17 beta-hydroxysteroid dehydrogenases--their role in pathophysiology

Synthesis and characterization of targeted 17β-hydroxysteroid dehydrogenase type 7 inhibitors

Sex steroid hormones such as estrogen estradiol (E2) and androgen dihydrotestosterone (DHT) are involved in the development of hormone-dependent cancers. Blockade of 17β-hydroxysteroid dehydrogenase type 7 (17β-HSD7), a member of the short chain dehydrogenase/reductase superfamily, is thought to decrease E2 levels while increasing those of DHT. Therefore, its unique double action makes this enzyme as an interesting drug target for treatment of breast cancer. The chemical synthesis, molecular characterization, and preliminary biological evaluation as 17β-HSD7 inhibitors of novel carbamate derivatives 3 and 4 are described. Like previous 17β-HSD7 inhibitors 1 and 2, compounds 3 and 4 bear a hydrophobic nonyl side chain at the C-17β position of a 4-aza-5α-androstane nucleus, but compound 3 has an oxygen atom replacing the CH2 in the steroid A-ring C-2 position, while compound 4 has a C17-spiranic E-ring containing a carbamate function. They both inhibited the in vitro transformation of estrone (E1) into E2 by 17β-HSD7, but the introduction of a (17 R)-spirocarbamate is preferable to replacing C-2 methylene with an oxygen atom since compound 4 (IC50 = 63 nM) is an inhibitor 14 times more powerful than compound 3 (IC50 = 900 nM). Furthermore, when compared to the reference inhibitor 1 (IC50 = 111 nM), the use of a C17-spiranic E-ring made it possible to introduce differently the hydrophobic nonyl side chain, without reducing the inhibitory activity.

Luteinizing hormone-releasing hormone agonists versus orchiectomy in the treatment of prostate cancer: A systematic review

Background

Orchiectomy has been replaced by medication represented by luteinizing hormone-releasing hormone (LHRH) agonist as the first-line therapy for androgen deprivation therapy (ADT). After the wide application of LHRH agonist, the side-effects of long-term ADT were noticed. It is time to reconsider the role of medication and surgeries in the treatment of prostate cancer.

Methods

Embase, Pubmed, Web of science and Cochrane library were searched for relevant trials. Quality of the studies and risk of bias were assessed by using the Newcastle-Ottawa Scale (NOS). Therapeutic and adverse effects, as well as long-term metabolic adverse effects were extracted from the selected studies. The data synthesized in meta-analyses were performed with R software (4.2.1). Risk ratio (RR) with its 95% confidence interval (CI) was calculated by combining outcome data including complete and partial response rate, progression rate, death rate and adverse effects such as hot flash and increase in pain. Descriptive analysis was performed among the prostate specific antigen (PSA), testosterone and metabolic adverse effects due to a lack of homogeneity of frailty measures.

Results

1,711 participants from 11 studies were included in our systematic review. 1,258 patients from six studies were included in the meta-analysis. Based on the meta-analysis, the therapeutic and adverse outcomes included overall response rate, complete response rate, partial response rate, stable rate, progression rate, death rate and hot flashes. No statistical significance was observed between LHRH agonists and orchiectomy. Compared with surgery, LHRH agonist elevated the risk of the increase in pain. In descriptive analysis, it was shown that the therapeutic effects between PSA and testosterone also showed no significant difference. Both groups had lipid and glucose metabolic disorders, and a few studies reported worse lipid metabolic performance in orchiectomy group and worse insulin resistance in LHRH agonist group.

Conclusion

We found that the therapeutic outcomes were similar between the two options. The results of lipid and glucose metabolic abnormality were controversial in existing studies. The direct comparison studies on metabolic adverse effects should be performed in the future. The therapeutic, metabolic, psychological and economical effects should be considered before applying ADT methods.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42022365891.

Distribution and Effects of Estrogen Receptors in Prostate Cancer: Associated Molecular Mechanisms

Estrogens are hormones that have been extensively presented in many types of cancer such as breast, uterus, colorectal, prostate, and others, due to dynamically integrated signaling cascades that coordinate cellular growth, differentiation, and death which can be potentially new therapeutic targets. Despite the historical use of estrogens in the pathogenesis of prostate cancer (PCa), their biological effect is not well known, nor their role in carcinogenesis or the mechanisms used to carry their therapeutic effects of neoplastic in prostate transformation. The expression and regulation of the estrogen receptors (ERs) ERα, ERβ, and GPER stimulated by agonists and antagonists, and related to prostate cancer cells are herein reviewed. Subsequently, the structures of the ERs and their splice variants, the binding of ligands to ERs, and the effect on PCa are provided. Finally, we also assessed the contribution of molecular simulation which can help us to search and predict potential estrogenic activities.

Blocking oestradiol synthesis pathways with potent and selective coumarin derivatives

A comprehensive set of 3-phenylcoumarin analogues with polar substituents was synthesised for blocking oestradiol synthesis by 17-β-hydroxysteroid dehydrogenase 1 (HSD1) in the latter part of the sulphatase pathway. Five analogues produced ≥62% HSD1 inhibition at 5 µM and, furthermore, three of them produced ≥68% inhibition at 1 µM. A docking-based structure-activity relationship analysis was done to determine the molecular basis of the inhibition and the cross-reactivity of the analogues was tested against oestrogen receptor, aromatase, cytochrome P450 1A2, and monoamine oxidases. Most of the analogues are only modestly active with 17-β-hydroxysteroid dehydrogenase 2 – a requirement for lowering effective oestradiol levels in vivo. Moreover, the analysis led to the synthesis and discovery of 3-imidazolecoumarin as a potent aromatase inhibitor. In short, coumarin core can be tailored with specific ring and polar moiety substitutions to block either the sulphatase pathway or the aromatase pathway for treating breast cancer and endometriosis.

Structure-Activity Relationship Analysis of 3-Phenylcoumarin-Based Monoamine Oxidase B Inhibitors

Monoamine oxidase B (MAO-B) catalyzes deamination of monoamines such as neurotransmitters dopamine and norepinephrine. Accordingly, small-molecule MAO-B inhibitors potentially alleviate the symptoms of dopamine-linked neuropathologies such as depression or Parkinson's disease. Coumarin with a functionalized 3-phenyl ring system is a promising scaffold for building potent MAO-B inhibitors. Here, a vast set of 3-phenylcoumarin derivatives was designed using virtual combinatorial chemistry or rationally de novo and synthesized using microwave chemistry. The derivatives inhibited the MAO-B at 100 nM−1 μM. The IC₅₀ value of the most potent derivative 1 was 56 nM. A docking-based structure-activity relationship analysis summarizes the atom-level determinants of the MAO-B inhibition by the derivatives. Finally, the cross-reactivity of the derivatives was tested against monoamine oxidase A and a specific subset of enzymes linked to estradiol metabolism, known to have coumarin-based inhibitors. Overall, the results indicate that the 3-phenylcoumarins, especially derivative 1, present unique pharmacological features worth considering in future drug development.

