Inhibitors Of Estrone Sulfatase Research Articles

Synthesis, Biological Evaluation and the Rationalisation of the Inhibitory Activity of a Range of Sulfonate Derivatives of Estrone (E1) in the Design of Reversible Inhibitors of Estrone Sulfatase (ES)

Synthesis, Biological Evaluation and the Rationalisation of the Inhibitory Activity of a Range of Sulfonate Derivatives of Estrone (E1) in the Design of Reversible Inhibitors of Estrone Sulfatase (ES)

Synthesis, In Vitro Activity and Rationalisation of a Series of Dialkyl Esters of 5-Aminosulfonylisophthanoate as Potential Estrone Sulfatase (ES) Inhibitors

Synthesis, In Vitro Activity and Rationalisation of a Series of Dialkyl Esters of 5-Aminosulfonylisophthanoate as Potential Estrone Sulfatase (ES) Inhibitors

Molecular Modelling, Design, Synthesis and Biochemical Evaluation of a Range of Non-Steroidal Thiosemicarbazone-Based Inhibitors of Estrone Sulfatase (ES) - A Potential Insight into the Action of a Range of Allosteric Inhibitors of ES

Results of the modelling of thiosemicarbazone-based inhibitors of ES suggest that these compounds interact with the calcium ion whilst undergoing hydrogen bonding interaction with the active site - the extent of H-bonding determining the overall inhibitory activity. Novel inhibitors were designed, synthesised and evaluated and found to possess potent inhibitory activity. Keywords: Allosteric inhibitors, Breast cancer, Estrone sulfatase, Estrone sulfatase, Non-steroidal inhibitors, Thiosemicarbazones, estrogens, coumarin-based compounds, inhibitory activity, phenacyl bromides, sulfamate-based inhibitors, cancer, Elkay, diaryl ketoximes, American Type Culture Collection (ATCC), Rota rod method

Using molecular docking to investigate the anti-breast cancer activity of low molecular weight compounds present on wild mushrooms

Mushrooms represent an unlimited source of compounds with anti-tumour and immunostimulating properties, and their intake has been shown to reduce the risk of breast cancer. A large number of low molecular weight (LMW) compounds present in mushrooms have been identified, including phenolic acids, flavonoids, tocopherols, carotenoids, sugars and fatty acids. In order to evaluate which wild mushroom LMW compounds may be involved in anti-breast cancer activity we selected a representative dataset of 43 LMW compounds and performed molecular docking against three known protein targets involved in breast cancer (aromatase, estrone sulfatase and 17β-HSD-1) using AutoDock4 as docking software. The estimated inhibition constants for all LMW compounds were determined, and the potential structure–activity relationships for the compounds with the best estimated inhibition constants are discussed for each compound family. 4-O-caffeoylquinic, naringin and lycopene stand out as the top-ranked potential inhibitors for aromatase, estrone sulfatase and 17β-HSD1, respectively, and the 3-D docked conformations for these compounds are discussed in detail. This information provides several interesting starting points for further development of aromatase, estrone sulfatase and 17β-HSD1 inhibitors.

Synthesis and Biological Evaluation of a Range of Thiosemicarbazone - Based Compounds as Potential Inhibitors of Estrone Sulfatase (ES)

Synthesis and Biological Evaluation of a Range of Thiosemicarbazone - Based Compounds as Potential Inhibitors of Estrone Sulfatase (ES)

Synthesis and In Vitro Biochemical Evaluation of a Series of Alkyl 6- Aminosulfonyl Naphthanoates as Potential Inhibitors of Human Placental Estrone Sulfatase (ES)

Synthesis and In Vitro Biochemical Evaluation of a Series of Alkyl 6- Aminosulfonyl Naphthanoates as Potential Inhibitors of Human Placental Estrone Sulfatase (ES)

Synthesis and In Vitro Biochemical Evaluation of a Series of Cycloalkyl Esters of 4-Sulfamoylated Benzoic Acid as Inhibitors of Estrone Sulfatase (ES)

We report the results of the synthesis and biochemical evaluation of esters of 4-[(aminosulfonyl)oxy]benzoate as potential inhibitors of estrone sulfatase (ES). Modelling the compounds shows that steric interaction between the inhibitor and the active site is a major factor responsible for the weak inhibitory activity observed within the synthesised compounds. Keywords: Estrone sulfatase, Synthesis, Evaluation, Cycloalkyl esters, Breast cancer, Inhibition

Synthesis and In Vitro Biochemical Evaluation of a Series of Compounds as Potential Inhibitors of Estrone Sulfatase (ES) and the Role of pKa in both the Synthesis and the Inhibitory Activity of the Potential Inhibitors

We report the results of our study into a series of 3,5-dibrominated derivatives of esters of 4- [(aminosulfonyl)oxy]benzoate as potential inhibitors of estrone sulfatase (ES). The results suggest that the compounds are weak inhibitors as a result of the incorporation of the bromine atoms which reduce the stability of the compound.

