In the human adrenal cortex, adrenocorticotropin (ACTH) activates steroid hormone biosynthesis by acutely increasing cholesterol delivery to the mitochondria and chronically up-regulating the transcription of steroidogenic genes (including CYP17). Sphingolipids are a diverse family of phospholipids and glycolipids that mediate a wide variety of cellular processes, including apoptosis, proliferation, and survival. Sterol regulatory element binding proteins (SREBPs) are a family of transcription factors that regulate genes that are involved in cholesterol biosynthesis and fatty acid metabolism. In this study, we investigated the role of sphingolipids in ACTH-dependent steroidogenesis. H295R human adrenocortical cells were treated with ACTH or dibutyryl cAMP (Bt2cAMP) for various time periods and the content of several sphingolipid species was quantified by mass spectrometry. Both ACTH and Bt2cAMP decreased cellular amounts of sphingomyelin, ceramides, sphingosine (So) and sphingosine-1-phosphate (S1P). However, both ACTH and Bt2cAMP increased the activity of sphingosine kinase and the amounts of S1P released into the media. Both So and S1P increased CYP17 mRNA expression and increased cortisol biosynthesis. This increase in CYP17 transcription occurs by promoting SREBP binding to an SRE at -450/-436 basepairs upstream of the transcription initiation site. Furthermore, chromatin immunoprecipitation (ChIP) assays revealed that Bt2cAMP and S1P treatment results in an increase in acetylation of histone H3 and SREBP1 binding to CYP17 promoter. Additionally, transient transfection studies using wild type or mutated hCYP17 promoters and RNA interference (RNAi) assays confirmed the role of SREBP1 in mediating the stimulatory effect of S1P on CYP17 transcription. In summary, our studies demonstrate a link between sphingolipid metabolism and ACTH-dependent steroidogenesis which requires the activation of SREBP1 in human adrenal cortex.

Thesis (PhD (Biochemistry))--Stellenbosch University, 2008. / This study describes: • the cloning and sequencing of cytochrome P450 17 -hydroxylase/17,20 lyase (CYP17), 3 -hydroxysteroid dehydrogenase (3 HSD) and cytochrome b5 from the South African Angora goat; • the identification of two CYP17 genes encoding two unique CYP17 isoforms in the Angora goat; • the development of a UPLC-APCI-LC method for the separation and quantification of seven adrenal steroids; • the characterisation of the enzymatic activity of the two Angora CYP17 isoforms expressed in non-steroidogenic COS-1 cells. The Km and Vvalues for the metabolism of pregnenolone and progesterone were determined; • the development of a rapid and accurate real-time PCR genotyping test for CYP17 in Angora goats. Three unique genotypes were identified; • the determination of blood cortisol levels upon the stimulation of the HPAaxis by intravenous insulin injection in the three Angora goat genotypes.

Prostate cancer constitutes the most common malignancy and the most common cause of cancer‐related death in Swedish men. A large body of evidence suggests that inherited genetic variants contribute to both development and progression of prostate cancer. The aim of this thesis is to identify genetic variants that alter prostate cancer risk and progression. All papers included in this thesis are based on a Swedish population‐based case‐control study (CAPS) comprising 2,965 incident prostate cancer cases and 1,823 controls. In paper I, we investigated if genetic variants in the E‐cadherin gene altered prostate cancer risk. Seven haplotype tagging SNPs(tagSNPs) were selected and genotyped in CAPS and families with hereditary prostate cancer. We confirmed association of a promoter SNP rs16260 previously reported to increase risk of hereditary prostate cancer (OR: 2.6; 95% CI: 1.6‐4.3) for homozygous ‘A’ carriers. In paper II, we assessed 46 polymorphisms earlier reported to be associated with prostate cancer risk. Six polymorphisms in five different genes were replicated. Interestingly, three of these genes were involved in the androgen biosynthesis. In paper III, we followed up on the results from paper II by genotyping 23 tagSNPs located in the hormone regulating genes AR, CYP17 and SRD5A2. Multiple SNPs and haplotypes were associated with prostate cancer risk, especially in the AR gene. Combining risk alleles from all genes revealed a substantial risk increase for each additional allele carried (OR: 1.12; 95% CI: 1.1‐1.2, P=0.00009). In paper IV, we collected information about cause of death for all case patients in CAPS. At time of follow‐up 300 study subjects were deceased from prostate cancer. We assessed AR, CYP17 and SRD5A2 variants for association with lethal prostate cancer and found overall no association. However, one AR promoter SNP was associated with an increased risk of dying from prostate cancer amongst men who received palliative hormonal therapy as primary treatment. In paper V, we assessed common genetic variation at the ERG locus for association between prostate cancer risk and survival. ERG is recognized as a protooncogene frequently overexpressed in prostate cancer. A total of 21 tagSNPs in the 5’ region of ERG were genotyped. There was no correlation between ERG SNPs and prostate cancer risk but common genetic variation located approximately 100,000 basepairs upstream of ERG was significantly associated with prostate cancer specific survival. In summary, our results suggest that common genetic variation in Ecadherin alters prostate cancer risk in Swedish men with a positive family history of prostate cancer. Moreover, common genetic variation in the androgen‐related genes AR, CYP17 and SRD5A2 affects the risk of developing prostate cancer but is unlikely to alter prostate cancer progression. However, genetic variants in AR may affect hormonal therapy response. Finally, ERG polymorphisms are associated with prostate cancer‐specific death but are not likely to play a role in prostate cancer development.

