Clinical significance of the estrogen-modifying enzymes steroid sulfatase and estrogen sulfotransferase in epithelial ovarian cancer

Steroid metabolism and hormonal dynamics in normal and malignant ovaries

The ovaries are key steroid hormone production sites in post-pubertal females. However, current research on steroidogenic enzymes, endogenous hormone concentrations and their effects on healthy ovarian function and malignant development is limited. Here, we discuss the importance of steroid enzymes in normal and malignant ovaries, alongside hormone concentrations, receptor expression and action. Key enzymes include STS, 3β-HSD2, HSD17B1, ARK1C3, and aromatase, which influence ovarian steroidal action. Both androgen and oestrogen action, via their facilitating enzyme, drives ovarian follicle activation, development and maturation in healthy ovarian tissue. In ovarian cancer, some data suggest STS and oestrogen receptor α may be linked to aggressive forms, while various oestrogen-responsive factors may be involved in ovarian cancer metastasis. In contrast, androgen receptor expression and action vary across ovarian cancer subtypes. For future studies investigating steroidogenesis and steroidal activity in ovarian cancer, it is necessary to differentiate between disease subtypes for a comprehensive understanding.

Steroid sulfatase and sulfotransferases in the estrogen and androgen action of gynecological cancers: current status and perspectives

Sulfatase (STS) and sulfotransferases (SULT) have important role in the biosynthesis and action of steroid hormones. STS catalyzes the hydrolysis of estrone-sulfate (E1-S) and dehydroepiandrosterone-sulfate (DHEA-S), while sulfotransferases catalyze the reverse reaction and require 3-phosphoadenosine-5-phosphosulfate as a sulfate donor. These enzymes control the concentration of active estrogens and androgens in peripheral tissues. Aberant expression of STS and SULT genes has been found in both, benign hormone-dependent diseases and hormone-dependent cancers. The aim of this review is to present the current knowledge on the role of STS and SULT in gynecological cancers, endometrial (EC) and ovarian cancer (OC). EC is the most common and OC the most lethal gynecological cancer. These cancers primarily affect postmenopausal women and therefore rely on the local production of steroid hormones from inactive precursors, either DHEA-S or E1-S. Following cellular uptake by organic anion transporting polypeptides (OATP) or organic anion transporters (OAT), STS and SULT regulate the formation of active estrogens and androgens, thus disturbed balance between STS and SULT can contribute to the onset and progression of cancer. The importance of these enzymes in peripheral estrogen biosynthesis has long been recognized, and this review provides new data on the important role of STS and SULT in the formation and action of androgens, their regulation and inhibition, and their potential as prognostic biomarkers.

From fallopian tube epithelium to high-grade serous ovarian cancer: A single-cell resolution review of sex steroid hormone signaling

High-grade serous ovarian cancer (HGSOC) represents the most lethal subtype of ovarian cancer, largely due to being commonly diagnosed at advanced stages. The early molecular mechanisms underlying ovarian carcinogenesis remain poorly defined, posing challenges to the development of prevention and early detection strategies. Here we dissect the molecular mechanisms of sex steroid hormone signaling throughout the decades-long evolution of HGSOC precursor lesions, which predominantly originate from secretory epithelial cells of fallopian tubes (FT). We also discuss the prognostic significance of sex steroid receptor isoforms and steroid metabolizing enzymes in HGSOCs. Finally, we provide a comprehensive gene expression atlases of sex steroid receptors, steroidogenic, and steroid-metabolizing enzymes across different cell populations in pre- and postmenopausal FTs, and HGSOCs, using published single-cell RNA sequencing datasets. These atlases reveal that secretory epithelial cells and stromal populations in FTs express sex steroid receptors and enzymes responsible for the formation and inactivation of genotoxic estrogen metabolites. In HGSOC, epithelial cells express various HSD17B isoforms and steroid conjugating enzymes, suggesting an enhanced ability to finely regulate the levels of bioactive sex steroids.

Targeting estrogen metabolism in high-grade serous ovarian cancer shows promise to overcome platinum resistance

The high mortality rate due to chemoresistance in patients with high-grade ovarian cancer (HGSOC) emphasizes the urgent need to determine optimal treatment strategies for advanced and recurrent cases. Our study investigates the interplay between estrogens and chemoresistance in HGSOC and shows clear differences between platinum-sensitive and -resistant tumors. Through comprehensive transcriptome analyzes, we uncover differences in the expression of genes of estrogen biosynthesis, metabolism, transport and action underlying platinum resistance in different tissues of HGSOC subtypes and in six HGSOC cell lines. Furthermore, we identify genes involved in estrogen biosynthesis and metabolism as prognostic biomarkers for HGSOC. Additionally, our study elucidates different patterns of estrogen formation/metabolism and their effects on cell proliferation between six HGSOC cell lines with different platinum sensitivity. These results emphasize the dynamic interplay between estrogens and HGSOC chemoresistance. In particular, targeting the activity of steroid sulfatase (STS) proves to be a promising therapeutic approach with potential efficacy in limiting estrogen-driven cell proliferation. Our study reveals potential prognostic markers as well as identifies novel therapeutic targets that show promise for overcoming resistance and improving treatment outcomes in HGSOC.