Thiosemicarbazones of Formyl Benzoic Acids as Novel Potent Inhibitors of Estrone Sulfatase

Thiosemicarbazones of the microbial metabolite madurahydroxylactone, a polysubstituted benzo[a]naphthacenequinone, have been previously reported by us as potent nonsteroidal inhibitors of the enzyme estrone sulfatase (cyclohexylthiosemicarbazone 1, IC50 0.46 microM). The active pharmacophore of 1 has now been identified to be 2-formyl-6-hydroxybenzoic acid cyclohexylthiosemicarbazone (25, IC50 4.2 microM). The active partial structure was derivatized in the search for novel agents against hormone-dependent breast cancer. Further substantial increases in activity were achieved by reversal of functional groups leading to the cyclohexylthiosemicarbazones of 5-formylsalicylic acid (35, IC50 0.05 microM) and 3-formylsalicylic acid (34, IC50 0.15 microM) as the most potent analogues identified to date. Both compounds were shown to be noncompetitive inhibitors of estrone sulfatase with Ki values of 0.13 microM and 0.12 microM, respectively. The compounds showed low acute toxicity in the hen's fertile egg screening test.

Inhibition of estrone sulfatase by aromatase inhibitor-based estrogen 3-sulfamates

Our rationale is based on the finding that estrone 3-sulfamate (EMATE, 2d), a typical estrone sulfatase (ES) inhibitor, can be hydrolyzed and the pharmacological effect of the free estrogen contributes to the bioactivity of the sulfamate. A number of 3-sulfamoylated derivatives of the good aromatase inhibitors, 2- and 4-halogeno (F, Cl, and Br) estrones and their estradiol analogs as well as 6β-methyl and phenyl estrones, were synthesized and evaluated as inhibitors of ES in human placental microsomes in comparison with the lead compound EMATE. Among them, 2-chloro- and 2-bromoestrone 3-sulfamates ( 2b and 2c), along with their estradiol analogs 3b and 3c, were powerful competitive inhibitors with K i's ranging between 4.0 and 11.3 nM ( K i for EMATE, 73 nM). These four sulfamates as well as the 2-fluoro analogs 2a and 3a inactivated ES in a time-dependent manner more efficiently than EMATE, and 2-halogeno estrone sulfamates 2 also caused a concentration-dependent loss of ES activity. The results may be useful for developing a new class of drugs having a dual function, ES inhibition and aromatase inhibition, for the treatment of breast cancer.

An Approach Towards the Quantitative Structure-Activity Relationships for Sulfamate-Based Estrone Sulfatase Inhibitors

Estrone sulfatase (ES) is a membrane-bound enzyme that is responsible for maintaining high levels of estrogens in breast cancer cells. This may be due to the conversion of estrone-sulfate into estrone by estronesulfatase, which acts as a pool of potentially available estrogens. There is now abundant evidence that estrogens have a pivotal role in the growth and development of hormone-dependent breast cancer. Thus, inhibitors of ES should have considerable therapeutic potential for the treatment of hormone-dependent breast cancer. Recently, a large number of sulfamate-based steroidal and non-steroidal ES inhibitors have been developed. The sulfamate moiety is believed to be involved in the irreversible inhibition of ES. In the present paper, we have undertaken quantitative structure-activity relationships for different series of non-steroidal sulfamate-based compounds in order to understand the chemical-biological interactions governing their inhibitory potency against ES. QSAR results have shown that the inhibitory potency against ES for these nonsteroidal sulfamate-based compounds is largely dependent on their hydrophobicity and molar refractivity. Keywords: breast cancer, estrone sulfatase inhibitors, hydrophobicity, molar refractivity, non-steroidal sulfamates, structureactivity relationships

Stilbene‐Based Inhibitors of Estrone Sulfatase with a Dual Mode of Action in Human Breast Cancer Cells.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Stilbene‐Based Inhibitors of Estrone Sulfatase with a Dual Mode of Action in Human Breast Cancer Cells