Glyphosate-based herbicides are the dominant pesticide on the market and are utilized worldwide in both the agricultural and forestry industries. Their prevalence comes at a time when concern over the potential effects of pesticide application in amphibian spawning grounds is growing. The primary goal of this thesis was to determine if the glyphosate-based herbicide WeatherMax® has the potential to disrupt sexual differentiation and growth in the wood frog (Lithobates sylvaticus) in a pulse exposure at the predicted maximal environmental concentration (PMEC) of 2.88 mg acid equivalent per liter. This was carried out in laboratory, mesocosm and in-situ field exposures, in an attempt to determine how a potential disruption might vary between experimental environments. In this study, tadpoles from three split-wetlands targeted at the PMEC for WeatherMax were found to display no significant change in survival or growth, however gene expression of several genes involved in steroidogenesis during sexual differentiation (cyp19, cyp17, star, foxl2) were found to be affected. The effects on these genes appeared to be dependant on the exposure concentration of WeatherMax in each wetland, which varied even though all three wetlands were meant to target the PMEC. The wetland that was measured as having the highest herbicide concentration (PMEC 13) was found to have a female biased sex ratio. The results found in the field varied from those found in the more artificial exposures. In the laboratory the PMEC of WeatherMax experienced complete mortality, whereas in the mesocosms survival was not significantly affected. Sex ratios were unaffected in the laboratory, however at the PMEC there was a significant male bias in the mesocosms. The discrepancies in the results obtained from the different exposure types highlights the importance of real world exposures. That the same concentration that caused complete mortality in the laboratory caused sublethal effects in the field is of importance as it denotes that these endpoints may not be easily investigated in these synthetic exposures. This project is a part of the Long Term Experimental Wetlands Area (LEWA) and contributes to the body of information amassed therein on the impact of a glyphosate-based herbicide on amphibians in a wetland ecosystem.

Steroidogenic factor (SF1) is an orphan nuclear receptor that is essential for steroid hormone-biosynthesis and endocrine development. Recent studies have demonstrated that phospholipids are ligands for SF1. In the present study our aim was to identify endogenous ligands for SF1 and characterize their functional significance in mediating cAMP-dependent transcription of human CYP17. Using mass spectrometry we show that in H295R adrenocortical cells SF1 is bound to sphingosine (SPH) under basal conditions and that cAMP stimulation decreases the amount of SPH bound to the receptor. We also show that silencing both acid and neutral ceramidases using siRNA induces CYP17 mRNA expression, suggesting that SPH acts as an inhibitory ligand. In vitro analysis of ligand binding using scintillation proximity assays show that several sphingolipids and phospholipids, including phosphatidic acid (PA), can compete with [3H]SPH for binding to SF1, suggesting that SF1 may have more than one ligand and binding specificity may change with the changes in intracellular fluxes of phospholipids. Further, phosphatidic acid (PA) induces SF1-dependent transcription of CYP17 reporter constructs. Inhibition of diacyglycerol kinase (DAGK) activity using R59949 and silencing DAGK- expression attenuates SF1-dependent CYP17 transcriptional. We propose that PA is an activating ligand for SF1 and that cAMP-stimulated activation of SF1 takes place by displacement of SPH.

