Dissertations / Theses on the topic 'Imp3p'

Le domaine C-terminal très conservé de la protéine Sup35, impliquée dans la terminaison de la traduction, possède un site potentiel de phosphorylation par la PKA au niveau de la Thréonine341. Nous avons recherché si ce résidu était phosphorylé in vivo et s’il était impliqué dans la régulation fonctionnelle de la protéine. Dans les conditions testées, aucune phosphorylation de Sup35p n’a pu être mise en évidence in vivo mais nous avons montré que le résidu T341 était critique pour la fonctionnalité de la protéine et pourrait être impliqué dans des interactions fonctionnelles entre les domaines N et C terminaux. Le domaine N de Sup35p est responsable du phénotype prion [PSI+]. Jusqu’à présent, les seules mutations caractérisées influençant les propriétés prion de cette protéine ont été localisées dans ce domaine N-terminal. Nous avons identifié une mutation dans le domaine C-terminal qui modifie les capacités d’agrégation de la protéine. Cette observation apporte de nouveaux éléments pour la compréhension du mécanisme de conversion de Sup35p vers un état agrégé. IMP3 est un gène essentiel codant une protéine impliquée dans la biogenèse des ribosomes. Nous avons construit une souche capable d’exprimer de façon endogène un allèle mutant hypomorphe du gène IMP3. Cette souche présente d’importants défauts de biogenèse de la petite sous unité 40S du ribosome. Nous avons montré que la fidélité de la traduction est affectée dans cette souche : l’efficacité de décalage du cadre lecture en +1 est augmentée. Nos expériences montrent que cette protéine pourrait être également impliquée dans la réparation de l’ADN et le contrôle de la taille des télomères
All Sup35 homologs share a potential phosphorylation site at threonine 341, suggesting a functional role for this residue. We investigated whether this residue is actually phosphorylated in yeast and if it is involved in the termination activity of the protein. In the conditions we tested, no phosphorylation of the Sup35 protein in vivo was detected. However our results point to a new critical residue involved in the translation termination activity of Sup35p and in functional interaction between the N- and C-domains of the protein. The N-terminal domain of Sup35p is required for prion propagation, driving the switch from the soluble, functional [psi-] state to the insoluble [PSI+] prion state. To date, all the critical elements for prion induction and propagation have been mapped to the N domain of the protein. Here we report for the first time a mutation in the C-terminal domain of Sup35p which alters the aggregation properties of Sup35p. This observation has important consequence for understanding the mechanism of prion conversion. The essential IMP3 gene encodes a component of the SSU processome, a large ribonucleoprotein required for processing of small subunit rRNA precursors. We constructed and analysed a mutant of the IMP3 gene able to sustain cell growth. A strain expressing this hypomorphic allele displayed ribosome biogenesis defects characteristic of a depletion in Imp3p. We demonstrated the +1 frameshifting was increased in the mutant strain. Our further characterization revealed involvement of the Imp3 protein in DNA repair and telomere length control, two pathways that are not directly related to ribosome biogenesis

Les protéines se liant à l’ARN de la famille IMP sont les protéines oncofoetales conservées, qui régulent le transport, la stabilité et la traduction de plusieurs ARNm cibles. Les IMPs sont impliqués dans la tumorigenèse et dans le développement embryonnaire par le contrôle de la prolifération cellulaire, la différenciation, la migration, la polarisation et d`autres processus cellulaires. IMP-3 est difficilement détectable dans des tissus adultes normaux, mais il est surexprimé dans les nombreux cancers, où il a été caractérisé comme un marqueur d’agressivité et de la croissance tumorale rapide, ainsi que d’un pronostic défavorable pour les patients. Dans notre étude, nous avons utilisé une lignée cellulaire RD de rhabdomyosarcome (RMS), où IMPs étaient initialement décrits comme des protéines régulatrices de l`ARNm de IGF-2. Nous avons essayé d'élucider le mécanisme par lequel IMP3 régule l’expression des cyclines D1 et D3, contribuant ainsi à la compréhension des processus oncogéniques dans les RMS et autres cancers.Nous avons montré que IMP3 régule l'expression des cyclines D1 et D3 d'une manière significative in vivo. Nous avons également démontré, qu'en absence de IMP3, les ARNm des cyclines sont exportés vers le cytoplasme et s’associent avec les polyribosomes, mais ne sont pas traduits. En outre, l'inhibition d`IMP3 n'a pas d'influence sur la stabilité des ARNm des cyclines. Nous démontrons que dans des cellules cancéreuses humaines, IMP3 interagit avec plusieurs protéines se liant à l'ARN, et que nombre de ces protéines a un effet sul l’expression des cyclines, ce que suggère l'existence d'un complexe régulateur multiprotéique sur les 3'UTR des cyclines D1 et D3. Nos résultat montrent que l'inhibition de deux protéines clés de RNA-induced silencing complex (RISC) (AGO2 et GW182/TNRC6), rétablit les niveaux d'expression des cyclines D1 et D3, qui ont été considérablement diminués en l’absence d’IMP3 ou de ses partenaires protéiques ILF3/NF90 et PTBP1. Nous concluons que les complexes d`IMP3 et RISC peuvent concourir pour la régulation des ARNm des cyclines. Nous avons également identifié les miARNs qui peuvent être impliqués dans ce processus, ainsi que les domaines fonctionnellement importants dans les 3 'UTR des cyclines, où se passe la competition entre les complexes d’IMP-3 et RISC. Nos résultats sont compatibles avec l'existence de IMP3 - contenant complexe multiprotéique, qui est associé à 3'UTRs des cyclines et régule leur traduction en les protégeant contre la répression traductionnelle par miRISC
RNA-binding proteins of the IMP family (IGF2 mRNA-binding proteins 1-3) are conserved oncofetal proteins, regulating transport, stability and decay of multiple mRNAs. IMPs are involved in embryonic developement and tumorigenesis by controlling cell proliferation, differentation, migration, polarization and many other important aspects of cell function. IMP-3 is hardly detectable in normal adult tissues, but is overexpressed in many cancers, where it has been reported as a marker of tumor aggressiveness, rapid growth, and bad prognosis for patients. In our research we utilized a rhabdomyosarcoma (RMS) cell line RD, where IMPs were first described as IGF-2 mRNA regulating proteins. We aimed to elucidate the mechanism by which IMP3 regulates the expression of cyclins D1 and D3, thereby contributing to the understanding of oncogenic processes in RMS.In this study, we show that IMP3 regulates the expression of cyclin D1 and D3 in a significant manner in vivo. We also demonstrate that in the absence of IMP3, the mRNAs of the cyclins are exported to the cytoplasm and associated with polyribosomes, but not translated. IMP3 inhibition does not influence the stability of cyclin mRNAs. We demonstrate that in human cancer cells, IMP3 interacts with multiple RNA-binding proteins, and that a number of these IMP-3 partners impacts on the expression of cyclins D1 and D3. These observations suggest the existence of a regulatory IMP-3 containing RNP complex on the 3’UTR of mRNAs of cyclin D1 and D3. Our results show that an inhibition of two key proteins of RNA-induced silencing complex (RISC) (AGO2 and GW182/TNRC6) rescues the expression of cyclin D1 and D3 proteins, which is significantly decreased in the absence of IMP3 or its protein partners ILF3/NF90 and PTBP1. Therefore, IMP3 and RISC complexes can compete for cyclin mRNAs translational repression/activation. We also identified a number of miRNAs that can be involved in this process, and characterized functionally important regions within 3’ UTRs of the cyclins, where the competition between IMP-3 and RISC complexes takes place. Our results are consistent with the existence of IMP3 - containing multiprotein complex, which is associated with 3’UTRs of the cyclins and regulates their translation by protecting them from miRISC-dependent translational repression

