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Small molecule proprotein convertase inhibitors for inhibition of embryo implantation.

Ho H, Singh H, Heng S, Nero TL, Paule S, Parker MW, Johnson AT, Jiao GS, Nie G - PLoS ONE (2013)

Bottom Line: Compound 1o is unique as it appears the most lipophilic among the five compounds.Our findings also highlight that human cell-based functional models are vital to complement the biochemical and in silico analyses in the selection of promising drug candidates.Further investigations for compound 1o are warranted in animal models to test its utility as an implantation-inhibiting contraceptive drug.

View Article: PubMed Central - PubMed

Affiliation: Prince Henry's Institute of Medical Research, Clayton, Victoria, Australia ; Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia.

ABSTRACT
Uterine proprotein convertase (PC) 6 plays a critical role in embryo implantation and is pivotal for pregnancy establishment. Inhibition of PC6 may provide a novel approach for the development of non-hormonal and female-controlled contraceptives. We investigated a class of five synthetic non-peptidic small molecule compounds that were previously reported as potent inhibitors of furin, another PC member. We examined (i) the potency of these compounds in inhibiting PC6 activity in vitro; (ii) their binding modes in the PC6 active site in silico; (iii) their efficacy in inhibiting PC6-dependent cellular processes essential for embryo implantation using human cell-based models. All five compounds showed potent inhibition of PC6 activity in vitro, and in silico docking demonstrated that these inhibitors could adopt a similar binding mode in the PC6 active site. However, when these compounds were tested for their inhibition of decidualization of primary human endometrial stromal cells, a PC6-dependent cellular process critical for embryo implantation, only one (compound 1o) showed potent inhibition. The lack of activity in the cell-based assay may reflect the inability of the compounds to penetrate the cell membrane. Because compound's lipophilicity is linked to cell penetration, a measurement of lipophilicity (logP) was calculated for each compound. Compound 1o is unique as it appears the most lipophilic among the five compounds. Compound 1o also inhibited another crucial PC6-dependent process, the attachment of human trophoblast spheroids to endometrial epithelial cells (a model for human embryo attachment). We thus identified compound 1o as a potent small molecule PC6 inhibitor with pharmaceutical potential to inhibit embryo implantation. Our findings also highlight that human cell-based functional models are vital to complement the biochemical and in silico analyses in the selection of promising drug candidates. Further investigations for compound 1o are warranted in animal models to test its utility as an implantation-inhibiting contraceptive drug.

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Related in: MedlinePlus

Inhibition of decidualization of HESCs.(A) Inhibition of decidualization by the five compounds at 10 µM using prolactin as the decidual marker. (B) Dose-dependent inhibition of decidualization by compound 1o using prolactin as the decidual marker. (C) Confirmation of decidualization inhibition by compound 1o with an additional decidual marker, IGFBP-1. The data are expressed as percentage reductions relative to control (no inhibitors). Each value represents mean ± SEM of three independent experiments. *P<0.05; **P<0.01
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pone-0081380-g004: Inhibition of decidualization of HESCs.(A) Inhibition of decidualization by the five compounds at 10 µM using prolactin as the decidual marker. (B) Dose-dependent inhibition of decidualization by compound 1o using prolactin as the decidual marker. (C) Confirmation of decidualization inhibition by compound 1o with an additional decidual marker, IGFBP-1. The data are expressed as percentage reductions relative to control (no inhibitors). Each value represents mean ± SEM of three independent experiments. *P<0.05; **P<0.01

Mentions: Decidualization of HESCs is a cellular process essential for embryo implantation. PC6 is critical for decidualization and blocking of PC6 activity inhibits the process [8], [25]. To determine whether the five compounds would also inhibit PC6-dependent decidualization, HESCs were cultured without (control) or with 10 µM of each compound in the presence of decidualizing stimuli [8]. Using prolactin as the decidual marker, of the five compounds, only compound 1o significantly inhibited decidualization, whereas the other four compounds had no effect (Figure 4A). Further experiments showed that compound 1o inhibited decidualization in a dose-dependent manner, inhibiting ∼60% at 1 µM, ∼80% at 5 µM and ∼85% at 10 µM (Figure 4B). Inhibition of decidualisation by compound 1o was also confirmed by a significant decrease in the level of an additional decidual marker, IGFBP-1 (Figure 4C).