Estrogen sulfotransferase and sulfatase in steroid homeostasis, metabolic disease, and cancer

Sulfation and desulfation of steroids are opposing processes that regulate the activation, metabolism, excretion, and storage of steroids, which account for steroid homeostasis. Steroid sulfation and desulfation are catalyzed by cytosolic sulfotransferase and steroid sulfatase, respectively. By modifying and regulating steroids, cytosolic sulfotransferase (SULT) and steroid sulfatase (STS) are also involved in the pathophysiology of steroid-related diseases, such as hormonal dysregulation, metabolic disease, and cancer. The estrogen sulfotransferase (EST, or SULT1E1) is a typical member of the steroid SULTs. This review is aimed to summarize the roles of SULT1E1 and STS in steroid homeostasis and steroid-related diseases.

17β-hydroxysteroid dehydrogenase type 1 improves survival in serous epithelial ovarian tumors

The incidence of ovarian cancer has been epidemiologically related to female reproductive events and hormone replacement therapy after menopause. This highlights the importance of evaluating the role of sexual steroid hormones in ovarian cancer by the expression of enzymes related to steroid hormone biosynthesis in the tumor cells. This study was aimed to evaluate the presence of 17β-hydroxysteroid dehydrogenase type 1 (17β-HSD1), aromatase and estrogen receptor alpha (ERα) in the tumor cells and their association with the overall survival in 111 patients diagnosed with primary ovarian tumors. Positive immunoreactivity for 17β-HSD1 was observed in 74% of the tumors. In the same samples, aromatase and ERα revealed 66% and 47% positivity, respectively. No association was observed of 17β-HSD1 expression with the histological subtypes and clinical stages of the tumor. The overall survival of patients was improved in 17β-HSD1-positive group in Kaplan-Meier analysis (P = 0.028), and 17β-HSD1 expression had a protective effect from multivariate proportional regression evaluation (HR = 0.44; 95% CI 0.24-0.9; P = 0.040). The improved survival was observed in serous epithelial tumors but not in nonserous ovarian tumors. The expression of 17β-HSD1 in the cells of the serous epithelial ovarian tumors was associated with an improved overall survival, whereas aromatase and ERα were not related to a better survival. The evaluation of hazard risk factors demonstrated that age and clinical stage showed worse prognosis, and 17β-HSD1 expression displayed a protective effect with a better survival outcome in patients of epithelial ovarian tumors.

Alteration in the expression of the chemotherapy resistance‑related genes in response to chronic and acute hypoxia in pancreatic cancer

Pancreatic cancer is currently one of the least curable types of human cancer and remains a key health problem. One of the most important characteristics of pancreatic cancer is its ability to grow under hypoxic conditions. Hypoxia is associated with resistance of cancer cells to radiotherapy and chemotherapy. It is a major contributor to pancreatic cancer genetic instability, which local and systemic resistance that may result in poor clinical outcome. Accordingly, identifying gene expression changes in cancer resistance genes that occur under hypoxic conditions may identify a new therapeutic target. The aim of the present study was to explore the association between hypoxia and resistance to chemotherapy and determine the alteration in the expression of cancer resistance-related genes in the presence of hypoxia. Pancreatic cancer cells (PANC-1) were exposed to 8 h hypoxic episodes (<1% oxygen) three times/week for a total of 20 episodes (chronic hypoxia) or 72 h hypoxic episodes twice/week for a total of 10 episodes (acute hypoxia). The alterations in gene expression were examined using reverse transcription-quantitative PCR array compared with normoxic cells. Chemoresistance of hypoxic cells toward doxorubicin was assessed using MTT cell proliferation assay. Both chronic and acute hypoxia induced chemoresistance toward doxorubicin in PANC-1 pancreatic cancer cell line. The greatest changes occurred in estrogen Receptor Alpha Gene (ESR1) and ETS Like-1 protein (ELK1) pathways, in nucleic transcription factor Peroxisome proliferator-activated receptors (PPARs) and in a cell cycle inhibitor cyclin dependent kinase inhibitor 1A (CDKN1A). The present study demonstrated that exposing cells to prolonged hypoxia results in different gene expression changes involving pleotropic pathways that serve a role in inducing resistance in pancreatic cancer.

