The aims of the studies described in the thesis were to investigate different treatment strategies in chronic myeloid leukemia (CML) patients. Furthermore, activity of imatinib was investigated by in vitro cytotoxicity assay, and the gene expression pattern in interferon treated patients. In a randomized prospective national study, we examined the influence of busulphan (n=89) versus hydroxyurea (n=90) treatment on time to blast crisis, and survival. There was no significant difference in survival between hydroxyurea and busulphan treated patients; median survival was 3.5 and 3.2 years, respectively. The 26 patients who underwent allogeneic stem cell transplantation had a significantly longer median survival (4.7 years) than those who were not transplanted. We investigated the feasibility of mobilizing Philadelphia chromosome negative blood stem cells with intensive chemotherapy and lenograstim in CML patients. Twenty-three patients (62%) were successfully mobilized. Twenty-one of these patients underwent autologous stem cell transplantation later on, with a 5-year overall survival at 68%. Fluorometric Microculture Cytotoxicity Assay was used to analyze 32 tumor cell samples from CML patients, (26 chronic phase and 6 blast crisis). Imatinib showed a higher in vitro activity and more positive drug interactions in cells from blast crisis than from chronic phase. Interferon, daunorubicin and arsenic trioxide had the greatest benefit from a combination with imatinib. Microarray-based gene expression analyses were performed on diagnostic CML samples prior to interferon treatment. We identified six genes that were differentially expressed in responders and non-responders to interferon. It might prove possible to use gene expression analysis to predict future response to interferon.

A leucemia mielóide crônica (LMC) é uma doença mieloproliferativa, resultante da expansão clonal da célula-tronco hematopoética pluripotente. A fisiopatologia da LMC está associada a uma translocação entre os braços longos dos cromossomos 9 e 22, o que promove o aparecimento do neogene bcr-abl, cujo gene codifica uma proteína denominada Bcr-Abl. A oncoproteína Bcr-Abl possui atividade tirosina-quinase constitutiva que é a responsável pelo fenótipo maligno da célula, incluindo resistência à apoptose. O tratamento da LMC pode ser realizado com hidroxiuréia, IFN- associado à citarabina, inibidores de TK (mesilato de imatinibe e dasatinibe) e transplante de medula óssea. O tratamento de escolha para pacientes com LMC na fase crônica é o inibidor de tirosina-quinase mesilato de imatinibe e para os refratários utiliza-se o dasatinibe. Apesar do conhecimento acerca do mecanismo de ação dos inibidores de TK, pouco se sabe sobre seu efeito na maquinaria apoptótica. Sendo assim, no presente trabalho foi detectada a expressão dos genes e proteínas anti- (A1, Bcl-2, Bcl-Xl, Bcl-W, C-Flip, Ciap-1, Ciap-2 e Mcl-1) e pró-apoptóticos (Bad, Bak, Bax, Bcl-Xs, Bid, Bik, Bimel, Bmf, Bok, Fas, Fasl, Noxa e Puma) em células mononucleares de 32 indivíduos saudáveis e 26 pacientes com LMC antes e após 12 meses da terapia com mesilato de imatinibe e dasatinibe. Dentre os 26 pacientes avaliados, 13 eram do sexo feminino e 13 do sexo masculino, três eram negros, um amarelo e 22 brancos, com idade média de 48 anos (faixa etária de 25 a 77 anos). O grupo controle foi composto por 32 indivíduos, 16 do sexo feminino e 16 do sexo masculino, 26 eram brancos, quatro negros e dois amarelos, com idade média de 45 anos (idade de 23 a 77 anos). O isolamento das células mononucleares foi realizado pelo método de Ficoll-Hypaque, a determinação da expressão gênica por PCR em tempo real e a protéica por western-blot. Os resultados foram expressos em unidade relativa de expressão (U.R.E.), comparados entre os diferentes grupos (controle e pacientes pré- e pós-tratamento), associados à resposta aos medicamentos e correlacionados ao índice de prognóstico de SOKAL. Na comparação dos dados de expressão gênica entre pacientes e controles, verificou-se que os pacientes apresentaram maior expressão dos genes bcl-xL, c-flip, mcl-1 e fas e níveis reduzidos de bik. O mesilato de imatinibe modulou significativamente a transcrição dos genes bcl-xL, bok, mcl-1 e noxa, enquanto que o dasatinibe agiu sobre a expressão dos genes a1, bmf, c-flip, ciap-1, ciap-2 e mcl-1. Os pacientes refratários ao mesilato de imatinibe apresentaram níveis elevados de expressão de a1 e c-flip e reduzida expressão de bcl-2, ciap-2, bak, bax, bid e fasl em relação aos pacientes em remissão. A expressão protéica refletiu os dados da quantificação do RNAm dos genes. Os dados da presente investigação indicam que as células mononucleares dos pacientes com LMC apresentam desregulação do processo de apoptose celular. Essa alteração pode ser parcialmente associada ao fenótipo de resistência das células leucêmicas Bcr-Abl+ à apoptose e ausência de resposta aos inibidores de TK. Os dados revelam ainda que os inibidores de tirosina-quinase interferem na transcrição e tradução das moléculas envolvidas na regulação do processo de apoptose. / Chronic myeloid leukemia (CML) is a myeloproliferative disease resultant of a clonal expansion of pluripotent hematopoietic stem cells. The CML physiopathology is associated with a translocation between chromosomes 9 