Development of new aromatase inhibitors analogues of letrozole: perspectives for treatment of male infertility
Autor(a) principal: | |
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Data de Publicação: | 2016 |
Tipo de documento: | Dissertação |
Idioma: | eng |
Título da fonte: | Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
Texto Completo: | http://hdl.handle.net/10400.6/6272 |
Resumo: | Nowadays, infertility is one of the major health issues. Human fertility depends on several psychological, physical and biochemical factors, with a successful spermatogenesis being the fundamental basis for male fertility. The male sexual function and the proper development of spermatogenic process are highly dependent on the hormonal regulation, particularly by the actions of sex steroid hormones, androgens and estrogens. 17ß-Estradiol (E2), the metabolite of testosterone (T) aromatization by the activity of aromatase, is the most potent estrogen produced in the human body. Aromatase is a member of the cytochrome P450 protein superfamily that regulates the last step of estrogen biosynthesis, aromatizing the A-ring of androgens such as T and androstenedione into E2 and estrone, respectively. Thus, in men, E2 is responsible for a number of effects originally attributed to T. On the other hand, men with a high serum E2/T ratio are infertile and it has been suggested that they can be treated with aromatase inhibitors (AIs). Indeed, AIs have been shown to increase T levels, and restore spermatogenesis, in infertile men with this endocrinopathy. Among other classes of compounds, letrozole is a nonsteroidal AI that has been widely used for treatment of male infertility. In order to develop more selective and efficient AIs, letrozole analogues were synthesized, where one of the rings of benzonitrile was substituted by a phenyl group in para position with different functional groups, and the methine bridge was substituted by a vinyl group. Furthermore, their reduced congeners were synthesized. Overall, the synthesis of nine letrozole analogues was performed. To the best of our knowledge, six letrozole analogues were reported for the first time in this dissertation. All compounds were structurally characterized with prominence by nuclear magnetic resonance spectrometry. Additionally, aromatase docking studies were performed. Giving the resemblance between all the letrozole analogues synthesized, it was not surprising that the results were very similar. The simulation revealed that the compounds in this study showed higher affinity to the enzyme, when compared with letrozole. After the synthesis, purification and characterization steps, two representative letrozole analogues namely 4-(2-phenyl-1-(1H-1,2,4-triazol-1-yl)vinyl)benzonitrile and 4-(2-phenyl-1-(1H-1,2,4-triazol-1-yl)ethyl)benzonitrile were selected for evaluation of their biological activity as potential AIs in testicular cells. For this purpose, rat seminiferous tubules (SeT) were cultured ex vivo in the presence or absence of 200 nM or 400 nM of letrozole and the vinyl and ethyl letrozole analogues. Steroid hormone production, the tubular differentiation index (TDI) and the glycolytic metabolism were evaluated. The synthesized letrozole analogues, which were selected for biological evaluation as potential AIs, seem to suppress glycolytic metabolism. On the other hand, letrozole increased the metabolizing of glucose with augmented production of lactate. Relatively to the TDI, it was significantly reduced in the SeT exposed to letrozole 200 nM and ethylbenzonitrile letrozole analogue both in 200 nM and 400 nM. However, no dose-dependent relationship was observed for the AIs under study. Moreover, without the radioimmunoassays results for quantifying T and E2 in the culture medium, it is not possible to advance a definitive conclusion about the distinct behavior of letrozole and its analogues studied in this dissertation. Nevertheless, considering the effects observed on TDI and glycolytic metabolism, only with 24 h of culture, it is possible to conclude that both letrozole analogues are biologically active. In the future, it would be of uttermost importance to evaluate the biological activity of the remaining synthesized compounds as AIs in testicular cells. |