Genome-wide analysis of brain and gonad transcripts reveals changes of key sex reversal-related genes expression and signaling pathways in three stages of Monopterus albus

Background

The natural sex reversal severely affects the sex ratio and thus decreases the productivity of the rice field eel (Monopterus albus). How to understand and manipulate this process is one of the major issues for the rice field eel stocking. So far the genomics and transcriptomics data available for this species are still scarce. Here we provide a comprehensive study of transcriptomes of brain and gonad tissue in three sex stages (female, intersex and male) from the rice field eel to investigate changes in transcriptional level during the sex reversal process.

Results

Approximately 195 thousand unigenes were generated and over 44.4 thousand were functionally annotated. Comparative study between stages provided multiple differentially expressed genes in brain and gonad tissue. Overall 4668 genes were found to be of unequal abundance between gonad tissues, far more than that of the brain tissues (59 genes). These genes were enriched in several different signaling pathways. A number of 231 genes were found with different levels in gonad in each stage, with several reproduction-related genes included. A total of 19 candidate genes that could be most related to sex reversal were screened out, part of these genes’ expression patterns were validated by RT-qPCR. The expression of spef2, maats1, spag6 and dmc1 were abundant in testis, but was barely detected in females, while the 17β-hsd12, zpsbp3, gal3 and foxn5 were only expressed in ovary.

Conclusion

This study investigated the complexity of brain and gonad transcriptomes in three sex stages of the rice field eel. Integrated analysis of different gene expression and changes in signaling pathways, such as PI3K-Akt pathway, provided crucial data for further study of sex transformation mechanisms.

In situ androgen and estrogen biosynthesis in endometrial cancer: focus on androgen actions and intratumoral production

In situ estrogen biosynthesis is considered to play pivotal roles in the development and progression of human endometrial carcinoma. However, the biological roles of androgen have remained virtually unknown. Various epidemiological studies have revealed that elevated serum androgen levels are generally associated with an increased risk of developing endometrial carcinoma; however, studies directly examining androgens in carcinoma tissues are relatively rare and reviews summarizing this information are scarce. Therefore, we summarized recent studies on androgens in endometrial carcinoma, especially focusing androgen actions and in situ androgen biosynthesis. Among the enzymes required for local biosynthesis of androgen, 17β-hydroxysteroid dehydrogenase type 5 (conversion from androstenedione to testosterone) and 5α-reductase (reduction of testosterone to dihydrotestosterone (DHT)) are the principal enzymes involved in the formation of biologically most potent androgen, DHT. Both enzymes and androgen receptor were expressed in endometrial carcinoma tissues, and in situ production of DHT has been reported to exist in endometrial carcinoma tissues. However, testosterone is not only a precursor of DHT production, but also a precursor of estradiol synthesis, as a substrate of the aromatase enzyme. Therefore, aromatase could be another key enzyme serving as a negative regulator for in situ production of DHT by reducing amounts of the precursor. In an in vitro study, DHT was reported to exert antiproliferative effects on endometrial carcinoma cells. Intracrine mechanisms of androgens, the downstream signals of AR, which are directly related to anticancer progression, and the clinical significance of DHT-AR pathway in the patients with endometrial carcinoma have, however, not been fully elucidated.

Viability screen on pediatric low grade glioma cell lines unveils a novel anti-cancer drug of the steroid biosynthesis inhibitor family

Pediatric low grade gliomas are the most common central nervous system tumors and are still incurable among a subset of patients despite current treatment modalities. Steroid biosynthesis occurs in a wide variety of organs including the brain, to mediate an assortment of functions, including a proposed role in the growth of gliomas. Hence, targeting steroid biosynthesis and/or their signaling pathways, is anticipated as an effective approach for treating gliomas. In this study, we investigated whether our chemical library of steroid inhibitors can modulate the growth of pediatric low grade glioma cell lines (Res186, Res259, R286), and subsequently identified a potent inhibitor of 17β-hydroxysteroid dehydrogenase type 3, referred to as DK16, which functions by attenuating cell viability, proliferation, migration/invasion and anchorage independent growth and conversely induces apoptosis and cell cycle arrest in a dose and duration dependent manner. Further investigations into the mechanisms of how DK16 functions showed that this drug increased the BAX/BCL2 expression ratio, induced phosphatidylserine externalization, and mitochondrial membrane depolarizations culminating to the release and nuclear translocation of AIF. In addition, treatments of low grade glioma cell lines with DK16 increased the expression of pro-apoptotic mediators including CDK2 and CTSL1, and with the converse diminished expression of pro-survival and migratory/invasion genes like PRKCA, TERT, MAPK8, MMP1 and MMP2. Our findings collectively demonstrate the potent anti-neoplastic properties of DK16, a steroid biosynthesis inhibitor, on the growth of pediatric low grade gliomas.

Down regulation of gene related sex hormone synthesis pathway in mouse testes by miroestrol and deoxymiroestrol

Miroestrol and deoxymiroestrol are phytoestrogens isolated from tuberous root of Pueraria candollei var. mirifica. Modulatory effects of miroestrol and deoxymiroestrol on enzymes involved in sex-hormone synthesis pathway in male C57BL/6 mice were investigated using semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). Miroestrol and deoxymiroestrol suppressed the expressions of 3β-HSD, 17β-HSD1, and CYP17 while CYP19 mRNA expression was slightly decreased. In addition, the expression of 17β-HSD2 was induced in correlation with those did by estradiol. These observations supported that miroestrol and deoxymiroestrol could exhibit the same effect as estradiol regarding regulation of testicular gene related sex hormone synthesis pathway.

