Cependant, les nombreux phénotypes observés au niveau de cellules déficientes en IP ou avec une mutation révèlent que l’IP influence des fonctions immunitaires indépendamment de la génération d’antigènes et peut atténuer le stress présent au niveau de cellules non-immunitaires. L’objectif de cette thèse était de caractériser les rôles de l’IP qui ne sont pas reliés à la génération d’antigènes associés au CMH-I. L’analyse du transcriptome de cellules dendritiques IP-déficientes en cours de maturation révèle que l’IP affecte l’expression de plus de 8 000 transcrits. L’IP affecte l’expression génique principalement au niveau transcriptionnel en contrôlant l’abondance de régulateurs de transcriptions tels que NF-κB et les membres des familles IRF et STAT. Les cellules dendritiques IP-déficientes sont également moins efficaces pour activer des lymphocytes T CD8+, même chargées artificiellement avec des quantités optimales d’antigènes associés au CMH-I. En outre, nos études montrent que l’IP est fortement exprimé au niveau de cellules de patients atteints de leucémie myéloïde aigue. L’expression de l’IP est intrinsèque aux leucémies, puisque qu’elle n’est pas corrélée à la présence de lymphocytes sécréteurs d’IFN-γ. De plus, l’expression d’IP est particulièrement élevée au niveau de leucémies monocytaires et/ou possédant un réarrangement MLL. Notamment, des analyses de corrélation montrent que l’IP est connecté à des gènes impliqués dans le métabolisme, l’activité mitochondriale et la réponse au stress. En effet l’inhibition de la sous-unité PSMB8 de l’IP mène à l’accumulation de protéines ubiquitinées et la mort de cellules leucémiques monocytaires. Globalement, nos travaux montrent que le rôle de l’IP n’est pas limité à la génération d’antigènes, mais qu’il peut contrôler l’expression génique et la survie des leucémies. / By regulating protein degradation, constitutive proteasomes (CP) control practically all cellular functions. In addition to CP, vertebrates express immunoproteasomes (IP), which display distinct substrate preferences. The first non-redundant role ascribed to IP is its enhanced ability to generate MHC I-associated antigens. However, deletion or inhibition of IP subunits can affect several immune cell functions independently of MHC-I antigen generation. Moreover, recent work has shown that IP can be expressed in non-immune cells to deal with cell stress. Thus, we wished to investigate the roles of IP that are not related to antigen generation and that are not redundant with the CP. Based on profiling of WT and IP-deficient maturing mouse dendritic cells (DCs), we report that IP regulate the expression of more than 8,000 transcripts. The broad impact of IP on gene expression is cell-autonomous, mediated mainly at the transcriptional level, and involves major signaling pathways including IRFs, NF-kB and STATs. Moreover, even when engineered to present optimal amounts of antigenic peptides, IP-deficient DCs are inefficient for in vivo T-cell priming. In addition, consistent with the fact that cancer cells endure proteotoxic stress, we report that acute myeloid leukemia (AML) cells from patients express high levels of IP genes. Expression of IP genes in AML is a cell-autonomous and IFN-independent feature that correlates with the methylation status of IP genes, and is particularly high in AML with a monocytic phenotype and/or MLL rearrangement. Notably, IP inhibition leads to accumulation of polyubiquitinated proteins and cell death in IPhigh but not IPlow AML cells. Co-clustering analysis reveals that genes correlated with IP subunits in monocytic AMLs are primarily implicated in cell metabolism and proliferation, mitochondrial activity and stress responses. Overall, our studies show that the role of IP is not limited to antigen processing and reveals major non-redundant roles for IP in transcription regulation and resistance to cell stress in AML.

Klasické schéma vývoje hematopoetických buněk předpokládá časné oddělení lymfoidního a myeloidního prekurzoru. V poslední době jsou navrhovány složitější modely, které předpokládají větší flexibilitu hematopoezy a navrhují existenci progenitorů s lymfoidním i myeloidním potenciálem. Akutní hybridní leukémie jsou malignity, které podle různých kritérií nelze jednoznačně zařadit k lymfoidní nebo k myeloidní linii a jejichž chování spíše dává za pravdu novým modelům hematopoezy. Předkládaná práce se zabývala především výzkumem dětských leukémií s přesmykem z lymfoidní do myeloidní linie během indukční léčby. Jedná se o rozsáhlý projekt, v jehož rámci si diplomová práce si kladla za úkol určit liniové zařazení leukemických blastů pomocí detekce přestaveb genů pro imunoglobuliny a T-buněčné receptory (TCR). Potvrdili jsme, že myeloidní buňky derivované v průběhu léčby pochází u všech pacientů z původního lymfoidního klonu. Dále jsme u těchto případů zkoumali expresi vytipovaných genů ve srovnání s běžnými druhy leukémií. Třetí částí práce byl výzkum prognostického významu přítomnosti přestaveb TCR (a tedy příslušnosti k lymfoidní linii) u leukémií z T-lymfoidní řady.