Estrone sulfate (E1S) is an endogenous prodrug that delivers estrone and, subsequently, estradiol to target cells, after hydrolysis by the enzyme estrone sulfatase, which is active in various tissues including hormone-dependent breast cancer. Blockade of this enzyme should reduce the estrogen level in breast cancer cells and prevent hormonal growth stimulation. In this study, a number of sulfamoyloxy-substituted stilbenes with side chains that guarantee antiestrogenic activity were synthesized and evaluated as inhibitors of estrone sulfatase. They inhibited this enzyme in human MDA-MB 231 breast cancer cells, with IC(50) values in the submicromolar range. The effects of both the free hydroxy derivatives and the sulfamates on gene activation were determined in transfected MCF-7/2a breast cancer cells stimulated either with estradiol or with estrone sulfate. The analysis of data revealed a dual mode of action of the majority of compounds. They blocked gene expression by inhibition of estrone sulfatase and by antiestrogenic action. This pharmacological profile was also observed in assays on antiproliferative activity. The most potent derivative 8 g inhibited the growth of wild-type human MCF-7 cells with an IC(50) value of 13 nM.

Inhibition of Estrone Sulfatase (ES) by Alkyl and Cycloalkyl Ester Derivatives of 4‐[(Aminosulfonyl)oxy] Benzoic Acid.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Inhibition of estrone sulfatase (ES) by alkyl and cycloalkyl ester derivatives of 4-[(aminosulfonyl)oxy] benzoic acid

In our search for potent inhibitors of the enzyme estrone sulfatase (ES), we have undertaken the synthesis and biochemical evaluation of a range of esters of 4-[(aminosulfonyl)oxy] benzoic acid. The results of the study show that the synthesised compounds possess potent inhibitory activity, indeed the cyclooctyl derivative was found to be more potent than 667-COUMATE, which is currently undergoing clinical trials.

The design, synthesis, and in vitro biochemical evaluation of a series of esters of 4-[(aminosulfonyl)oxy]benzoate as novel and highly potent inhibitors of estrone sulfatase

We report the initial results of our study into the use of a potential transition-state (TS) of the reaction catalysed by the enzyme estrone sulfatase (ES) in the design of a series of cyclic esters of 4-[(aminosulfonyl)oxy]benzoate as novel inhibitors of ES. The results of the study show that these compounds are some of the most potent inhibitors known todate, possessing greater inhibitory activity than the three standard compounds: 4-methylcoumarin-7- O-sulfamate (COUMATE); the tricyclic derivative of COUMATE, namely 667-COUMATE (which is in Phase I of clinical trials) and; the steroidal inhibitor estrone-3- O-sulfamate (EMATE).

In vitro and in vivo models for the evaluation of new inhibitors of human steroid sulfatase, devoid of residual estrogenic activity

The goal of our research project is to develop a new class of orally active drugs, estrone sulfatase inhibitors, for the treatment of estrogen-dependent (receptor positive) breast cancer. Several compounds were synthesized and their pharmacological potencies explored. Based on encouraging preliminary results, three of them, TX 1299, TX 1492 and TX 1506 were further studied in vitro as well as in vivo. They proved to be strong inhibitors of estrone sulfatase when measured on the whole human JEG-3 choriocarcinoma and MCF-7 breast cancer cells and their IC 50s found to be in the range of known standard inhibitors. Their residual estrogenic activity was checked as negative in the test of induction of alkaline phosphatase (APase) activity in whole human endometrial adenocarcinoma Ishikawa cells. In addition, their effect on aromatase activity in JEG-3 cells was also examined, since the goal of inhibiting both sulfatase and aromatase activities appears very attractive. However, it has been unsuccessful so far. Then, in vivo potencies of TX 1299, the lead compound in our chemical series, were evaluated in comparison with 6,6,7-COUMATE, a non-steroidal standard, in two different rat models and by oral route. First, the absence of any residual estrogenic activity for these compounds was checked in the uterotrophic model in prepubescent female rats. Second, antiuterotrophic activity in adult ovariectomized rat supplemented with estrone sulfate (E 1S), showed that both compounds were potent inhibitors, the power of TX 1299 relative to 6,6,7-COUMATE being around 80%. This assay was combined with uterine sulfatase level determination and confirmed the complete inhibition of this enzyme within the target organ. Preliminary studies indicated that other non-steroid compounds in the Théramex series were potent in vitro and in vivo inhibitors of estrone sulfatase in rats and further studies are in progress.

