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Hematopoiesis is the highly regenerative process of producing billions of blood cells each day, including white blood cells, red blood cells, and platelets. Given the relatively short life span of these mature cells, hematopoiesis is dependent on stem and progenitor cells to generate renewed progeny, which represents a tightly regulated process. This includes cell intrinsic and external factors, and where dysregulation can lead to anemia and cancer. As such, the hematopoietic hierarchy has been intensely studied for nearly a century and represents a gold standard model of cell fate and developmental biology, in research and clinical applications. Cellular models, such as in vitro culture and human-mouse xenografts in vivo, have been developed to explain complex phenomena pertaining to hematopoiesis and also interrogate processes which are too invasive to study in humans. Hematopoietic generation is required beyond sustaining homeostasis, and progenitors can be damaged through cytotoxic injuries such as radiation and standard chemotherapy, and also undergo leukemic transformation. There are two main treatment modalities for leukemia patients (a) receiving a stem cell transplant, and (b) drug or radiation-based therapy. In the former, shortages of donors and stem cells has remained an unmet clinical need for decades. In the latter, selective targeting of genetic mutations has become a successful standard-of-care in leukemias such as chronic myelogenous leukemia and acute promyelocytic leukemia. However, in the most common adult hematologic malignancy, chronic lymphocytic leukemia (CLL), similar targeting therapies have not been developed. Altogether, shortages of stem cells from healthy donors, chemotherapy-induced immune dysfunction, and a lack of targeted therapies, all reinforce the immediate need for innovative cellular models to address these clinical problems. To generate additional sources of human hematopoietic progenitors for laboratory study, human PSCs have been used. Unlike hematopoietic progenitor cells collected from healthy and leukemic donors, human pluripotent stem cells (PSC) can be easily propagated and expanded in vitro. PSCs can generate hematopoietic progenitor cells, but they remain poorly understood and have not been robustly applied to solve the aforementioned deficiencies related to patient treatment. Importantly, the biological regulation of both hematopoiesis and PSCs has been experimentally confirmed to significantly deviate between humans and other animals, such as mice, further reinforcing the importance of human-specific cell models of hematopoiesis. Therefore, I hypothesized that human stem cell models provide a focused approach to interrogate the regulation of hematopoiesis from the apex of the hierarchy, which can be used to understand the promotion of healthy hematopoiesis and understand malignant transformation. Collectively, the data presented within this thesis offer a deeper conceptualization of human stem cell models and the deconvolution of several complex components of hematopoietic regulation. This work has revealed novel, clinically relevant, and actionable targets to ultimately enable the promotion of healthy hematopoiesis on multiple fronts. / Thesis / Doctor of Philosophy (PhD) / This thesis presents research on novel molecular and genetic regulatory pathways of self-renewal and differentiation in models of healthy and malignant human hematopoiesis. The origin of healthy hematopoietic regulation stems from a large body of work spanning decades and encompasses many efforts by others to derive hematopoietic stem cells from human pluripotent cells. The development of a genetic model for the malignant regulation of CLL was truly serendipitous, was propelled through robust and intriguing results that begged for further exploration, and filled a clinical gap in identifying actionable targets in CLL. Lastly, these two projects, along with my supportive roles in other published works throughout my graduate studies, instructed me to develop a human-mouse transplant model to uncover the biology of regenerating healthy hematopoiesis during injury.

No / Tenovin-6 (Tnv-6) is a bioactive small molecule with anti-neoplastic activity. Inhibition of the Sirtuin class of protein deacetylases with activation of p53 function is associated with the pro-apoptotic effects of Tnv-6 in many tumors. Here, we demonstrate that in chronic lymphocytic leukemia (CLL) cells, Tnv-6 causes non-genotoxic cytotoxicity, without adversely affecting human clonogenic hematopoietic progenitors in vitro, or murine hematopoiesis. Mechanistically, exposure of CLL cells to Tnv-6 did not induce cellular apoptosis or p53-pathway activity. Transcriptomic profiling identified a gene program influenced by Tnv-6 that included autophagy-lysosomal pathway genes. The dysregulation of autophagy was confirmed by changes in cellular ultrastructure and increases in the autophagy-regulatory proteins LC3 (LC3-II) and p62/Sequestosome. Adding bafilomycin-A1, an autophagy inhibitor to Tnv-6 containing cultures did not cause synergistic accumulation of LC3-II, suggesting inhibition of late-stage autophagy by Tnv-6. Thus, in CLL, the cytotoxic effects of Tnv-6 result from dysregulation of protective autophagy pathways.

