Browsing by Author "Socorro, Sílvia"
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- Androgens and low density lipoprotein-cholesterol interplay in modulating prostate cancer cell fate and metabolismPublication . Cardoso, Henrique J.; Figueira, Marília I.; Carvalho, Tiago M.A.; Serra, Catarina D.M.; Vaz, Cátia V.; Madureira, Patricia; Socorro, SílviaBackground: Androgens, the known drivers of prostate cancer (PCa), have been indicated as important metabolic regulators with a relevant role in stimulating lipid metabolism. Also, the relationship between obesity and the aggressiveness of PCa has been established. However, it is unknown if the androgenic hormonal environment may alter the response of PCa cells to lipid availability. Purpose: The present study evaluated the effect of 5 alpha-dihydrotestosterone (DHT) in regulating lipid metabolism, and the interplay between this hormone and low-density lipoprotein (LDL)-cholesterol in modulating PCa cells fate.Methods: Non-neoplastic and neoplastic PCa cells were treated with 10 nM DHT, and the expression of fatty acids transporter, fatty acid synthase (FASN), and carnitine palmitoyltransferase 1A (CPT1A) evaluated. PCa cells were also exposed to LDL (100 mu g/ml) in the presence or absence of DHT.Results: Treatment with DHT upregulated the expression of FASN and CPT1A in androgen-sensitive PCa cells. In contrast, LDL supplementation suppressed FASN expression regardless of the presence of DHT, whereas aug-menting CPT1A levels. Our results also showed that LDL-cholesterol increased PCa cells viability, proliferation, and migration dependently on the presence of DHT. Moreover, LDL and DHT synergistically enhanced the accumulation of lipid droplets in PCa cells.Conclusions: The obtained results show that androgens deregulate lipid metabolism and enhance the effects of LDL increasing PCa cells viability, proliferation and migration. The present findings support clinical data linking obesity with PCa and first implicate androgens in this relationship. Also, they sustain the application of phar-macological approaches targeting cholesterol availability and androgens signaling simultaneously.
- Clonagem do cDNA do receptor de estrogénios na dourada Sparus aurata (Linnaeus, 1758)Publication . Socorro, Sílvia; Canário, AdelinoO receptor de estrogénios (ER), um factor de transcrição que regula a transactivação de vários genes, pertence à superfamília de receptores nucleares que inclui receptores para as hormonas esteróides, tiróidea, vitaminas e para vários ligandos ainda não identificados. O ER tem sido dividido em 6 domínios funcionais (A-F), com os domínios C (ligação ao DNA) e E (ligação à hormona) altamente conservados entre várias espécies, dos peixes aos mamíferos. O objectivo deste estudo foi determinar a sequência do cDNA do ER da dourada, Sparus aurata (dER). Um banco de cDNA de figado de dourada com 9,1x108 clones, construido em ?LZapII, foi pesquisado com um fragmento do receptor de estrogénios de Salmo salar (Dr. Glenn Sweeney, Universidade de Cardiff). Foram identificados vários positivos putativos, os quais foram isolados e analisados por Southem blotting, usando a sonda do salmão, com o intuito de seleccionar os clones de maior tamanho e os que apresentavam um sinal mais intenso. Ao mesmo tempo, tentou-se obter por PCR uma sonda homóloga para detecção do cDNA do dER. Os iniciadores foram desenhados através da comparação das sequências do ER em várias espécies e usados no PCR com cDNA de fígado de animais previamente estimulados com estradiol-17B. Os fragmentos obtidos foram clonados e sequenciados para confirmar a respectiva identidade.
- Cloning and characterisation of seabream (Sparus Aurata) Estrogen ReceptorsPublication . Socorro, Sílvia; Canário, Adelino; Power, DeborahThe steroid hormone estrogen is known to have important actions in vertebrates influencing growth, differentiation and functioning of several systems. In fish has been recognised that estradiol-176 (E2) exert a role in feminisation of the gonads, induction and maintenance of vitellogenesis in the liver and in the feedback mechanisms in the pituitary. The estrogen effects are mediated in cells by binding to a specific nuclear protein, the estrogen receptor (ER). In turn, the ER acts as a transcription factor binding to DNA specific sequences and regulating the transcription of estrogen target genes. As an initial step to further understand the roles of estrogen in seabream, Sparus aurata, a protandrous hermaphrodite developing a testis during their first year of life and undergoing sex reversal to female between the second and the third years, this thesis aimed to clone and characterise the seabream ER (sbER). Within these proposed research goals was achieved the cloning of two distinct forms of sbERs and its sequences were analysed and compared to the ER available sequences in other vertebrate species. The expression of ERs in seabream adult tissues and early life stages was characterised. A potential distinct function for each ER in seabream was also investigated by analysing its expression in response to E2- stimulation and during induced sex reversal.
- Molecular cloning and sequence of gilthead sea bream (Sparus aurata) alpha-skeletal actin: tissue and developmental expressionPublication . Moutou, K. A.; Socorro, Sílvia; Power, Deborah; Mamuris, Z.; Canario, Adelino V. M.In the present study, the Sparus aurata -skeletal actin was cloned from a mixed larvae complementary DNA library. The clone isolated was 1523 bp long with an open reading frame of 1134 bp coding for a 377-amino acid protein. The deduced amino acid sequence of sea bream -actin is identical to Fugu -actin-1. The expression of -actin was initiated at the onset of segmentation. In adult fish, -actin is expressed predominantly in white and red muscle.
- Two estrogen receptors expressed in the teleost fish, Sparus aurata: cDNA cloning, characterization and tissue distributionPublication . Socorro, Sílvia; Power, Deborah; Olsson, P. E.; Canario, Adelino V. M.Estrogen is an essential hormone for many reproductive and non-reproductive functions. The function of estrogen in the reproductive cycle of seabream (Sparus aurata), a protandrous hermaphrodite teleost fish, is complex but it is understood to be involved in sex inversion, a process that occurs in some individuals during the second reproductive season. Estrogen action is mediated by two estrogen receptor (ER) subtypes designated alpha and beta. As a step to understanding the mechanisms of estrogen action during natural and induced sex reversal in seabream, we have isolated two cDNAs encoding distinct forms of ER homologous to mammalian ERalpha and ERbeta. The seabream ERalpha clone (sbERalpha1), which was truncated in the A/B domain, corresponded to a variant differing in five amino acids from another recently cloned sbERalpha. The ERbeta clone (sbERbeta) encoded a protein 559 amino acids long and showed only 40% identity to sbERalpha. Northern blot analysis of liver and ovary mRNA indicated the presence of several transcripts of the two receptor subtypes. PCR analysis showed that the two receptors differed in their expression pattern. sbERalpha had a more restricted distribution, occurring mainly in testis, liver and heart, and sbERbeta was present in most tissues, being more abundant in ovary, testis, liver, intestine and kidney. The presence in seabream of two ERs with several ER transcripts and their pattern of distribution are consistent with the widespread effects of estrogen in different tissues.