BACKGROUND:Serous tubal intraepithelial carcinoma (STIC) and the p53 signature in tubal mucosa have been supported to be precursor lesions in high-grade serous carcinoma (HGSC) of the fallopian tube, ovary, and peritoneum. It remains critical to find biomarkers for precursor lesions in order to detect HGSCs efficiently. IMP3 is an oncoprotein that has been explored in human malignancies. No studies have specifically addressed the expression of IMP3 in precursor or early lesions of HGSC. The main purposes of this study are to evaluate if IMP3 plays any role in the process of pelvic serous carcinogenesis by examining its expression in HGSC precursor lesions, to examine the relationship between IMP3 and p53 in those precursor lesions, and to check if IMP3 can be used as a biomarker for early diagnosis.METHODS:Immunohistochemistry for IMP3 and p53 was performed and evaluated in 48 HGSCs with STIC, 62 HGSCs without STIC, and 60 benign cases as negative controls. Sections of fallopian tubes with or without STIC , as well as cancers within the ovaries, were studied. IMP3 signature was defined as strong IMP3 cytoplasmic staining in 10 or more consecutive benign-looking tubal epithelial cells. The relationship between IMP3 and p53 overexpression was examined.RESULTS:In the 48 HGSC patients with STIC, IMP3 was positive in 46% of STIC lesions and had a similar positive rate in the invasive components of HGSC. IMP3 was also expressed in normal appearing tubal epithelia (IMP3 signature) in 15 (31%) of 48 HGSC cases with STIC and 10 (16%) of 62 cases without STIC. In contrast, no single IMP3 signature was found in the benign control group. Concordant expression of IMP3 and p53 signatures in the STIC group was found in up to one-third of the cases. There were also five (10%) STIC cases with positive IMP3 and negative p53.CONCLUSIONS:We conclude that IMP3 may be involved in the process and progression of pelvic HGSC and may serve as a complimentary biomarker in diagnosing STIC.

Made available in DSpace on 2015-12-10T14:22:44Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-08-28. Added 1 bitstream(s) on 2015-12-10T14:28:56Z : No. of bitstreams: 1 000853894.pdf: 932709 bytes, checksum: 0fe73496b79c388c307c277adca72273 (MD5)
Introdução:O Carcinoma de Nasofaringe(CNF) é uma neoplasia epitelial maligna agressiva, com principal incidência entre homens de 40-60 anos de idade, com distribuição geográfica e étnica variada. Está associado à infecção pelo Epstein- BarrVirus (EBV), e a presença deste nas células tumorais parece ter impacto no prognóstico. Porém, outros fatores que podem estar relacionados ao desfecho do CNF, têm sido pesquisados. O biomarcador IMP3, proteína de ligação ao mRNA que tem reconhecida função na ação das células tumorais, vem sendo analisado como um marcador factível correlacionado com a sobrevida global nos pacientes com câncer. Métodos: Para explorar a expressão do IMP3 nas amostras tumorais de pacientes com CNF vistos no Hospital das Clinicas da Faculdade de Medicina de Botucatu- UNESP, foram compilados 35 prontuários e documentados de acordo com as características morfológicas e tempo de sobrevida. A expressão imunohistoquímica foi mensurada e correlacionada com os diversos parâmetros clínicopatológicos. Conclusão: mostrou-se elevado índice de recidiva e morbimortalidade, com grande número de casos avançados ao diagnóstico, e potencial correlação de melhor prognóstico com a alta expressão do marcador analisado. Impacto: Um melhor entendimento do IMP3 comobiomarcador, proporcionando novas perspectivas no prognóstico do carcinoma de nasofaringe
Background: The nasopharyngeal carcinoma (NPC) is an agressive malignant epithelial neoplasm, mainly prevalent among 40-60-year-old men, with varied geographic and ethnic distribution. It is associated with Epstein Barr Virus (EBV), whose presence in the tumor cell seems to impact the prognosis. However, other factors that may be related to NPC's clinical impact and have been studied. The IMP3 biomarker, a mRNA binding protein, which has a recognized role in the tumor cell formation, has been analized as a feasible marker correlated to the overall survival of cancerpatients. Given this evidence, the object of this research isanalyze possible correlation of this biomarker to the clinical out come of these patients. Methods: To explore the IMP3 expression in the CNF patients' tumor samples seen at the Hospital das Clínicas da Faculdade de Medicina in Botucatu- UNESP, were compiled 35 cases and documented in basis of their morphological features and status of life. The immunohistochemical expression was measured and correlated with the several clinic-pathologic parameters. Results: The analysis showed high rates of relapse and mortality, also a significant number of local advanced tumors at diagnosis, and potential correlation of better prognosis with the high expression of the biomarkeranalized. Impact: A betterunderstandingof IMP3 as a biomarker, providing new routesofprognosis in nasopharynx carcinoma