Inhibition of estrogen actions in human gynecological malignancies: new aspects of endocrine therapy for endometrial cancer and ovarian cancer

Endometrial carcinoma and possibly ovarian carcinoma are considered "estrogen-dependent tumors" in human gynecological malignancies. In endometrial carcinoma, the enzymes responsible for intratumoral estrogen metabolism and biosynthesis are different from those in human breast carcinoma, although both of them are considered "estrogen-dependent malignancies". Specific and effective endocrine treatment of endometrial carcinoma should be explored, although progestin agents have been widely used for a long time. Aromatase inhibitors, the most effective endocrine agents of breast carcinoma, retinoids, metabolites of vitamin A, and synthetic peroxisome proliferator-activated receptor (PPAR) gamma ligands, used for the treatment of insulin resistance in type II diabetes mellitus, may be the important candidates for possible endocrine treatment of endometrial carcinoma. In ovarian carcinoma, several clinical studies recently demonstrated that aromatase inhibitors had some therapeutic activity against recurrent ovarian carcinoma. However, at least at this juncture, further studies should be required to establish an aromatase inhibitor treatment as one form of endocrine therapy of ovarian carcinoma in future.

Aromatase, estrone sulfatase, and 17β-hydroxysteroid dehydrogenase: structure-function studies and inhibitor development

Aromatase, estrone sulfatase, and 17β-hydroxysteroid dehydrogenase type 1 are involved in the key steps of 17β-estradiol biosynthesis. Structure-function studies of aromatase, estrone sulfatase and 17β-hydroxysteroid dehydrogenase type 1 are important to evaluate the molecular basis of the interaction between these enzymes and their inhibitors. Selective and potent inhibitors of the three enzymes have been developed as antiproliferative agents in hormone-dependent breast carcinoma. New treatment strategies for hormone-dependent breast cancer are discussed.

Contribution to the development of inhibitors of 17β-hydroxysteroid dehydrogenase types 1 and 7: key tools for studying and treating estrogen-dependent diseases

17β-Hydroxysteroid dehydrogenases (17β-HSDs) belong to a group of key enzymes involved in the biosynthesis of steroidal hormones by catalyzing the reduction of 17-ketosteroids or the oxidation of 17β-hydroxysteroids. From three members known in the early nineties, the 17β-HSD functional family has grown to 15 members over the last 20 years. This growing number of 17β-HSD isoforms questioned the importance of each member, especially in their implication in estrogen- and androgen-dependent diseases, such as breast and prostate cancers. One of the strategies used to address the physiological importance of 17β-HSDs is to use potent and selective inhibitors. Furthermore, enzyme inhibitors could also be of therapeutic interest by reducing the level of estradiol (E2). Focusing on estrogens, we targeted 17β-HSD types 1 and 7, two enzymes able to transform the weak estrogen estrone (E1) into the potent estrogen E2. The present review article gives a description of different classes of inhibitors of 17β-HSD1 (C6-derivatives of E2, C16-derivatives of E2 as alkylating and dual action compounds, E2-adenosine hybrids, E2-simplified adenosine hybrids, and C16-derivatives of E1 or E2) and of inhibitors of 17β-HSD7, all these inhibitors developed in our laboratory. The chemical structures and inhibitory activity of these steroidal inhibitors, their potential as therapeutic agents, and their use as tools to elucidate the role of these enzymes in particular biological systems will be discussed. Article from the Special issue on Targeted Inhibitors.

Identification of chemically diverse, novel inhibitors of 17β-hydroxysteroid dehydrogenase type 3 and 5 by pharmacophore-based virtual screening

17β-Hydroxysteroid dehydrogenase type 3 and 5 (17β-HSD3 and 17β-HSD5) catalyze testosterone biosynthesis and thereby constitute therapeutic targets for androgen-related diseases or endocrine-disrupting chemicals. As a fast and efficient tool to identify potential ligands for 17βHSD3/5, ligand- and structure-based pharmacophore models for both enzymes were developed. The models were evaluated first by in silico screening of commercial compound databases and further experimentally validated by enzymatic efficacy tests of selected virtual hits. Among the 35 tested compounds, 11 novel inhibitors with distinct chemical scaffolds, e.g. sulfonamides and triazoles, and with different selectivity properties were discovered. Thereby, we provide several potential starting points for further 17β-HSD3 and 17β-HSD5 inhibitor development. Article from the Special issue on Targeted Inhibitors.

Species used for drug testing reveal different inhibition susceptibility for 17beta-hydroxysteroid dehydrogenase type 1

Steroid-related cancers can be treated by inhibitors of steroid metabolism. In searching for new inhibitors of human 17beta-hydroxysteroid dehydrogenase type 1 (17β-HSD 1) for the treatment of breast cancer or endometriosis, novel substances based on 15-substituted estrone were validated. We checked the specificity for different 17β-HSD types and species. Compounds were tested for specificity in vitro not only towards recombinant human 17β-HSD types 1, 2, 4, 5 and 7 but also against 17β-HSD 1 of several other species including marmoset, pig, mouse, and rat. The latter are used in the processes of pharmacophore screening. We present the quantification of inhibitor preferences between human and animal models. Profound differences in the susceptibility to inhibition of steroid conversion among all 17β-HSDs analyzed were observed. Especially, the rodent 17β-HSDs 1 were significantly less sensitive to inhibition compared to the human ortholog, while the most similar inhibition pattern to the human 17β-HSD 1 was obtained with the marmoset enzyme. Molecular docking experiments predicted estrone as the most potent inhibitor. The best performing compound in enzymatic assays was also highly ranked by docking scoring for the human enzyme. However, species-specific prediction of inhibitor performance by molecular docking was not possible. We show that experiments with good candidate compounds would out-select them in the rodent model during preclinical optimization steps. Potentially active human-relevant drugs, therefore, would no longer be further developed. Activity and efficacy screens in heterologous species systems must be evaluated with caution.

Proteomic analysis of the transitional endoplasmic reticulum in hepatocellular carcinoma: an organelle perspective on cancer

The transitional endoplasmic reticulum (tER) is composed of both rough and smooth ER membranes and thus participates in functions attributed to both these two subcellular compartments. In this paper we have compared the protein composition of tER isolated from dissected liver tumor nodules of aflatoxin B1-treated rats with that of tER from control liver. Tandem mass spectrometry (MS), peptide counts and immunoblot validation were used to identify and determine the relative expression level of proteins. Inhibitors of apoptosis (i.e. PGRMC1, tripeptidyl peptidase II), proteins involved in ribosome biogenesis (i.e. nucleophosmin, nucleolin), proteins involved in translation (i.e. eEF-2, and subunits of eIF-3), proteins involved in ubiquitin metabolism (i.e. proteasome subunits, USP10) and proteins involved in membrane traffic (i.e. SEC13-like 1, SEC23B, dynactin 1) were found overexpressed in tumor tER. Transcription factors (i.e. Pur-beta, BTF3) and molecular targets for C-Myc and NF-kappa B were observed overexpressed in tER from tumor nodules. Down-regulated proteins included cytochrome P450 proteins and enzymes involved in fatty acid metabolism and in steroid metabolism. Unexpectedly expression of the protein folding machinery (i.e. calreticulin) and proteins of the MHC class I peptide-loading complex did not change. Proteins of unknown function were detected in association with the tER and the novel proteins showing differential expression are potential new tumor markers. In many cases differential expression of proteins in tumor tER was comparable to that of corresponding genes reported in the Oncomine human database. Thus the molecular profile of tumor tER is different and this may confer survival advantage to tumor cells in cancer.

