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京都大学 / 新制・課程博士 / 博士(医学) / 甲第24189号 / 医博第4883号 / 新制||医||1060(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 小林 恭, 教授 羽賀 博典, 教授 伊藤 貴浩 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

The neuronal cytoskeleton is vital for normal growth and differentiation of the nervous system, as well as for maintenance of the normal intracellular environment. Without it, major functional deficits occur due to interference with cellular transport of membrane components, proteins and neurotransmitter substances and as a result, inadequate maintenance of the distal axon occurs. Through the study of both nervous tissue and primary neuronal culture, specific cytoskeletal markers have been found to predominate in axonal or dendritic processes, as well as in different stages of neuronal development. In vitro study of neuroblastoma cell lines has also been utilized to develop hypotheses of neuronal development. These hypotheses attempt to explain the appearance of certain cytoskeletal elements, such as phosphorylated neurofilament proteins, in relationship to functional maturity of the neuron. We used SY5Y human neuroblastoma cells as an in vitro model of neurotoxicity to investigate cytoskeletal changes that may occur from the exposure of the nervous system to a known neurotoxicant. Cells were differentiated with either retinoic acid (RA) or dibutyryl cyclic adenosine monophosphate (dbcAMP) and 3-isobutyl-1- methyl-xanthine (IBMX). Differentiation was based morphologically on the appearance of neuritic processes in a majority (>50%) of the cells. Using the peroxidase-antiperoxidase technique, cells were labeled with monoclonal antibodies to cytoskeletal proteins (phosphorylated neurofilament, microtubule associated protein 2, vimentin and low molecular weight neurofilament protein) either specific for axonal markers or linked to stages in neuronal development. Staining patterns were compared to undifferentiated cells using the same protocol. There were no differences in staining patterns found between methods of differentiation or between differentiated cells and undifferentiated controls. Axonal markers of differentiation, defined as phosphorylated neurofilament immunopositivity, were only detected in cells exposed to retinoic acid for 9 days. Once these studies were completed, both differentiated and undifferentiated cultures were exposed to acrylamide as an example of a neurotoxicant with known cytoskeletal effects. Cells were fixed and stained after the observation of cellular swelling 24 hours post acrylamide treatment. In spite of obvious alterations in morphology in unstained cells in culture, the cytoskeletal staining pattern was unchanged after acrylamide treatment. We conclude that there is no difference in the cytoskeletal immunoreactivity of SY5Y neuroblastoma cells when differentiated with RA or dbcAMP/IBMX after three days. Retinoic acid differentiated cells, however, do develop immunoreactivity to axonal markers of differentiation after nine days of treatment. We also conclude that acrylamide does not affect the cytoskeletal structure of SY5Y neuroblastoma cells in undifferentiated or in RA or dbc AMP differentiated cells at the time and concentration tested. / Master of Science

The N6-methyladenosine, also known as m6A, is the most common post-transcriptional modification in mRNAs and long non-coding RNAs and that profoundly influences mRNA biology, from early processing in the nucleus to final steps of translation and decay in the cytoplasm. Taking into consideration the importance of RNA in shaping cell fate, m6A is widely recognized as an additional layer in the regulation of gene expression, also thanks to its dynamic and reversible nature. Therefore, it is not surprising that any misregulation in m6A content might lead to the loss of cellular homeostasis. This effect is particularly evident when it comes to stem cells differentiation, embryo development and cancer. In a tumorigenic context, the m6A could affect the development, progression, cancer stem cells (CSCs) renewal and drug resistance of solid and liquid tumours. So, the m6A is consistently becoming a new attractive pharmacological target. Neuroblastoma (NB) is a neuroendocrine tumour of early childhood that derives from undifferentiated cells of the sympathoadrenal lineage of the neural crest. About 50% of patients have a very aggressive form of NB, with an overall survival rate of less than 30% despite heavy treatments. Moreover, NB is a challenging druggable tumour due to a low rate of somatic mutations. Somatic mutations at significant frequency have been identified in only five genes that also show detectable expression. Among these, only one is currently a directly validated druggable target. Two m6A regulators (METTL14 and ALKBH5) are aberrantly expressed in high-risk NB patients, and their alteration in NB cell lines affects tumour aggressiveness. Specifically, the overexpression of the methyltransferase METTL14 increases cell proliferation and invasion in vitro and tumour growth in mice acting as an oncogene, while ALKBH5 restoration affects cell proliferation, apoptosis and invasion in an opposite fashion. Importantly, the demethylase ALKBH5 impaired tumour formation in vivo when costitutively expressed and dramatically slows down tumor progression in mice when is induced by causing massive apoptosis. These data suggest that ALKBH5 acts as a potent tumour suppressor in NB. We discovered that METTL14 and ALKBH5 exert their effect on different levels by affecting mRNA stability or translation, respectively. Although the contribution to NB of the altered stability of transcripts related to mRNA processing in METTL14-overexpressing cells is less understand, the increase translation of pro-apoptotic genes in the ALKBH5-overexpression condition leaves little doubts. Our results unveil the m6A and its regulators as potential therapeutic targets for treating NB. Indeed, in collaboration with the Laboratory of Genomic Screening of Professor Alessandro Provenzani, we presented an encouraging proof-of-concept of the reader YTHDF1 as a possible pharmacological target.