Orientador: Maria Aparecida Custódio Domingues
Coorientador: Vitor Nakajima
Banca: Maria Luiza Cotrim Sartor de Oliveira
Banca: Alexandre Todorovic Fabro
Banca: Abina Altemani
Resumo: Introdução:O Carcinoma de Nasofaringe(CNF) é uma neoplasia epitelial maligna agressiva, com principal incidência entre homens de 40-60 anos de idade, com distribuição geográfica e étnica variada. Está associado à infecção pelo Epstein- BarrVirus (EBV), e a presença deste nas células tumorais parece ter impacto no prognóstico. Porém, outros fatores que podem estar relacionados ao desfecho do CNF, têm sido pesquisados. O biomarcador IMP3, proteína de ligação ao mRNA que tem reconhecida função na ação das células tumorais, vem sendo analisado como um marcador factível correlacionado com a sobrevida global nos pacientes com câncer. Métodos: Para explorar a expressão do IMP3 nas amostras tumorais de pacientes com CNF vistos no Hospital das Clinicas da Faculdade de Medicina de Botucatu- UNESP, foram compilados 35 prontuários e documentados de acordo com as características morfológicas e tempo de sobrevida. A expressão imunohistoquímica foi mensurada e correlacionada com os diversos parâmetros clínicopatológicos. Conclusão: mostrou-se elevado índice de recidiva e morbimortalidade, com grande número de casos avançados ao diagnóstico, e potencial correlação de melhor prognóstico com a alta expressão do marcador analisado. Impacto: Um melhor entendimento do IMP3 comobiomarcador, proporcionando novas perspectivas no prognóstico do carcinoma de nasofaringe
Abstract: Background: The nasopharyngeal carcinoma (NPC) is an agressive malignant epithelial neoplasm, mainly prevalent among 40-60-year-old men, with varied geographic and ethnic distribution. It is associated with Epstein Barr Virus (EBV), whose presence in the tumor cell seems to impact the prognosis. However, other factors that may be related to NPC's clinical impact and have been studied. The IMP3 biomarker, a mRNA binding protein, which has a recognized role in the tumor cell formation, has been analized as a feasible marker correlated to the overall survival of cancerpatients. Given this evidence, the object of this research isanalyze possible correlation of this biomarker to the clinical out come of these patients. Methods: To explore the IMP3 expression in the CNF patients' tumor samples seen at the Hospital das Clínicas da Faculdade de Medicina in Botucatu- UNESP, were compiled 35 cases and documented in basis of their morphological features and status of life. The immunohistochemical expression was measured and correlated with the several clinic-pathologic parameters. Results: The analysis showed high rates of relapse and mortality, also a significant number of local advanced tumors at diagnosis, and potential correlation of better prognosis with the high expression of the biomarkeranalized. Impact: A betterunderstandingof IMP3 as a biomarker, providing new routesofprognosis in nasopharynx carcinoma
Mestre

BACKGROUND:Recent advances suggest fallopian tube as the main cellular source for women's pelvic serous carcinoma (PSC). In addition to TP53 mutations, many other genetic changes are involved in pelvic serous carcinogenesis. IMP3 is an oncofetal protein which has recently been observed to be overexpressed in benign-looking tubal epithelia. Such findings prompted us to examine the relationship between IMP3 over-expression, patient age and the likelihood of development of PSC.METHODS:Fallopian tubes from three groups (low-risk, high-risk, and PSC) of patients with matched ages were studied. Age was recorded in 10years intervals ranging from age 20 to older than 80. The number of IMP3 signatures (defined by 10 or more tubal secretory cells stained positively and continuously in benign appearing tubal mucosa) from both tubal fimbria and ampulla segments was measured. The data was analyzed by standard contingency table and Poisson distribution methods after age adjustment. IMP3 overexpression was also examined in serous tubal intraepithelial carcinoma and PSC.RESULTS:The positive IMP3-stained cells are mainly tubal secretory cells. The absolute number of tubal IMP3 signatures increased significantly within each age group. Age remained a significant risk factor for serous neoplasia after age adjustment. IMP3 signatures were more frequent in the patients of both high-risk and PSC groups. The presence of IMP3 signatures in tubal mucosa was significantly associated with tubal or pelvic serous carcinogenesis (p<0.001).CONCLUSIONS:The findings suggest that tubal secretory cells with IMP3 signatures showing growth advantage could potentially serve as a latent precancer biomarker for tubal or pelvic serous carcinomas in women.

Made available in DSpace on 2015-12-10T14:23:12Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-02-19. Added 1 bitstream(s) on 2015-12-10T14:29:27Z : No. of bitstreams: 1 000849806.pdf: 849500 bytes, checksum: fbe135630fc95ef07e7c2a3ad5436dca (MD5)
O Linfoma de Hodgkin (LH) é uma neoplasia hematopoiética que acomete caracteristicamente adultos jovens e apresenta, quando não tratado, curso clínico fatal. O diagnóstico precoce e preciso desse linfoma, associado à terapia moderna, por outro lado, tem proporcionado diminuição dramática das taxas de letalidade. Ainda assim, cerca de 15-20% dos pacientes evoluem de maneira insatisfatória com resistência a terapia primária ou recaída precoce pós-tratamento. Nesse sentido, há estudos variados na tentativa de buscar perfis prognósticos capazes de selecionar pacientes candidatos a terapias particulares. O IMP3 (insulin-like growth factor mRNA binding protein 3) tem sido descrito como biomarcador relacionado a pior prognóstico em diversas neoplasias, especialmente carcinomas, mas ainda pouco estudado em neoplasias hematopoiéticas. Para avaliar seu potencial papel prognóstico no LH, foi estudada a expressão do IMP3 em 61 casos, incluindo estratificação da imunocoloração em intensidades (0, 1+, 2+ e 3+) e relação com sobrevida, dados clínicos, aspectos morfológicos e imuno-histoquímicos. A expressão forte (intensidade 3+) para IMP3 foi observada em 61% (34/56) dos LH e apresentou forte indicio de associação com melhor sobrevida livre de doença. Nossos achados mostram o IMP3 como potencial biomarcador de melhor prognóstico em LH
Hodgkin lymphoma (HL) is a hematopoietic neoplasm that characteristically affects young adults and, if untreated, presents a fatal clinical course. Early and accurate diagnosis of this lymphoma associated with modern therapeutic management, on the other hand, has promoted a dramatic decrease in mortality rates. Despite this, around 15-20% of patients show unsatisfactory progression, with resistance to primary therapy or early relapse following treatment. The literature comprises numerous studies attempting to determine prognostic profiles that are capable of selecting candidate patients for specific therapies. Insulin-like growth factor mRNA binding protein 3 (IMP3) has been described as a biomarker that indicates worse prognosis in several malignancies, particularly carcinomas; however, studies of IMP3 in hematopoietic malignancies are rare. To assess their potential prognostic role in HL, IMP3 expression was studied in 61 cases and included stratification of immunostaining intensities (0, +, ++ and +++) and their relation to status of life, clinical data and morphological and immunohistochemical features. Intense IMP3 expression (+++) was observed in 61% (34/56) cases and showed a strong indication of association with better disease-free survival. Our findings show that IMP3 is a potential biomarker of better prognosis in HL