and 22 long arms, promoting the formation of a bcr-abl neogene, which codifies the Bcr-Abl protein. The Bcr-Abl oncoprotein presents tyrosine-kinase activity that is responsible for the malign phenotype which includes apoptosis resistance. CML treatment may be performed with hydroxyurea, IFN- plus cytarabine, tyrosine-kinase inhibitors (imatinib mesylate and dasatinib) and bone marrow transplantation. The standard treatment for CML patients in chronic phase is the tyrosine-kinase inhibitor imatinib mesylate (IM) and for IM-refractory patients dasatinibe is employed. Despite of the knowledge related to the mechanism of action of tyrosine-kinase inhibitors, little is known about its effects on the apoptosis machinery. In this work we characterized both the mRNA and protein patterns of expression of the anti- (A1, Bcl-2, Bcl-Xl, Bcl-W, C-Flip, Ciap-1, Ciap-2 e Mcl-1) and pro-apoptotic (Bad, Bak, Bax, Bcl-Xs, Bid, Bik, Bimel, Bmf, Bok, Fas, Fasl, Noxa e Puma) regulators in peripheral blood mononuclear cells (PBMC) from 32 healthy individual and 26 CML patients before and after 12 months of imatinib mesylate and dasatinibe therapy. Thirteen patients were female and thirteen were male, three were black, one was japanese and 22 were white, the mean age was 48 years (varying from 25 to 77 years). The control group was composed of 32 individuals, 16 were female and 16 were male, 26 were white, four black and two japanese, the mean age was 45 years (varying from 23 to 77 years). PBMC isolation was performed by Ficoll-Hypaque, gene expression was assessed by real time PCR and protein expression was carried out by western-blot methodology. Results were given by the relative expression, after comparison between the different groups (control and patients before and after treatment), associated with drug response and related to Sokal index. The comparison of gene expression profiles between patients and controls showed that CML patients present increased levels of bcl-xL, c-flip, mcl-1 and fas expression and reduced levels of bik gene expression. The imatinib mesylate significantly modulated the transcription of bcl-xL, bok, mcl-1 and noxa, whereas dasatinib affected the expression of a1, bmf, c-flip, ciap-1, ciap-2 and mcl-1. MI-refractory patients present higher levels of a1 and c-flip and lower levels of bcl-2, ciap-2, bak, bax, bid and fasl when compared to patients who achieved complete cytogenetic response. Overall, the patterns of protein expression agree with the profiles of mRNA expression. Taken together, the results described in this investigation indicate that PBMC from CML patients present deregulation in cell death pathways. These alterations could partly account for the apoptosis resistance phenotype observed in Bcr-Abl+ leukemic cells and for lack of response to tyrosine kinase inhibitors. Furthermore, our data also reveal that tyrosine kinase inhibitors interfere in the transcription and translation of molecules that regulate the apoptosis process.

Na leucemia mielóide crônica (LMC) a proteína Bcr-Abl possui atividade tirosina-quinase constitutivamente ativada, induzindo a mieloproliferação e a resistência das células à apoptose. A maioria dos pacientes na fase crônica da LMC tratados com inibidores de tirosina-quinase (TKIs), como o mesilato de imatinibe, apresenta remissão citogenética completa da doença, mas uma parcela desses pacientes tem se mostrado resistente à terapia. A fisiopatologia da LMC e os mecanismos celulares e moleculares envolvidos na resistência à terapia com TKIs são diversos e precisam ser melhor estudados. Nesse contexto, o objetivo do presente estudo foi quantificar os níveis de expressão do gene DIDO, incluindo suas diferentes isoformas (DIDO 1, 2 e 3) e promotores (DIDO PP e PD) em controles e em pacientes com LMC nas diferentes fases da doença, tratados ou não com TKIs, bem como em linhagens celulares BCR-ABL1+ sensíveis (S) e resistentes (R) ao mesilato de imatinibe (MI). A literatura relata que DIDO 1 participa do processo de apoptose e que alterações na expressão de DIDO 2 e DIDO 3 podem estar associadas com o desenvolvimento de neoplasias mielóides. Dessa forma, foram estudados 60 pacientes com LMC e 57 controles, assim como as linhagens celulares HL-60, HL-60.Bcr-Abl+, LAMA 84 S, LAMA 84 R, KCL 22 S e KCL 22 R. Foram separadas as células mononucleares de sangue periférico dos pacientes e controles, com posterior extração de RNA e síntese de cDNA, que foi então empregado nas reações de PCR em tempo real (qPCR) para quantificação das expressões gênicas de DIDO 1, 2, 3, PP, PD e ORF. As linhagens celulares foram tratadas por 4h com TKIs e então a expressão das diferentes isoformas de DIDO foi também quantificada por qPCR. A avaliação da expressão proteica de Bcr-Abl, c-Abl e proteínas fosforiladas nas linhagens foi realizada por Western-blotting. A expressão de DIDO 1 e 2 foi maior nos pacientes nas fases avançadas da LMC e nos pacientes na fase crônica da doença tratados com TKIs (mesilato de imatinibe ou dasatinibe) do que nos controles. Os pacientes na fase crônica da LMC tratados com MI expressaram mais DIDO 1 e 3 do que os pacientes na fase crônica sem tratamento. Houve uma correlação positiva entre expressão de BCR-ABL1 e de DIDO 2 e entre índice de Sokal dos pacientes e expressão de DIDO 2. Na linhagem