Targeting the formation of estrogens for treatment of hormone dependent diseases-current status

Local formation and action of estrogens have crucial roles in hormone dependent cancers and benign diseases like endometriosis. Drugs that are currently used for the treatment of these diseases act at the receptor and at the pre-receptor levels, targeting the local formation of estrogens. Since 1980s the local formation of estrogens has been targeted by inhibitors of aromatase that catalyses their formation from androgens. Steroidal and non-steroidal inhibitors have successfully been used to treat postmenopausal breast cancer and have also been evaluated in clinical studies in patients with endometrial, ovarian cancers and endometriosis. Over the past decade also inhibitors of sulfatase that catalyses the hydrolysis of inactive estrogen-sulfates entered clinical trials for treatment of breast, endometrial cancers and endometriosis, with clinical effects observed primarily in breast cancer. More recently, inhibitors of 17beta-hydroxysteroid dehydrogenase 1, an enzyme responsible for formation of the most potent estrogen, estradiol, have shown promising results in preclinical studies and have already entered clinical evaluation for endometriosis. This review aims to provide an overview of the current status of the use of hormonal drugs for the major hormone-dependent diseases. Further, it aims to explain the mechanisms behind the -sometimes- observed weak effects and low therapeutic efficacy of these drugs and the possibilities and the advantages of combined treatments targeting several enzymes in the local estrogen formation, or drugs acting with different therapeutic mechanisms.

Inhibition of human sulfotransferases (SULTs) by per- and polyfluoroalkyl substances (PFASs) and structure-activity relationship

Per- and polyfluoroalkyl substances (PFASs) are a family of highly fluorinated aliphatic substances widely used in industrial and commercial applications. This study aims to determine the inhibition of PFASs towards sulfotransferases (SULTs) activity, and trying to explain the toxicity mechanism of PFASs. In vitro recombinant SULTs-catalyzed sulfation of p-nitrophenol (PNP) was utilized as a probe reaction. The incubation system was consisted of PFASs, SULTs, PNP, 3'-phosphoadenosine-5'-phosphosulfate, MgCl₂ and Tris-HCl buffer. Ultra-performance liquid chromatography was employed for analysis of the metabolites. All tested PFASs showed inhibition towards SULTs. The longer the carbon chain length of the PFASs terminated with -COOH, the higher is its capability of inhibiting SULT1A3. PFASs with -SO₃H had a relatively higher ability to inhibit SULT1A3 activity than those with -COOH, -I and -OH. The inhibition kinetic parameter was 2.16 and 1.42 μM for PFOS-SULT1A1, PFTA-SULT1B1. In vitro in vivo extrapolation showed that the concentration of PFOS and PFTA in human matrices might be higher than the threshold for inducing inhibition of SULTs. Therefore, PFASs could interfere with the metabolic pathways catalyzed by SULTs in vivo. All these results will help to understand the toxicity of PFASs from the perspective of metabolism.

Model Cell Lines and Tissues of Different HGSOC Subtypes Differ in Local Estrogen Biosynthesis

Simple Summary

Ovarian cancer (OC) comprises a heterogeneous group of hormone-dependent diseases with very high mortality. Estrogens have been shown to promote the progression of OC; however, their exact role in OC subtypes remains unknown. Here, we investigated the local estrogen biosynthesis in OC. We performed targeted transcriptomics and estrogen metabolism analyses in high-grade serous OC (HGSOC) cell lines that differed in chemoresistance status and compared these data with publicly available transcriptome and proteome data for HGSOC tissues. In HGSOC cells, estrogen metabolism decreased with increasing chemoresistance. In highly chemoresistant cells and platinum-resistant HGSOC tissues, HSD17B14 expression was increased. Proteome data showed differential levels of HSD17B10, SULT1E1, CYP1B1, and NQO1 between the four HGSOC subtypes. Our results confirm that estrogen biosynthesis differs between different HGSOC cell models and possibly between different HGSOC subtypes. Such differentially expressed enzymes have potential as targets in the search of new treatment options.