Anemia aplástica adquirida (AAA) é doença rara e seu diagnóstico diferencial inclui a Síndrome mielodisplásica hipocelular (SMD-h). A evolução de AAA para SMD/LMA (Síndrome mielodisplásica/Leucemia mieloide aguda) ocorre em até 15% dos casos. Este estudo propõe-se a comparar parâmetros histológicos e imuno-histoquímicos de pacientes adultos e crianças com AAA que evoluíram e não para SMD/LMA. Seu objetivo é avaliar a ocorrência dos critérios morfológicos/imunofenotípicos nas biópsias de medula óssea do grupo pediátrico (<19 anos) com o grupo de adultos, comparar esses critérios associados à evolução para SMD/LMA nestes dois grupos e verificar se estes critérios superpõem-se àqueles descritos na literatura na SMD-hipocelular do adulto e, mais recentemente, na SMD pediátrica (Citopenia refratária da infância - CRI). Espera-se trazer uma contribuição para a discussão da intersecção entre essas entidades e a AAA, estudando essa \"zona cinzenta\" do ponto de vista dos pacientes com AAA, particularmente aqueles que progrediram para SMD/LMA. Foram analisadas, retrospectivamente, 118 biópsias de medula óssea ao diagnóstico de AAA, idiopática ou não, realizadas no Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo entre 1993 e 2012. O diagnóstico de AAA foi estabelecido de acordo com critérios clássicos. A evolução de AAA para SMD ou LMA foi considerada na presença de: disgranulopoese ou dismegacariopoese acentuadas, mais de 15% de sideroblastos em anel, blastos em sangue periférico ou mais de 5% de blastos na medula óssea ao mielograma e/ou à biópsia de medula óssea ou na presença de estudo citogenético (FISH ou cariótipo) da medula óssea, apresentando monossomia ou deleção do braço longo do cromossomo 7. Todas as biópsias foram submetidas à análise morfológica e imuno-histoquímica (MPO, Glicoforina A, Fator VIII, CD34, CD117 e Ki-67) por dois hematopatologistas sem conhecimento prévio da evolução dos pacientes. As variáveis qualitativas nominais foram analisadas pelo teste exato de Fisher para verificar se houve desproporção significativa entre os grupos. As variáveis qualitativas ordinais foram analisadas para a diferença entre os grupos pelo teste de Mann-Whitney. O nível de significância adotado foi 5% (p=0,05). A correlação entre os valores de celularidade geral das amostras e seu índice proliferativo foi avaliada pelo teste não paramétrico Rô de Spearman. Setenta e um pacientes (60,2%) eram do gênero masculino com mediana de idade 24,4 anos (mínimo de 7 meses até 76 anos), 42 do grupo pediátrico e 76 adultos, e tempo de seguimento de 5,1 anos (de 1 mês a 22,1 anos). Doze (10,2%) (seis em cada grupo) pacientes evoluíram para SMD/LMA. Avaliação dos parâmetros morfológicos e imuno-histoquímicos mostrou distribuição irregular do tecido hematopoético em 59 (50%) casos, mediana de celularidade geral de 10% (de 1% a 40%), distúrbio de maturação da série granulocítica (critério 1) em três (2,5%) casos, localização anormal da eritropoiese em 13 (11%) casos, agregados de pelo menos 20 precursores eritroides (critério 2), em 54 (45,7%) casos, presença de formas jovens eritroides (proeritroblastos) (critério 3) em 32 (27,1%) casos, aumento do número de mitoses dos elementos eritroides (critério 4) em 24 (20,3%) casos, displasia de megacariócitos (micromegacariócitos, megacariócitos bi ou multinucleados e elementos hipo ou monolobados) (critério 5) em 15 (12,7%) casos, localização anormal de megacariócitos em quatro (3,3%) casos, megacariócitos CD34-positivos não foram identificados, blastos CD34-positivos em 11 (9,3%) casos, reticulogênese discretamente aumentada (grau 1) em três (2,5%) casos e índice proliferativo (Ki-67) com mediana de 30 (de 0% a 90%). Critérios descritos por Bennett e Orazi sugestivos de SMD-h (critérios 1 e/ou 5) foram detectados em 16 (13,6%) casos. Critérios descritos por Baumann et al. sugestivos de SMD da infância (critérios 2 + 3 com ou sem 4) foram observados em 30 (25,4%) casos. Não houve diferença estatística nos achados morfológicos/imuno-histoquímicos entre a população total, adultos e crianças que evoluíram e que não evoluíram para SMD/LMA, incluindo a presença de critérios Bennett e Orazi para SMD-h do adulto. Houve diferença quanto aos critérios de Baumann et al. para CRI, e o grupo que não evoluiu para SMD/LMA apresentou com mais frequência os critérios do que o que evoluiu (p=0,036), ao contrário do