O neuroblastoma é o tumor sólido mais comum e com maior índice de letalidade em crianças. Diversas famílias de retrovírus endógenos humanos (HERV) estão presentes no genoma humano, em diferentes níveis de integridade, e são reativadas sob diferentes circunstâncias. A atividade de HERV tem sido cada vez mais sido associada a doenças como câncer, doenças autoimunes e ainda com a infecção por vírus exógenos. O principal objetivo deste projeto foi avaliar a expressão de retrovírus endógenos das famílias H (HH), W (HW) e K (HK) em pacientes diagnosticados com neuroblastoma. Amostras tumorais e amostras controle foram submetidas a extração de RNA total, síntese de cDNA e PCR em fase única. Os produtos de HERV foram submetidos ao sequenciamento em larga escala. No total, 43 loci de HH e 14 loci de HW foram diferencialmente expressos entre os grupos e 202 loci de HK foram detectados. As análises de expressão somadas ao contexto genético e epigenético de neuroblastoma, permitiram com que várias hipóteses fossem levantadas acerca da regulação da expressão de HERV neste tumor. A hipometilação geral do tecido tumoral pode ter um papel importante na expressão gênica e na reativação de retrotransposons, podendo ser a principal razão para a expressão de HERV neste contexto. / Neuroblastoma represents the most common solid tumor as well as the most lethal form of tumor in children. Several families of human endogenous retroviruses (HERV) are present in human genome in different integrity levels, and they are reactivated under different circumstances. HERV activity has been linked to diseases such as cancer, autoimmune diseases and even with the infection by exogenous viruses. The main goal of this project was to evaluate the expression of endogenous retroviruses families H (HH), W (HW) and K (HK) in patients diagnosed with neuroblastoma. Tumor samples and control samples were subjected to RNA extraction and a single round in-house RT-PCR. HERVs amplicons were next generation sequenced to access the specific origin of transcripts. Overall, 43 HH loci and 14 HW loci were differentially expressed between groups and, 202 HK loci was detected. Taken together, HERV expression analysis and genetic and epigenetic context of neuroblastoma provided several hypotheses about regulation of HERV expression in this type of tumor. The global hypomethylation of tumoral tissue may have a role in genes expression and retrotransposons reactivation, which may be the main reason for HERV expression in this context.