HL60.Bcr-Abl+, a expressão de proteínas fosforiladas reduziu após tratamento de 4h com TKIs, mas não houve alteração na expressão gênica de DIDO. Nas linhagens celulares S e R, houve aumento da expressão de DIDO 1 após o tratamento de 4h com MI. Conclui-se, portanto, que as diferentes isoformas de DIDO parecem exercer funções distintas na leucemia mielóide crônica; que o tratamento de pacientes e linhagens BCR-ABL1 positivas com inibidores de tirosina-quinase aumenta expressão de DIDO 1; e que a expressão de DIDO 2 correlaciona-se positivamente à expressão de BCR-ABL1 e ao índice de Sokal dos pacientes. / In chronic myeloid leukemia (CML) the Bcr-Abl protein has constitutively activated tyrosine kinase activity, that induces to myeloproliferation and apoptosis resistance of the cells. Most patients in chronic phase of CML treated with the tyrosine kinase inhibitor (TKI) imatinib mesylate have a complete cytogenetic remission, but a portion of these patients have been shown to be resistant to therapy. The pathophysiology of CML and the cellular and molecular mechanisms involved in resistance to TKIs therapy are diverse and require further study. In this sense, the aim of this study was to quantify the expression levels of the DIDO gene, including its isoforms (DIDO 1, 2 and 3) and promoters (DIDO PP and PD) in controls and in patients with CML in different phases of the disease treated or not treated with TKIs, as well as in cell lines BCR-ABL1+ sensitive (S) and resistant (R) to imatinib mesylate (IM). The literature reports that DIDO 1 is involved in apoptosis process and that alterations of DIDO 2 and DIDO 3 expression may be associated with the development of myeloid neoplasms. Thus, 60 CML patients, 57 control individuals and the cell lines HL-60, HL-60.Bcr-Abl+, LAMA 84 S, LAMA 84 R, KCL 22 S and KCL 22 R were studied. Peripheral blood mononuclear cells of patients and controls were isolated and RNA extraction and cDNA synthesis were performed. The cDNA samples were used in Real-Time PCR reactions (qPCR) to quantify the DIDO 1, 2, 3, PP, PD and ORF gene expression. The cell lines were treated during 4h with TKIs and then the expression of DIDO different isoforms was also quantified by qPCR. The assessment of protein expression of Bcr-Abl, c-Abl and phosphorylated proteins in this cell lines was performed by Western blotting. The DIDO 1 and 2 expression was higher in advanced phases patients and in chronic phase patients CML treated with TKIs (imatinib mesylate and dasatinib) than in controls. Chronic phase CML Patients treated with IM expressed more DIDO 1 and 3 than chronic phase untreated patients. There was a positive correlation between BCR-ABL1 expression and DIDO 2 expression and between Sokal score prognostic and DIDO 2 expression. In HL60.Bcr-Abl+ cells the expression of phosphorylated proteins was lower after treatment during 4h with TKIs, but there was no change in DIDO gene expression. There were an increase of DIDO 1 expression in all S and R cell lines after treatment during 4h with IM. Therefore we conclude that the DIDO different isoforms may have different functions in chronic myeloid leukemia; the treatment of patients and BCR-ABL1+ cell lines with TKIs increases DIDO 1 expression; and that the DIDO 2 expression is positively correlated to the BCR-ABL1 expression and Sokal score prognostic of CML patients.

abstract: The phycologist, M. R. Droop, studied vitamin B12 limitation in the flagellate Monochrysis lutheri and concluded that its specific growth rate depended on the concentration of the vitamin within the cell; i.e. the cell quota of the vitamin B12. The Droop model provides a mathematical expression to link growth rate to the intracellular concentration of a limiting nutrient. Although the Droop model has been an important modeling tool in ecology, it has only recently been applied to study cancer biology. Cancer cells live in an ecological setting, interacting and competing with normal and other cancerous cells for nutrients and space, and evolving and adapting to their environment. Here, the Droop equation is used to model three cancers. First, prostate cancer is modeled, where androgen is considered the limiting nutrient since most tumors depend on androgen for proliferation and survival. The model's accuracy for predicting the biomarker for patients on intermittent androgen deprivation therapy is tested by comparing the simulation results to clinical data as well as to an existing simpler model. The results suggest that a simpler model may be more beneficial for a predictive use, although further research is needed in this field prior to implementing mathematical models as a predictive method in a clinical setting. Next, two chronic myeloid leukemia models are compared that consider Imatinib treatment, a drug that inhibits the constitutively active tyrosine kinase BCR-ABL. Both models describe the competition of leukemic and normal cells, however the first model also describes intracellular dynamics by considering BCR-ABL as the limiting nutrient. Using clinical data, the differences in estimated parameters between the models and the capacity for each model to predict drug resistance are analyzed. Last, a simple model is presented that considers ovarian tumor growth and tumor induced angiogenesis, subject to on and off anti-angiogenesis treatment. In this environment, the cell quota represents the intracellular concentration of necessary nutrients provided through blood supply. Mathematical analysis of the model is presented and model simulation results are compared to pre-clinical data. This simple model is able to fit both on- and off-treatment data using the same biologically relevant parameters. / Dissertation/Thesis / Doctoral Dissertation Applied Mathematics 2015