previamente suposto. No entanto, ao testar esta hipótese no grupo adulto separado do pediátrico, a diferença estatística não foi comprovada. Houve uma correlação estatisticamente significante entre os valores da celularidade geral das amostras e seu índice proliferativo (p < 0,001). Pacientes adultos e pediátricos com AAA, incluindo os que evoluíram para SMD/LMA, têm características morfológicas/imuno-histoquímicas semelhantes. Algumas alterações descritas por Baumann et al. para SMD pediátrica são também encontradas em casos pediátricos e de adultos com AAA. Além disso, o índice proliferativo pode ser aumentado em casos de AAA, este dado não tem correlação com a evolução para SMD/LMA. Alterações morfológicas/imuno-histoquímicas em biópsias de medula óssea em AAA não identificaram um grupo com maior risco de progressão para SMD/LMA em nossa casuística / Acquired Aplastic Anemia (AAA) is a rare disease which progresses to MDS / AML in up to 15% of cases. When this happens, hematopathologists are asked whether the diagnosis of hypocellular Myelodisplastic Syndrome (h-MDS) would not have been confused morphologically with aplastic anemia. This study aims to identify morphological/immunophenotypical findings that could predict this adverse prognosis in adults and children ( < 19y) diagnosed as AAA and verify if those criteria match with the ones described in literature in adult h-MDS and, more recently, in pediatric MDS (Refractory cytopenia of childhood - RCC), contributing to the discussion of this \"grey zone\". We retrospectively analyzed 118 patients/bone marrow (BM) biopsies at the moment of AAA diagnosis at Clinical Hospital of São Paulo Medical School from 1993 to 2012. Diagnosis of AAA was carried out according to classical criteria. Evolution to MDS or AML was considered in the presence of at least one of the findings: significant dysgranulopoiesis or dysmegakaryocytopoiesis, more than 15% ring sideroblasts, blasts in peripheral blood or more than 5% blasts in bone marrow smear and/or biopsy, or in the presence of monosomy or deletion of the long arm of chromosome 7 by cytogenetic analysis (FISH or karyotype) of the BM. All biopsies were submitted to morphological and immunophenotypic (MPO, Glycophorin A, Factor VIII, CD34, CD117 and Ki67) evaluation by two hematopathologists without previous knowledge about the evolution of the patients. Nominal qualitative variables were analyzed by using Fisher\'s exact test to check significant disproportion between the groups. The ordinal qualitative variables were analyzed for differences between groups by Mann-Whitney test. The significance level was 5% (p = 0.05). The correlation between the overall cellularity values of the samples and their proliferative index was evaluated by nonparametric Spearman Rô test. Seventy-one (60,2%) were male, median age 24.4 years (7 months to 76 years old), 42 belongs to the pediatric group and 76 to the adults group. Median follow-up was 5.1y (range, 1 month to 22.1 years). Twelve patients (12%) (6 in each group) progressed to MDS/AML. Evaluation of morphological/immunohistochemical parameters showed irregular distribution of hematopoietic tissue in 59 (50%) cases, median BM overall cellularity of 10% (range, 1 to 40%), marrow dysgranulopoiesis (criteria 1) in 3 (2,5%) cases, abnormal localization of erythropoiesis in 13 (11%) cases, clusters of at least 20 erythroid precursors (criteria 2) in 54 (45.7%) cases, increased number of proerythroblasts (criteria 3) in 32 (27,1%) cases, increased number of mitoses of the erythroid elements (criteria 4) in 24 (20,3%) cases, marrow dysplasia of megakaryocytes (micromegakaryocytes , two or more separeted nuclei, small round nuclei) (criteria 5) in 15 (12,7%) cases, abnormal localization of megakaryocytes in 4 (3,3%) cases, CD34-positive megakaryocytes were not identified, CD34-positive blast cells (criteria 6) in 11 (9,3%) cases, increment in reticulin fibers in 3 (2,5%) cases, and median proliferative index (Ki-67) 30 (range, 0 to 90%). Criteria described by Bennett and Orazi suggestive of h-SMD (criteria 1 and/or 5) were detected in 16 (13,6%) cases. Criteria described by Baumann et al suggestive of childhood MDS (criteria 2 + 3 with or without 4) were observed in 30 (25.4%) cases. There was no statistical difference in morphological/immunohistochemical findings among total population, adults and children