Binary and ternary crystal structure analyses of a novel inhibitor with 17β-HSD type 1: a lead compound for breast cancer therapy

Oestradiol is a well-characterized sex hormone that stimulates breast cancer and other oestrogen-related diseases. 17β-hydroxysteroid dehydrogenase type 1 (17β-HSD1) catalyses the last step in the synthesis of oestradiol and androstenediol in breast tumour tissue. The enzyme's high expression and activity after simultaneous blockade of oestrogen receptors and inhibition of aromatase in the tumour shows the necessity for its inhibition as a requirement for breast cancer therapy. In the present paper, we report structures of the binary and ternary complexes of 17β-HSD1 with a new inhibitor E2B {3-[3′,17′β-dihydroxyestra-1′,3′,5′(10′)-trien-16′β-methyl]benzamide}, and the enzyme inhibition by the later. The IC50 value for E2B was determined to be 42 nM in T47D cells. Multiple interactions between E2B and the enzyme include hydrogen bonds and hydrophobic interactions, as well as π–π interactions. A kinetic study demonstrated that E2B inhibits the enzyme's reduction forming oestradiol from oestrone, with a Ki of 0.9±0.15 nM. Such strong inhibition is in agreement with its extensive interaction with the enzyme, suggesting its potential as a lead compound for breast cancer therapy. In fact, this possibility is enhanced by its capacity for cell penetration similar to natural steroids. Such inhibitors that block oestrogen synthesis to suppress the sulfatase pathway producing oestradiol can be used in adjuvant therapies with oestrogen receptor blockade, opening a new orientation of breast cancer treatment.

Design, chemical synthesis, and in vitro biological evaluation of simplified estradiol–adenosine hybrids as inhibitors of 17β-hydroxysteroid dehydrogenase type 1

A series of estradiol (E2) derivatives were designed to interact with both the substrate- and the cofactor-binding sites of 17β-hydroxysteroid dehydrogenase type 1 (17β-HSD1). These analogues of potent E2–adenosine hybrid inhibitor EM-1745, where the adenosine moiety was replaced by a more stable benzene derivative, were synthesized from estrone using alkene cross-metathesis and Sonogashira coupling reactions as key steps. In vitro biological evaluation of these steroid derivatives revealed that a spacer of 13 methylenes, between the 16β-position of E2 and the adenosine mimic bearing a carboxylic acid group, gave the best inhibition of 17β-HSD1.

Selective inhibition of 17beta-hydroxysteroid dehydrogenase type 1 (17betaHSD1) reduces estrogen responsive cell growth of T47-D breast cancer cells

The most potent estrogen estradiol (E2) plays a pivotal role in the initiation and progression of estrogen dependent diseases. 17beta-Hydroxysteroid dehydrogenase type 1 (17betaHSD1) catalyses the NADPH-dependent E2-formation from estrone (E1). It is often overexpressed in breast cancer and endometriosis. For this reason, inhibition of 17betaHSD1 is a promising strategy for the treatment of these diseases. In the present paper, we investigate the estrogen responsive cell growth of T47-D breast cancer cells, the intracellular inhibitory activity of non-steroidal 17betaHSD1-inhibitors and their effects on estrogen dependent cell growth in vitro. At equal concentrations the estrogens E1 and E2 induced the same extent of growth stimulation indicating fast intracellular conversion of E1 into E2. Application of inhibitors selectively prevented stimulation of proliferation evoked by E1-treatment whereas E2-mediated stimulation was not affected. Furthermore, intracellular E2-formation from E1 was significantly inhibited with IC(50)-values in the nanomolar range. In conclusion, our findings strongly support suitability of non-steroidal 17betaHSD1-inhibitors for the treatment of estrogen dependent diseases.

Disturbed estrogen and progesterone action in ovarian endometriosis

Endometriosis is a very common disease in pre-menopausal women, where defective metabolism of steroid hormones plays an important role in its development and promotion. In the present study, we have examined the expression of 11 estrogen and progesterone metabolizing enzymes and their corresponding receptors in samples of ovarian endometriomas and control endometrium. Expression analysis revealed significant up-regulation of enzymes involved in estradiol formation (aromatase, sulfatase and all reductive 17beta-hydroxysteroid dehydrogenases) and in progesterone inactivation (AKR1C1 and AKR1C3). Among the estrogen and progesterone receptors, ERalpha was down-regulated, ERbeta was up-regulated, and there was no significant difference in expression of progesterone receptors A and B (PRAB). Our data indicate that several enzymes of estrogen and progesterone metabolism are aberrantly expressed in endometriosis, which can lead to increased local levels of mitogenic estradiol and decreased levels of protective progesterone. Changes in estrogen receptor expression suggest that estradiol may also act via non-estrogen receptor-mediated pathways, while expression of progesterone receptors still needs further investigation.

The role of the heterocycle in bis(hydroxyphenyl)triazoles for inhibition of 17beta-Hydroxysteroid Dehydrogenase (17beta-HSD) type 1 and type 2

17beta-Hydroxysteroid dehydrogenase type 1 (17beta-HSD1) is responsible for the catalytic reduction of the weak estrogen estrone (E1) into the highly potent 17beta-estradiol (E2). As 17beta-HSD1 is often overexpressed in mammary tumors and endometriosis, the selective inhibition of this enzyme is discussed as a promising approach for the treatment of estrogen-dependent diseases. Recently, we reported on bis(hydroxyphenyl)azoles as a new class of potent inhibitors of 17beta-HSD1. In this paper, we focused on bis(hydroxyphenyl)triazoles. The influence of nitrogens on the potency as well as the space available around the heterocycle was investigated. Substituents were introduced on the triazole core in order to establish additional interactions with the enzyme active site. The compounds were evaluated for activity towards 17beta-HSD1 and selectivity with regard to 17beta-HSD2, the enzyme which is responsible for the deactivation of E2 into E1. 3-[4-(4-Hydroxyphenyl)-1H-1,2,3-triazol-1-yl]phenol (3) was the most active compound discovered in this study with an IC(50) value of 840nM and a reasonable selectivity towards 17beta-HSD2.