Orientador: Maria Aparecida Custódio Domingues
Banca: Flávio de Oliveira Lima
Banca: Gabriela Gualco
Resumo: O Linfoma de Hodgkin (LH) é uma neoplasia hematopoiética que acomete caracteristicamente adultos jovens e apresenta, quando não tratado, curso clínico fatal. O diagnóstico precoce e preciso desse linfoma, associado à terapia moderna, por outro lado, tem proporcionado diminuição dramática das taxas de letalidade. Ainda assim, cerca de 15-20% dos pacientes evoluem de maneira insatisfatória com resistência a terapia primária ou recaída precoce pós-tratamento. Nesse sentido, há estudos variados na tentativa de buscar perfis prognósticos capazes de selecionar pacientes candidatos a terapias particulares. O IMP3 (insulin-like growth factor mRNA binding protein 3) tem sido descrito como biomarcador relacionado a pior prognóstico em diversas neoplasias, especialmente carcinomas, mas ainda pouco estudado em neoplasias hematopoiéticas. Para avaliar seu potencial papel prognóstico no LH, foi estudada a expressão do IMP3 em 61 casos, incluindo estratificação da imunocoloração em intensidades (0, 1+, 2+ e 3+) e relação com sobrevida, dados clínicos, aspectos morfológicos e imuno-histoquímicos. A expressão forte (intensidade 3+) para IMP3 foi observada em 61% (34/56) dos LH e apresentou forte indicio de associação com melhor sobrevida livre de doença. Nossos achados mostram o IMP3 como potencial biomarcador de melhor prognóstico em LH
Abstract: Hodgkin lymphoma (HL) is a hematopoietic neoplasm that characteristically affects young adults and, if untreated, presents a fatal clinical course. Early and accurate diagnosis of this lymphoma associated with modern therapeutic management, on the other hand, has promoted a dramatic decrease in mortality rates. Despite this, around 15-20% of patients show unsatisfactory progression, with resistance to primary therapy or early relapse following treatment. The literature comprises numerous studies attempting to determine prognostic profiles that are capable of selecting candidate patients for specific therapies. Insulin-like growth factor mRNA binding protein 3 (IMP3) has been described as a biomarker that indicates worse prognosis in several malignancies, particularly carcinomas; however, studies of IMP3 in hematopoietic malignancies are rare. To assess their potential prognostic role in HL, IMP3 expression was studied in 61 cases and included stratification of immunostaining intensities (0, +, ++ and +++) and their relation to status of life, clinical data and morphological and immunohistochemical features. Intense IMP3 expression (+++) was observed in 61% (34/56) cases and showed a strong indication of association with better disease-free survival. Our findings show that IMP3 is a potential biomarker of better prognosis in HL
Mestre

Orientador: Mariângela Esther Alencar Marques
Resumo: INTRODUÇÃO: O melanoma apresentou aumento na sua incidência com o passar dos anos. A despeito das melhorias no diagnóstico e tratamento, demonstra mortalidade considerável. A incapacidade de prever com maior precisão sua evolução ainda intriga os pesquisadores. Dois marcadores imuno-histoquímicos, FOXP3 e IMP3 vêm sendo relacionados a pior prognóstico em vários estudos. OBJETIVO: Avaliar se a presença de FOXP3 e IMP3 é diferente entre os subtipos clínicos e se há correlação entre a sua presença e pior prognóstico. MÉTODOS: Estudo do tipo coorte retrospectiva, que avaliou todos os pacientes diagnosticados com Melanoma a partir do exame anatomopatológico no período de 2003 a 2011 provenientes dos serviços de Dermatologia e Patologia da Faculdade de Medicina de Botucatu (UNESP). As lâminas foram reanalisadas por dois patologistas e uma dermatologista, para assegurar subtipo clinico, Breslow, presença de ulceração, mitoses e regressão histológica. A partir dos blocos mantidos em arquivo se realizou a técnica imuno-histoquímica dos marcadores FOXP3 e IMP3. Além disso, foi realizado estudo de prontuário para avaliar aspectos demográficos, clínicos e de evolução do paciente. Foram aplicados os testes Qui-Quadrado ou Exato de Fisher, Kruskall Wallis, Teste de Dunn e Modelo de Regressão de Cox. Foi considerado estatisticamente significante p<0,05. RESULTADOS: A maioria de casos teve positividade < ou = a 25% tanto para IMP3 como para FOXP3. A positividade deles não pôde ser correlacio... (Resumo completo, clicar acesso eletrônico abaixo)
Mestre