A leucemia linfóide aguda nos adultos apresenta prognóstico reservado. Os objetivos deste estudo são descrição e análise de parâmetros clínicos, laboratoriais e fatores prognósticos em 102 pacientes tratados com diferentes protocolos de quimioterapia no período de 1990 a 2005, no Serviço de Hematologia do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo. Em estudo de coorte retrospectivo, com exclusão de LLA subtipo L3 (FAB) ou B-IV (EGIL), foram analisadas a taxa de remissão completa (RC), sobrevida global (SG) e sobrevida livre de doença (SLD) para a população geral e para os dois principais protocolos de tratamento. A análise estatística foi feita pelo programa SPSS 10.0. Associação entre variáveis, fatores prognósticos e resposta foram observados através do teste ?2 de Person. Curvas de SG e SLD foram construídas pelo método de Kaplan-Meier e as diferenças analisadas pelo teste de log-rank. A idade média foi de 30,6 anos (12 a 82 anos) e predominou o sexo masculino (55,9%). Ao diagnóstico, os achados clínicos foram: fadiga (58,2%), esplenomegalia (59,7%), hepatomegalia (54,6%), linfadenopatia (52,6), febre (38,8%), dor óssea(28,6%), sangramento (27,5%) e cefaléia (15,3%). Envolvimento do sistema nervoso central (SNC) foi detectado em 11 (11,8%) pacientes, enquanto envolvimento testicular acometeu um paciente. O valor médio de hemoglobina, leucócitos e plaquetas foram 8,5g/dl, 84.341/mm3 e 76.275/mm3, respectivamente. 98,7% dos pacientes apresentaram linfoblastos no sangue periférico. A classificação FAB foi igualmente observada entre os tipos L1 e L2. As LLA B e T foram observadas em 69,7% e 30,2%, respectivamente. O cariótipo foi realizado em 40 pacientes, e t (9;22) foi identificada em 20% (8/40) dos casos. Os pacientes foram tratados com quatro diferentes protocolos: BFM 86 modificado (BFM 86M) em 47,15% (48/102), Linker et al em 39,2% (40/102), Lister et al em 5,9% (6/102) e CHOP em 7,8% (8/102). Na análise para a população geral, na fase de indução, 70,6% (65/92) dos pacientes entraram em RC. Idade inferior a 18 anos e ausência de infiltração de SNC foram fatores preditores positivos de resposta em análise multivariada (p=0,03). Com mediana de seguimento de 49 meses, observamos taxa de 30,5% e 27% para SG e SLD em 4 anos. Ausência de sangramento e hepatomegalia, ao diagnóstico, e idade < 35 anos estiveram associados à maior SG através de análise multivariada (p=0,01). Os dois protocolos com maior número de pacientes, apresentaram distribuição semelhante de parâmetros clínicos e laboratoriais, a exceção da variável FAB. RC foi obtida em 76,7% e 63,9% dos pacientes tratados respectivamente com os protocolos BFM 86M e Linker (p=0,21). A SG foi de 49,5% com o BFM 86M em 4 anos Vs 16% com o protocolo Linker (p=0,004). Observou-se que o protocolo BFM86M teve melhor SG para pacientes com idade <35 anos (p=0,01), sem sangramento e hepatomegalia ao diagnóstico (p=0,03 e p=0,01) e sem leucocitose (B <30.000mm3 e T <100.000mm) (p=0,04); enquanto que pacientes com LLA T tratados com o protocolo Linker apresentaram SG inferior (p=0,05). A diferença de SLD entre os dois protocolos não foi significativa (p=0,58), entretanto na faixa etária entre 21-35 anos, o protocolo BFM se mostrou superior (p=0,03). Verificamos que o BFM 86M é superior ao Linker et al, sendo um bom protocolo para tratamento de LLA em pacientes adolescentes e adultos jovens sem fatores de risco. / Acute lymphoblastic leukemia in adults has a poor outcome. The aim of this study is to describe and evaluate clinical, laboratory and prognostic factors in 102 patients reated with different protocols of chemotherapy from 1990 to 2005. Adult ALLsubtype L3 (FAB) or B-IV (EGIL) was excluded. We evaluated complete remission (CR), overall survival (OS) and disease free survival (DFS) rates for the whole population and for the two principal treatment protocols. This retrospective cohort was done in hematology department of the FMUSP. Statistical analysis was done by SPSS 10.0. The association of features and prognosis was assessed by Person\'s chi-square. OS and DFS curves were constructed by Kaplan-Meier method and the differences were calculated by the log-rank test. Mean age was 30,6 (12 to 82) years and 55,9% was male. Clinical findings, at diagnosis, were fatigue (58,2%), splenomegaly (59,7%), hepatomegaly (54,6%), ymphadenopathy (52,6%), fever (38,8%), bone pain (28,6%), bleeding (27,5%) and headache (15,3%). Involvement of central nervous system (CNS) was detected in 11 (11,8%) patients and testicular involvement was observed in one patient. Mean blood values were 8,5g/dl, 84.341/mm3 and 76.275/mm3 for hemoglobin, leucocytes and platelets respectively. 