Ho, Lai Ying. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 213-238). / Abstract also in Chinese. / Abstract --- p.i / Abstract in Chinese (摘要） --- p.iv / Acknowledgements --- p.vii / List of abbreviations --- p.ix / Table of contents --- p.xiv / Chapter Chapter One: --- General Introduction_ --- p.1 / Chapter 1.1 --- Neuroblastoma --- p.2 / Chapter 1.1.1 --- An overview on neuroblastoma --- p.2 / Chapter 1.1.2 --- Classification of neuroblastoma --- p.4 / Chapter 1.1.3 --- Epidemiology of neuroblastoma --- p.7 / Chapter 1.1.4 --- Clinical manifestation of neuroblastoma --- p.10 / Chapter 1.1.5 --- Diagnosis of neuroblastoma --- p.10 / Chapter 1.1.6 --- Conventional therapy of neuroblastoma --- p.12 / Chapter 1.1.7 --- Novel treatments of neuroblastoma --- p.14 / Chapter 1.2 --- Conjugated linolenic acid (CLN) --- p.16 / Chapter 1.2.1 --- An overview of polyunsaturated fatty acids and conjugated fatty acids --- p.16 / Chapter 1.2.2 --- Chemical structure and physical properties of CLNs --- p.18 / Chapter 1.2.3 --- Natural occurrence of CLNs --- p.21 / Chapter 1.2.4 --- Synthesis of CLNs --- p.22 / Chapter 1.2.5 --- Metabolism and pharmacokinetics of CLNs --- p.24 / Chapter 1.2.6 --- Major biological and pharmacological activities of CLNs --- p.25 / Chapter 1.2.6.1 --- Hypolipidemic and anti-obese effects --- p.25 / Chapter 1.2.6.2 --- Anti-cancer effects --- p.27 / Chapter 1.2.6.2.1 --- Anti-proliferation --- p.27 / Chapter 1.2.6.2.2 --- Chemoprevention --- p.28 / Chapter 1.2.6.2.3 --- Apoptosis-inducing --- p.28 / Chapter 1.3 --- Aims and scope of the study --- p.31 / Chapter Chapter Two: --- Materials and Methods_ --- p.34 / Chapter 2.1 --- Materials --- p.35 / Chapter 2.1.1 --- Animals --- p.35 / Chapter 2.1.2 --- Cell lines --- p.35 / Chapter 2.1.3 --- "Cell culture medium, buffers and other reagents" --- p.37 / Chapter 2.1.4 --- Reagents for DNA extraction --- p.46 / Chapter 2.1.5 --- Reagents for gel electrophoresis of nucleic acids --- p.47 / Chapter 2.1.6 --- Reagents and buffers for flow cytometry --- p.49 / Chapter 2.1.7 --- Reagents and buffers for measuring caspase activity --- p.50 / Chapter 2.1.8 --- Reagents for Hoechst staining --- p.53 / Chapter 2.1.9 --- Reagents and buffers for RNA extraction --- p.53 / Chapter 2.1.10 --- Reagents and buffers for DNA digestion --- p.54 / Chapter 2.1.11 --- Reagents and buffers for reverse transcription --- p.55 / Chapter 2.1.12 --- Reagents for real-time polymerase chain reaction --- p.57 / Chapter 2.1.13 --- Reagents and buffers for Western blotting --- p.59 / Chapter 2.2 --- Methods --- p.64 / Chapter 2.2.1 --- Culture of cell lines --- p.64 / Chapter 2.2.2 --- Preparation of NIH-3T3 conditioned medium --- p.65 / Chapter 2.2.3 --- Determination of cell viability --- p.65 / Chapter 2.2.4 --- Determination of cell proliferation by tritiated thymidine incorporation assay --- p.66 / Chapter 2.2.5 --- Cytotoxicity test of CLNs on murine peritoneal macrophages --- p.67 / Chapter 2.2.6 --- Cytotoxicity test of CLNs on murine bone marrow cells --- p.68 / Chapter 2.2.7 --- Cytotoxicity test of CLNs on murine splenocytes --- p.68 / Chapter 2.2.8 --- Cytotoxicity tests of CLNs on human peripheral blood mononuclear cells --- p.69 / Chapter 2.2.9 --- Carboxyfluorescein diacetate succinimidyl ester (CFSE) staining analyzed by flow cytometry --- p.69 / Chapter 2.2.10 --- Determination of colony forming ability --- p.70 / Chapter 2.2.11 --- Determination of cell invasiveness --- p.70 / Chapter 2.2.12 --- In vivo tumorigenicity assay --- p.71 / Chapter 2.2.13 --- Analysis of cell cycle profile/ DNA content by flow cytometry --- p.72 / Chapter 2.1.14 --- Measurements of apoptosis --- p.72 / Chapter 2.1.15 --- Measurements of differentiation --- p.77 / Chapter 2.1.16 --- Gene expression study --- p.78 / Chapter 2.2.17 --- Protein expression study --- p.81 / Chapter 2.2.18 --- Statistical Analysis --- p.84 / Chapter Chapter Three: --- Anti-proliferative Effect of CLN Isomers on Human Neuroblastoma cells --- p.86 / Chapter 3.1 --- Introduction --- p.87 / Chapter 3.2 --- Results --- p.89 / Chapter 3.2.1 --- Anti-proliferative effect of CLN isomers on various human neuroblastoma cell lines in vitro --- p.89 / Chapter 3.2.2 --- Direct cytotoxic effect of jacaric acid on neuroblastoma LA-N-1 cells in vitro --- p.100 / Chapter 3.2.3 --- Cytotoxicity of jacaric acid on primary murine cells and human normal cell lines --- p.103 / Chapter 3.2.4 --- Kinetic and reversibility studies of the anti-proliferative effect of jacaric acid on LA-N-1 cells --- p.106 / Chapter 3.2.5 --- Synergistic anti-proliferative effect of jacaric acid with daidzein and retinoic acid on LA-N-1 cells in vitro --- p.110 / Chapter 3.2.6 --- Modulatory effect of jacaric acid on the number of cell division in LA-N-1 cells --- p.113 / Chapter 3.2.7 --- Effect of jacaric acid on the cell cycle profile of LA-N-1 cells --- p.115 / Chapter 3.2.8 --- Effect of jacaric acid on the invasiveness of LA-N-1 cells --- p.118 / Chapter 3.2.9 --- Effect of jacaric acid on the colony forming ability of LA-N-1 cells in soft agar --- p.120 / Chapter 3.2.10 --- Effect of jacaric acid on the in vivo tumorigenicity of the LA-N-1 cells --- p.122 / Chapter 3.3 --- Discussion --- p.124 / Chapter Chapter Four: --- Apoptosis- and Differentiation-inducing Effects of Jacaric Acid on Human Neuroblastoma Cells --- p.133 / Chapter 4.1 --- Introduction --- p.134 / Chapter 4.2 --- Results --- p.138 / Chapter 4.2.1 --- Induction of DNA fragmentation and apoptotic ultrastructural changes in LA-N-1 cells by jacaric acid --- p.138 / Chapter 4.2.2 --- Induction of phosphatidylserine externalization by jacaric acid in human neuroblastoma cells as detected by Annexin V-GFP/ PI dual staining --- p.142 / Chapter 4.2.3 --- Effect of jacaric acid on the mitochondrial membrane potential in human neuroblastoma cells --- p.146 / Chapter 4.2.4 --- Effect of jacaric acid on the caspase-3 activity in LA-N-1 cells --- p.150 / Chapter 4.2.5 --- Effect of jacaric acid on the reactive oxygen species (ROS) generation in human neuroblastoma cells --- p.153 / Chapter 4.2.6 --- Morphological changes induced by jacaric acid in SH-SY5Y cells --- p.158 / Chapter 4.3 --- Discussion --- p.162 / Chapter Chapter Five: --- Mechanistic Studies of Anti-proliferative Effect of Jacaric Acid on Human Neuroblastoma Cells --- p.171 / Chapter 5.1 --- Introduction --- p.172 / Chapter 5.2 --- Results --- p.178 / Chapter 5.2.1 --- Effect of antioxidant a-tocopherol on the anti-proliferative effect of jacaric acid on LA-N-1 cells --- p.178 / Chapter 5.2.2 --- Effect of caspase inhibitors on the anti-proliferative effect of jacaric acid on LA-N-1 cells --- p.180 / Chapter 5.2.3 --- Jacaric acid modulated the mRNA expression of N-myc and other related transcription factors in LA-N-1 cells --- p.182 / Chapter 5.2.4 --- Jacaric acid modulated the protein expression of N-myc --- p.186 / Chapter 5.2.5 --- Jacaric acid modulated the mRNA expression of apoptosis-associated genes --- p.188 / Chapter 5.3 --- Discussion --- p.191 / Chapter Chapter Six: --- Conclusions and Future Perspectives --- p.202 / References --- p.212

O neuroblastoma é o tumor sólido mais comum e com maior índice de letalidade em crianças. Diversas famílias de retrovírus endógenos humanos (HERV) estão presentes no genoma humano, em diferentes níveis de integridade, e são reativadas sob diferentes circunstâncias. A atividade de HERV tem sido cada vez mais sido associada a doenças como câncer, doenças autoimunes e ainda com a infecção por vírus exógenos. O principal objetivo deste projeto foi avaliar a expressão de retrovírus endógenos das famílias H (HH), W (HW) e K (HK) em pacientes diagnosticados com neuroblastoma. Amostras tumorais e amostras