Glyphosate-based herbicides are the dominant pesticide on the market and are utilized worldwide in both the agricultural and forestry industries. Their prevalence comes at a time when concern over the potential effects of pesticide application in amphibian spawning grounds is growing. The primary goal of this thesis was to determine if the glyphosate-based herbicide WeatherMax® has the potential to disrupt sexual differentiation and growth in the wood frog (Lithobates sylvaticus) in a pulse exposure at the predicted maximal environmental concentration (PMEC) of 2.88 mg acid equivalent per liter. This was carried out in laboratory, mesocosm and in-situ field exposures, in an attempt to determine how a potential disruption might vary between experimental environments. In this study, tadpoles from three split-wetlands targeted at the PMEC for WeatherMax were found to display no significant change in survival or growth, however gene expression of several genes involved in steroidogenesis during sexual differentiation (cyp19, cyp17, star, foxl2) were found to be affected. The effects on these genes appeared to be dependant on the exposure concentration of WeatherMax in each wetland, which varied even though all three wetlands were meant to target the PMEC. The wetland that was measured as having the highest herbicide concentration (PMEC 13) was found to have a female biased sex ratio. The results found in the field varied from those found in the more artificial exposures. In the laboratory the PMEC of WeatherMax experienced complete mortality, whereas in the mesocosms survival was not significantly affected. Sex ratios were unaffected in the laboratory, however at the PMEC there was a significant male bias in the mesocosms. The discrepancies in the results obtained from the different exposure types highlights the importance of real world exposures. That the same concentration that caused complete mortality in the laboratory caused sublethal effects in the field is of importance as it denotes that these endpoints may not be easily investigated in these synthetic exposures. This project is a part of the Long Term Experimental Wetlands Area (LEWA) and contributes to the body of information amassed therein on the impact of a glyphosate-based herbicide on amphibians in a wetland ecosystem.

Made available in DSpace on 2015-07-22T20:49:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-22. Added 1 bitstream(s) on 2015-08-11T03:25:37Z : No. of bitstreams: 1 Publico-046.pdf: 880322 bytes, checksum: 128ded79001d290a9d22d62c499f8d08 (MD5) / OBJETIVO: Avaliar a influência do polimorfismo do CYP17 em mulheres menopausadas em terapia estrogênica. Um total de 130 mulheres foram recrutadas, porém apenas 100 mulheres foram selecionadas seguindo os critérios de inclusão e exclusão; foi administrado 0.3mg/dia de estrogênios conjugados eqüinos. Após um ano, terminamos o estudo com 70 pacientes. Analisamos o Índice Menopausal de Kupperman (IMK) através de cartão diário. Amostras de sangue foram analisadas e as mulheres foram divididas em 2 grupos de acordo com o polimorfismo da 5’ região não traduzida do gene CYP17: GA (selvagem homozigoto e heterozigoto) e GB (mutado homozigoto). RESULTADOS: Os valores do IMK foram similares nos dois grupos no ínicio do estudo. Os sintomas diminuíram nos dois grupos após um ano de tratamento quando comparados ao tempo zero. A taxa de melhora foi de aproximadamente 27.09% e 32.18% no GA e GB, respectivamente. Os níveis de estrogênio após o tratamento foram maiores nos dois grupos quando comparados ao inicio do tratamento. O nível de testosterona aumentou no GB após 1 ano de terapia estrogênica (0.48 ± 0.16) alcançando níveis maiores do que o GA após o término do estudo. O nível de SHBG mostrou um aumento significativo após 1 ano de tratamento no GB ultrapassando os níveis iniciais e o GA (p<0.01). CONCLUSÃO: Nossos dados sugerem que o polimorfismo do CYP17 não influencia a resposta estrogênica após 1 ano de tratamento. A produção extra de androgênio e estrogênio pode ter sido anulada pela elevação da SHBG. / To evaluate the influence of CYP17 polymorphism on menopausal symptoms after estrogen treatment. Design: A total of 130 women were recruited, but only 100 of these were selected according to inclusion and exclusion criteria, and they were treated with 0.3mg/day of conjugated equine estrogens. One year later the study was completed with 70 women. The analysis of the Kuppermann Menopausal Index (KMI) symptoms was made with information provided by the patients on daily diary cards. Blood samples were analyzed and the