Steroidal oxathiazine inhibitors of estrone sulfatase

The presence of estrone sulfatase in breast tumors and the high levels of circulating estrone sulfate may contribute the major portion of estrogen synthesized locally in breast tissues through conversion of estrone sulfate to estrone by the enzyme. Using inhibitors of estrone sulfatase for the treatment of estrogen-dependent (estrogen receptor positive, ER +) breast cancer could be a very effective therapeutic strategy for the treatment of estrogen-dependent breast tumors in postmenopausal women. Therefore, we designed and synthesized several steroidal 2′,3′-oxathiazines that inhibit estrone sulfatase and have greatly reduced estrogenic side effects. Our in vitro studies indicate that the oxathiazine compounds have inhibitory activity on estrone sulfatase in MCF-7 human breast cancer cells. These estrone sulfatase inhibitors (ESIs) also inhibit the growth of MCF-7 cells induced by estrone sulfate. In addition, our in vivo experiments demonstrate that our ESIs have moderate antitumor activity against MCF-7 breast cancer xenografts in Balb/c athymic nude mice. The synthesis and biological activity of a number of these unique steroidal ESIs are described.

Estrone 3-sulfate mimics, inhibitors of estrone sulfatase activity: homology model construction and docking studies.

Steroid sulfatase (STS) is a new target for the endocrine therapy of breast cancer. To ascertain some of the requirements for inhibition of estrone sulfatase activity, a number of novel analogues of estrone 3-O-sulfate possessing sulfate surrogates were synthesized and evaluated as inhibitors of estrone sulfatase (STS) in comparison to a lead inhibitor, estrone-3-O-methylthiophosphonate (E1-3-MTP). Using a selective enzyme digestion, one of the diastereoisomers of this compound, (R(p))-E1-3-MTP, could be prepared and evaluated. From structure-activity studies, we show that chirality at the phosphorus atom, hydrophobicity, basicity, size, and charge all influence the ability of a compound to inhibit estrone sulfatase activity. Of these, hydrophobicity seems to be the most important since simple, active nonsteroidal inhibitors, based on 5,6,7,8-tetrahydronaphth-2-ol (THN), can be prepared, provided that they are lipophilic enough to partition into a nonpolar environment. Also, a negatively charged group is favorable for optimal binding, although it appears that the presence of a potentially cleavable group can compensate for lack of charge in certain cases. A homology model of STS has been constructed from the STS sequence, and molecular docking studies of inhibitors have been performed to broaden the understanding of enzyme/inhibitor interactions. This model clearly shows the positions of the key amino acid residues His136, His290, Lys134, and Lys368 in the putative catalytic region of the formylglycine at position 75, with residues Asp35, Asp36, Asp342, and Gln343 as ligands in the coordination sphere of the magnesium ion. Docking studies using the substrate and estrone-3-sulfate mimics that are active inhibitors indicate they are positioned in the area of proposed catalysis, confirming the predictive power of the model.

Sulfamoyloxy-substituted 2-phenylindoles: Antiestrogen-based inhibitors of the steroid sulfatase in human breast cancer cells

Estrone sulfate (E1S) is an endogenous prodrug that delivers estrone and, subsequently, estradiol to the target cells following the hydrolysis by the enzyme estrone sulfatase which is active in various tissues including hormone dependent breast cancer cells. Blockade of this enzyme should reduce the estrogen level in breast cancer cells and prevent hormonal growth stimulation. Sulfamates of a variety of phenolic compounds have been shown to be inhibitors of estrone sulfatase. Our rational is based on findings that these inhibitors can undergo hydrolysis and the pharmacological effects of the free hydroxy compounds contribute to the bioactivity of the sulfamates. A desirable action of the metabolites would be an estrogen antagonism to block stimulatory effects of residual amounts of estrogens. Thus, we synthesized a number of sulfamoyloxy-substituted 2-phenylindoles with side chains at the indole nitrogen that guarantee antiestrogenic activity. All of the new sulfamates were studied for their inhibitory effects on the enzyme estrone sulfatase from human breast cancer cells and their (anti)hormonal activities in stably transfected human MCF-7/2a mammary carcinoma cells. The hormonal profile of the sulfamates was partly reflected by the properties of the corresponding hydroxy precursors. Some of the sulfamoylated antiestrogens strongly inhibited estrone sulfatase activity with IC 50 values in the submicromolar range. They were devoid of agonist activity and suppressed estrone sulfate-stimulated gene expression mainly by blocking the enzyme. Examples are the disulfamates of the indoles ZK 119, 010 and ZK 164, 015. Their IC 50s for sulfatase inhibition were 0.3 and 0.2 μM, respectively, and 50 and 80 nM, respectively, for the inhibition of E1S-stimulated luciferase expression in transfected MCF-7 cells. With some of the new sulfamates an additional direct antiestrogenic effect was noticed which might be due to a partial hydrolysis during incubation and would improve the growth inhibitory effect on estrogen-sensitive breast cancer cells.