Abstract

Ovarian cancer (OC) is highly lethal and heterogeneous. Several hormones are involved in OC etiology including estrogens; however, their role in OC is not completely understood. Here, we performed targeted transcriptomics and estrogen metabolism analyses in high-grade serous OC (HGSOC), OVSAHO, Kuramochi, COV632, and immortalized normal ovarian epithelial HIO-80 cells. We compared these data with public transcriptome and proteome data for the HGSOC tissues. In all model systems, high steroid sulfatase expression and weak/undetected aromatase (CYP19A1) expression indicated the formation of estrogens from the precursor estrone-sulfate (E1-S). In OC cells, the metabolism of E1-S to estradiol was the highest in OVSAHO, followed by Kuramochi and COV362 cells, and decreased with increasing chemoresistance. In addition, higher HSD17B14 and CYP1A2 expressions were observed in highly chemoresistant COV362 cells and platinum-resistant tissues compared to those in HIO-80 cells and platinum-sensitive tissues. The HGSOC cell models differed in HSD17B10, CYP1B1, and NQO1 expression. Proteomic data also showed different levels of HSD17B10, CYP1B1, NQO1, and SULT1E1 between the four HGSOC subtypes. These results suggest that different HGSOC subtypes form different levels of estrogens and their metabolites and that the estrogen-biosynthesis-associated targets should be further studied for the development of personalized treatment.

Survival Is Related to Estrogen Signal Transduction Pathway Activity in Postmenopausal Women Diagnosed with High-Grade Serous Ovarian Carcinoma

High-grade serous ovarian carcinoma (HGSC), the most common subtype of ovarian cancer, has a high mortality rate. Although there are some factors associated with survival, such as stage of disease, there are remarkable differences in survival among women diagnosed with advanced stage disease. In this study, we investigate possible relations between survival and signal transduction pathway (STP) activity. We assessed the functional activity of the androgen receptor (AR), estrogen receptor (ER), phosphoinositide-3-kinase (PI3K), Hedgehog (HH), transforming growth factor beta (TGF-β) and canonical wingless-type MMTV integration site (Wnt) pathway in 85 primary tumor samples of patients with FIGO stage IIIC to IVB HGSC and disease-free survival (DFS) below 12 (n = 52) or over 24 months (n = 33). There were no significant differences in median pathway activity between patients with a short and long DFS. In univariate Cox proportional hazards analysis, ER pathway activity was related to a favorable DFS and overall survival (OS) in postmenopausal women (p = 0.033 and p = 0.041, respectively), but not in premenopausal women. We divided the postmenopausal group into subgroups based on ER pathway activity quartiles. Survival analysis revealed that postmenopausal women in the lowest ER quartile had a shorter DFS and OS (log-rank p = 0.006 and p < 0.001, respectively). Furthermore, we were able to form subgroups of patients based on an inverse relation between ER and PI3K pathway activity. In conclusion, in postmenopausal patients with advanced stage HGSC, a poorer survival outcome was associated with low functional ER pathway activity.

Estrogens and the Schrödinger's Cat in the Ovarian Tumor Microenvironment

Simple Summary

Ovarian cancer is a complex pathology for which we require effective screening and therapeutical strategies. Apart from the cancer cell portion, there exist plastic immune and non-immune cell populations, jointly constituting the context-adaptive tumor microenvironment, which is pivotal in tumorigenesis. Estrogens might be synthesized in the ovarian tumor tissue and actively contribute to the shaping of an immunosuppressive microenvironment. Current immune therapies have limited effectiveness as a multitude of factors influence the outcome. A thorough understanding of the ovarian cancer biology is crucial in the efforts to reestablish homeostasis.

Abstract

Ovarian cancer is a heterogeneous disease affecting the aging ovary, in concert with a complex network of cells and signals, together representing the ovarian tumor microenvironment. As in the “Schrödinger’s cat” thought experiment, the context-dependent constituents of the—by the time of diagnosis—well-established tumor microenvironment may display a tumor-protective and -destructive role. Systemic and locally synthesized estrogens contribute to the formation of a pro-tumoral microenvironment that enables the sustained tumor growth, invasion and metastasis. Here we focus on the estrogen biosynthetic and metabolic pathways in ovarian cancer and elaborate their actions on phenotypically plastic, estrogen-responsive, aging immune cells of the tumor microenvironment, altogether highlighting the multicomponent-connectedness and complexity of cancer, and contributing to a broader understanding of the ovarian cancer biology.

Simultaneous expression of steroid sulfatase and androgen receptor reduced overall survival of patients with epithelial ovarian tumors

BACKGROUND

Ovarian cancer is usually diagnosed at an advanced stage due to its early asymptomatic course and late-stage non-specific symptoms. This highlights the importance of researching the molecular mechanisms involved in ovarian carcinogenesis as well as the discovery of novel prognostic markers that could help improve the survival outcome of patients. The aim of this study was to evaluate the expression of the steroid sulfatase (STS) in 154 samples of primary ovarian tumors. This protein is crucial in the intracellular conversion of sulfated steroid hormones to active steroid hormones. The presence of STS, 3β-HSD, and 17β-HSD1 result in the production of testosterone which act through the androgen receptor (AR) in the tumor cell. The presence of STS and AR in epithelial ovarian tumors and their association to the overall survival of patients was evaluated using Kaplan-Meier and Cox regression analyses.