Orientador: Célia Regina Nogueira / Resumo: A Leucemia Mielóide Crônica (LMC) é uma doença malígna, clonal, da célula tronco hematopoética. A descoberta do cromossomo filadélfia e subsequente identificação do gene BCR-ABL, levaram a compreensão da biologia da doença que culminou com o desenvolvimento de drogas alvo-específicas, assim como o de métodos moleculares para o monitoramento da doença. O foco atual das pesquisas em LMC está voltado para o maior entendimento dos mecanismos moleculares e epigenéticos que levam a resistência terapêutica e progressão da doença. Estudos recentes demonstram que a expressão de micro-RNAs específicos modula oncogenes e genes supressores envolvidos no desenvolvimento de neoplasias. Ao encontro a esta tendência, propomos um estudo que procurou identificar o perfil de micro-RNAs dos pacientes bons respondedores aos tratamentos de primeira linha para LMC. Avaliamos o perfil de micro-RNAs, de 41 pacientes com LMC que atingiram resposta citogenética completa (ausência do cromossomo Filadélfia) após o tratamento com inibidor de tirosinaquinase e transplante alogênico de células progenitoras hematopoéticas, por meio do sistema de micro-RNA PCR arrays (TaqMan® Human Micro-RNA Array A e B). Identificamos uma assinatura de micro-RNA distinta entre os grupos tratados, apesar de se encontrarem no mesmo patamar de resposta clínica e citogenética. Palavras-chave: Leucemia Mielóide Crônica, micro-RNA, imatinibe, transplante, qPCR array. / Abstract: Chronic Myeloid Leukemia (CML) is a malignant clonal hematopoietic stem cell disease. The discovery of the Philadelphia chromosome and subsequent identification of the gene BCR-ABL have led to understanding the biology of the disease and the development of target-specific drugs, as well as molecular methods for monitoring the disease. The current focus of research in the CML is facing the greatest understanding of the molecular and epigenetic mechanisms that lead to therapy resistance and disease progression. Recent studies show that the expression of specific micro-RNAs modulates oncogenes and tumor suppressor genes involved in cancer development.We are proposing a new study in the literature that aims to identify the profile of micro-RNAs of patients good responders to first-line treatments for CML.Evaluated the profile of micro-RNAs in 41 CML patients who achieved a complete cytogenetic response (absence of Philadelphia chromosome) after treatment with tyrosine kinase inhibitor and allogeneic bone marrow transplantation, through the micro-RNA- PCR arrays (TaqMan® Human Micro-RNA Array A e B). We identified a distinct micro-RNA signature between the treated groups, despite being on the same level of cytogenetic and clinical response.Key Words: Chronic Myeloid LeuKemia, micro-RNA, imatinib, bone marrow transplantation, qPCR array. / Mestre

A leucemia mieloide crônica (LMC) é uma expansão clonal da célula progenitora hematopoiética, traduzindo-se por hiperplasia mielóide, 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 produz uma proteína com elevada atividade tirosinoquinase que tem um papel central da patogenia da LMC. O mesilato de imatinibe (MI) é um derivado da fenilaminopirimidina que inibe a proteína-tirosina quinase ABL in vitro e in vivo. O MI interage com transportadores de membrana de efluxo, como o ATP binding cassette B1 (ABCB1). Polimorfismos no gene ABCB1 têm sido associados com alteração na sua funcionalidade e podem estar envolvidos na resposta ao tratamento farmacológico. Este estudo tem por objetivo investigar a relação dos polimorfismos C1236T, C3435T e G2677T/A no gene ABCB1 com marcadores de resposta ao tratamento com MI, em indivíduos com LMC, e determinar os fatores de predisposição de resposta ao MI. Foram incluídos 118 pacientes portadores de LMC. Foram constituídos dois grupos: Grupo 1 com 70 pacientes com resposta citogenética completa com a dose padrão de MI (400 mg/dia de MI) por 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 . Amostras de sangue foram obtidas para: quantificação de BCR-ABL1, extração de DNA genômico e análise citogenética de banda G. As análises dos polimorfismos foram realizadas por PCR-RFLP. A resposta ao tratamento foi avaliada segundo os critérios da European LeukemiaNet. A distribuição da frequência dos genótipos dos polimorfismos C1236T, C3435T e G2677T/A foi similar nos dois gêneros e entre brancos e não brancos. Não houve influência dos polimorfismos estudados no risco de desenvolvimento da LMC e na resposta ao MI. O haplótipo ABCB1 1236CT/2677GT/3435CT (para os polimorfismos C1236T/G2677T/C3435T no gene ABCB1) foi encontrado em 51,7% dos pacientes com resposta molecular maior (P=0,010). Houve tendência a maior frequência de pacientes portadores de genótipos 1236 CT e TT no grupo de respondedores (86,7%) quando foi analisada a resposta