women were divided into two groups based on the CYP17, 5´ untranslated region: GA (wild-type homozygote and heterozygote) and GB (mutated homozygote). Results: The values of KMI were similar in both groups (GA = 31.11 ± 9.95 and GB= 30.39 ± 7.74) at baseline. The symptoms in both groups decreased after one year of treatment when compared to those at baseline. The improvement rate was approximately 27.09% and 32.18%, in GA and GB, respectively. The levels of estrogen after treatment were higher in both groups in comparison with the baseline values. The testosterone level rose in GB with the one-year treatment (0.48 ± 0.16) reaching a higher level than the GA level after treatment. The SHBG level showed a significant increase after the one-year treatment in GB surpassing both the baseline and the after treatment values of GA (p<0.01). Conclusion: Our data suggest CYP17 polymorphism did not influence the unopposed estrogen during the one-year treatment. The extra production of estrogen and androgen may have been countered by the elevation of SBHG.Key words: Polymorphism; CYP17; estrogen; hot flashes. / TEDE / BV UNIFESP: Teses e dissertações

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-06-21T19:18:47Z No. of bitstreams: 1 NorbertoDeKassioVieiraMonteiro_TESE.pdf: 7192293 bytes, checksum: 5db84120cda0bcf05ee26ed563d1586f (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-06-21T21:51:10Z (GMT) No. of bitstreams: 1 NorbertoDeKassioVieiraMonteiro_TESE.pdf: 7192293 bytes, checksum: 5db84120cda0bcf05ee26ed563d1586f (MD5) / Made available in DSpace on 2016-06-21T21:51:10Z (GMT). No. of bitstreams: 1 NorbertoDeKassioVieiraMonteiro_TESE.pdf: 7192293 bytes, checksum: 5db84120cda0bcf05ee26ed563d1586f (MD5) Previous issue date: 2015-10-09 / Esta tese foi realizada em quatro cap?tulos, todos a n?vel te?rico, enfocados principalmente na densidade eletr?nica. No primeiro cap?tulo, nos descrevemos a aplica??o de um minicurso para estudo das rea??es de Diels-Alder na Universidade Federal do Rio Grande do Norte. Utilizando ferramentas de qu?mica computacional, os estudantes puderam construir um determinado conhecimento e puderam associar importantes aspectos da f?sico-qu?mica e da qu?mica org?nica. No segundo cap?tulo, estudamos um novo tipo de intera??o qu?mica envolvendo ?tomos de hidrog?nio de carga neutra, denominada de liga??o hidrog?nio-hidrog?nio (H-H). Nesse estudo realizado com alcanos complexados, fornece novas e importantes informa??es acerca das suas estabilidades envolvendo esse tipo de intera??o. Mostramos que a liga??o H-H desempenha um papel secund?rio na estabilidade de alcanos ramificados em compara??o aos seus is?meros menos ramificados ou lineares. No terceiro cap?tulo, estudamos a estrutura eletr?nica e a estabilidade do tetraedrano, de tetraedranos substitu?dos e seus parentes de sil?cio e germ?nio. Avaliamos o efeito do substituinte na gaiola de carbono dos derivados do tetraedrano e os resultados indicam que fortes grupos retiradores de el?trons (GRE) causam pequena instabilidade na gaiola carb?nica, em contrapartida, fracos GRE resulta em grande instabilidade. Mostramos que na aromaticidade-?, GRE e grupos doadores de el?trons (GDE) resultam em um decr?scimo e em aumento, respectivamente, dos ?ndices de aromaticidade NICS e D3BIA. Em adi??o, outro fator pode ser utilizado para explicar a estabilidade do tetra-tert-butiltetraedrano, assim como a liga??o H-H. GVB e ADMP tamb?m foram utilizados para avaliar o efeito de substituintes na gaiola do tetraedrano. No quarto cap?tulo, n?s realizamos uma investiga??o te?rica do efeito inibit?rio do f?rmaco abiraterona (ABE), utilizado no tratamento do c?ncer de pr?stata, frente ? enzima CYP17, comparando as energias de intera??o e densidade eletr?nica desse f?rmaco com o substrato natural, a pregnenolona (PREG). Din?mica molecular e docking foram utilizados para obter os complexos CYP17-ABE e CYP17-PREG. ? partir da din?mica molecular, foi obtido que a ABE possui uma maior tend?ncia de difus?o ?gua ? s?tio de intera??o da enzima CYP17, quando com a mesma tend?ncia da PREG. Com o m?todo ONIOM (B3LYP:AMBER), encontramos que a energia de intera??o da ABE ? 