controle foram submetidas a extração de RNA total, síntese de cDNA e PCR em fase única. Os produtos de HERV foram submetidos ao sequenciamento em larga escala. No total, 43 loci de HH e 14 loci de HW foram diferencialmente expressos entre os grupos e 202 loci de HK foram detectados. As análises de expressão somadas ao contexto genético e epigenético de neuroblastoma, permitiram com que várias hipóteses fossem levantadas acerca da regulação da expressão de HERV neste tumor. A hipometilação geral do tecido tumoral pode ter um papel importante na expressão gênica e na reativação de retrotransposons, podendo ser a principal razão para a expressão de HERV neste contexto. / Neuroblastoma represents the most common solid tumor as well as the most lethal form of tumor in children. Several families of human endogenous retroviruses (HERV) are present in human genome in different integrity levels, and they are reactivated under different circumstances. HERV activity has been linked to diseases such as cancer, autoimmune diseases and even with the infection by exogenous viruses. The main goal of this project was to evaluate the expression of endogenous retroviruses families H (HH), W (HW) and K (HK) in patients diagnosed with neuroblastoma. Tumor samples and control samples were subjected to RNA extraction and a single round in-house RT-PCR. HERVs amplicons were next generation sequenced to access the specific origin of transcripts. Overall, 43 HH loci and 14 HW loci were differentially expressed between groups and, 202 HK loci was detected. Taken together, HERV expression analysis and genetic and epigenetic context of neuroblastoma provided several hypotheses about regulation of HERV expression in this type of tumor. The global hypomethylation of tumoral tissue may have a role in genes expression and retrotransposons reactivation, which may be the main reason for HERV expression in this context.

A família proteína quinases C (PKC) é composta por dez isoenzimas, as quais são capazes de fosforilar resíduos de serina e treonina. A ativação dessas quinases envolve mudanças conformacionais, como a remoção do pseudo-substrato do sítio ativo e associação dessas enzimas com lipídeos em membranas biológicas. Além disso, três fosforilações são importantes para a maturação/ enovelamento da enzima e não estão associadas com o estado de ativação das cPKCs. Apesar dessas quinases estarem envolvidas em vários processos patológicos, como carcinogênese e doenças cardiovasculares, ainda não se estabeleceu a relação entre estado de ativação das PKCs com essas doenças. Isso se deve, em parte, à ausência de ferramentas que possibilitam a distinção das formas ativas e inativas das PKCs. Na presente tese, baseando-se em mudanças conformacionais sofridas pelas PKCs durante o processo de ativação, dois anticorpos contra cPKCs ativas foram racionalmente desenvolvidos, sendo um anticorpo policlonal (anti-C2Cat) e outro monoclonal (4.8E). O anticorpo anti-C2Cat foi desenvolvido a partir de imunização de coelhos com um peptídeo localizado na região de interação entre os domínios C2 e catalítico na PKC inativa. Já o anticorpo monoclonal 4.8E foi produzido após a imunização de camundongos Balb/ C com extrato de proteínas proveniente de células HEK293T superexpressando formas constitutivamente ativas da PKCβI. A seletividade de anti-C2Cat e 4.8E por cPKCs ativas foi demonstrada por ensaios de ELISA e de imunoprecipitação, sendo que os anticorpos sempre apresentaram maior afinidade por cPKCs ativas purificadas, superexpressas ou mesmo as endógenas. O anticorpo anti-C2Cat foi capaz de monitorar a dinâmica espaço-temporal da ativação das cPKCs em linhagens de neuroblastoma (Neuro-2A e SK-N-SH) estimuladas com PMA, morfina, ATP ou glutamato por diferentes tempos. Ainda, um maior conteúdo de cPKCs ativas foi detectado por anti-C2Cat na linhagem de câncer de mama