Structure-activity study in the class of 6-(3'-hydroxyphenyl)naphthalenes leading to an optimization of a pharmacophore model for 17beta-hydroxysteroid dehydrogenase type 1 (17beta-HSD1) inhibitors

17beta-Hydroxysteroid dehydrogenase type 1 (17beta-HSD1) catalyzes the transformation of estrone (E1) into the most potent estrogen, estradiol (E2), which stimulates cell proliferation and decreases apoptosis. 17beta-HSD1 is often strongly overexpressed in estrogen-dependent diseases (like breast cancer and endometriosis). Thus, this over expressed enzyme is a promising novel target for the development of selective inhibitors, which could be used as drugs for the treatment of these diseases. Using a structure- and ligand-based approach, a pharmacophore model was proposed and a new class of non-steroidal inhibitors of 17beta-HSD1 was designed. Enzyme inhibition was evaluated in vitro using the human enzyme. After identification of the 6-(3'-hydroxyphenyl)-2-naphthol scaffold 1, the potency of this class of inhibitors was further improved by substitution of the 1-position of the naphthalene ring by a phenyl group (compound 18, IC(50)=20nM). Compound 18 also showed a good selectivity toward 17beta-HSD2 and the estrogen receptors alpha and beta.

HSD17B1 genetic variants and hormone receptor-defined breast cancer

HSD17B1 is an important candidate gene in breast cancer via its role in converting estrone to estradiol. A nonsynonymous G-to-A transition (rs605059) and an intronic C-to-A (rs676387) single-nucleotide polymorphism, which captured most common variation in HSD17B1, were evaluated in several breast cancer studies with inconclusive results. We followed up these findings in the Polish Breast Cancer Study (1,995 cases; 2,296 controls) and the British Studies of Epidemiology and Risk Factors in Cancer Heredity study (4,470 cases; 4,560 controls). Meta-analyses of published data and our own were also conducted among Caucasian women. Consistent with previous reports, we found little to no association with overall risk for heterozygotes and minor allele homozygotes compared with major allele homozygotes for rs605059 [summary odds ratios (95% confidence intervals), 0.93 (0.87-0.99) for GA and 0.96 (0.85-1.08), based on 11,762 cases and 14,329 controls from 10 studies] and for rs676387 [summary odds ratios (95% confidence intervals), 1.04 (0.97-1.12) and 1.12 (0.99-1.27), based on analyses of 11,074 cases and 13,605 controls from 8 studies]. Data from the Polish [n=586 estrogen receptor-negative (ER-) cases] and British (n=407) studies did not support the previous findings that ER- tumors were inversely associated with rs676387 AA genotype and positively associated with rs605059 GG genotype, based on subanalyses in 5 prospective cohorts with 354 ER- cases. In conclusion, it is unlikely that common genetic variation in HSD17B1 is associated with a moderate modulation in breast cancer risk overall; however, we cannot exclude the possibility of a very weak effect. Associations between HSD17B1 genotypes and risk for ER- breast cancer were inconsistent across studies and should be studied further.

Design, synthesis, biological evaluation and pharmacokinetics of bis(hydroxyphenyl) substituted azoles, thiophenes, benzenes, and aza-benzenes as potent and selective nonsteroidal inhibitors of 17beta-hydroxysteroid dehydrogenase type 1 (17beta-HSD1)

17beta-Estradiol (E2), the most potent female sex hormone, stimulates the growth of mammary tumors and endometriosis via activation of the estrogen receptor alpha (ERalpha). 17beta-Hydroxysteroid dehydrogenase type 1 (17beta-HSD1), which is responsible for the catalytic reduction of the weakly active estrogen estrone (E1) into E2, is therefore discussed as a novel drug target. Recently, we have discovered a 2,5-bis(hydroxyphenyl) oxazole to be a potent inhibitor of 17beta-HSD1. In this paper, further structural optimizations were performed: 39 bis(hydroxyphenyl) azoles, thiophenes, benzenes, and aza-benzenes were synthesized and their biological properties were evaluated. The most promising compounds of this study show enhanced IC 50 values in the low nanomolar range, a high selectivity toward 17beta-HSD2, a low binding affinity to ERalpha, a good metabolic stability in rat liver microsomes, and a reasonable pharmacokinetic profile after peroral application. Calculation of the molecular electrostatic potentials revealed a correlation between 17beta-HSD1 inhibition and the electron density distribution.

Critical role for transcription factor C/EBP-beta in regulating the expression of death-associated protein kinase 1

Transcription factor C/EBP-beta regulates a number of physiological responses. During an investigation of the growth-suppressive effects of interferons (IFNs), we noticed that cebpb(-/-) cells fail to undergo apoptosis upon gamma IFN (IFN-gamma) treatment, compared to wild-type controls. To examine the basis for this response, we have performed gene expression profiling of isogenic wild-type and cebpb(-/-) bone marrow macrophages and identified a number of IFN-gamma-regulated genes that are dependent on C/EBP-beta for their expression. These genes are distinct from those regulated by the JAK-STAT pathways. Genes identified in this screen appear to participate in various cellular pathways. Thus, we identify a new pathway through which the IFNs exert their effects on cellular genes through C/EBP-beta. One of these genes is death-associated protein kinase 1 (dapk1). DAPK1 is critical for regulating the cell cycle, apoptosis, and metastasis. Using site-directed mutagenesis, RNA interference, and chromatin immunoprecipitation assays, we show that C/EBP-beta binds to the promoter of dapk1 and is required for the regulation of dapk1. Both mouse dapk1 and human dapk1 exhibited similar dependences on C/EBP-beta for their expression. The expression of the other members of the DAPK family occurred independently of C/EBP-beta. Members of the C/EBP family of transcription factors other than C/EBP-beta did not significantly affect dapk1 expression. We identified two elements in this promoter that respond to C/EBP-beta. One of these is a consensus C/EBP-beta-binding site that constitutively binds to C/EBP-beta. The other element exhibits homology to the cyclic AMP response element/activating transcription factor binding sites. C/EBP-beta binds to this site in an IFN-gamma-dependent manner. Inhibition of ERK1/2 or mutation of an ERK1/2 site in the C/EBP-beta protein suppressed the IFN-gamma-induced response of this promoter. Together, our data show a critical role for C/EBP-beta in a novel IFN-induced cell growth-suppressive pathway via DAPK1.