molecular completa (p=0,069). O mesmo aconteceu no grupo de não respondedores quando foi considerado o polimorfismo C1236T. Houve tendência a maior frequência de resposta molecular completa em portadores de genótipo 2677 GT+TT+TA nos dois grupos (respondedores P=0,074 e não respondedores P=0,076). Em conclusão, os genótipos e haplótipos para os polimorfismos ABCB1 C1236T, C3435T e G2677T/A estão associados com a resposta molecular em portadores de LMC respondedores ao tratamento com MI. / The chronic myeloid leukemia (CML) is a clonal expansion of the hematopoietic progenitor cell, representing myeloid hyperplasia, leukocytosis, neutrophilia, basophilia and splenomegaly. The Philadelphia chromosome is peculiar on the disease, being the result of the translocation t(9; 22) (q34; q11), leading on the fusion of the ABL and BCR genes. This merger creates a hybrid gene that produces a protein with high activity of tyrosine kinase that is the main pathogenesis of CML. The Imatinib mesylate (IM) is a fenilaminopirimidine derivative which inhibits the ABL protein-tyrosine kinase in vitro and in vivo. The MI interacts with membrane efflux transporters, such as ATP binding cassette B1 (ABCB1). Polymorphisms in the ABCB1 gene have been associated with changes in its functionality and may be involved on the response to drug treatment. This study aims to investigate the relationship of C1236T, C3435T and G2677T / A polymorphisms in ABCB1 gene with response markers for MI treatment in individuals with CML, and to determine the predisposing factors of response to MI. 118 patients with CML were included and divided in two groups. Group 1: 70 patients with complete cytogenetic response and a standard dose of IM (400 mg / day IM) for up to 18 months. Group 2: 48 patients without a complete cytogenetic response and initial dose of 400 mg / day IM or whith response lost throughout the treatment. Blood samples were obtained for: quantification of BCR-ABL1, genomic DNA extraction and band G cytogenetic analysis. The analysis of the polymorphisms were performed by PCR-RFLP. The treatment response was evaluated according to European LeukemiaNet criteria. The frequency distribution of genotypes of C1236T, C3435T and G2677T / A polymorphisms were similar in both sexes and between whites and nonwhites. The polymorphisms studied had no influence on the CML development or MI response. The haplotype ABCB1 1236CT/2677GT/3435CT (for C1236T/G2677T/C3435T polymorphisms in the ABCB1) was found in 51.7% patients with major molecular response (P = 0.010). There was a tendency for higher frequency of patients with 1236 CT and TT genotypes in the responders group (86.7%) when the molecular response was analyzed (p = 0.069). The same happened in the nonresponders group when the C1236T polymorphism was considered. There was a tendency for a higher frequency of complete molecular response in patients with 2677 GT + TT + TA genotype in both groups (responders P = 0.074 and nonresponders P = 0.076). In conclusion, genotypes and haplotypes for ABCB1 C1236T, C3435T and G2677T / A polymorphisms are associated with molecular response in patients with CML that respond to MI treatment.

Orientadores: Karin Spat Albino Barcellos Silveira, Sara Teresinha Olalla Saad / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-23T03:35:28Z (GMT). No. of bitstreams: 1 Bernusso_VanessaAline_M.pdf: 2366309 bytes, checksum: d89f227d922fcfaba6696c0e1af0fdae (MD5) Previous issue date: 2013 / Resumo: VASP (Vasodilator-stimulated phosphoprotein) e Zyxin são proteínas reguladoras de actina que controlam a adesão célula-célula. Zyxin dirige a montagem da actina através da interação e recrutamento da VASP a sítios específicos da adesão. A fosforilação da VASP ou da Zyxin altera suas atividades nas junções aderentes. PKA fosforila VASP em serina 157, regulando, assim, importantes funções celulares de VASP. VASP interage com ABL e é substrato da oncoproteína BCR-ABL. A presença da proteína BCR-ABL promove a oncogênese em pacientes com leucemia mieloide crônica (LMC) devido à ativação constitutiva da atividade tirosina quinase. Apesar de já descrita alteração da expressão de VASP e Zyxin em diferentes tumores epiteliais, o papel de VASP e Zyxin na LMC, na via de sinalização BCR-ABL e a participação destas proteínas na hematopoiese são desconhecidos. Desta maneira, demonstramos aqui ausência de p-VASP ser157 em células de medula óssea de pacientes com LMC, em contraste com a presença de p-VASP ser157 em doadores saudáveis. Pacientes com LMC em remissão, responsivos a inibidores de tirosina quinase, apresentam p-VASP ser157, enquanto os pacientes resistentes não expressam p-VASP ser157. Utilizando células K562 inibidas para VASP ou Zyxin, observamos que VASP e Zyxin modulam as proteínas anti-apoptóticas BCL-2 e BCL-XL da via de sinalização do BCR-ABL. Em adição, células K562 silenciadas para a VASP apresentam diminuição na atividade de FAK y925 e demonstramos que VASP interage com FAK. A expressão de VASP e Zyxin e de suas formas ativas aumenta durante a diferenciação megacariocítica e a inibição de VASP implica em diminuição na expressão do marcador CD61. Identificamos no presente estudo a participação de VASP e Zyxin na via do BCR-ABL, regulando a expressão de proteínas efetoras anti-apoptóticas e, também, na