who developed and did not develop MDS/AML, including the presence of Bennett and Orazi criteria for h-MDS. Regarding Baumann et al criteria were more frequently identified in the group that did not progress to MDS/AML than the one that did (p=0,036), the opposite of what was expected. But when the criteria were tested in pediatric and adults\' groups separately, the statistical significance was no longer observed. There was a statistical significant correlation between the overall cellularity values of the samples and their proliferative index (p=0,001). Adult and pediatric patients with AAA, including those that progress to MDS/AML, have similar morphological/immunohistochemical characteristics. Some changes described by Baumann et al for pediatric MDS are also found in pediatric and adults\' cases with AAA. In addition, the proliferative index may be increased in cases of AAA and this finding has no correlation with progression to MDS/AML. Morphological/immunohistochemical changes in bone marrow biopsies in AAA have failed to identify a group at higher risk for progression to MDS/AML in our series

Recentemente, a expressão gênica dos receptores TLR foi encontrada em diversos tipos de células tumorais. A sua participação na biologia do câncer é controversa já que foram descritas ações pró e anti-tumorais após a ativação de sua sinalização. Na Leucemia Mielóide Crônica (LMC) nada se tem demonstrado. BCR-ABL é uma oncoproteína quimérica cujo sítio tirosina quinasa constitutivamente ativado promove inúmeras vias de sinalizações que desencadeia a transformação celular. Este trabalho se inicia com a hipótese de existir uma relação entre o oncogene BCR-ABL e a expressão dos receptores TLRs. Nós verificamos em células murinas TonB210.1 com expressão de BCR-ABL induzível por doxiciclina que Tlr1 e Tlr2 tem sua expressão gênica relativa aumentada na presença da oncoproteína. A regulação positiva de Tlr1 é dependente da ação tirosina quinasa de BCR-ABL. Também mostramos que as vias p38 e JNK estão reprimindo a expressão de Tlr1 induzida por BCR-ABL enquanto que a via ERK é utilizada pelo BCR-ABL para promovê-la. Por outro lado, observamos que a ligação de TLR1/TLR2 com seu agonista sintético Pam3CSK4 em células TonB210.1 BCR-ABL positivas induz um aumento da produção de IL-6 e leva ao aumento da resistência a morte quando induzida pelas drogas Ara-C e VP16. Em conclusão, estes resultados indicam que BCR-ABL esta regulando a expressão gênica de alguns TLRs. Por tanto esses dados contribuem para a compreensão sobre o comportamento de células tumorais BCR-ABL positivas em um contexto de infecção e por conseqüência, dão margem ao estudo de novos alvos de fator de risco para a LMC. / Recently, the gene expression of TLR receptors have been described in several kinds of tumour cells. Its participation in cancer biology is controversial because roles were already been described in pro and anti-tumoral activities after their signaling activation. In Chronic Myeloid Leukemia (CML) there are no published data. BCR-ABL is a quimeric protein and its tyrosine-kinase site is activated constitutively. Thus, many signaling pathways are activated and several cell processes are altered thereby resulting in cellular transformation. This work has started with the hypothesis that a putative relationship between the oncogene BCR-ABL and the expression of TLR receptors could exists. We verified in murine cells TonB210.1 BCR-ABL expression inducible by doxycicline that Tlr1 and Tlr2 have their relative gene expression up-regulated in the presence of the oncoprotein. Therefore the Tlr1 regulation is dependent of BCR-ABL tyrosine kinase action. Using MAPK inhibitors we showed that p38 and JNK pathways are suppressing the TLR1 induction by BCR-ABL while ERK pathway is used by the oncoprotein for promote it. On the other hand, we observed in TonB210.1 BCR-ABL positive cells that the binding of TLR1/TLR2 heterodimer to their synthetic agonist Pam3CSK4 induced an increased production of IL-6 and when these cells were induced by Ara-C and VP-16 drugs the apoptosis resistance increased. In conclusion, these results indicate that the oncoprotein regulates the gene expression of some TLRs. Therefore, this fact gives us data about the behavior of BCR-ABL positive tumor cells in the context of infection and in consequence the study of new risk factor targets for CML.