Biological roles of estrogen and progesterone in human endometrial carcinoma--new developments in potential endocrine therapy for endometrial cancer

Endometrial carcinoma is one of the most common female pelvic malignancies. It is well known that uterine endometrial cell proliferation is under the control of both estrogen and progesterone. In this review, results of the recent studies on the biosynthesis and action of estrogen and progestin in normal endometrium and its disorders will be summarized and the new aspects of hormonal therapies in the patients with endometrial carcinoma will be discussed including its future prospectives. We reported that the enzymes responsible for intratumoral estrogen metabolism and biosynthesis are markedly different between human breast and endometrial carcinoma, although both of them are considered "estrogen-dependent malignancies". In addition, the biological significance of Progesterone receptor (PR) isoforms is considered to differ between endometrial and breast carcinomas. Clinical data concerning Hormone replacement therapy (HRT) and estrogen-dependent cancer risk also support these findings. These basic and clinical findings help to understand the biology and provide the new knowledge for prevention, diagnosis and treatment of human endomerial carcinoma. Specific endocrine treatment of endometrial carcinoma should be explored in future, although aromatase inhibitors are the most effective endocrine treatments of estrogen-responsive breast carcinoma. Retinoid, metabolities of vitamin A, and synthetic peroxisome proliferator-activated receptor (PPAR) gamma ligands, which have been used for the treatment of insulin resistance in type II diabetes mellitus, may be the important candidates as drugs not only for prevention but also for possible endocrine treatment of endometrial carcinoma.

Hormone replacement therapy and cancers: the biological roles of estrogen and progestin in tumorigenesis are different between the endometrium and breast

Hormone replacement therapy (HRT) has become available over the past few decades, but the risk of breast cancer with HRT remains controversial. The Women's Health Initiative Study has recently demonstrated that women receiving estrogen plus progestin (HRT) have an increased risk of invasive breast carcinoma, although women receiving estrogen alone (estrogen replacement therapy) exhibit no increased risk of breast carcinoma. By contrast, the risk of endometrial carcinoma increases with estrogen replacement therapy, while HRT reduces the risk of endometrial carcinoma. These clinical findings suggest that the biological roles of estrogen and progestin in tumorigenesis are certainly different between the endometrium and breast, although both are considered "estrogen-dependent tissues". In this review, I summarize the recent studies and indicate that the enzymes responsible for intratumoral estrogen metabolism and biosynthesis are markedly different between human breast and endometrial carcinomas. 17beta-hydroxysteroid dehydrogenases (17-HSDs) are enzymes estrogen replacement therapyinvolved in the formation of active sex steroids. Estrogens are interconverted by two enzymes, 17-HSD types 1 and 2. Type 1 converts estrone to estradiol, and type 2 catalyzes the reverse reaction. 17-HSD type 5 reduces androstenedione to testosterone. 17-HSD type 1 plays an important role in the regulation of high estradiol levels in breast carcinoma tissues, whereas 17-HSD types 2 and 5 appear to be essential for the maintenance of estradiol concentrations in endometrial carcinoma tissues. In addition, the biological significance of progesterone receptor isoforms differs between endometrial and breast carcinomas. These findings may provide new insights into the biology of "estrogen-dependent tissues".

Stromal cells of endometriosis fail to produce paracrine factors that induce epithelial 17beta-hydroxysteroid dehydrogenase type 2 gene and its transcriptional regulator Sp1: a mechanism for defective estradiol metabolism

OBJECTIVE

In endometrium, stromal progesterone receptors mediate production of paracrine factors, which enhance binding of the transcription factor specific protein-1 to the promoter of the gene encoding the 17beta-hydroxysteroid dehydrogenase type 2 enzyme responsible for converting biologically active estradiol to estrone in epithelium. The objective of this study is to define the cellular defect responsible for the disruption of this stromal-epithelial interaction in endometriosis.

STUDY DESIGN

We determined the effects of conditioned media generated from primary human eutopic endometrial stromal cells vs endometriotic stromal cells on Ishikawa malignant endometrial epithelial cells.

RESULTS

Conditioned media from progestin-pretreated eutopic endometrial stromal cells but not endometriotic stromal cells significantly stimulated specific protein-1 protein levels, 17beta-hydroxysteroid dehydrogenase type 2 messenger RNA levels and promoter activity, and binding activity of specific protein-1 to the 17beta-hydroxysteroid dehydrogenase type 2 promoter region in Ishikawa cells.

CONCLUSION

A stromal cell defect in endometriosis blocks formation of progesterone-dependent production of factors leading to 17beta-hydroxysteroid dehydrogenase type 2 deficiency and defective conversion of estradiol to estrone in epithelium.

Expression analysis of the genes involved in estradiol and progesterone action in human ovarian endometriosis

Endometriosis is defined as the presence of endometrial glands and stroma within extrauterine sites, and it is well known that endometriosis is an estrogen-dependent disease. The defective formation and metabolism of steroid hormones is responsible for the promotion and development of endometriosis. In the present study we examined the mRNA levels of six enzymes that are involved in the metabolism of estrogen and progesterone--aromatase, 17beta-hydroxysteroid dehydrogenase (17beta-HSD) types 1, 2 and 7, sulfatase and sulfotransferase--and of the steroid receptors--estrogen receptors alpha and beta (ERalpha, ERbeta) and progesterone receptors A and B (PRAB)--implicated in human ovarian endometriosis. We analyzed 16 samples of ovarian endometriosis and 9 of normal endometrium. The real-time polymerase chain reaction analyses revealed that six of the nine genes investigated are differentially regulated. Aromatase, 17beta-HSD types 1 and 7, sulfatase and ERbeta were statistically significantly upregulated, while ERalpha was significantly downregulated, in the endometriosis group compared with the control group. There were no significant differences in 17beta-HSD type 2, sulfotransferase and PRAB gene expression. Our results indicate that, in addition to the previously reported upregulation of aromatase, upregulation of 17beta-HSD types 1 and 7 and sulfatase can also increase the local estradiol concentration. This could thus be responsible for the estrogen-dependent growth of endometriotic tissue. Surprisingly ERalpha was downregulated.