diferenciação megacariocítica. Desta maneira, a expressão alterada da atividade de VASP nos pacientes com LMC pode contribuir para a patogênese da doença, seja afetando a diferenciação celular ou a adesão das células leucêmicas / Abstract: VASP (vasodilator-stimulated phosphoprotein) and Zyxin are actin regulatory proteins that control cell-cell adhesion. Zyxin directs actin assembly by interacting and recruiting VASP to specific sites of adhesion. The phosphorylation of VASP and Zyxin modifies their activity in cell-cell junctions. PKA phosphorylates VASP at serine 157 regulating VASP cellular functions. VASP interacts with ABL and VASP is a substrate of BCR-ABL oncoprotein. The presence of BCR-ABL protein drives oncogenesis in patients with chronic myeloid leukemia (CML) due to a constitutive activation of tyrosine kinase activity. It has been described an altered expression of VASP and Zyxin in different types of tumor; however the function of VASP and Zyxin in CML, in BCR-ABL pathway and in hematopoiesis remains unknown. We describe here the absence of p-VASP ser157 in CML bone marrow cells, in contrast to p-VASP ser157 expression in healthy donors. Patients responsive to tyrosine kinase inhibitors present p-VASP ser157, while resistant patients do not have p-VASP ser157. In K562 cells we observed that VASP and Zyxin modulate anti-apoptotic proteins BCL-2 and BCL-XL. VASP depletion in K562 cells decreases FAK y925 activity and VASP interacts with FAK. Expression of VASP, p-VASP, Zyxin and p-Zyxin increases during megakaryocyte differentiation and VASP inhibition affects this differentiation through reduced CD61 expression in VASP depleted cells. We identify here the participation of VASP and Zyxin in BCR-ABL pathway affecting anti-apoptotic proteins and, also, in megakaryocyte differentiation. Then, the altered expression of VASP activity in CML patients may contribute to CML pathogenesis, affecting cellular differentiation or leukemic cell adhesion / Mestrado / Fisiopatologia Médica / Mestra em Ciências

La Leucémie Myéloïde Chronique (LMC) est une maladie clonale caractérisée par la présence du chromosome Philadelphie codant pour Bcr-Abl, une tyrosine kinase constitutivement active responsable de la leucémogenèse. Bien que très efficaces, les inhibiteurs de tyrosine kinase (ITKs) restent cependant inactifs sur les cellules souches leucémiques. Ce travail de thèse montre que la signalisation calcique, connue pour réguler de nombreux processus dans les cellules saines et cancéreuses, est importante dans la signalisation cellulaire au décours de la LMC. Le rôle des entrées calciques dépendantes des stocks (SOCEs) médiées par STIM1 (STromal Interaction Molecule 1) et les canaux Orai1 et TRPC1 ainsi que des entrées calciques induites par la thrombine a été étudié dans la leucémogenèse. Nous avons observé une diminution de ces entrées dans les cellules exprimant Bcr-Abl pouvant être expliquée par le changement de stœchiométrie Orai1/STIM1. Ceci entraîne la diminution de l'activation de NFAT (Nuclear Factor of Activated T-cells) ainsi que des conséquences sur la prolifération et la migration cellulaire mais pas sur l'apoptose. De plus, les SOCEs sont restaurées dans les cellules cancéreuses après traitement à l'Imatinib, le principal ITK. Nous proposons alors que l'expression de Bcr-Abl joue un rôle sur l'homéostasie calcique en entraînant une dérégulation générale des fonctions cellulaires dans les cellules leucémiques notamment via la voie PKC (Protein Kinase C). Ainsi, ces résultats montrent une dérégulation des entrées calciques dans les cellules exprimant Bcr-Abl, suggérant que la signalisation calcique puisse être une cible thérapeutique en parallèle avec les ITKs. / Chronic Myeloid Leukemia (CML) is a clonal disease characterized by the presence of the Philadelphia chromosome encoding for Bcr-Abl, a constitutively active tyrosine kinase responsible for leukemogenesis. Although Bcr-Abl tyrosine kinase inhibitors (TKIs) have revolutionized the therapy of Ph+ leukemia, the complete eradication of CML is limited by the emergence of resistance in hematopoietic stem cells. This thesis proposes that calcium (Ca2+) signaling pathways, known to govern a large number of functions in normal and cancer cells, may be important in CML cell signaling. Therefore, we studied the role of Store Operated-Calcium entry (SOCE) (i.e. STromal Interaction Molecule 1 (STIM1), Orai1 and TRPC1 channels) and thrombin induced Ca2+ entry in leukemogenesis. We found a decrease in both calcium entries in Bcr-Abl-expressing cells compared to normal cells. The reduced SOCE seems related to a change in stoichiometry of Orai1/STIM1. This leads to a reduction of the Nuclear Factor of Activated T-cells (NFAT) translocation and functional consequences on cell proliferation and migration but not on apoptosis. Moreover, we showed that SOCE is restored in malignant cells after treatment with Imatinib, the main TKI. We proposed that Bcr-Abl expression could impact on Ca2+ homeostasis enhancing a general disorganization of cell functions in leukemia cells notably via Protein Kinase C (PKC) pathway. Altogether this work shows a deregulation of Ca2+ entry in Bcr-Abl-expressing cells, suggesting that the Ca2+ signaling pathway could be a therapeutic target in parallel with TKIs.