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Development of new aromatase inhibitors analogues of letrozole: perspectives for treatment of male infertilityAnálogos do LetrozoleControlo HormonalEspermatogéneseInfertilidade MasculinaInibidores da AromataseMetabolismo CelularTúbulos Seminíferos.Domínio/Área Científica::Ciências Médicas::Ciências BiomédicasNowadays, infertility is one of the major health issues. Human fertility depends on several psychological, physical and biochemical factors, with a successful spermatogenesis being the fundamental basis for male fertility. The male sexual function and the proper development of spermatogenic process are highly dependent on the hormonal regulation, particularly by the actions of sex steroid hormones, androgens and estrogens. 17ß-Estradiol (E2), the metabolite of testosterone (T) aromatization by the activity of aromatase, is the most potent estrogen produced in the human body. Aromatase is a member of the cytochrome P450 protein superfamily that regulates the last step of estrogen biosynthesis, aromatizing the A-ring of androgens such as T and androstenedione into E2 and estrone, respectively. Thus, in men, E2 is responsible for a number of effects originally attributed to T. On the other hand, men with a high serum E2/T ratio are infertile and it has been suggested that they can be treated with aromatase inhibitors (AIs). Indeed, AIs have been shown to increase T levels, and restore spermatogenesis, in infertile men with this endocrinopathy. Among other classes of compounds, letrozole is a nonsteroidal AI that has been widely used for treatment of male infertility. In order to develop more selective and efficient AIs, letrozole analogues were synthesized, where one of the rings of benzonitrile was substituted by a phenyl group in para position with different functional groups, and the methine bridge was substituted by a vinyl group. Furthermore, their reduced congeners were synthesized. Overall, the synthesis of nine letrozole analogues was performed. To the best of our knowledge, six letrozole analogues were reported for the first time in this dissertation. All compounds were structurally characterized with prominence by nuclear magnetic resonance spectrometry. Additionally, aromatase docking studies were performed. Giving the resemblance between all the letrozole analogues synthesized, it was not surprising that the results were very similar. The simulation revealed that the compounds in this study showed higher affinity to the enzyme, when compared with letrozole. After the synthesis, purification and characterization steps, two representative letrozole analogues namely 4-(2-phenyl-1-(1H-1,2,4-triazol-1-yl)vinyl)benzonitrile and 4-(2-phenyl-1-(1H-1,2,4-triazol-1-yl)ethyl)benzonitrile were selected for evaluation of their biological activity as potential AIs in testicular cells. For this purpose, rat seminiferous tubules (SeT) were cultured ex vivo in the presence or absence of 200 nM or 400 nM of letrozole and the vinyl and ethyl letrozole analogues. Steroid hormone production, the tubular differentiation index (TDI) and the glycolytic metabolism were evaluated. The synthesized letrozole analogues, which were selected for biological evaluation as potential AIs, seem to suppress glycolytic metabolism. On the other hand, letrozole increased the metabolizing of glucose with augmented production of lactate. Relatively to the TDI, it was significantly reduced in the SeT exposed to letrozole 200 nM and ethylbenzonitrile letrozole analogue both in 200 nM and 400 nM. However, no dose-dependent relationship was observed for the AIs under study. Moreover, without the radioimmunoassays results for quantifying T and E2 in the culture medium, it is not possible to advance a definitive conclusion about the distinct behavior of letrozole and its analogues studied in this dissertation. Nevertheless, considering the effects observed on TDI and glycolytic metabolism, only with 24 h of culture, it is possible to conclude that both letrozole analogues are biologically active. In the future, it would be of uttermost importance to evaluate the biological activity of the remaining synthesized compounds as AIs in testicular cells.Atualmente, a infertilidade é considerada um importante problema de saúde, estando dependente de diversos fatores psicológicos, físicos e bioquímicos, o que no caso da infertilidade masculina assenta fundamentalmente no sucesso da espermatogénese. A função sexual masculina e o adequado desenvolvimento do processo espermatogénico estão altamente dependentes da regulação hormonal, particularmente da ação exercida pelas hormonas sexuais esteróides, androgénios e estrogénios. O 17ß-Estradiol (E2), produto da aromatização da testosterona (T) através da aromatase, é o estrogénio mais potente produzido no corpo humano. A aromatase pertence ao grupo molecular das enzimas do citocromo P450 e regula o último passo da biossíntese dos estrogénios, aromatizando o anel A de androgénios tais como a T e a androstenediona, em E2 e estrona, respetivamente. Deste modo, o E2 é responsável por inúmeros efeitos originalmente atribuídos à T no homem. Por outro lado, homens que apresentam um rácio plasmático E2/T elevado são inférteis, tendo sido proposto o uso de inibidores da aromatase (AIs) para