Submitted by SILAS OTERO REIS SALUM null (silas.salum@terra.com.br) on 2016-12-10T00:38:35Z No. of bitstreams: 1 Mestrado docx.docx: 19521900 bytes, checksum: 4e1d4a3af3658602bae918ee500c7ef1 (MD5)
Rejected by Felipe Augusto Arakaki (arakaki@reitoria.unesp.br), reason: Solicitamos que realize uma nova submissão seguindo as orientações abaixo: A versão final da dissertação/tese deve ser submetida no formato PDF (Portable Document Format). O arquivo PDF não deve estar protegido e a dissertação/tese deve estar em um único arquivo, inclusive os apêndices e anexos, se houver. Por favor, corrija o formato do arquivo e realize uma nova submissão. Agradecemos a compreensão. on 2016-12-13T11:15:03Z (GMT)
Submitted by SILAS OTERO REIS SALUM null (silas.salum@terra.com.br) on 2016-12-13T20:42:00Z No. of bitstreams: 1 Mestrado pdf 13:12:2016.pdf: 92061303 bytes, checksum: f7154447eecdf5d9ae67dd8a32da8256 (MD5)
Approved for entry into archive by Felipe Augusto Arakaki (arakaki@reitoria.unesp.br) on 2016-12-19T18:56:17Z (GMT) No. of bitstreams: 1 salum_sor_me_bot.pdf: 92061303 bytes, checksum: f7154447eecdf5d9ae67dd8a32da8256 (MD5)
Made available in DSpace on 2016-12-19T18:56:17Z (GMT). No. of bitstreams: 1 salum_sor_me_bot.pdf: 92061303 bytes, checksum: f7154447eecdf5d9ae67dd8a32da8256 (MD5) Previous issue date: 2016-11-24
Introdução: O câncer de endométrio (CE) é a neoplasia ginecológica mais comum em países desenvolvidos, e tem um comportamento heterogêneo sob o aspecto clínico, biológico, e morfológico, com taxas de recorrência de 15 a 20% após a cirurgia. Este estudo avaliou, a associação entre a proteína 3 de ligação ao mRNA com fator de crescimento insulina símile II (IMP3), e fatores prognósticos e morfológicos do CE. Métodos: Realizou-se um estudo retrospectivo tipo transversal analítico, com avaliação anátomo-clínica em 79 pacientes com CE, com 70 casos de adenocarcinoma-endometrióide (ACEE) e 9 casos de carcinoma seroso, entre 1992 e 2010. Setenta e quatro amostras de endométrio benigno, obtidas de pacientes com patologias benignas (mioma e pólipo), foram utilizadas como controle. A expressão da IMP3 foi avaliada por imunohistoquímica e quantificada em intensidade e extensão, e então associada a fatores morfológicos e prognósticos, e claudinas (CLDNs) 3 e 4, receptor de estrogênio (ER) e receptores de progesterona (PR), p53 e KI-67. Resultados: Foi evidenciada associação entre a expressão da IMP3 no carcinoma seroso, em comparação com o ACEE, tanto em intensidade (p=0,044) quanto em extensão (p<0,001), bem como nos seguintes fatores prognósticos: grau de diferenciação (p =0,024; p<0,010), estadiamento (p<0,001; p<0,001), metástase (p=0,002; p<0,001). A expressão de IMP3 foi significativa em extensão (p=0,002), nos tumores de endométrio quando comparados aos controles. Houve associação da proteína p53 (p<0,001; p<0,001) em intensidade e extensão, e KI-67 (p=0,01) em extensão. Conclusão: A expressão de IMP3 foi maior nos tumores serosos de endométrio, comparados aos ACEE. Também houve maior expressão no CE quando comparadas aos controles e com fatores de pior prognóstico.
Introduction: Endometrial cancer (EC) is the main gynecological cancer in developed countries. Clinically, biologically and morphologically it presents heterogeneous behavior and has a recurrence rate of 15 to 20%. This study evaluated the association between insulin-like growth factor II mRNA-binding protein 3 (IMP3) and the morphological features and prognosis of EC. Methods: A retrospective cross-sectional analytical study was conducted involving the anatomical and clinical evaluation of 79 patients with EC, 70 cases of endometrioid adenocarcinoma (EAC) and 9 cases of serous carcinoma, between 1992 and 2010. Seventy-four benign endometrial samples, obtained from patients with benign pathologies (myomas and polyps), were used as controls. IMP3 expression was evaluated by immunohistochemistry and quantified according to staining intensity and extension, and then associated with morphological and prognostic factors, claudin markers (CLDN 3 and 4), estrogen receptor and progesterone receptors p53 and Ki-67. Results: Associations were observed for IMP3 expression in serous carcinomas compared with EACs both in staining intensity (p=0.044) and extension (p<0.001) and for the following prognostic factors: degree of differentiation (p=0.024; p<0.010), stage (p<0.001; p<0.001), and metastasis (p=0.002; p<0.001). The extension of IMP3 expression was significant (p=0.002) in endometrial tumors compared with control samples. Associations were observed for p53 (p<0.001; p<0.001) in intensity and extension, and for KI-67 (p=0.01) in extension. Conclusion: IMP3 expression was higher in serous tumors of the endometrium compared with EACs. Higher expression was also observed in endometrial tumors compared with controls and with factors of poor prognosis.

Notre étude porte sur un décalage observé entre la conscience des intentions exprimées par des éducateurs togolais ayant en charge des enfants déficients intellectuels et IMC et la cohérence de leurs pratiques éducatives. Elle a donc pour but d’objectiver les représentations sociales ethniques de la déficience propres aux éducateurs spécialisés prenant en charge des enfants d’un IMPP du Togo, pays africain connaissant deux siècles de présence occidentale. Les personnes déficientes ont de tout temps suscité répugnance et peur dans la plupart des sociétés. L’Occident les avait éliminées, rejetées, ou surprotégées. Par la suite, ce rejet a été suivi par une ambivalence qui avec les progrès scientifiques a abouti depuis des décennies à leur éducation. La personne déficiente est éduquée pour une meilleure intégration, même si parfois les représentations archaïques refont encore surface. En Afrique sub-saharienne, l’enfant déficient encore éliminé, reste une créature inhumaine. Au Togo, il est chez la plupart des ethnies, monstre, diable, bon diable et quelques rares fois, dieu. Ni le Christianisme, ni l’Islam n’ont pu ébranler ces ethnothéories concernant la déficience mentale. L’objet principal de notre étude porte sur le rapport entre la double référence des éducateurs et le décalage que l’on peut constater entre leurs intentions et leurs pratiques. Des éducateurs qui « ne peuvent nier leur culture », comprennent et semblent approuver les pratiques traditionnelles malgré un discours très techniciste au niveau des typologies de la déficience mentale. Pour eux les causes de la déficience restent toujours surnaturelles. La double référence en effet, engendre chez une partie des éducateurs un rejet et chez d’autres une ambivalence. Ou encore elle crée chez ces éducateurs, compatissants ou non, un décalage entre un savoir professionnel et des attitudes négatives envers les enfants déficients mentaux qui seront sans doute éliminés à moins d’être « un peu sauvés » par une religion monothéiste

Mestrado em Engenharia Alimentar - Instituto Superior de Agronomia / UL
As microalgas são ainda um recurso aquático em fase inicial de exploração. A composição em ácidos gordos, compostos fenólicos, perfil fenólico e bioatividades foram analisadas em três novas estirpes de microalgas: Tetraselmis sp. IMP3, Tetraselmis sp. CTP4 e Skeletonema sp. Foi também estudada a estabilidade de extratos de Skeletonema sp. não encapsulados e microencapsulados em inulina
N/A