Anemia aplástica adquirida (AAA) é doença rara e seu diagnóstico diferencial inclui a Síndrome mielodisplásica hipocelular (SMD-h). A evolução de AAA para SMD/LMA (Síndrome mielodisplásica/Leucemia mieloide aguda) ocorre em até 15% dos casos. Este estudo propõe-se a comparar parâmetros histológicos e imuno-histoquímicos de pacientes adultos e crianças com AAA que evoluíram e não para SMD/LMA. Seu objetivo é avaliar a ocorrência dos critérios morfológicos/imunofenotípicos nas biópsias de medula óssea do grupo pediátrico (<19 anos) com o grupo de adultos, comparar esses critérios associados à evolução para SMD/LMA nestes dois grupos e verificar se estes critérios superpõem-se àqueles descritos na literatura na SMD-hipocelular do adulto e, mais recentemente, na SMD pediátrica (Citopenia refratária da infância - CRI). Espera-se trazer uma contribuição para a discussão da intersecção entre essas entidades e a AAA, estudando essa \"zona cinzenta\" do ponto de vista dos pacientes com AAA, particularmente aqueles que progrediram para SMD/LMA. Foram analisadas, retrospectivamente, 118 biópsias de medula óssea ao diagnóstico de AAA, idiopática ou não, realizadas no Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo entre 1993 e 2012. O diagnóstico de AAA foi estabelecido de acordo com critérios clássicos. A evolução de AAA para SMD ou LMA foi considerada na presença de: disgranulopoese ou dismegacariopoese acentuadas, mais de 15% de sideroblastos em anel, blastos em sangue periférico ou mais de 5% de blastos na medula óssea ao mielograma e/ou à biópsia de medula óssea ou na presença de estudo citogenético (FISH ou cariótipo) da medula óssea, apresentando monossomia ou deleção do braço longo do cromossomo 7. Todas as biópsias foram submetidas à análise morfológica e imuno-histoquímica (MPO, Glicoforina A, Fator VIII, CD34, CD117 e Ki-67) por dois hematopatologistas sem conhecimento prévio da evolução dos pacientes. As variáveis qualitativas nominais foram analisadas pelo teste exato de Fisher para verificar se houve desproporção significativa entre os grupos. As variáveis qualitativas ordinais foram analisadas para a diferença entre os grupos pelo teste de Mann-Whitney. O nível de significância adotado foi 5% (p=0,05). A correlação entre os valores de celularidade geral das amostras e seu índice proliferativo foi avaliada pelo teste não paramétrico Rô de Spearman. Setenta e um pacientes (60,2%) eram do gênero masculino com mediana de idade 24,4 anos (mínimo de 7 meses até 76 anos), 42 do grupo pediátrico e 76 adultos, e tempo de seguimento de 5,1 anos (de 1 mês a 22,1 anos). Doze (10,2%) (seis em cada grupo) pacientes evoluíram para SMD/LMA. Avaliação dos parâmetros morfológicos e imuno-histoquímicos mostrou distribuição irregular do tecido hematopoético em 59 (50%) casos, mediana de celularidade geral de 10% (de 1% a 40%), distúrbio de maturação da série granulocítica (critério 1) em três (2,5%) casos, localização anormal da eritropoiese em 13 (11%) casos, agregados de pelo menos 20 precursores eritroides (critério 2), em 54 (45,7%) casos, presença de formas jovens eritroides (proeritroblastos) (critério 3) em 32 (27,1%) casos, aumento do número de mitoses dos elementos eritroides (critério 4) em 24 (20,3%) casos, displasia de megacariócitos (micromegacariócitos, megacariócitos bi ou multinucleados e elementos hipo ou monolobados) (critério 5) em 15 (12,7%) casos, localização anormal de megacariócitos em quatro (3,3%) casos, megacariócitos CD34-positivos não foram identificados, blastos CD34-positivos em 11 (9,3%) casos, reticulogênese discretamente aumentada (grau 1) em três (2,5%) casos e índice proliferativo (Ki-67) com mediana de 30 (de 0% a 90%). Critérios descritos por Bennett e Orazi sugestivos de SMD-h (critérios 1 e/ou 5) foram detectados em 16 (13,6%) casos. Critérios descritos por Baumann et al. sugestivos de SMD da infância (critérios 2 + 3 com ou sem 4) foram observados em 30 (25,4%) casos. Não houve diferença estatística nos achados morfológicos/imuno-histoquímicos entre a população total, adultos e crianças que evoluíram e que não evoluíram para SMD/LMA, incluindo a presença de critérios Bennett e Orazi para SMD-h do adulto. Houve diferença quanto aos critérios de Baumann et al. para CRI, e o grupo que não evoluiu para SMD/LMA apresentou com mais frequência os critérios do que o que evoluiu (p=0,036), ao contrário do previamente suposto. No entanto, ao testar esta hipótese no grupo adulto separado do pediátrico, a diferença estatística não foi comprovada. Houve uma correlação estatisticamente significante entre os valores da celularidade geral das amostras e seu índice proliferativo (p < 0,001). Pacientes adultos e pediátricos com AAA, incluindo os que evoluíram para SMD/LMA, têm características morfológicas/imuno-histoquímicas semelhantes. Algumas alterações descritas por Baumann et al. para SMD pediátrica são também encontradas em casos pediátricos e de adultos com AAA. Além