o seu tratamento. De facto, a administração de AIs aumentou significativamente os níveis de T o que foi associado a uma recuperação na espermatogénese em homens com esta endocrinopatia. O letrozole é o AI não esteroidal que exibe maior capacidade de inibição da aromatase, tendo por isso, vindo a ser usado no tratamento da infertilidade masculina. De forma a desenvolver AIs mais selectivos e potentes, foram sintetizados novos inibidores da aromatase análogos ao letrozole, em que um dos dois anéis benzonitrilo é substituído por um fenilo substituído na posição para com diferentes grupos funcionais, e a ponte metino é substituída por um grupo vinilo. Para além disso, foram também sintetizados os seus congéneres reduzidos. Assim, foram sintetizados nove análogos do letrozole, sendo que seis deles foram descritos pela primeira vez nesta dissertação. Todos os compostos foram caracterizados através de ressonância magnética nuclear. Foram ainda realizados testes de docking molecular. Dada a semelhança existente entre os análogos do letrozole sintetizados, era espectável que estes apresentassem resultados similares. A simulação revelou que os compostos em estudo apresentam alta afinidade para a enzima no centro ativo quando comparados com o letrozole. Após a síntese, caracterização e purificação dos compostos, dois análogos do letrozole, nomeadamente o 4-(2-fenil-1-(1H-1,2,4-triazol-1-il)vinil)benzonitrilo e o 4-(2-fenil-1-(1H-1,2,4-triazol-1-il)etil)benzonitrilo, foram selecionados para avaliação do seu potencial biológico como AIs em células testiculares. Para tal, foram avaliados a produção de hormonas esteróides, o índice de diferenciação tubular (TDI), e o metabolismo glicolítico em culturas ex vivo de túbulos seminíferos (SeT) de ratos, na ausência ou na presença do letrozole, e dos análogos do letrozole vinilo e etilo em diferentes concentrações (200 e 400 nM). Ambos os análogos do letrozole pareceram suprimir o metabolismo glicolítico. Por outro lado, o letrozole mostrou aumentar a produção de lactato, o que indica um aumento do metabolismo glicolítico. Relativamente ao TDI, este mostrou-se significativamente reduzido na presença de letrozole 200 nM ou do análogo do letrozole etilo em ambas as concentrações de 200 e 400 nM. No entanto, não foi observada uma relação dose-resposta nos AIs estudados. Contudo, sem os resultados dos radioimunoensaios para a quantificação de T e E2 no meio de cultura, não é possível obter, neste momento, uma conclusão definitiva relativamente aos efeitos do letrozole e dos seus análogos estudados. Porém, face aos resultados observados no TDI e no metabolismo glicolítico, visíveis com apenas 24h de cultura, podemos concluir que ambos os análogos do letrozole estudados são biologicamente ativos. No futuro, seria de extrema importância avaliar ainda a atividade biológica dos restantes compostos sintetizados como potenciais AIs em células testiculares.Almeida, Paulo Jorge da SilvaSocorro, Sílvia Cristina da Cruz MarquesuBibliorumCoelho, Anaísa Nascimento2018-11-05T14:37:31Z2016-10-102016-11-072016-11-07T00:00:00Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisapplication/pdfhttp://hdl.handle.net/10400.6/6272TID:201771470enginfo:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2023-12-15T09:44:40Zoai:ubibliorum.ubi.pt:10400.6/6272Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-20T00:47:02.089503Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse |
dc.title.none.fl_str_mv |
Development of new aromatase inhibitors analogues of letrozole: perspectives for treatment of male infertility |
title |
Development of new aromatase inhibitors analogues of letrozole: perspectives for treatment of male infertility |
spellingShingle |
Development of new aromatase inhibitors analogues of letrozole: perspectives for treatment of male infertility Coelho, Anaísa Nascimento Análogos do Letrozole Controlo Hormonal Espermatogénese Infertilidade Masculina Inibidores da Aromatase Metabolismo Celular Túbulos Seminíferos. Domínio/Área Científica::Ciências Médicas::Ciências Biomédicas |
title_short |
Development of new aromatase inhibitors analogues of letrozole: perspectives for treatment of male infertility |
title_full |
Development of new aromatase inhibitors analogues of letrozole: perspectives for treatment of male infertility |
title_fullStr |
Development of new aromatase inhibitors analogues of letrozole: perspectives for treatment of male infertility |
title_full_unstemmed |
Development of new aromatase inhibitors analogues of letrozole: perspectives for treatment of male infertility |
title_sort |
Development of new aromatase inhibitors analogues of letrozole: perspectives for treatment of male infertility |
author |
Coelho, Anaísa Nascimento |
author_facet |
Coelho, Anaísa Nascimento |