Improved Homogeneous Proximity-Based Screening Assay of Potential Inhibitors of 17β-Hydroxysteroid Dehydrogenases

17beta-Hydroxysteroid dehydrogenases (17beta-HSDs) are substrate- and tissue-specific isoenzymes that regulate activation and inactivation of steroid hormones. Up-regulation and downregulation in expression of 17beta-HSDs are linked to onset of many steroid-dependent diseases, such as colon, prostate, and breast cancer; thus 17beta-HSDs are potential drug screening targets. Currently their enzymatic activities are usually measured using laborious chromatographic separations followed by radioactive detection of substrate and product. We have previously reported the use of a homogeneous luminescence resonance energy transfer-based immunoassay for 17beta-estradiol in screening of potential inhibitors of 17beta-HSD type 1 (17beta-HSD-1). By replacing the previously used cell-based enzyme reactions with recombinant enzyme reactions the sensitivity of the screening assay improved considerably. In addition, the single assay was able to detect the influence of a tested compound not only on 17beta-HSD-1 but also on 17beta-HSD type 2 (17beta-HSD-2), catalyzing the opposite reaction. The screening results of the tested molecules obtained from the optimized immunoassay were very similar when compared with the results of high performance liquid chromatography separation analysis. The Z factors were 0.79 and 0.83 for 17beta-HSD-1 and 17beta-HSD-2 assays, respectively. Thus the immunoassay measuring samples converted with the recombinant enzymes was a very suitable method for primary high throughput screening, and it could be used also in further characterization of potential drugs.

Synthesis of Libraries of 16β-Aminopropyl Estradiol Derivatives for Targeting Two Key Steroidogenic Enzymes

Two libraries, each consisting of 48 16beta-aminopropyl estradiol derivatives, phenols and sulfamates, respectively, were synthesized by solid-phase parallel chemistry through a seven-step reaction sequence. Following the attachment of a C18-steroid sulfamate precursor on a trityl chloride resin, diversity elements were first introduced on the 16beta-aminopropyl chain of the steroid by acylation reactions with eight Fmoc-amino acids. After deprotection, the free amine function of the resulting compounds was reacted with six carboxylic acids for the introduction of a second diversity level. The two variants employed for the cleavage of compounds from the solid support, acidic and nucleophilic, allowed the corresponding libraries of sulfamate and phenol derivatives in yields of 8-50 % and 13-58 % to be obtained with an average HPLC purity of 94 % and 91 %, respectively. Potent steroid sulfatase inhibitors and interesting SAR results were generated from the screening of the sulfamate library. Furthermore, moderate inhibitors of type 1 17beta-HSD resulted from the partial screening of phenol library. Thus, these two categories of compounds were synthesized to rapidly identify potential inhibitors of steroid biosynthesis for the hormonal therapy of estrogen-dependent diseases, and also to demonstrate the versatility and efficiency of the recently developed sulfamate linker.

Genetic determinants modulate susceptibility to pregnancy-associated tumourigenesis in a recombinant line of Min mice

Min mice provide a good model of human familial adenomatous polyposis. Recently, we have reported on two recombinant inbred lines (I and V) and the location of a modifier (Mom3) close to Apc, which altered polyp numbers in our mice possibly by modifying the frequency of wild-type (WT) allele loss at Apc; mice with severe disease (line V) showed elevated rates of loss. We now show that in line I only, a single pregnancy caused a significant increase in adenoma multiplicity compared with virgin controls (P<0.001) and that an additional pregnancy conferred a similar risk. Pregnancy was linked to both adenoma initiation and enhanced tumour growth in line I mice, and interline crosses indicated that susceptibility to pregnancy-associated adenomas was under genetic control. We found no evidence for the involvement of oestrodial metabolizing genes or the oestrogen receptors (Esr1 and 2) in tumour multiplicity. Importantly, a significantly elevated frequency of WT allele loss at Apc was observed in adenomas from parous mice (line and backcrossed) carrying the line I Min allele relative to equivalent virgin controls (P=0.015). Our results provide the first experimental evidence for genetic determinants controlling pregnancy-associated tumourigenesis; analogous genetic factors may exist in humans.

Aging Reduces the Efficacy of Estrogen Substitution to Attenuate Cardiac Hypertrophy in Female Spontaneously Hypertensive Rats

Clinical trials failed to show a beneficial effect of postmenopausal hormone replacement therapy, whereas experimental studies in young animals reported a protective function of estrogen replacement in cardiovascular disease. Because these diverging results could in part be explained by aging effects, we compared the efficacy of estrogen substitution to modulate cardiac hypertrophy and cardiac gene expression among young (age 3 months) and senescent (age 24 months) spontaneously hypertensive rats (SHRs), which were sham operated or ovariectomized and injected with placebo or identical doses of 17beta-estradiol (E2; 2 microg/kg body weight per day) for 6 weeks (n=10/group). Blood pressure was comparable among sham-operated senescent and young SHRs and not altered by ovariectomy or E2 treatment among young or among senescent rats. Estrogen substitution inhibited uterus atrophy and gain of body weight in young and senescent ovariectomized SHRs, but cardiac hypertrophy was attenuated only in young rats. Cardiac estrogen receptor-alpha expression was lower in intact and in ovariectomized senescent compared with young SHRs and increased with estradiol substitution in aged rats. Plasma estradiol and estrone levels were lower not only in sham-operated but surprisingly also in E2-substituted senescent SHRs and associated with a reduction of hepatic 17beta-hydroxysteroid dehydrogenase type 1 enzyme activity, which converts weak (ie, estrone) into potent estrogens, such as E2. Aging attenuates the antihypertrophic effect of estradiol in female SHRs and is associated with profound alterations in cardiac estrogen receptor-alpha expression and estradiol metabolism. These observations contribute to explain the lower efficiency of estrogen substitution in senescent SHRs.

SP1 and SP3 mediate progesterone-dependent induction of the 17beta hydroxysteroid dehydrogenase type 2 gene in human endometrium

The opposing actions of estrogen and progesterone during the menstrual cycle regulate the cyclical and predictable endometrial proliferation and differentiation that is required for implantation. Progesterone indirectly stimulates the expression of 17beta hydroxysteroid dehydrogenase type 2 (HSD17B2), which catalyzes the conversion of biologically potent estradiol to weakly estrogenic estrone in the endometrial epithelium. We previously demonstrated upregulation of the HSD17B2 gene in human endometrial epithelial cells by factors secreted from endometrial stromal cells in response to progesterone. We investigated the underlying mechanism by which these stroma-derived, progesterone-induced paracrine factors stimulate HSD17B2 expression. Here, we show that transcription factors SP1 and SP3 interact with specific motifs in HSD17B2 promoter to upregulate enzyme expression in human endometrial epithelial cell lines. Conditioned medium (CM) from progestin-treated stromal cells increased levels of SP1 and SP3 in endometrial epithelial cells and induced HSD17B2 mRNA expression. Mithramycin A, an inhibitor of SP1-DNA interaction, reduced epithelial HSD17B2 promoter activity in a dose-dependent manner. Serial deletion and site-directed mutants of the HSD17B2 promoter demonstrated that two overlapping SP1 motifs (nt -82/-65) are essential for induction of promoter activity by CM or overexpression of SP1/SP3. CM markedly enhanced, whereas anti-SP1/SP3 antibodies inhibited, binding of nuclear proteins to this region of the HSD17B2 promoter. In vivo, we demonstrated a significant spatiotemporal association between epithelial SP1/SP3 and HSD17B2 levels in human endometrial biopsies. Taken together, these data suggest that HSD17B2 expression in endometrial epithelial cells, and, therefore, estrogen inactivation, is regulated by SP1 and SP3, which are downstream targets of progesterone-dependent paracrine signals originating from endometrial stromal cells.

