Estrone sulfatase and its inhibitors
Department of Pharmacy, School of Pharmacy and Chemistry, Kingston University, Penrhyn Road, Kingston upon Thames, Surrey KT12EE, UK. Anti-cancer agents in medicinal chemistry
(Impact Factor: 2.47).
A high proportion (approximately 40%) of breast cancers are hormone-dependent and it is the female hormone estradiol (E2) that is believed to play a key role in the initiation, promotion and progression of this disease. In the fight against this disease, compounds which are potent inhibitors of the cytochrome P-450 enzyme aromatase (AR) (which catalyses the conversion of the C19 androgens to the C18 estrogens) have been the major target. However, the administration of AR inhibitors alone does not prevent the localised biosynthesis of estrone (E1) (and therefore the subsequent synthesis of E2) within breast tumour cells via alternative non-AR routes. This has therefore been the major impetus for the development of steroid sulfatase (E1STS) inhibitors. The E1STS enzyme regulates the formation of E1 from estrone sulfate (E1S), a steroid conjugate present in high concentrations in tissue and blood in women with breast cancer. The STS enzyme has also been shown to catalyse the formation of dehydroepiandrosterone (DHEA) from DHEA-sulfate (DHEAS). This is important since DHEA can be converted to 5-androstene-3beta,17beta-diol, which has been shown to possess weak estrogenic properties, however, due to the high concentration of this steroid, it is able to stimulate the growth of breast cancer cells in vitro and in vivo. Considerable progress has been made in recent years in the development of a number of potent E1STS inhibitors, as such both steroidal and non-steroidal compounds have been considered and a number of highly potent inhibitors have been produced and evaluated against what is now considered a crucial enzyme in the fight against hormone-dependent breast cancer. The review therefore summarises the work that has been undertaken todate.
Available from: Maria Bondesson
- "It is a metabolic intermediate in the biosynthesis of androgens and estrogens, and it is produced in the adrenal glands and in the gonads. 5-Diol is a metabolite of DHEA (reviewed in ), and 3β-Adiol is metabolized from 5α- dihydrotestosterone (reviewed in ). E2 is the most abundant and potent endogenous estrogen in female vertebrates during the reproductive years. "
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ABSTRACT: Estrogen receptors are expressed and their cognate ligands produced in all vertebrates, indicative of important and conserved functions. Through evolution estrogen has been involved in controlling reproduction, affecting both the development of reproductive organs and reproductive behavior. This review broadly describes the synthesis of estrogens and the expression patterns of aromatase and the estrogen receptors, in relation to estrogen functions in the developing fetus and child. We focus on the role of estrogens for development of reproductive tissues, as well as non-reproductive effects on the developing brain. We collate data from human, rodent, bird and fish studies and highlight common and species-specific effects of estrogen signaling on fetal development. Morphological malformations originating from perturbed estrogen signaling in estrogen receptor and aromatase knockout mice are discussed, as well as the clinical manifestations of rare estrogen receptor alpha and aromatase gene mutations in humans. This article is part of a Special Issue entitled: Nuclear receptors in animal development.
Available from: PubMed Central
- "E1S is a steroid conjugate present in high concentrations in tissue and blood in women with breast cancer. E1S is considered an important source for the formation of active estrogens which is able to be produced by STS activity (Aidoo-Gyamfi et al., 2009). "
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ABSTRACT: Steroid sulfatase (STS) is responsiblefor the conversion of estrone sulfate to estrone that can stimulate growth in endocrine-dependent tumors such as prostate cancer. Although STS is considered as a therapeutic target for the estrogen-dependent diseases, cellular function of STS are still not clear. Previously, we found that tumor necrosis factor (TNF)-α significantly enhances steroid sulfatase expression in PC-3 human prostate cancer cells through PI3K/Akt-dependent pathways. Here, we studied whether bacterial lipopolysaccharides (LPS) which are known to induce TNF-α may increase STS expression. Treatment with LPS in PC-3 cells induced STS mRNA and protein in concentration- and time-dependent manners. Using luciferase reporter assay, we found that LPS enhanced STS promoter activity. Moreover, STS expression induced by LPS increased PC-3 tumor cell migration determined by wound healing assay. We investigated that LPS induced IL-6 expression and IL-6 increased STS expression. Taken together, these data strongly suggest that LPS induces STS expression through IL-6 pathway in human prostate cancer cells.
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ABSTRACT: IMPORTANCE IN THE FIELD: Primary bone tumors are considered as (sex steroid) hormone-dependent tumors. Osteosarcoma, osteoblastoma and bone cysts are preferentially found in males, while giant cell tumors are more common in females. Indeed, bone tumor development and progression are influenced by sex steroid hormones derived from in situ synthesis in bone cells.
This review describes intracrine mechanisms for local formation of the biologically most active estrogen, 17beta-estradiol (E2), from circulating steroid precursors through the 'aromatase' (aromatization of androgens) and the 'sulfatase' (conversion of inactive estrone-sulfate) pathway.
The reader gains knowledge on both pathways and the enzymes, which contribute to the in situ availability of active hormones, namely 3beta-hydroxysteroid dehydrogenases, 17beta-hydroxysteroid dehydrogenases, aromatase, steroid sulfatases and sulfotransferases. An overview is given and the expression and function of these enzymes in bone tumors are discussed.
Knowledge on pathways for the in situ formation of E2 in bone cells may allow the identification of potential targets for i) novel endocrine therapeutic options in primary bone tumors and ii) future preventive interventions.
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