author_role |
author |
dc.contributor.none.fl_str_mv |
Almeida, Paulo Jorge da Silva Socorro, Sílvia Cristina da Cruz Marques uBibliorum |
dc.contributor.author.fl_str_mv |
Coelho, Anaísa Nascimento |
dc.subject.por.fl_str_mv |
Análogos do Letrozole Controlo Hormonal Espermatogénese Infertilidade Masculina Inibidores da Aromatase Metabolismo Celular Túbulos Seminíferos. Domínio/Área Científica::Ciências Médicas::Ciências Biomédicas |
topic |
Análogos do Letrozole Controlo Hormonal Espermatogénese Infertilidade Masculina Inibidores da Aromatase Metabolismo Celular Túbulos Seminíferos. Domínio/Área Científica::Ciências Médicas::Ciências Biomédicas |
description |
Nowadays, infertility is one of the major health issues. Human fertility depends on several psychological, physical and biochemical factors, with a successful spermatogenesis being the fundamental basis for male fertility. The male sexual function and the proper development of spermatogenic process are highly dependent on the hormonal regulation, particularly by the actions of sex steroid hormones, androgens and estrogens. 17ß-Estradiol (E2), the metabolite of testosterone (T) aromatization by the activity of aromatase, is the most potent estrogen produced in the human body. Aromatase is a member of the cytochrome P450 protein superfamily that regulates the last step of estrogen biosynthesis, aromatizing the A-ring of androgens such as T and androstenedione into E2 and estrone, respectively. Thus, in men, E2 is responsible for a number of effects originally attributed to T. On the other hand, men with a high serum E2/T ratio are infertile and it has been suggested that they can be treated with aromatase inhibitors (AIs). Indeed, AIs have been shown to increase T levels, and restore spermatogenesis, in infertile men with this endocrinopathy. Among other classes of compounds, letrozole is a nonsteroidal AI that has been widely used for treatment of male infertility. In order to develop more selective and efficient AIs, letrozole analogues were synthesized, where one of the rings of benzonitrile was substituted by a phenyl group in para position with different functional groups, and the methine bridge was substituted by a vinyl group. Furthermore, their reduced congeners were synthesized. Overall, the synthesis of nine letrozole analogues was performed. To the best of our knowledge, six letrozole analogues were reported for the first time in this dissertation. All compounds were structurally characterized with prominence by nuclear magnetic resonance spectrometry. Additionally, aromatase docking studies were performed. Giving the resemblance between all the letrozole analogues synthesized, it was not surprising that the results were very similar. The simulation revealed that the compounds in this study showed higher affinity to the enzyme, when compared with letrozole. After the synthesis, purification and characterization steps, two representative letrozole analogues namely 4-(2-phenyl-1-(1H-1,2,4-triazol-1-yl)vinyl)benzonitrile and 4-(2-phenyl-1-(1H-1,2,4-triazol-1-yl)ethyl)benzonitrile were selected for evaluation of their biological activity as potential AIs in testicular cells. For this purpose, rat seminiferous tubules (SeT) were cultured ex vivo in the presence or absence of 200 nM or 400 nM of letrozole and the vinyl and ethyl letrozole analogues. Steroid hormone production, the tubular differentiation index (TDI) and the glycolytic metabolism were evaluated. The synthesized letrozole analogues, which were selected for biological evaluation as potential AIs, seem to suppress glycolytic metabolism. On the other hand, letrozole increased the metabolizing of glucose with augmented production of lactate. Relatively to the TDI, it was significantly reduced in the SeT exposed to letrozole 200 nM and ethylbenzonitrile letrozole analogue both in 200 nM and 400 nM. However, no dose-dependent relationship was observed for the AIs under study. Moreover, without the radioimmunoassays results for quantifying T and E2 in the culture medium, it is not possible to advance a definitive conclusion about the distinct behavior of letrozole and its analogues studied in this dissertation. Nevertheless, considering the effects observed on TDI and glycolytic metabolism, only with 24 h of culture, it is possible to conclude that both letrozole analogues are biologically active. In the future, it would be of uttermost importance to evaluate the biological activity of the remaining synthesized compounds as AIs in testicular cells. |
publishDate |
2016 |
dc.date.none.fl_str_mv |
2016-10-10 2016-11-07 2016-11-07T00:00:00Z 2018-11-05T14:37:31Z |
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info:eu-repo/semantics/publishedVersion |
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