La technologie iPSC (induced pluripotent stem cells) permet l’obtention d’une source cellulaire illimitée pour la modélisation et la thérapie de maladies génétiques, la médecine régénérative, l’étude pharmacologique et récemment la modélisation et l’étude du cancer. La leucémie myéloïde chronique (LMC) est la pathologie modèle du concept de « cellule souche cancéreuse » : des cellules souches LMC (CS-LMC) s’avèrent résistantes aux inhibiteurs de tyrosine kinases (ITK), traitement conventionnel de ce syndrome myéloprolifératif. Elles sont responsables de la persistance d’une maladie résiduelle et de rechutes lors de l’interruption du traitement. Malheureusement, leur isolement est difficile. Nous proposons dans ce travail de modéliser les CS-LMC par les iPSC LMC. Nous montrons pour la première fois dans les iPSC LMC que BCR-ABL1 réprime l’expression des facteurs clés de la pluripotence (OCT4,NANOG, le cluster miR302-367) via les kinases ERK1/2. Les ITK, en bloquant l’activité deBCR-ABL1, entraîne une hausse des niveaux d’expression de ces marqueurs. L’effet « prosouche» des ITK, découvert dans les iPSC LMC, est également observé lors du traitement de CS-LMC primaires. L’agent thérapeutique pourrait ainsi, en maintenant ou renforçant le compartiment LMC immature, participer paradoxalement à la persistance de la maladie résiduelle. Étonnamment, les ITK augmentent également l’expression des marqueurs« souches » dans les iPSC et CS hématopoïétiques normales. Ce résultat suggère un effet« pro-souche » généralisé à plusieurs types cellulaires. / IPSC (induced pluripotent stem cells) offer renewable source of biologically relevant human cells for genetic diseases modelling and therapy, regenerative medicine, pharmacological study and, recently, cancer research. The proof of « cancer stem cell concept » was established in chronic myeloid leukemia (CML) : CML stem cells (CML-SC) are resistant to treatment (tyrosine kinase inhibitors (TKI)). They are involved in residual disease persistence and relapse when treatment is discontinued in the majority of patients. We modelled CML-SC with CML iPSC. We showed, for the first time, that BCR-ABL1 acts as a repressor of key stemness markers (OCT4, NANOG, miR302-367 cluster) via ERK1/2 in human CML iPSC. By blocking BCR–ABL1 activity, TKI increase pluripotency gene expression. Interestingly, a similar pro-stemness effect was observed during CML-SC treatment. By inducing a more primitive stemness phenotype, TKI could promote residual disease and relapse. Interestingly, an increase of stemness gene expression was also observed during TKI treatment of healthy cells (iPSC and hematopoietic stem cells). These data suggest a global TKI pro-stemness effect in other stem cell types.

Orientador: Katia Borgia Barbosa Pagnano / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-26T19:42:43Z (GMT). No. of bitstreams: 1 Ribeiro_BeatrizFelicio_M.pdf: 2588401 bytes, checksum: 356f862f97d6467c69db0ac9b13f28d5 (MD5) Previous issue date: 2015 / Resumo: A Leucemia Mielóide Crônica (LMC) é uma neoplasia mieloproliferativa crônica caracterizada pela presença do cromossomo Filadélfia (Ph) e produção da fusão proteica BCR-ABL que possui atividade tirosina quinase. O tratamento da LMC é realizado com inibidores de tirosina quinase (TKIs) e apesar das altas taxas de respostas obtidas com imatinibe, alguns pacientes são resistentes ou intolerantes ao tratamento, sendo necessário a troca para um TKI de segunda geração (nilotinibe ou dasatinibe). O monitoramento das respostas obtidas ao longo do tratamento permite identificar os pacientes que estão em um "estado seguro" (resposta ótima) e os que podem falhar ao tratamento. Os mecanismos de resistência ao tratamento são multifatoriais e a identificação desses mecanismos pode contribuir para o desenvolvimento de novas estratégias para o tratamento dos casos resistentes. Em um trabalho anterior do nosso grupo foram identificados diversos genes e RNAs longos não codificantes diferencialmente expressos em pacientes responsivos e não responsivos ao dasatinibe, entre eles os genes ABCF2, ALOX15B, PAWR, ncFOXO3A, ncMYLIP e ncSLC44A2. O objetivo desse trabalho foi avaliar a resposta molecular em pacientes com LMC em uso de inibidores de tirosina quinase de segunda geração (dasatinibe ou nilotinibe) após falha ou intolerância a um ou dois TKIs e avaliar a expressão dos genes ABCF2, ALOX15B, PAWR, ncFOXO3A, ncMYLIP e ncSLC44A2 em pacientes responsivos e resistentes ao dasatinibe. A metodologia utilizada para avaliação dos níveis de trancritos BCR-ABL e da expressão gênica foi o PCR quantitativo em tempo real. A pesquisa de mutações no domínio quinase do BCR-ABL foi realizada nos casos resistentes, através da técnica de sequenciamento direto. Setenta e um pacientes tratados com dasatinibe ou nilotinibe após falha ou intolerância ao imatinibe foram avaliados quanto à resposta molecular. Sessenta e sete porcento, 43% e 33% dos pacientes em fase crônica (FC), acelerada (FA) e crise blástica (CB) obtiveram resposta molecular maior (RMM), respectivamente, ao longo do tratamento. Os pacientes com respostas moleculares precoces (transcritos BCR-ABL <10% aos 3 meses e <1% aos 6 meses) apresentaram maiores SLP e SLE do que os casos que não alcançaram esses níveis de transcritos BCR-ABL aos 3 e/ou aos 6 meses. A avaliação molecular aos 3 meses e aos 6 meses permitiu a melhor identificação dos pacientes com pior prognóstico. Foram também avaliados 25 pacientes tratados com