MDA-MB-231 (triplo- negativa) do que em células MCF-7 (ER+). Em acordo com esses dados, anti-C2Cat identificou uma maior ativação de cPKCs em tumores mais agressivos de câncer de mama (subtipo triplo-negativo) do que em tumores menos agressivos (ER+, subtipo luminal). Os anticorpos conformacionais anti-C2Cat e 4.8E foram aplicados para elucidar vias de sinalização que levam à carcinogênese em células MDA-MB-231, por meio da realização de ensaios de co-imunoprecipitação, seguida pela identificação das proteínas por espectrometria de massas. Usando essa abordagem, os resultados sugerem que as cPKCs ativas possam estar envolvidas com a tradução de proteínas envolvidas na migração celular, como actina. Em conjunto, os resultado obtidos na presente tese demonstram duas formas racionais de desenvolver anticorpos contra cPKCs ativas, sendo que algumas aplicações para estas ferramentas foram demonstradas. Estratégias baseadas em mudanças conformacionais, similares às apresentadas aqui, poderão ser utilizadas para a produção racional de anticorpos contra outras quinases ou proteínas / The protein kinase C family (PKC) is composed of ten isoenzymes, which are capable of phosphorylating serine and threonine amino acid residues. PKC activation involves conformational changes, such as removing the pseudo-substrate from the active site and binding of the enzyme to lipids in biological membranes. In addition, PKC undergoes three phosphorylations that are important for the maturation/ folding of the enzyme and are not linked with activation status. Despite the fact that these kinases are involved in various pathological processes, such as carcinogenesis and cardiovascular disease, a relationship between PKC activation status with these diseases has not yet been established. This is partly due to the lack of tools to detect active PKC in tissue samples. In this thesis, based on conformational changes suffered by PKC during its activation, two antibodies against active cPKCs were rationally developed; a polyclonal antibody (anti-C2Cat) and a monoclonal (4.8E). Anti-C2Cat was produced after immunization of rabbits with a peptide located at the interface between the C2 and catalytic domains of cPKCs in an inactive PKC. The monoclonal antibody 4.8E was produced after immunization of Balb/C mice with total lysates from HEK293T cells overexpressing constitutively active forms of PKCβI. The anti-C2Cat and 4.8E specificity by active cPKCs was demonstrated by ELISA and immunoprecipitation assays, where the antibodies always showed higher affinity to active cPKCs. Anti-C2Cat was able to detect the temporal and spatial dynamics of cPKC activation upon receptor (morphine, ATP or glutamate) or phorbol ester stimulation in neuroblastoma lines (Neuro-2A and SK-N-SH). Futhermore, anti-C2Cat is able to detect active PKC in human tissues. Higher levels of active cPKC were observed in the more aggressive triple negative breast cancer tumors as compared to the less aggressive estrogen receptor positive tumors. Also, both antibodies were applied to study signaling pathways that lead to carcinogenesis in MDA-MB-231 cells by performing co-immunoprecipitation and mass spectrometry. Using this approach, the results suggest that active cPKCs may be involved in translation of proteins involved in cell migration, such as actin. Taken together, the results obtained in this thesis showed two rational ways to develop antibodies against active cPKCs and some applications for these tools were demonstrated. Strategies based on conformational changes, similar to those presented herein may be used for rational production of antibodies against other kinases and proteins.

Thesis (Ph. D.)--West Virginia University, 2007. / Title from document title page. Document formatted into pages; contains vi, 130 p. : ill. (some col.). Includes abstract. Includes bibliographical references.