Les protéines Ras jouent un rôle majeur dans le développement cellulaire. Faisant partie de la catégorie de petites GTPases, elles sont dotées d'un mécanisme fonctionnant tel un interrupteur moléculaire qui, dans leur cas, contrôle la transmission de signaux de croissance cellulaire. Liées au GTP, ces protéines adoptent une conformation leur permettant d'interagir avec des effecteurs en aval et, ainsi, activer la réplication et différenciation cellulaires. La réaction d'hydrolyse du GTP qui se déroule en leur centre, est accompagnée d'un changement conformationnel qui met fin à ces interactions, conduisant ainsi à l'état inactif de Ras, lié au GDP. Des mutations spécifiques de résidus bien déterminés entraînent une baisse du taux d'hydrolyse, laissant ainsi Ras liée au GTP. Or, de fortes concentrations de cette forme active de Ras ont été associées à une prolifération cellulaire anormale, caractéristique de la dissémination de tissus cancéreux. Il apparaît alors que l'élucidation des mécanismes employés par Ras pour accélérer le clivage du GTP constitue une étape majeure dans le développement de thérapies ciblées contre le cancer. Elles consisteraient à rétablir, au sein des mutants oncogéniques, un taux d'hydrolyse proche à celui mesuré au sein du type sauvage. Dans le but de mieux comprendre au niveau atomique les propriétés catalytiques de Ras, nous avons mené des simulations de dynamique moléculaire (MD) en décrivant le domaine G à différents niveaux de théorie (Mécanique Moléculaire (MM), Semi-empirique et Théorie de la Fonctionnelle de la Densité (DFT)). Ces calculs ont été réalisés pour les formes sauvage et mutées au niveau du résidu 61 de NRas. Ils ont été couplées à des caractérisations biomécaniques des complexes protéine-ligand étudiés, en utilisant la méthode des modes statiques. Cette méthode permet d'identifier des points chauds, réactifs, de la biomolécule et qui, suivant le critère de contrainte choisi, ont une influence mécanique sur la fonction GTPase de la protéine. Par conséquent, ils pourraient servir en temps que sites appropriés pour héberger des molécules médicamenteuses contenant des groupes chimiques spécifiques qui faciliteraient l'hydrolyse du GTP. Tout d'abord, les résultats obtenus montrent que le positionnement des molécules d'eau dans le cite actif est crucial pour catalyser efficacement la réaction. En effet, la répartition précise du solvant, observée dans le type sauvage, est perdue au sein des mutants de NRas considérés ici. Cette distribution différente des molécules d'eau ainsi que les modifications structurales du site actif engendrées par les substitutions du résidu Gln 61, ont un impact direct sur la densité électronique du GTP. Cette dernière présente un profil de type GDP au sein de la protéine de type sauvage uniquement, comme déterminé expérimentalement dans des études précédentes. Il apparaît donc que les mutations oncogéniques de Gln 61 perturbent cet effet catalytique majeur de NRas. Parmi trois propositions faites au cours de cette thèse sur des modifications à apporter à la forme mutée Q61R de NRas, une est présentée pendant la soutenance tandis que toutes les trois sont décrites dans le manuscript. Les groupes chimiques insérés au niveau du site identifié permettent de rétablir une distribution de l'eau comme celle observée dans le type sauvage. Pour terminer, lors de la soutenance uniquement, un chemin réactionnel alternatif de l'hydrolyse enzymatique du GTP est proposé
Ras subfamily of small GTPase proteins holds a key position in cell proliferation pathways. Indeed, the transmission of cell growth signals is controlled by proteins belonging to it. In their GTP-bound conformation, these proteins interact and activate downstream effectors of cell replication and differentiation. The hydrolysis reaction that takes place in their center, terminates these interactions, thereby leading to the GDP-bound inactive state. Point mutations of key residues lead to a hydrolysis rate drop that keeps Ras in a GTP-bound active state. Now, high concentrations of active Ras have been associated to abnormal cell proliferation, emblematic of cancerous tissues dissemination. With this into consideration, the elucidation of Ras mechanisms for accelerating GTP cleavage appears as a major step in the development of cancer targeted therapies that would consist in restoring the hydrolysing capabilities within oncogenic Ras to a wild-type rate. In an attempt to gain insight into Ras catalysing properties at the atomic level, unconstrained Molecular Dynamics (MD) simulations describing the G domain at different levels of theory (Molecular Mechanics (MM), Semi-empirical and Density Functional Theory (DFT)) were carried out for NRas member in its wild-type and Gln 61 mutated forms. These simulations were coupled to biomechanic characterisations of the complexes under inspection employing the static modes approach. The latter method, allows the identification of hot spots {\it i.e.} responsive residues of the biomolecule, that have a mechanical influence on the GTPase function of the protein. Hence, they could serve as suitable sites to host drug-like molecules containing specific chemical groups that would facilitate GTP hydrolysis. The obtained results show that water molecules positioning is crucial for efficiently catalysing the reaction that takes place in NRas center. Indeed, the precise positioning observed within the wild-type is lost within the mutants studied here. Furthermore, the active site structural modifications undergone upon Gln 61 substitutions, together with solvent distribution in it, impact directly GTP electronic density. The latter is accommodated to a GDP-like state within the wild-type protein only, as experimentally determined in previous investigations. Thus, oncogenic Gln 61 mutations impair this major catalysing effect. Among three engineered NRas proteins of the Q61R mutated form, proposed during this thesis, one is presented during the defence while the three are described in the manuscript. The chemical groups inserted at the identified site enable the recovery of water distribution as within the wild-type. To end, during the defence only, an alternative reaction pathway of the enzymatic reaction is proposed

In the last decade, the development and deployment of Uninhabited Airborne Vehicles (UAVs) has increased dramatically. This has in turn increased the desire to operate UAVs in civilian-airspace. Current UAV platforms can be integrated into civilian-airspace, with other air traffic, however they place a high burden on their human operators in order to do so. In order to meet the competing objectives of improved integration and low operator workload it will be necessary to increase the intelligence on-board the UAV. This thesis presents the results of the research which has been conducted into increasing the on-board intelligence of the UAV. The intent in increasing the on-board intelligence is to improve the ability of a UAV to integrate into civilian-airspace whilst also reducing the workload placed upon the UAV's operator. The research has focused upon increasing the intelligence in two key areas: mission planning; and mission piloting. Mission planning is the process of determining how to fly from one location to another, whilst avoiding entities (eg. airspace boundaries and terrain) on the way. Currently this task is typically performed by a trained human operator. This thesis presents a novel multidisciplinary approach for enabling a UAV to perform, on-board, its own mission planning. The novel approach draws upon techniques from the 3D graphics and robotics fields in order to enable the UAV to perform its own mission planning. This enables the UAV's operator to provide the UAV with the locations (waypoints) to fly to. The UAV will then determine for itself how to reach the locations safely. This relieves the UAV's operator of the burden of performing the mission planning for the UAV. As part of this novel approach to on-board mission planning, the UAV constructs and maintains an on-board situational awareness of the airspace environment. Through techniques drawn from the 3D graphics field the UAV becomes capable of constructing and interacting with a 3D digital representation of the civilian-airspace environment. This situational awareness is a fundamental component of enabling the UAV to perform its own mission planning and piloting. The mission piloting research has focused upon the areas of collision avoidance and communications. These are tasks which are often handled by a human operator. The research identified how these processes can be performed on-board the UAV through increasing the on-board intelligence. A unique approach to collision avoidance was developed, which was inspired by robotics techniques. This unique approach enables the UAV to avoid collisions in a manner which adheres to the applicable Civil Aviation Regulations, as defined by the Civil Aviation Safety Authority (CASA) of Australia. Furthermore, the collision avoidance algorithms prioritise avoiding collisions which would result in a loss of life or injury. Finally, the communications research developed a natural language-based interface to the UAV. Through this interface, the UAV can be issued commands and can also be provided with updated situational awareness information. The research focused upon addressing issues related to using natural language for a civilian-airspace-integrated UAV. This area has not previously been addressed. The research led to the definition of a vocabulary targeted towards a civilian-airspace-integrated UAV. This vocabulary caters for the needs of both Air Traffic Controllers and general UAV operators. This requires that the vocabulary cater for a diverse range of skill levels. The research established that a natural language-based communications system could be applied to a civilian-airspace-integrated UAV for both command and information updates. The end result of this research has been the development of the Intelligent Mission Planner and Pilot (IMPP). The IMPP represents the practical embodiment of the novel algorithms developed throughout the research. The IMPP was used to evaluate the performance of the algorithms which were developed. This testing process involved the execution of over 3000 hours of simulated flights. The testing demonstrated the high performance of the algorithms developed in this research. The research has led to the successful development of novel on-board situational awareness, mission planning, collision avoidance and communications capabilities. This thesis presents the development, implementation and testing of these capabilities. The algorithms which provide these capabilities go beyond the existing body of knowledge and provide a novel contribution to the established research. These capabilities enable the UAV to perform its own mission planning, avoid collisions and receive natural language-based communications. This provides the UAV with a direct increase in the intelligence on-board the UAV, which is the core objective of this research. This increased on-board intelligence improves the integration of the UAV into civilian-airspace whilst also reducing the operator's workload.