Expression of enzymes involved in estrogen metabolism in human prostate

There is evidence that estrogens can directly modulate human prostate cell activity. It has also been shown that cultured human prostate cancer LNCaP can synthesize the active estrogen estradiol (E2). To elucidate the metabolism of estrogens in the human prostate, we have studied the expression of enzymes involved in the formation and inactivation of estrogens at the cellular level. 17beta-Hydroxysteroid dehydrogenase (17beta-HSD) types 1, 2, 4, 7, and 12, as well as aromatase mRNA and protein expressions, were studied in benign prostatic hyperplasia (BPH) specimens using in situ hybridization and immunohistochemistry. For 17beta-HSD type 4, only in situ hybridization studies were performed. Identical results were obtained with in situ hybridization and immunohistochemistry. All the enzymes studied were shown to be expressed in both epithelial and stromal cells, with the exception of 17beta-HSD types 4 and 7, which were detected only in the epithelial cells. On the basis of our previous results, showing that 3beta-HSD and 17beta-HSD type 5 are expressed in human prostate, and of the present data, it can be concluded that the human prostate expresses all the enzymes involved in the conversion of circulating dehydroepiandrosterone (DHEA) to E2. The local biosynthesis of E2 might be involved in the development and/or progression of prostate pathology such as BPH and prostate cancer through modulation of estrogen receptors, which are also expressed in epithelial and stromal cells.

3Beta-alkyl-androsterones as inhibitors of type 3 17beta-hydroxysteroid dehydrogenase: inhibitory potency in intact cells, selectivity towards isoforms 1, 2, 5 and 7, binding affinity for steroid receptors, and proliferative/antiproliferative activities on AR+ and ER+ cell lines

Type 3 17beta-hydroxysteroid dehydrogenase (17beta-HSD) is involved in the biosynthesis of the potent androgen testosterone (T), which plays an important role in androgen-sensitive diseases. In an attempt to design compounds to lower the level of T, we designed androsterone (ADT) derivatives substituted at the position 3beta as inhibitors of type 3 17beta-HSD, and then selected the eight most potent ones (compounds 1-8) for additional studies. In an intact cell assay, they inhibited efficiently the conversion of natural substrate 4-androstene-3,17-dione into T, although they were less active in intact cells (IC50 approximately 1 microM) than in homogenated cells (IC50=57-100 nM). A study of the inhibitory potency with four other 17beta-HSDs revealed they were selective, since they do not inhibit reductive types 1, 5 and 7, nor oxidative type 2. Interestingly, they did not show any binding affinity for steroid receptors (androgen, estrogen, glucocorticoid and progestin). Only two inhibitors, 3beta-phenyl-ADT (5) and 3beta-phenylmethyl-ADT (6) showed some proliferative activities on an AR+ cell line and on an ER+ cell line, but their effects were not mediated through the androgen or estrogen receptors. This study identified selective inhibitors of type 3 17beta-HSD acting through a mixed-type inhibition, and devoid of non-suitable androgenic and estrogenic proliferative activities. The more potent inhibitors were 3beta-hexyl-ADT (2), 3beta-cyclohexylethyl-ADT (4) and 3beta-phenylethyl-ADT (7).

Cinnamates and cinnamamides inhibit fungal 17beta-hydroxysteroid dehydrogenase

The 17beta-hydroxysteroid dehydrogenases (17beta-HSDs) have important roles in the regulation of steroid hormone actions through their catalysis of the oxidation or reduction of estrogens and androgens at position 17. Dysfunctions of the human 17beta-HSDs have been associated with reproduction disorders, neuronal diseases and the development of hormone-dependent forms of cancers. Therefore, these enzymes represent interesting targets for the development of new drugs. Here we present a series of new cinnamic acid esters and amides that inhibit the oxidative and reductive reaction catalyzed by 17beta-HSD from the fungus Cochliobolus lunatus, a model enzyme of the short-chain dehydrogenase/reductase superfamily. We found that esters of unsubstituted cinnamic acid were better inhibitors than esters of 3,4,5-trimethoxycinnamic acid. Cinnamates were also more potent inhibitors than structurally related cinnamamides. The compounds presented in this paper are potential leads for the development of inhibitors of human 17beta-HSD isoforms, which may prove to have different therapeutic applications.

17Beta-hydroxysteroid dehydrogenases in human endometrium and its disorders

In situ estrogen metabolism and synthesis have been considered to play a very important role in the development and progression of human endometrial carcinoma. 17Beta-hydroxysteroid dehydrogenases (17-HSDs) are enzymes involved in the formation of active sex steroids, including testosterone, estrone (E1) and estradiol (E2). Estrogens are interchanged by two enzymes, 17-HSD types 1 and 2, type 1 converts E1 to E2, and type 2 does reverse actions. 17-HSD type 5 catalyzes the reduction of androstenedione to testosterone. 17-HSD type 2 expression was decreased through normal endometrium, hyperplasia and carcinoma accordingly. There was a significant inverse correlation between intratumoral E2 concentration and the level of 17-HSD type 2 mRNA in endometrial carcinoma. 17-HSD type 5 expression was significantly increased through normal endometrium, hyperplasia and carcinoma accordingly. These results indicated that 17-HSD types 2 and 5 play an important role in the regulation of in situ estrogen production in endometrial carcinoma.

Inhibitory effects of fluorine-substituted estrogens on the activity of 17beta-hydroxysteroid dehydrogenases

In search for new inhibitors of human 17beta-hydroxysteroid dehydrogenase type 1 (h17beta-HSD1) a specific group of steroids with interesting properties including novel compounds was investigated. Several estratriene derivatives with fluorine-substitution in position 17 of the steroidal scaffold were synthesised and tested in vitro towards recombinant h17beta-HSD1, 2, 4, 5 and 7. Moderate, mostly unselective inhibitors of h17beta-HSD1 and h17beta-HSD2 and a selective inhibitor of h17beta-HSD5 were identified. The structure-activity relationship with respect to inhibitory strengths and selectivity of these compounds on five h17beta-HSDs is discussed.