disso, o índice proliferativo pode ser aumentado em casos de AAA, este dado não tem correlação com a evolução para SMD/LMA. Alterações morfológicas/imuno-histoquímicas em biópsias de medula óssea em AAA não identificaram um grupo com maior risco de progressão para SMD/LMA em nossa casuística / Acquired Aplastic Anemia (AAA) is a rare disease which progresses to MDS / AML in up to 15% of cases. When this happens, hematopathologists are asked whether the diagnosis of hypocellular Myelodisplastic Syndrome (h-MDS) would not have been confused morphologically with aplastic anemia. This study aims to identify morphological/immunophenotypical findings that could predict this adverse prognosis in adults and children ( < 19y) diagnosed as AAA and verify if those criteria match with the ones described in literature in adult h-MDS and, more recently, in pediatric MDS (Refractory cytopenia of childhood - RCC), contributing to the discussion of this \"grey zone\". We retrospectively analyzed 118 patients/bone marrow (BM) biopsies at the moment of AAA diagnosis at Clinical Hospital of São Paulo Medical School from 1993 to 2012. Diagnosis of AAA was carried out according to classical criteria. Evolution to MDS or AML was considered in the presence of at least one of the findings: significant dysgranulopoiesis or dysmegakaryocytopoiesis, more than 15% ring sideroblasts, blasts in peripheral blood or more than 5% blasts in bone marrow smear and/or biopsy, or in the presence of monosomy or deletion of the long arm of chromosome 7 by cytogenetic analysis (FISH or karyotype) of the BM. All biopsies were submitted to morphological and immunophenotypic (MPO, Glycophorin A, Factor VIII, CD34, CD117 and Ki67) evaluation by two hematopathologists without previous knowledge about the evolution of the patients. Nominal qualitative variables were analyzed by using Fisher\'s exact test to check significant disproportion between the groups. The ordinal qualitative variables were analyzed for differences between groups by Mann-Whitney test. The significance level was 5% (p = 0.05). The correlation between the overall cellularity values of the samples and their proliferative index was evaluated by nonparametric Spearman Rô test. Seventy-one (60,2%) were male, median age 24.4 years (7 months to 76 years old), 42 belongs to the pediatric group and 76 to the adults group. Median follow-up was 5.1y (range, 1 month to 22.1 years). Twelve patients (12%) (6 in each group) progressed to MDS/AML. Evaluation of morphological/immunohistochemical parameters showed irregular distribution of hematopoietic tissue in 59 (50%) cases, median BM overall cellularity of 10% (range, 1 to 40%), marrow dysgranulopoiesis (criteria 1) in 3 (2,5%) cases, abnormal localization of erythropoiesis in 13 (11%) cases, clusters of at least 20 erythroid precursors (criteria 2) in 54 (45.7%) cases, increased number of proerythroblasts (criteria 3) in 32 (27,1%) cases, increased number of mitoses of the erythroid elements (criteria 4) in 24 (20,3%) cases, marrow dysplasia of megakaryocytes (micromegakaryocytes , two or more separeted nuclei, small round nuclei) (criteria 5) in 15 (12,7%) cases, abnormal localization of megakaryocytes in 4 (3,3%) cases, CD34-positive megakaryocytes were not identified, CD34-positive blast cells (criteria 6) in 11 (9,3%) cases, increment in reticulin fibers in 3 (2,5%) cases, and median proliferative index (Ki-67) 30 (range, 0 to 90%). Criteria described by Bennett and Orazi suggestive of h-SMD (criteria 1 and/or 5) were detected in 16 (13,6%) cases. Criteria described by Baumann et al suggestive of childhood MDS (criteria 2 + 3 with or without 4) were observed in 30 (25.4%) cases. There was no statistical difference in morphological/immunohistochemical findings among total population, adults and children who developed and did not develop MDS/AML, including the presence of Bennett and Orazi criteria for h-MDS. Regarding Baumann et al criteria were more frequently identified in the group that did not progress to MDS/AML than the one that did (p=0,036), the opposite of what was expected. But when the criteria were tested in pediatric and adults\' groups separately, the statistical significance was no longer observed. There was a statistical significant correlation between the overall cellularity values of the samples and their proliferative index (p=0,001). Adult and pediatric patients with AAA, including those that progress to MDS/AML, have similar morphological/immunohistochemical characteristics. Some changes described by Baumann et al for pediatric MDS are also found in pediatric and adults\' cases with AAA. In addition, the proliferative index may be increased in cases of AAA and this finding has no correlation with progression to MDS/AML. Morphological/immunohistochemical changes in bone marrow biopsies in AAA have failed to identify a group at higher risk for progression to MDS/AML in our series

No description available.