碩士
國立陽明大學
生物藥學研究所
92
Telomeres, the DNA-protein complex located at the ends of most eukaryotes, protect chromosome ends from nucleolytic digestion and facilitate complete replication of the genome. Cdc13p is a telomere binding protein of Saccharomyces cerevisiae. Through a screen for proteins that interact with Cdc13p in a two-hybrid system, we identified a protein Imp4p that interact with Cdc13p both in vivo and in vitro. Imp4p is a component of the U3 snoRNPs (small nucleolar ribonucleproteins) that is involving in pre-18S rRNA processing. It encodes 290 amino acids with molecular mass of 32 kDa. Sequence analysis of Imp4p indicated that it has a brix domain and σ70-like motif. The brix domain is considered to be responsible for ribosome synthesis andσ70-like motif with prokaryotic origins has ability to binding single strand RNA homopolymer. These conserved sequences indicate that Imp4p may participate in DNA or RNA binding. Applying an in vitro gel shift assay, we found that Imp4p is capable of binding to single strand telomeric DNA, suggest that Imp4p is a component of telomeric complex. We also found that Imp4p bound to telomerase RNA, TLC1, with high affinity. Since Imp4p was identified in partially purified telomerase fractions and TLC1 RNA was detected in the Imp4p immunoprecipitates together these results indicated that Imp4p is also a component of telomerase complex. We created the site-directed mutation inσ70-like motif and Brix domain to study the function of Imp4p involved in the telomere. Unfortunately, these two mutated Imp4pE249Aand Imp4pR234A does not affect the binding activity of Imp4p to ss telomeric DNA or the cell viability. Besides, the overexpression of Imp4p does not affect the telomere length in vivo. Since Imp4p is capable to interact with both telomeres and telomerase complex. We propose that Imp4p may play a role in telomere function in mediate accessibility of telomerase to telomeres.

Das Mantelzelllymphom (MCL) gehört zu den aggressiven, mit bislang zur Verfügung stehenden Therapien nicht heilbaren, Non-Hodgkin-Lymphomen (NHL). Das MCL weist eine schlechte Prognose auf. Charakteristisch für das MCL ist die t(11,14)- Translokation, die das Cyclin D1- Gen betrifft. Darüber hinaus finden sich zahlreiche weitere genetische Alterationen mit Häufung bestimmter Zugewinne und Verluste von genetischem Material. Einer der am häufigsten chromosomal zugewonnene Abschnitte in MCL ist der kurze Arm von Chromosom 7 (7p). In Fällen mit dieser genetischen Veränderung fand sich das IMP3/IGF2BP3-Gen (Insulin-like growth factor 2 mRNAbinding protein 3) unter den am stärksten differentiell exprimierten Genen. In dieser Arbeit konnte in einer immunhistochemischen Analyse eine stark variable IMP3-Protein-Expression in einer Serie von insgesamt 172 primären MCL gezeigt werden. Darüber hinaus fand sich in diesem Kollektiv eine signifikante Korrelation der IMP3-Expression mit der Proliferationsfraktion (Ki67-Immunhistochemie) sowie auch eine Assoziation mit einer blastoiden Morphologie. Es konnte jedoch letztlich keine statistisch signifikante Assoziation der IMP-3-Protein-Expression mit einem chromosomalen Zugewinn von 7p, dem Genort von IMP3, nachgewiesen werden, so dass hier offenbar auch noch andere Mechanismen für die Regulation eine wichtige Rolle spielen. In einer darüber hinaus untersuchten Vergleichsgruppe von 20 Fällen von Lymphknoten mit Infiltraten durch ein small lymphocytic Lymphoma (SLL) zeigte sich insgesamt nur eine geringe IMP3-Expression. Der Befund einer vermehrten IMP3-Protein-Expression in einer Teilgruppe von MCL mit erhöhter Tumorzellproliferation unterstützt die Idee, dass eine Aktivierung des IGFSignalweges in MCL möglicherweise die Proliferation und biologische Aggressivität begünstigt. Daher könnte eine therapeutische Manipulation dieses Signalweges vermutlich eine zukünftige therapeutische Option für das MCL darstellen
The mantle cell lymphoma (MCL) is one of the most aggressive non-Hodgkin´s lymphomas (NHL) with poor prognosis. As of today, no therapy is capable to cure this lymphoma. One of the key MCL characteristics is the t(11,14)-translocation, involving the cyclin D1 gene. In addition, there are numerous further genetic alterations, especially gains and losses of genetic material. One of the most commonly affected chromosomal sections is the short arm of chromosome 7 (7p). IMP3/IGF2BP3 gene (insulin-like growth factor 2mRNAbinding protein3) is among the strongest differentially expressed genes in cases with this genetic alteration. This work analyses a series of 172 primary MCL cases with the help of immunohistochemistry. These cases have highly variable IMP3 protein expression. This thesis showed significant correlation between the IMP3 expression and the proliferation levels (Ki67 immunohistochemistry), as well with the blastoid morphology of these cases. However, no statistically significant association was found between the IMP3 protein expression and the chromosomal gains of 7p (the locus of IMP3), suggesting that other mechanisms can be responsible for the regulation of IMP3 in MCL. The analysis of the control group (20 cases of lymphnodes infiltrated with a small lymphocytic lymphoma - SLL) showed overall only a small IMP3 expression. The study of seven secondary MCL cases showed no major differences in IMP3 protein expression between the primary diagnoses and later relapses. The findings of the correlation between the IMP3 protein expression and the increased proliferation support the idea that the activation of the IGF signaling pathway possibly favors proliferation and biological aggressiveness in MCL. Therefore, future MCL therapy research could include therapeutic manipulation of the IGF signaling pathway