RESULTS

Immunoreactivity for STS was detected in 65% of the tumors and no association was observed with histological subtypes and clinical stages of the tumor. The STS expression in the tumors exhibiting immunoreactive AR resulted in a reduced survival (log-rank test, p = 0.032) and a risk factor in univariate and multivariate analysis, HR = 3.46, CI_95% 1.00-11.92, p = 0.049 and HR = 5.92, CI_95% 1.34-26.09, p = 0.019, respectively.

CONCLUSIONS

These findings suggest that the intracellular synthesis of testosterone acting through its receptor can promote tumor growth and progression. Moreover, the simultaneous expression of STS and AR constitutes an independent predictor of poor prognosis in epithelial ovarian tumors.

Sex-specific expression mechanism of hepatic estrogen inactivating enzyme and transporters in diabetic women

Circulating estrogens levels significantly decrease in menopause and levels off in postmenopausal women. Accordingly, the liver represses levels of enzymes and membrane transporters, thereby decreasing capability of inactivating and excreting estrogens. Women increasingly develop type 2 diabetes during or after menopause. Estrogens are known to promote liver diseases in these women. Here, we have found that the estrogen inactivating sulfotransferase (SULT1E1) and an ATP-binding cassette subfamily G member 2 (ABCG2), a gene encoding breast cancer resistance protein that exports sulfated estrogens, increased their expression levels in diabetic women but not men. For the sulfotransferase gene, phosphorylated nuclear receptors ERα and RORα, at Ser212 and Ser100, respectively, bind their response elements to activate the SULT1E1 promoter in women. This coordinated increase in estrogen inactivation and excretion, and the phosphorylated nuclear receptor-mediated gene activation could be a defense mechanism against toxicities of estrogens through inactivation and excretion in the livers of women.

Steroid Sulphatase and Its Inhibitors: Past, Present, and Future

Steroid sulphatase (STS), involved in the hydrolysis of steroid sulphates, plays an important role in the formation of both active oestrogens and androgens. Since these steroids significantly impact the proliferation of both oestrogen- and androgen-dependent cancers, many research groups over the past 30 years have designed and developed STS inhibitors. One of the main contributors to this field has been Prof. Barry Potter, previously at the University of Bath and now at the University of Oxford. Upon Prof. Potter's imminent retirement, this review takes a look back at the work on STS inhibitors and their contribution to our understanding of sulphate biology and as potential therapeutic agents in hormone-dependent disease. A number of potent STS inhibitors have now been developed, one of which, Irosustat (STX64, 667Coumate, BN83495), remains the only one to have completed phase I/II clinical trials against numerous indications (breast, prostate, endometrial). These studies have provided new insights into the origins of androgens and oestrogens in women and men. In addition to the therapeutic role of STS inhibition in breast and prostate cancer, there is now good evidence to suggest they may also provide benefits in patients with colorectal and ovarian cancer, and in treating endometriosis. To explore the potential of STS inhibitors further, a number of second- and third-generation inhibitors have been developed, together with single molecules that possess aromatase-STS inhibitory properties. The further development of potent STS inhibitors will allow their potential therapeutic value to be explored in a variety of hormone-dependent cancers and possibly other non-oncological conditions.

Steroid sulfatase inhibitors: the current landscape

Introduction: Steroid sulfatase (STS) enzyme is responsible for transforming the inactive sulfate metabolites of steroid sex hormones into the active free steroids. Both the deficiency and the over-expression of STS are associated with the pathophysiology of certain diseases. This article provides the readership with a comprehensive review about STS enzyme and its recently reported inhibitors.Areas covered: In the present article, we reviewed the structure, location, and substrates of STS enzyme, physiological functions of STS, and disease states related to over-expression or deficiency of STS enzyme. STS inhibitors reported during the last five years (2016-present) have been reviewed as well.Expert opinion: Irosustat is the most successful STS inhibitor drug candidate so far. It is currently under investigation in clinical trials for treatment of estrogen-dependent breast cancer. Non-steroidal sulfamate is the most favorable scaffold for STS inhibitor design. They can be beneficial for the treatment of hormone-dependent cancers and neurodegenerative disorders without significant estrogenic side effects. Moreover, dual-acting molecules (inhibitors of STS + another synergistic mechanism) can be therapeutically efficient.