dasatinibe/nilotinibe após falha ou intolerância a dois TKIs. RMM foi obtida em somente 24% dos casos (em FC, um paciente em FA). As taxas de SG e SLP em 5 anos para pacientes em FC foram de 94% e 94%, respectivamente. Poucos pacientes alcançam respostas e essas respostas não são duráveis. Embora seja uma opção para pacientes não elegíveis ao TMO, é necessário o desenvolvimento de um tratamento mais eficaz para esses pacientes. Para avaliação da expressão dos genes ABCF2, ALOX15B, PAWR, ncFOXO3A, ncMYLIP e ncSLC44A2 foram utilizadas amostras de 9 pacientes ao diagnóstico (sem tratamento prévio), 39 pacientes tratados com dasatinibe (25 responsivos com RCC e 14 resistentes) e 13 doadores saudáves. Não houve diferença de expressão do gene ncSLC44A2 entre os grupos avaliados. Os genes ALOX15B e ncMYLIP estavam hipoexpressos em pacientes com LMC ao diagnóstico em relação aos pacientes com LMC tratados com dasatinibe e ao grupo controle. O gene ncFOXO3A apresentou expressão diminuída em pacientes com LMC ao diagnóstico em relação aos pacientes tratados com dasatinibe. O genes ABCF2 e PAWR estavam hipoexpressos em pacientes ao diagnóstico e nos pacientes tratados com dasatinibe em relação ao grupo controle. Além disso, o gene PAWR estava pouco expresso em pacientes resistentes ao dasatinibe em relação aos pacientes responsivos. Portanto, os genes ABCF2, ALOX15B, PAWR, ncMYLIP e ncFOXO3A foram encontrados com expressão alterada nos grupos estudados e podem estar associados a mecanismos importantes relacionados ao desenvolvimento e resistência da LMC, o que deve ser elucidado em estudos prospectivos / Abstract: Chronic myeloid leukemia (CML) is a chronic myeloproliferative neoplasm characterized by the presence of Philadelphia chromosome (Ph) and production of BCR-ABL fusion protein that has tyrosine kinase activity. Currently, the treatment of CML is accomplished with tyrosine kinase inhibitors (TKIs). Despite the high rates of responses obtained with imatinib, some patients are resistant or intolerant to treatment and need to switch to second generation TKIs (dasatinib or nilotinib). Monitoring responses during treatment allows the identification of patients who are in a "safe haven" (optimal response) and patients who may fail to treatment. Mechanisms of resistance to treatment are multifactorial and identification of these mechanisms may contribute to the development of new strategies for treatment of resistant cases. In a previous report of our group were identified several genes and long non-coding RNAs differentially expressed in CML patients responders and non-responders to dasatinib, including ABCF2, ALOX15B, PAWR, ncFOXO3A, ncMYLIP and ncSLC44A2 genes. The aim of this study was to evaluate molecular responses in CML patients treated with second generation TKIs (dasatinib or nilotinib) after failure or intolerance to one or two TKIs and to evaluate the expression of ABCF2, ALOX15B, PAWR, ncFOXO3A, ncMYLIP and ncSLC44A2 genes in patients responsive and resistant to dasatinib. The methodology used to evaluate BCR-ABL transcript leves and the gene expression was quantitative real time PCR. BCR-ABL kinase domain mutations analysis was performed in resistant cases by direct sequencing. Seventy-one patients treated with dasatinib/nilotinib after failure or intolerance with imatinib were evaluated according to molecular responses. Sixty-seven percent, 43% and 37% of chronic phase (CP), accelerated phase (AP) and blast crisis (BC) CML patients achieved major molecular response (MMR), respectively, during treatment. Patients with early molecular responses (BCR-ABL1<10% at 3 months and <1% at 6 months) had superior PFS and EFS than patients that not achieved these landmarks. The evaluation at 3 and 6 months allows better identication of patients with worse prognosis. We analyzed molecular responses in 25 patients treated with dasatinib/nilotinib after failure or intolerance with two TKIs. MMR was achieved in 24% of cases (all in CP, one in AP). Five-year OS and PFS rates for CP-CML patients were 94% and 94%, respectively. Few patients achieved responses and these responses are not durable. Although, dasatinib/nilotinib had been options for patients not elegible for bone morrow transplantation, its necessary the development of a treatment more effective to these patients. To evaluate the expression of ABCF2, ALOX15B, PAWR, ncFOXO3A, ncMYLIP e ncSLC44A2 genes was used samples of 9 patients newly diagnosed (without treatment), 39 patients treated with dasatinib (25 responsives with CCyR and 14 resistant) and 13 healthy donors. There¿s no difference of ncSLC44A2 gene expression between the groups analized. ALOX15B and ncMYLIP genes were down-regulated in CML patients newly diagnosed in comparison with CML patients treated with dasatinib and control group. ncFOXO3A gene presented decreased expression in CML patients at diagnosis in comparison with patients treated with dasatinib. ABCF2 and PAWR genes were down-regulated in CMl patients newly diagnosed and in CML patients treated with dasatinib in comparison with control group. Moreover, PAWR gene was down-regulated in CML patient¿s resistants to dasatinib in comparison with responsives. ABCF2, ALOX15B, PAWR, ncMYLIP and ncFOXO3A were found with altered expression between the groups evaluated and may be associated with mechanisms related to the development and resistance of CML, which should be elucidated in prospective studies / Mestrado / Clinica Medica / Mestra em Ciências