| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 1.93 MB | Adobe PDF |
Authors
Abstract(s)
A aromatase é a enzima chave da síntese do estrogénio e constitui um alvo terapêutico
para o tratamento do cancro da mama recetor estrogénio positivo na pós-menopausa.
Os fitoestrogénios, principais componentes da soja, são utilizados muitas vezes como
substituto hormonal feminino devido às suas propriedades estrogénicas.
Com este estudo, pretende-se determinar se os fitoestrogénios genisteína e daidzeína
interferem na atividade da aromatase e na terapêutica do cancro da mama, utilizando
um potente inibidor da aromatase.
Com o ensaio, procurámos estudar a influência da genisteína e da daidzeína (em
diferentes concentrações) na atividade da aromatase de células de adenocarcinoma da
mama recetor estrogénio positivo, MCF-7, na presença e na ausência do letrozol, um
potente inibidor da aromatase, em comparação com o substrato fisiológico 17ßestradiol.
Para a realização do ensaio, foi necessária a otimização do volume de lisado celular. A
atividade específica da aromatase foi determinada por fluorescência, com utilização do
Aromatase (CYP19A) Activity Assay kit, e correlacionada com a quantificação de
proteínas totais nas amostras, utilizando o Pierce BCA Protein Assay.
Os resultados mostram que a genisteína e a daidzeína, nas diferentes concentrações
testadas, aumentaram a atividade da aromatase e diminuíram o efeito inibitório do
letrozol. Esses resultados destacam que se deve ter precaução no consumo de
isoflavonas da soja por mulheres na pós-menopausa com cancro da mama recetor
estrogénio positivo em tratamento com inibidores da aromatase, uma vez que foi
evidenciada uma diminuição da ação inibitória do letrozol.
Aromatase is the key enzyme of the estrogen synthesis and constitutes a therapeutic target for the treatment of estrogen receptor positive breast cancer in postmenopausal women. Phytoestrogens, the main components of soy, are often used as female hormonal substitutes, due to their estrogenic properties. This research aims to determine if genistein and daidzein, predominant soya isoflavones, interfere with aromatase activity and with breast cancer therapy, using a potent aromatase inhibitor. With this research we intended to study the influence of genistein and daidzein (in different concentrations), on aromatase activity in breast carcinoma estrogen receptor positive cell line MCF-7, in the presence and absence of letrozol, a potent aromatase inhibitor, comparing with physiological substrate 17ß-estradiol. For this purpose, the lysates cells volumes were optimized. The specific aromatase activity was determined by fluorometric assay assessed, using Aromatase (CYP19A) Activity Assay kit, and correlated with the total protein concentration in the samples, using Pierce BCA Protein Assay. The research showed that genistein and daidzein, in all the tested concentrations, increased aromatase activity and decreased the inhibitory effect of letrozole. Based on our results, the present study highlights the concern about the consumption of soy isoflavones by postmenopausal women with estrogen receptor positive breast cancer in treatment with aromatase inhibitors, since there is evidence of a decrease in letrozole's inhibitory action.
Aromatase is the key enzyme of the estrogen synthesis and constitutes a therapeutic target for the treatment of estrogen receptor positive breast cancer in postmenopausal women. Phytoestrogens, the main components of soy, are often used as female hormonal substitutes, due to their estrogenic properties. This research aims to determine if genistein and daidzein, predominant soya isoflavones, interfere with aromatase activity and with breast cancer therapy, using a potent aromatase inhibitor. With this research we intended to study the influence of genistein and daidzein (in different concentrations), on aromatase activity in breast carcinoma estrogen receptor positive cell line MCF-7, in the presence and absence of letrozol, a potent aromatase inhibitor, comparing with physiological substrate 17ß-estradiol. For this purpose, the lysates cells volumes were optimized. The specific aromatase activity was determined by fluorometric assay assessed, using Aromatase (CYP19A) Activity Assay kit, and correlated with the total protein concentration in the samples, using Pierce BCA Protein Assay. The research showed that genistein and daidzein, in all the tested concentrations, increased aromatase activity and decreased the inhibitory effect of letrozole. Based on our results, the present study highlights the concern about the consumption of soy isoflavones by postmenopausal women with estrogen receptor positive breast cancer in treatment with aromatase inhibitors, since there is evidence of a decrease in letrozole's inhibitory action.
Description
Keywords
Letrozol 17ß-Estradiol Atividade da Aromatase Cancro da Mama Daidzeína Genisteína Mcf-7