Functional estrogen receptor signaling pathway activity in high-grade serous ovarian carcinoma as compared to estrogen receptor protein expression by immunohistochemistry

Purpose

Anti-estrogen therapy may be used as a palliative treatment option in high-grade serous ovarian carcinomas (HGSC). However, clinical implementation is limited as the use of estrogen receptor (ER) protein expression by immunohistochemistry remains insufficient in predicting therapy response. To determine the accuracy of ER protein expression as a marker for ER signaling pathway activity, we aimed to correlate ER protein expression to functional ER signaling pathway activity in HGSC.

Methods

Immunohistochemical ER protein expression was visually scored using total percentages of stained tumor cells and histoscores. Subsequently, mRNA was extracted, and RT-qPCR analysis was performed. Functional ER pathway activity was assessed by a computational Bayesian model inferring ER signaling pathway activity from mRNA levels of ER-specific target genes.

Results

Our analysis of 29 HGSCs shows that neither total percentage of ER protein expression, nor ER histoscores are significantly correlated to ER signaling pathway activity (respectively, p = 0.473 and p = 0.606). Classification of HGSC into three groups based on ER histoscores 0–100 (n = 6), 101–200 (n = 15) and 201–300 (n = 8) resulted in comparable mean ER signaling pathway activity among the groups (p = 0.356). Several samples in the higher ER histoscore groups had low ER signaling pathway activity, indicating that nuclear ER protein expression is not sufficient to describe transcriptional ER activation.

Conclusion

Positive immunohistochemical ER staining is not always indicative of an active ER signaling pathway and is, therefore, a poor predictor of anti-estrogen response. Further research is needed to prove the predictive value of ER signaling pathway activity regarding anti-estrogen sensitivity in HGSC patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13402-021-00600-5.

The Role of Sulfotransferases in Liver Diseases

The cytosolic sulfotransferases (SULTs) are phase II conjugating enzymes that catalyze the transfer of a sulfonate group from the universal sulfate donor 3'-phosphoadenosine-5'-phosphosulfate to a nucleophilic group of their substrates to generate hydrophilic products. Sulfation has a major effect on the chemical and functional homeostasis of substrate chemicals. SULTs are widely expressed in metabolically active or hormonally responsive tissues, including the liver and many extrahepatic tissues. The expression of SULTs exhibits isoform-, tissue-, sex-, and development-specific regulations. SULTs display a broad range of substrates including xenobiotics and endobiotics. The expression of SULTs has been shown to be transcriptionally regulated by members of the nuclear receptor superfamily, such as the peroxisome proliferator-activated receptors, pregnane X receptor, constitutive androstane receptor, vitamin D receptor, liver X receptors, farnesoid X receptor, retinoid-related orphan receptors, estrogen-related receptors, and hepatocyte nuclear factor 4α These nuclear receptors can be activated by numerous xenobiotics and endobiotics, such as fatty acids, bile acids, and oxysterols, many of which are substrates of SULTs. Due to their metabolism of xenobiotics and endobiotics, SULTs and their regulations are implicated in the pathogenesis of many diseases. This review is aimed to summarize the central role of major SULTs, including the SULT1 and SULT2 subfamilies, in the pathophysiology of liver and liver-related diseases. SIGNIFICANCE STATEMENT: Sulfotransferases (SULTs) are indispensable in the homeostasis of xenobiotics and endobiotics. Knowing SULTs and their regulations are implicated in human diseases, it is hoped that genetic or pharmacological manipulations of the expression and/or activity of SULTs can be used to affect the clinical outcome of diseases.

Metabolism of Estrogens: Turnover Differs Between Platinum-Sensitive and -Resistant High-Grade Serous Ovarian Cancer Cells

High-grade serous ovarian cancer (HGSOC) is currently treated with cytoreductive surgery and platinum-based chemotherapy. The majority of patients show a primary response; however, many rapidly develop drug resistance. Antiestrogens have been studied as low toxic treatment options for HGSOC, with higher response rates in platinum-sensitive cases. Mechanisms for this difference in response remain unknown. Therefore, the present study investigated the impact of platinum resistance on steroid metabolism in six established HGSOC cell lines sensitive and resistant against carboplatin using a high-resolution mass spectrometry assay to simultaneously quantify the ten main steroids of the estrogenic metabolic pathway. An up to 60-fold higher formation of steroid hormones and their sulfated or glucuronidated metabolites was observed in carboplatin-sensitive cells, which was reversible by treatment with interleukin-6 (IL-6). Conversely, treatment of carboplatin-resistant cells expressing high levels of endogenous IL-6 with the monoclonal anti-IL-6R antibody tocilizumab changed their status to “platinum-sensitive”, exhibiting a decreased IC₅₀ value for carboplatin, decreased growth, and significantly higher estrogen metabolism. Analysis of these metabolic differences could help to detect platinum resistance in HGSOC patients earlier, thereby allowing more efficient interventions.