Small molecule proprotein convertase inhibitors for inhibition of embryo implantation.

Ho H, Singh H, Heng S, Nero TL, Paule S, Parker MW, Johnson AT, Jiao GS, Nie G - PLoS ONE (2013)

Inhibition of decidualization of HESCs.(A) Inhibition of decidualization by the five compounds at 10 µM using prolactin as the decidual marker. (B) Dose-dependent inhibition of decidualization by compound 1o using prolactin as the decidual marker. (C) Confirmation of decidualization inhibition by compound 1o with an additional decidual marker, IGFBP-1. The data are expressed as percentage reductions relative to control (no inhibitors). Each value represents mean ± SEM of three independent experiments. *P<0.05; **P<0.01
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3852413&req=5

pone-0081380-g004: Inhibition of decidualization of HESCs.(A) Inhibition of decidualization by the five compounds at 10 µM using prolactin as the decidual marker. (B) Dose-dependent inhibition of decidualization by compound 1o using prolactin as the decidual marker. (C) Confirmation of decidualization inhibition by compound 1o with an additional decidual marker, IGFBP-1. The data are expressed as percentage reductions relative to control (no inhibitors). Each value represents mean ± SEM of three independent experiments. *P<0.05; **P<0.01
Mentions: Decidualization of HESCs is a cellular process essential for embryo implantation. PC6 is critical for decidualization and blocking of PC6 activity inhibits the process [8], [25]. To determine whether the five compounds would also inhibit PC6-dependent decidualization, HESCs were cultured without (control) or with 10 µM of each compound in the presence of decidualizing stimuli [8]. Using prolactin as the decidual marker, of the five compounds, only compound 1o significantly inhibited decidualization, whereas the other four compounds had no effect (Figure 4A). Further experiments showed that compound 1o inhibited decidualization in a dose-dependent manner, inhibiting ∼60% at 1 µM, ∼80% at 5 µM and ∼85% at 10 µM (Figure 4B). Inhibition of decidualisation by compound 1o was also confirmed by a significant decrease in the level of an additional decidual marker, IGFBP-1 (Figure 4C).

Bottom Line: Compound 1o is unique as it appears the most lipophilic among the five compounds.Our findings also highlight that human cell-based functional models are vital to complement the biochemical and in silico analyses in the selection of promising drug candidates.Further investigations for compound 1o are warranted in animal models to test its utility as an implantation-inhibiting contraceptive drug.

View Article: PubMed Central - PubMed

Affiliation: Prince Henry's Institute of Medical Research, Clayton, Victoria, Australia ; Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia.

ABSTRACT
Uterine proprotein convertase (PC) 6 plays a critical role in embryo implantation and is pivotal for pregnancy establishment. Inhibition of PC6 may provide a novel approach for the development of non-hormonal and female-controlled contraceptives. We investigated a class of five synthetic non-peptidic small molecule compounds that were previously reported as potent inhibitors of furin, another PC member. We examined (i) the potency of these compounds in inhibiting PC6 activity in vitro; (ii) their binding modes in the PC6 active site in silico; (iii) their efficacy in inhibiting PC6-dependent cellular processes essential for embryo implantation using human cell-based models. All five compounds showed potent inhibition of PC6 activity in vitro, and in silico docking demonstrated that these inhibitors could adopt a similar binding mode in the PC6 active site. However, when these compounds were tested for their inhibition of decidualization of primary human endometrial stromal cells, a PC6-dependent cellular process critical for embryo implantation, only one (compound 1o) showed potent inhibition. The lack of activity in the cell-based assay may reflect the inability of the compounds to penetrate the cell membrane. Because compound's lipophilicity is linked to cell penetration, a measurement of lipophilicity (logP) was calculated for each compound. Compound 1o is unique as it appears the most lipophilic among the five compounds. Compound 1o also inhibited another crucial PC6-dependent process, the attachment of human trophoblast spheroids to endometrial epithelial cells (a model for human embryo attachment). We thus identified compound 1o as a potent small molecule PC6 inhibitor with pharmaceutical potential to inhibit embryo implantation. Our findings also highlight that human cell-based functional models are vital to complement the biochemical and in silico analyses in the selection of promising drug candidates. Further investigations for compound 1o are warranted in animal models to test its utility as an implantation-inhibiting contraceptive drug.

Show MeSH
Related in: MedlinePlus