21,38 kcal mol-1 mais est?velem compara??o ? PREG. Os resultados obtidos atrav?s da QTAIM indicam que essa estabilidade se d? devido a uma maior densidade eletr?nica das intera??es entre a ABE e a CYP17. / This thesis was performed in four chapters, at the theoretical level, focused mainly on electronic density. In the first chapter, we have applied an undergraduate minicourse of Diels-Alder reaction in Federal University of Rio Grande do Norte. By using computational chemistry tools students could build the knowledge by themselves and they could associate important aspects of physical-chemistry with Organic Chemistry. In the second chapter, we studied a new type of chemical bond between a pair of identical or similar hydrogen atoms that are close to electrical neutrality, known as hydrogen-hydrogen (H-H) bond. In this study performed with complexed alkanes, provides new and important information about their stability involving this type of interaction. We show that the H-H bond playing a secondary role in the stability of branched alkanes in comparison with linear or less branched isomers. In the third chapter, we study the electronic structure and the stability of tetrahedrane, substituted tetrahedranes and silicon and germanium parents, it was evaluated the substituent effect on the carbon cage in the tetrahedrane derivatives and the results indicate that stronger electron withdrawing groups (EWG) makes the tetrahedrane cage slightly unstable while slight EWG causes a greater instability in the tetrahedrane cage. We showed that the sigma aromaticity EWG and electron donating groups (EDG) results in decrease and increase, respectively, of NICS and D3BIA aromaticity indices. In addition, another factor can be utilized to explain the stability of tetra-tert-butyltetrahedrane as well as HH bond. GVB and ADMP were also used to explain the stability effect of the substituents bonded to the carbon of the tetrahedrane cage. In the fourth chapter, we performed a theoretical investigation of the inhibitory effect of the drug abiraterone (ABE), used in the prostate cancer treatment as CYP17 inhibitor, comparing the interaction energies and electron density of the ABE with the natural substrate, pregnenolone (PREG). Molecular dynamics and docking were used to obtain the CYP1ABE and CYP17-PREG complexes. From molecular dynamics was obtained that the ABE has higher diffusion trend water CYP17 binding site compared to the PREG. With the ONIOM (B3LYP:AMBER) method, we find that the interaction electronic energy of ABE is 21.38 kcal mol-1 more stable than PREG. The results obtained by QTAIM indicate that such stability is due a higher electronic density of interactions between ABE and CYP17

Glyphosate-based herbicides are the dominant pesticide on the market and are utilized worldwide in both the agricultural and forestry industries. Their prevalence comes at a time when concern over the potential effects of pesticide application in amphibian spawning grounds is growing. The primary goal of this thesis was to determine if the glyphosate-based herbicide WeatherMax® has the potential to disrupt sexual differentiation and growth in the wood frog (Lithobates sylvaticus) in a pulse exposure at the predicted maximal environmental concentration (PMEC) of 2.88 mg acid equivalent per liter. This was carried out in laboratory, mesocosm and in-situ field exposures, in an attempt to determine how a potential disruption might vary between experimental environments. In this study, tadpoles from three split-wetlands targeted at the PMEC for WeatherMax were found to display no significant change in survival or growth, however gene expression of several genes involved in steroidogenesis during sexual differentiation (cyp19, cyp17, star, foxl2) were found to be affected. The effects on these genes appeared to be dependant on the exposure concentration of WeatherMax in each wetland, which varied even though all three wetlands were meant to target the PMEC. The wetland that was measured as having the highest herbicide concentration (PMEC 13) was found to have a female biased sex ratio. The results found in the field varied from those found in the more artificial exposures. In the laboratory the PMEC of WeatherMax experienced complete mortality, whereas in the mesocosms survival was not significantly affected. Sex ratios were unaffected in the laboratory, however at the PMEC there was a significant male bias in the mesocosms. The discrepancies in the results obtained from the different exposure types highlights the importance of real world exposures. That the same concentration that caused complete mortality in the laboratory caused sublethal effects in the field is of importance as it denotes that these endpoints may not be easily investigated in these synthetic exposures. This project is a part of the Long Term Experimental Wetlands Area (LEWA) and contributes to the body of information amassed therein on the impact of a glyphosate-based herbicide on amphibians in a wetland ecosystem.