Chromosomal alterations involving the RUNXI or CBFB genes are specifically and recurrently associated with human acute myeloid leukemia (AML). One such chromosomal alteration, a pericentric inversion of chromosome 16, is present in the majority of cases of the AML subtype M4Eo. This inversion joins CBFB with the smooth muscle myosin gene MYH11 creating the fusion CBFB-MYH11. Knock-in studies in the mouse have demonstrated that expression of the protein product of the Cbfb-MYH11fusion, Cbfβ-SMMHC, predisposes mice to AML and that chemical mutagenesis both accelerates and increases the penetrance of the disease (Castilla et al., 1999). However, the mechanism of transformation and the associated collaborating genetic events remain to be resolved. As detailed in Chapter 2, we used retroviral insertional mutagenesis (RIM) to identify mutations in Cbfb-MYH11 chimeric mice that contribute to AML. The genetic screen identified 54 independent candidate cooperating genes including 6 common insertion sites: Plag1, Plagl2, Runx2, H2T23, Pstpip2, and Dok1. Focusing on the 2 members of the Plag family of transcription factors, Chapter 3 presents experiments demonstrating that Plag1 and Plagl2 independently cooperate with Cbfβ-SMMHC in vivo to efficiently trigger leukemia with short latency in the mouse. In addition, Plag1 and PLAGL2 increased proliferation and in vitro cell renewal in Cbfβ-SMMHC hematopoietic progenitors. Furthemore, PLAG1 and PLAGL2 expression was increased in 20% of human AML samples suggesting that PLAG1 and PLAGL2 may also contribute to human AML. Interestingly, PLAGL2was preferentially increased in samples with chromosome 16 inversion, t(8;21), and t(15;17). To define the mechanism by which PLAGL2 contributes to leukemogenesis, Chapter 4 presents studies assessing the role of the Mp1 signaling cascade as a Plagl2 downstream pathway in leukemia development. Using microarray analysis we discovered that PLAGL2 induces the expression of Mp1 transcript in primary bone marrow cells that express Cbfβ-SMMHC and that this induction is maintained in leukemogenesis. We have also performed luciferase assays to confirm that the Mp1 proximal promoter can be directly bound and activated by PLAGL2. Furthermore, we demonstrate increased Mp1 expression leads to hypersensitivity to the Mp1 ligand thrombopoietin (TPO) in PLAGL2/Cbfβ-SMMHC leukemic cells. To test the functional relevance in leukemia formation, we performed a bone-marrow transplantation assay and demonstrate that overexpression of Mp1 is indeed sufficient to cooperate with Cbfβ-SMMHC in leukemia induction. This data reveals that PLAGL2 cooperates with Cbfβ-SMMHC at least in part by inducing the expression of the cytokine receptor Mp1. Thus, we have identified the Mp1 signal transduction pathway as a novel target for therapeutic intervention in AML.