98,7% of the patients presented with lymphoblasts in peripheral blood. FAB classification was equally observed between L1 and L2. B and T ALL was noted in 69,7% and 30,2% respectively. Karyotype analysis was performed in 40 cases, where Philadelphia chromosome (ph) was identified in 20% (8/40) of them. Patients were treated with four different protocols: BFM 86 modified (BFM 86M) in 47,1% (48/102), Linker et al in 39,2% (40/102), Lister et al in 5,9% (6/102) and CHOP in 7,8% (8/102) of the patients. In the judgment for the entire population, in induction treatment, 70,6% (65/92) of the patients had CR. Age below 18 years and no infiltration in CNS were positive factors for CR in multivariate analyses (p=0,03). In a median follow up of 49 months, we have observed a 4 years OS and DFS of 30,5% and 27% respectively. No bleeding and hepatomegaly, at diagnosis, and age less than 35 years were factors associated a better OS in multivariate analyses (p=0, 01). Protocols with highest number of patients (BFM and Linker) showed the same distribution of clinical and laboratory factors; exception FAB classification. CR were seen in 76,7% and 63,9% of the patients treated with BFM 86M and Linker respectively. (p=0,21). OS was 49,5% with BFM protocol in 4 years Vs 16% with Linker (p=0,004). We observed a better OS for patients with age below 35 years (p=0,01), no bleeding and no hepatomegaly at diagnosis (p=0,03 ; p=0,01) and no leucocytosis ( B < 30000/mm3 and T < 100000/mm3) treated with BFM 86M; however ALL - T treated with Linker protocols had inferior OS (p=0,05). DFS between protocols wasn\'t significant (p=0,58), but with age between 21 and 35 years BFM was better (p=0,03). We conclude that BFM 86M is superior than Linker et al and it is a good treatment for childhood / young adults without risk factors

A leucemia linfóide aguda nos adultos apresenta prognóstico reservado. Os objetivos deste estudo são descrição e análise de parâmetros clínicos, laboratoriais e fatores prognósticos em 102 pacientes tratados com diferentes protocolos de quimioterapia no período de 1990 a 2005, no Serviço de Hematologia do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo. Em estudo de coorte retrospectivo, com exclusão de LLA subtipo L3 (FAB) ou B-IV (EGIL), foram analisadas a taxa de remissão completa (RC), sobrevida global (SG) e sobrevida livre de doença (SLD) para a população geral e para os dois principais protocolos de tratamento. A análise estatística foi feita pelo programa SPSS 10.0. Associação entre variáveis, fatores prognósticos e resposta foram observados através do teste ?2 de Person. Curvas de SG e SLD foram construídas pelo método de Kaplan-Meier e as diferenças analisadas pelo teste de log-rank. A idade média foi de 30,6 anos (12 a 82 anos) e predominou o sexo masculino (55,9%). Ao diagnóstico, os achados clínicos foram: fadiga (58,2%), esplenomegalia (59,7%), hepatomegalia (54,6%), linfadenopatia (52,6), febre (38,8%), dor óssea(28,6%), sangramento (27,5%) e cefaléia (15,3%). Envolvimento do sistema nervoso central (SNC) foi detectado em 11 (11,8%) pacientes, enquanto envolvimento testicular acometeu um paciente. O valor médio de hemoglobina, leucócitos e plaquetas foram 8,5g/dl, 84.341/mm3 e 76.275/mm3, respectivamente. 98,7% dos pacientes apresentaram linfoblastos no sangue periférico. A classificação FAB foi igualmente observada entre os tipos L1 e L2. As LLA B e T foram observadas em 69,7% e 30,2%, respectivamente. O cariótipo foi realizado em 40 pacientes, e t (9;22) foi identificada em 20% (8/40) dos casos. Os pacientes foram tratados com quatro diferentes protocolos: BFM 86 modificado (BFM 86M) em 47,15% (48/102), Linker et al em 39,2% (40/102), Lister et al em 5,9% (6/102) e CHOP em 7,8% (8/102). Na análise para a população geral, na fase de indução, 70,6% (65/92) dos pacientes entraram em RC. Idade inferior a 18 anos e ausência de infiltração de SNC foram fatores preditores positivos de resposta em análise multivariada (p=0,03). Com mediana de seguimento de 49 meses, observamos taxa de 30,5% e 27% para SG e SLD em 4 anos. Ausência de sangramento e hepatomegalia, ao diagnóstico, e idade < 35 anos estiveram associados à maior SG através de análise multivariada (p=0,01). Os dois protocolos com maior número de pacientes, apresentaram distribuição semelhante de parâmetros clínicos e laboratoriais, a exceção da variável FAB. RC foi obtida em 76,7% e 63,9% dos pacientes tratados respectivamente com os protocolos BFM 86M e Linker (p=0,21). A SG foi de 49,5% com o BFM 86M em 4 anos Vs 16% com o protocolo Linker (p=0,004). Observou-se que o protocolo BFM86M teve melhor SG para pacientes com idade <35 anos (p=0,01), sem sangramento e hepatomegalia ao diagnóstico (p=0,03 e p=0,01) e sem leucocitose (B <30.000mm3 e T <100.000mm) (p=0,04); enquanto que pacientes com LLA T tratados com o protocolo Linker apresentaram SG inferior (p=0,05). A diferença de SLD entre os dois protocolos não foi significativa (p=0,58), entretanto na faixa etária entre 21-35 anos, o protocolo BFM se mostrou superior (p=0,03). Verificamos que o BFM 86M é superior ao Linker et al, sendo um bom protocolo para tratamento de LLA em pacientes adolescentes e adultos jovens sem fatores de risco. / Acute lymphoblastic leukemia in adults has a poor outcome. The aim of this study is to describe and evaluate clinical, laboratory and prognostic factors in 102 patients reated with different protocols of chemotherapy from 1990 to 2005. Adult ALLsubtype L3 (FAB) or B-IV (EGIL) was excluded. We evaluated complete remission (CR), overall survival (OS) and disease free survival (DFS) rates for the whole population and for the two principal treatment protocols. This retrospective cohort was done in hematology department of the FMUSP. Statistical analysis was done by SPSS 10.0. The association of features and prognosis was assessed by Person\'s chi-square. OS and DFS curves were constructed by Kaplan-Meier method and the differences were calculated by the log-rank test. Mean age was 30,6 (12 to 82) years and 55,9% was male. Clinical findings, at diagnosis, were fatigue (58,2%), splenomegaly (59,7%), hepatomegaly (54,6%), ymphadenopathy (52,6%), fever (38,8%), bone pain (28,6%), bleeding (27,5%) and headache (15,3%). Involvement of central nervous system (CNS) was detected in 11 (11,8%) patients and testicular involvement was observed in one patient. Mean blood values were 8,5g/dl, 84.341/mm3 and 76.275/mm3 for hemoglobin, leucocytes and platelets respectively. 98,7% of the patients presented with lymphoblasts in peripheral blood. FAB classification was equally observed between L1 and L2. B and T ALL was noted in 69,7% and 30,2% respectively. Karyotype analysis was performed in 40 cases, where Philadelphia chromosome (ph) was identified in 20% (8/40) of them. Patients were treated with four different protocols: BFM 86 modified (BFM 86M) in 47,1% (48/102), Linker et al in 39,2% (40/102), Lister et al in 5,9% (6/102) and CHOP in 7,8% (8/102) of the patients. In the judgment for the entire population, in induction treatment, 70,6% (65/92) of the patients had CR. Age below 18 years and no infiltration in CNS were positive factors for CR in multivariate analyses (p=0,03). In a median follow up of 49 months, we have observed a 4 years OS and DFS of 30,5% and 27% respectively. No bleeding and hepatomegaly, at diagnosis, and age less than 35 years were factors associated a better OS in multivariate analyses (p=0, 01). Protocols with highest number of patients (BFM and Linker) showed the same distribution of clinical and laboratory factors; exception FAB classification. CR were seen in 76,7% and 63,9% of the patients treated with BFM 86M and Linker respectively. (p=0,21). OS was 49,5% with BFM protocol in 4 years Vs 16% with Linker (p=0,004). We observed a better OS for patients with age below 35 years (p=0,01), no bleeding and no hepatomegaly at diagnosis (p=0,03 ; p=0,01) and no leucocytosis ( B < 30000/mm3 and T < 100000/mm3) treated with BFM 86M; however ALL - T treated with Linker protocols had inferior OS (p=0,05). DFS between protocols wasn\'t significant (p=0,58), but with age between 21 and 35 years BFM was better (p=0,03). We conclude that BFM 86M is superior than Linker et al and it is a good treatment for childhood / young adults without risk factors