Novel steroid sulfatase inhibitors based on N‐thiophosphorylated 3‐(4‐aminophenyl)‐coumarin‐7‐O‐sulfamates

Abstract

In the present work, we described convenient methods for the synthesis of N‐thiophosphorylated 3‐(4‐aminophenyl)‐coumarin‐7‐O‐sulfamates as steroid sulfatase (STS) inhibitors. To design the structures of the potential STS inhibitors, molecular modeling techniques were used. A computational docking method was used to determine the binding modes of the synthesized inhibitors as well as to identify potential interactions between specified functional groups on the inhibitors and the amino acid residues present in the active site of the enzyme. The inhibitory activities of the synthesized compounds were tested in an enzymatic assay with STS isolated from a human placenta. Within the set of newly synthesized compounds, 9e demonstrated the highest inhibitory activity in the enzymatic assay with an IC50 value of 0.201 μM (the IC50 value of 667‐COUMATE in the same test was 0.062 μM). Furthermore, we tried to verify if the obtained STS inhibitors are able to pass through the cellular membrane effectively in cell line experiments. In the course of our study, we determined the STS activity in the MCF‐7 cell line after incubation in the presence of the inhibitors (at 100 nM concentration). For this evaluation, we included newly synthesized compounds 9a‐g and their N‐phosphorylated analogs 6a‐h, whose synthesis has been previously described. We found that the lowest STS activities were measured in the presence of N‐phosphorylated derivatives 6e (0.1% of STS activity) and 6f (0.2% of STS activity). The measured STS activity in the presence of 667‐COUMATE (used as a reference) was 0.1%. Moreover, at concentrations up to 1 μM, the most active compounds (6e, 6f, 9b, and 9e) did not exert any toxic effects on zebrafish embryos.

3-Phenylcoumarins as a Privileged Scaffold in Medicinal Chemistry: The Landmarks of the Past Decade

“…Fluorinated-, 4-aminophenyl-N-phosphorylated-and N-thiophosphorylated-7-O-sulphamate-3-arylcoumarins (compounds 63, 64 and 65 respectively) have been studied by the same research group, showing more than 10 times higher inhibitory potency than coumarin-7-O-sulfamate as inhibitors of STS. Amongst the studied compounds, the most interesting proved to be compound 63, both displaying IC 50 values of 0.27 µM [148], a similar IC 50 of approximately 0.20 µM for the phosphorylated derivatives (compounds 64 and 65) [149,150]. Supported by molecular modelling techniques, fluorinated compound 66 has been designed, synthetized and then tested, proving to display an IC 50 of 0.18 µM against STS, and an IC 50 of 15.9 µM and 8.7 µM, respectively, against MCF-7 and hypotriploid human cells (T47D) [151].…”

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

“…The molecular docking studies indicated that sulphamate moieties in compounds 44 and 45 were located within the STS catalytic region, while phosphoroamidate groups were within a short distance of the Arg98 residue, suggesting the presence of additional stabilising interactions. When the phosphoroamidates were replaced with thiophosphoroamidates, the next group of STS inhibitors was obtained 85 . In this case, the activity of the most active compound 46 (Table 3) (IC 50 value of 200 nM) was comparable with derivatives 44 and 45 (when evaluated in an enzymatic assay).…”

Components of the human-specific, p53-mediated “kill switch” tumor suppression mechanism are usurped by human tumors, creating the possibility of therapeutic exploitation

“…Similar to OATPs, STS has become an active target for inhibitor synthesis, in an attempt to prevent circulating DHEAS from contributing to tumor growth [ 17 , 18 ] . As with OATPs, we propose an alternative strategy: using STS appropriated by various tumors to activate novel compounds to their tumoricidal forms [ 19 ] [Figure 2] .…”