Human steroid biosynthesis, metabolism and excretion are differentially reflected by serum and urine steroid metabolomes: A comprehensive review

Advances in technology have allowed for the sensitive, specific, and simultaneous quantitative profiling of steroid precursors, bioactive steroids and inactive metabolites, facilitating comprehensive characterization of the serum and urine steroid metabolomes. The quantification of steroid panels is therefore gaining favor over quantification of single marker metabolites in the clinical and research laboratories. However, although the biochemical pathways for the biosynthesis and metabolism of steroid hormones are now well defined, a gulf still exists between this knowledge and its application to the measured steroid profiles. In this review, we present an overview of steroid hormone biosynthesis and metabolism by the liver and peripheral tissues, specifically highlighting the pathways linking and differentiating the serum and urine steroid metabolomes. A brief overview of the methodology used in steroid profiling is also provided.

Clinical Significance of Organic Anion Transporting Polypeptide Gene Expression in High-Grade Serous Ovarian Cancer

High-grade serous ovarian cancer (HGSOC) is considered the most deadly and frequently occurring type of ovarian cancer and is associated with various molecular compositions and growth patterns. Evaluating the mRNA expression pattern of the organic anion transporters (OATPs) encoded by SLCO genes may allow for improved stratification of HGSOC patients for targeted invention. The expression of SLCO mRNA and genes coding for putative functionally related ABC-efflux pumps, enzymes, pregnane-X-receptor, ESR1 and ESR2 (coding for estrogen receptors ERα and ERß) and HER-2 were assessed using RT-qPCR. The expression levels were assessed in a cohort of 135 HGSOC patients to elucidate the independent impact of the expression pattern on the overall survival (OS). For identification of putative regulatory networks, Graphical Gaussian Models were constructed from the expression data with a tuning parameter K varying between meaningful borders (Pils et al., 2012; Auer et al., 2015, 2017; Kurman and Shih Ie, 2016; Karam et al., 2017; Labidi-Galy et al., 2017; Salomon-Perzynski et al., 2017; Sukhbaatar et al., 2017). The final value used (K = 4) was determined by maximizing the proportion of explained variation of the corresponding LASSO Cox regression model for OS. The following two networks of directly correlated genes were identified: (i) SLCO2B1 with ABCC3 implicated in estrogen homeostasis; and (ii) two ABC-efflux pumps in the immune regulation (ABCB2/ABCB3) with ABCC3 and HER-2. Combining LASSO Cox regression and univariate Cox regression analyses, SLCO5A1 coding for OATP5A1, an estrogen metabolite transporter located in the cytoplasm and plasma membranes of ovarian cancer cells, was identified as significant and independent prognostic factor for OS (HR = 0.68, CI 0.49-0.93; p = 0.031). Furthermore, results indicated the benefits of patients with high expression by adding 5.1% to the 12.8% of the proportion of explained variation (PEV) for clinicopathological parameters known for prognostic significance (FIGO stage, age and residual tumor after debulking). Additionally, overlap with previously described signatures that indicated a more favorable prognosis for ovarian cancer patients was shown for SLCO5A1, the network ABCB2/ABCB3/ABCC4/HER2 as well as ESR1. Furthermore, expression of SLCO2A1 and PGDH, which are important for PGE₂ degradation, was associated with the non-miliary peritoneal tumor spreading. In conclusion, the present findings suggested that SLCOs and the related molecules identified as potential biomarkers in HGSOC may be useful for the development of novel therapeutic strategies.

SULFATION PATHWAYS: Insights into steroid sulfation and desulfation pathways

Sulfation and desulfation pathways represent highly dynamic ways of shuttling, repressing and re-activating steroid hormones, thus controlling their immense biological potency at the very heart of endocrinology. This theme currently experiences growing research interest from various sides, including, but not limited to, novel insights about phospho-adenosine-5'-phosphosulfate synthase and sulfotransferase function and regulation, novel analytics for steroid conjugate detection and quantification. Within this review, we will also define how sulfation pathways are ripe for drug development strategies, which have translational potential to treat a number of conditions, including chronic inflammatory diseases and steroid-dependent cancers.