碩士
國立陽明大學
生物藥學研究所
93
Telomeres are the physical ends of eukaryotic chromosomes. They are important for maintaining the integrity of chromosomes and this function is mediated through a number of protein factors. In Saccharomyces cerevisiae, Cdc13p binds to telomeres and affects telomere maintenance, telomere position effect, and cell cycle progression through G2/M phase. Imp4p was identified that interacted with the amino acids 1-252 of Cdc13p through a yeast two-hybrid screening system. It is a member of U3 snoRNP which is involved in the maturation of 18 S rRNA. Even though Imp4p was reported to be a component of rRNA processing machinery, it appears to participate in telomere function as well. The interaction between Cdc13p and Imp4p is direct as judged by in vitro pull-down assays. Co-immunoprecipitation experiments also showed that they interacted in vivo. Moreover, purified recombinant Imp4p could bind single-strand telomeric DNA and telomerase RNA in vitro using electrophoretic mobility shift assays. To define the region within Imp4p essential for cells’ viability, different Imp4p fragments were constructed and analyzed by plasmid loss assay. Our results indicated that the C-terminal fourteen amino acids of Imp4p are not required for its essential function. But when this region was deleted, the telomere shortened. The region within Imp4p that interacts with Cdc13p was localized using yeast two-hybrid analysis. We found that the Cdc13p-interacting region of Imp4p is within amino acid residues 38-87. Sequence analysis of Imp4p indicated it contained a brix domain, which is also identified in several proteins involved in RNA metabolism. The brix domain was postulated to be involved in binding to RNA. To localize the region within Imp4p that interacts with telomeric DNA or telomerase RNA, the binding ability of purified recombinant Imp4p brix domain were analyzed using electrophoretic mobility shift assays. The results indicated that the purified recombinant Imp4p brix domain can bind to single-stranded TG1-3 DNA. Together we have mapped the regions within Imp4p that is involved for its essential function, interacting with Cdc13p, and telomeirc DNA or telomease RNA. These results reveal the important role of Imp4p in telomere function.

碩士
國立成功大學
生理學研究所
106
Huntington’s disease (HD) is an inherited neurodegenerative disease leading to motor control dysfunction and cognitive deficit in patients, resulting from the neurotoxicity primarily in the central nervous system (CNS) along with altered gene expression. Previously, our research had found that overexpression of miR-196a ameliorated pathological phenotypes of HD models in vitro and in vivo and provided beneficial regulations for neuronal cytoskeleton. We now elucidate the mechanism of the neuroprotective effects of miR-196a. Bioinformatics predicts that insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3 or IMP3) is a potential target gene of miR-196a, which is involved in cytoskeleton remodeling during malignant transformation in cancers. Therefore, we hypothesize that miR-196a may improve the neuronal morphology through targeting IMP3. Here, we confirm that miR-196a inhibits the endogenous expression level of IMP3 in N2a cells by targeting the 3’UTR of IMP3 transcript. Besides, the endogenous IMP3 is suppressed in miR-196a transgenic mice. We further show that miR-196a inhibits IMP3 in N2a cells differentiated by retinoic acid and in mouse primary cortical neurons, and overexpression of IMP3 blocks the morphology protective effect of miR-196a. Additionally, the exogenous IMP3 restrains the neurite outgrowth and leads to abnormal morphology, including decreased F-actin intensity and flattened cell shape. Furthermore, in screening the expression profiling of IMP3 in the R6/2 HD mouse model, we find an ectopic expression pattern of IMP3 in their adult cortical tissues, which is distinct from the wild type mice and correlated with disease progression. These results implicate a detrimental role of elevated IMP3 in neuronal pathogenesis, and miR-196a may provide beneficial effects for neuronal morphology through targeting IMP3. In future work, we will study the role of IMP3 in the neuroprotective effect of miR-196a in HD models in vitro and in vivo. We anticipate that this study will shed light on promising treatment strategies for HD.

碩士
國立成功大學
生物資訊與訊息傳遞研究所
101
Leukemia is a broad term covering a spectrum of diseases. The acute myeloid leukemia (AML) is a common subtype occurred in adults and also the majority type of all leukemia patients to result in death. Instead of killing cancer cells through cytotoxicity, forcing malignant cells to undergo differentiation is one of the strategies in AML therapy. However, the patients always failed to complete remission due to drug resistance is still a challenge. IL-18 is a pro-inflammatory cytokine. IL-18 was observed to be overexpressed in some hematologic malignancies and associated with a poor clinical outcome. Importantly, although the protumor effect of IL-18 was suggested in solid tumors, the effects and details remain less to be elucidated in hematopoietic neoplasms. In this study, we found that IL-18 has no effect on the proliferation but showed an antiapoptotic effect on U937 and THP-1 cells. Increase of COX-2 expression is responsive to IL-18 treatment through a post-transcriptional regulation in U937 cells, especially in differentiated U937 cells. Two RNA binding proteins HuR and IMP-3 mediate the stabilization of COX-2 mRNA. IL-18 has no effect on the levels of HuR and IMP-3 but induced their shuttle from nucleus to cytoplasm and interaction. Importantly, IL-18 induces the bindings of HuR and IMP-3 on the 3’UTR of COX-2 mRNA. JNK and ERK1/2 signaling pathways contribute to IL-18-enhanced COX-2 transcripts and the shuttle of HuR, but not IMP-3, from nucleus to cytoplasm in differentiated U937 cells. These results suggested that IL-18 can stabilize COX-2 mRNA through the JNK- and/or ERK1/2-regulated HuR nucleocytoplasmic shuttle. It also implied that the IL-18 and COX-2 inhibitors could represent a potential adjuvant to be combined with differentiation therapy for AML therapy.