A família proteína quinases C (PKC) é composta por dez isoenzimas, as quais são capazes de fosforilar resíduos de serina e treonina. A ativação dessas quinases envolve mudanças conformacionais, como a remoção do pseudo-substrato do sítio ativo e associação dessas enzimas com lipídeos em membranas biológicas. Além disso, três fosforilações são importantes para a maturação/ enovelamento da enzima e não estão associadas com o estado de ativação das cPKCs. Apesar dessas quinases estarem envolvidas em vários processos patológicos, como carcinogênese e doenças cardiovasculares, ainda não se estabeleceu a relação entre estado de ativação das PKCs com essas doenças. Isso se deve, em parte, à ausência de ferramentas que possibilitam a distinção das formas ativas e inativas das PKCs. Na presente tese, baseando-se em mudanças conformacionais sofridas pelas PKCs durante o processo de ativação, dois anticorpos contra cPKCs ativas foram racionalmente desenvolvidos, sendo um anticorpo policlonal (anti-C2Cat) e outro monoclonal (4.8E). O anticorpo anti-C2Cat foi desenvolvido a partir de imunização de coelhos com um peptídeo localizado na região de interação entre os domínios C2 e catalítico na PKC inativa. Já o anticorpo monoclonal 4.8E foi produzido após a imunização de camundongos Balb/ C com extrato de proteínas proveniente de células HEK293T superexpressando formas constitutivamente ativas da PKCβI. A seletividade de anti-C2Cat e 4.8E por cPKCs ativas foi demonstrada por ensaios de ELISA e de imunoprecipitação, sendo que os anticorpos sempre apresentaram maior afinidade por cPKCs ativas purificadas, superexpressas ou mesmo as endógenas. O anticorpo anti-C2Cat foi capaz de monitorar a dinâmica espaço-temporal da ativação das cPKCs em linhagens de neuroblastoma (Neuro-2A e SK-N-SH) estimuladas com PMA, morfina, ATP ou glutamato por diferentes tempos. Ainda, um maior conteúdo de cPKCs ativas foi detectado por anti-C2Cat na linhagem de câncer de mama MDA-MB-231 (triplo- negativa) do que em células MCF-7 (ER+). Em acordo com esses dados, anti-C2Cat identificou uma maior ativação de cPKCs em tumores mais agressivos de câncer de mama (subtipo triplo-negativo) do que em tumores menos agressivos (ER+, subtipo luminal). Os anticorpos conformacionais anti-C2Cat e 4.8E foram aplicados para elucidar vias de sinalização que levam à carcinogênese em células MDA-MB-231, por meio da realização de ensaios de co-imunoprecipitação, seguida pela identificação das proteínas por espectrometria de massas. Usando essa abordagem, os resultados sugerem que as cPKCs ativas possam estar envolvidas com a tradução de proteínas envolvidas na migração celular, como actina. Em conjunto, os resultado obtidos na presente tese demonstram duas formas racionais de desenvolver anticorpos contra cPKCs ativas, sendo que algumas aplicações para estas ferramentas foram demonstradas. Estratégias baseadas em mudanças conformacionais, similares às apresentadas aqui, poderão ser utilizadas para a produção racional de anticorpos contra outras quinases ou proteínas / The protein kinase C family (PKC) is composed of ten isoenzymes, which are capable of phosphorylating serine and threonine amino acid residues. PKC activation involves conformational changes, such as removing the pseudo-substrate from the active site and binding of the enzyme to lipids in biological membranes. In addition, PKC undergoes three phosphorylations that are important for the maturation/ folding of the enzyme and are not linked with activation status. Despite the fact that these kinases are involved in various pathological processes, such as carcinogenesis and cardiovascular disease, a relationship between PKC activation status with these diseases has not yet been established. This is partly due to the lack of tools to detect active PKC in tissue samples. In this thesis, based on conformational changes suffered by PKC during its activation, two antibodies against active cPKCs were rationally developed; a polyclonal antibody (anti-C2Cat) and a monoclonal (4.8E). Anti-C2Cat was produced after immunization of rabbits with a peptide located at the interface between the C2 and catalytic domains of cPKCs in an inactive PKC. The monoclonal antibody 4.8E was produced after immunization of Balb/C mice with total lysates from HEK293T cells overexpressing constitutively active forms of PKCβI. The anti-C2Cat and 4.8E specificity by active cPKCs was demonstrated by ELISA and immunoprecipitation assays, where the antibodies always showed higher affinity to active cPKCs. Anti-C2Cat was able to detect the temporal and spatial dynamics of cPKC activation upon receptor (morphine, ATP or glutamate) or phorbol ester stimulation in neuroblastoma lines (Neuro-2A and SK-N-SH). Futhermore, anti-C2Cat is able to detect active PKC in human tissues. Higher levels of active cPKC were observed in the more aggressive triple negative breast cancer tumors as compared to the less aggressive estrogen receptor positive tumors. Also, both antibodies were applied to study signaling pathways that lead to carcinogenesis in MDA-MB-231 cells by performing co-immunoprecipitation and mass spectrometry. Using this approach, the results suggest that active cPKCs may be involved in translation of proteins involved in cell migration, such as actin. Taken together, the results obtained in this thesis showed two rational ways to develop antibodies against active cPKCs and some applications for these tools were demonstrated. Strategies based on conformational changes, similar to those presented herein may be used for rational production of antibodies against other kinases and proteins.