Recentemente, a expressão gênica dos receptores TLR foi encontrada em diversos tipos de células tumorais. A sua participação na biologia do câncer é controversa já que foram descritas ações pró e anti-tumorais após a ativação de sua sinalização. Na Leucemia Mielóide Crônica (LMC) nada se tem demonstrado. BCR-ABL é uma oncoproteína quimérica cujo sítio tirosina quinasa constitutivamente ativado promove inúmeras vias de sinalizações que desencadeia a transformação celular. Este trabalho se inicia com a hipótese de existir uma relação entre o oncogene BCR-ABL e a expressão dos receptores TLRs. Nós verificamos em células murinas TonB210.1 com expressão de BCR-ABL induzível por doxiciclina que Tlr1 e Tlr2 tem sua expressão gênica relativa aumentada na presença da oncoproteína. A regulação positiva de Tlr1 é dependente da ação tirosina quinasa de BCR-ABL. Também mostramos que as vias p38 e JNK estão reprimindo a expressão de Tlr1 induzida por BCR-ABL enquanto que a via ERK é utilizada pelo BCR-ABL para promovê-la. Por outro lado, observamos que a ligação de TLR1/TLR2 com seu agonista sintético Pam3CSK4 em células TonB210.1 BCR-ABL positivas induz um aumento da produção de IL-6 e leva ao aumento da resistência a morte quando induzida pelas drogas Ara-C e VP16. Em conclusão, estes resultados indicam que BCR-ABL esta regulando a expressão gênica de alguns TLRs. Por tanto esses dados contribuem para a compreensão sobre o comportamento de células tumorais BCR-ABL positivas em um contexto de infecção e por conseqüência, dão margem ao estudo de novos alvos de fator de risco para a LMC. / Recently, the gene expression of TLR receptors have been described in several kinds of tumour cells. Its participation in cancer biology is controversial because roles were already been described in pro and anti-tumoral activities after their signaling activation. In Chronic Myeloid Leukemia (CML) there are no published data. BCR-ABL is a quimeric protein and its tyrosine-kinase site is activated constitutively. Thus, many signaling pathways are activated and several cell processes are altered thereby resulting in cellular transformation. This work has started with the hypothesis that a putative relationship between the oncogene BCR-ABL and the expression of TLR receptors could exists. We verified in murine cells TonB210.1 BCR-ABL expression inducible by doxycicline that Tlr1 and Tlr2 have their relative gene expression up-regulated in the presence of the oncoprotein. Therefore the Tlr1 regulation is dependent of BCR-ABL tyrosine kinase action. Using MAPK inhibitors we showed that p38 and JNK pathways are suppressing the TLR1 induction by BCR-ABL while ERK pathway is used by the oncoprotein for promote it. On the other hand, we observed in TonB210.1 BCR-ABL positive cells that the binding of TLR1/TLR2 heterodimer to their synthetic agonist Pam3CSK4 induced an increased production of IL-6 and when these cells were induced by Ara-C and VP-16 drugs the apoptosis resistance increased. In conclusion, these results indicate that the oncoprotein regulates the gene expression of some TLRs. Therefore, this fact gives us data about the behavior of BCR-ABL positive tumor cells in the context of infection and in consequence the study of new risk factor targets for CML.

L’objectif général de cette thèse a été de mettre en évidence la contribution de l’approche transcriptomique dans la physiopathologie et le traitement des hémopathies malignes. En particulier, comment la technologie des microarrays nous a aidée à étudier diverses problématiques en onco-hématologie.Dans la première partie, notre objectif était d’étudier les cellules Natural killer (Nk) chez les patients atteints de leucémie aiguë myéloïde (LAM). Nous avons comparé la signature transcriptomique des cellules Nk de patients LAM à celle des cellules Nk de sujet sains et suggéré que le facteur de transcription ETS-1 est un bon candidat capable de réguler les récepteurs activateurs NCR (natural cytotoxicity receptors) dont les gènes sont situés sur deux chromosomes différents, même si leur expression reste fortement cordonnée.Dans la seconde partie, nous nous sommes intéressés à la prédiction du sepsis en utilisant une approche transcriptomique dans le cadre de l’autogreffe de cellules souches hématopoïétiques (auto-CSH). En utilisant le même modèle, dans la troisième partie, nous avons mis en évidence l’effet du melphalan en tant que chimiothérapie de conditionnement sur les cellules mononuclées du sang périphérique et identifié un marqueur potentiel de rechute précoce chez les patients atteints de myélome dans le cas de l’auto-CSH. Enfin, dans la dernière partie, notre objectif a été d’analyser le profil d’expression génique des lymphomes B diffus à grandes cellules liés à l’infection par le VIH afin de vérifier ou pas l’existence des sous-types décrits chez les patients immunocompétents. / The aim of this research is to demonstrate transcriptomic approach contribution in the physiopathology and treatment of hematological malignancies. In particular, how microarrays technology is used to study several oncohematology difficulties; which remain deaths-related infection, as well as the failure to obtain remission and death related relapse. In the first part, our focus was to study natural killer cells (Nks) in patients affected with acute myeloid leukemia (AML). We compared transcriptomic AML-NKs signature with healthy donors-NKs signature and suggested that ETS-1 transcription factor is a good candidate able to regulate the natural cytotoxicity receptors (NCRs), whose coding genes, are located on two different chromosomes even if their expression remain strongly coordinated.Our second part, aimed to predict sepsis using a transcriptomic approach in the case of autologous stem cell transplantation (auto-HSCT). Using the same model, in the third part, we highlighted the melphalan high-dose chemotherapy effect on peripheral blood mononuclear cells and identified a potential good biomarker of early relapse in patients affected by myeloma in the case of auto-HSCT.Our final focus was to analyze gene expression profile of HIV-related large diffuse B-cell lymphoma type in order to verify the existence of subgroups described in immune-competent patients.