SULFATION PATHWAYS: Steroid sulphatase inhibition via aryl sulphamates: clinical progress, mechanism and future prospects

Steroid sulphatase is an emerging drug target for the endocrine therapy of hormone-dependent diseases, catalysing oestrogen sulphate hydrolysis to oestrogen. Drug discovery, developing the core aryl O-sulphamate pharmacophore, has led to steroidal and non-steroidal drugs entering numerous clinical trials, with promising results in oncology and women's health. Steroidal oestrogen sulphamate derivatives were the first irreversible active-site-directed inhibitors and one was developed clinically as an oral oestradiol pro-drug and for endometriosis applications. This review summarizes work leading to the therapeutic concept of sulphatase inhibition, clinical trials executed to date and new insights into the mechanism of inhibition of steroid sulphatase. To date, the non-steroidal sulphatase inhibitor Irosustat has been evaluated clinically in breast cancer, alone and in combination, in endometrial cancer and in prostate cancer. The versatile core pharmacophore both imbues attractive pharmaceutical properties and functions via three distinct mechanisms of action, as a pro-drug, an enzyme active-site-modifying motif, likely through direct sulphamoyl group transfer, and as a structural component augmenting activity, for example by enhancing interactions at the colchicine binding site of tubulin. Preliminary new structural data on the Pseudomonas aeruginosa arylsulphatase enzyme suggest two possible sulphamate-based adducts with the active site formylglycine as candidates for the inhibition end product via sulphamoyl or sulphonylamine transfer, and a speculative choice is suggested. The clinical status of sulphatase inhibition is surveyed and how it might develop in the future. Also discussed are dual-targeting approaches, development of 2-substituted steroidal sulphamates and non-steroidal derivatives as multi-targeting agents for hormone-independent tumours, with other emerging directions.

Melatonin: An Anti-Tumor Agent in Hormone-Dependent Cancers

Melatonin (N-acetyl-5-methoxytryptamine) is a hormone synthesized and secreted by the pineal gland mainly during the night, since light exposure suppresses its production. Initially, an implication of this indoleamine in malignant disease was described in endocrine-responsive breast cancer. Data from several clinical trials and multiple experimental studies performed both in vivo and in vitro have documented that the pineal hormone inhibits endocrine-dependent mammary tumors by interfering with the estrogen signaling-mediated transcription, therefore behaving as a selective estrogen receptor modulator (SERM). Additionally, melatonin regulates the production of estradiol through the control of the enzymes involved in its synthesis, acting as a selective estrogen enzyme modulator (SEEM). Many more mechanisms have been proposed during the past few years, including signaling triggered after activation of the membrane melatonin receptors MT-1 and MT-2, or else intracellular actions targeting molecules such as calmodulin, or binding intranuclear receptors. Similar results have been obtained in prostate (regulation of enzymes involved in androgen synthesis and modulation of androgen receptor levels and activity) and ovary cancer. Thus, tumor metabolism, gene expression, or epigenetic modifications are modulated, cell growth is impaired and angiogenesis and metastasis are inhibited. In the last decade, many more reports have demonstrated that melatonin is a promising adjuvant molecule with many potential beneficial consequences when included in chemotherapy or radiotherapy protocols designed to treat endocrine-responsive tumors. Therefore, in this state-of-the-art review, we aim to compile the knowledge about the oncostatic actions of the indoleamine in hormone-dependent tumors, and the latest findings concerning melatonin actions when administered in combination with radio- or chemotherapy in breast, prostate, and ovary cancers. As melatonin has no toxicity, it may be well deserve to be considered as an endogenously generated agent helpful in cancer prevention and treatment.

Melatonin as a promising agent to treat ovarian cancer: molecular mechanisms

Ovarian cancer (OC) has the highest mortality rate of all gynecological cancers, and most patients develop chemoresistance after first-line treatments. Despite recent advances, the 5-year relative survival is ~45% for all OC subtypes, and invasive epithelial OC has only a 17% survival rate when diagnosed at a late stage. Identification of new efficacious molecules or biomarkers represents important opportunities in the treatment of OC. The pharmacological and physiological properties of melatonin indicate this agent could be useful against OC progression and metastasis. In normal cells, melatonin has potent antioxidant and anti-apoptotic actions. Conversely, melatonin has pro-oxidant as well as anti-proliferative, anti-angiogenic and immunomodulatory properties in many cancer types including hormone-dependent cancers. Although melatonin receptors have been identified in OC cells, the exact mechanism by which melatonin induces anticancer activities remains incompletely understood. Clinical studies have reported negative correlation between aggressiveness of OC and serum levels of melatonin, reinforcing the idea that melatonin may be a critical factor determining OC development. In vitro and in vivo studies suggest melatonin differentially regulates multiple signaling pathways in OC cells. This focused review explores the potential mechanisms of action of melatonin on cultured OC cells and in experimental models of OC in an attempt to clarify how melatonin modulates the signaling pathways involved in cancer cell apoptosis, survival, inflammation, proliferation and metabolic processes. Based on the evidence presented, we feel that melatonin, as an agent that controls cellular signals associated with malignancy, may be beneficial in combination with other therapeutics for OC treatment.