Antisulfatase, Osteogenic, and Anticancer Activities of Steroid Sulfatase Inhibitor EO-33 in Mice

Targeted Recruitment and Degradation of Estrogen Receptor α by Photothermal Polydopamine Nanoparticles for Breast Tumor Ablation

The major challenges of photothermal therapy (PTT) toward clinical application are the severe skin injury and inflammation response associated with high power laser irradiation. Herein, polydopamine nanoparticles (PDA-EST and PDA-RAL) targeted to estrogen receptor α (ERα) for efficient ablation of breast tumor under a low irradiation density of 0.1 W cm^-2 are reported. These nanoparticles are capable of recruiting ERα on their surface and induce a complete ERα degradation via localized heat. Owing to the ERα targetability, PDA-EST and PDA-RAL strongly suppress the proliferation of breast cancer cells without causing significant inflammation. This work provides a generalized method for enhancing PTT efficacy under low irradiation density.

16-Picolyl-androsterone derivative exhibits potent 17β-HSD3 inhibitory activity, improved metabolic stability and cytotoxic effect on various cancer cells: Synthesis, homology modeling and docking studies

A new androsterone derivative bearing a 16β-picolyl group (compound 5; FCO-586-119) was synthetized in four steps from the lead compound 1 (RM-532-105). We measured its inhibitory activity on 17β-HSD3 using microsomal fraction of rat testes as well as transfected LNCaP[17β-HSD3] cells. We then assessed its metabolic stability as well as its cytotoxic effect against a panel of cancer cell lines. The addition of a picolyl moiety at C-16 of RM-532-105 steroid core improves the 17β-HSD3 inhibitory activity in the microsomal fraction of rat testes, but not in whole LNCaP[17β-HSD3] cells. Interestingly, this structural modification enhances 3-fold the metabolic stability in conjunction with a significant cytotoxic effect against pancreatic, ovarian, breast, lung, and prostate cancer cells. Because the inhibitory activity data against 17β-HSD3 suggested that both steroid derivatives are non-competitive inhibitors, we performed docking and molecular dynamics simulations using a homology model of this membrane-associated enzyme. The results of these simulations revealed that both RM-532-105 (1) and FCO-586-119 (5) can compete for the cofactor-binding site displaying better binding energy than NADP+.

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.

Recent progress in the development of steroid sulphatase inhibitors - examples of the novel and most promising compounds from the last decade

The purpose of this review article is to provide an overview of recent achievements in the synthesis of novel steroid sulphatase (STS) inhibitors. STS is a crucial enzyme in the biosynthesis of active hormones (including oestrogens and androgens) and, therefore, represents an extremely attractive molecular target for the development of hormone-dependent cancer therapies. The inhibition of STS may effectively reduce the availability of active hormones for cancer cells, causing a positive therapeutic effect. Herein, we report examples of novel STS inhibitors based on steroidal and nonsteroidal cores that contain various functional groups (e.g. sulphamate and phosphorus moieties) and halogen atoms, which may potentially be used in therapies for hormone-dependent cancers. The presented work also includes examples of multitargeting agents with STS inhibitory activities. Furthermore, the fundamental discoveries in the development of the most promising drug candidates exhibiting STS inhibitory activities are highlighted.

Design and synthesis of dansyl-labeled inhibitors of steroid sulfatase for optical imaging

Steroid sulfatase (STS) is an important enzyme regulating the conversion of sulfated steroids into their active hydroxylated forms. Notably, the inhibition of STS has been shown to decrease the levels of active estrogens and was translated into clinical trials for the treatment of breast cancer. Based on quantitative structure-activity relationship (QSAR) and molecular modeling studies, we herein report the design of fluorescent inhibitors of STS by adding a dansyl group on an estrane scaffold. Synthesis of 17α-dansylaminomethyl-estradiol (7) and its sulfamoylated analog 8 were achieved from estrone in 5 and 6 steps, respectively. Inhibition assays on HEK-293 cells expressing exogenous STS revealed a high level of inhibition for compound 7 (IC₅₀ = 69 nM), a value close to the QSAR model prediction (IC₅₀ = 46 nM). As an irreversible inhibitor, sulfamate 8 led to an even more potent inhibition in the low nanomolar value (IC₅₀ = 2.1 nM). In addition, we show that the potent STS inhibitor 8 can be employed as an optical imaging tool to investigate intracellular enzyme sub-localization as well as inhibitory behavior. As a result, confocal microscopy analysis confirmed good penetration of the STS fluorescent inhibitor 8 in cells and its localization in the endoplasmic reticulum where STS is localized.