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Discovery of novel aromatase inhibitors using a homogeneous time-resolved fluorescence assay.

Ji JZ, Lao KJ, Hu J, Pang T, Jiang ZZ, Yuan HL, Miao JS, Chen X, Ning SS, Xiang H, Guo YM, Yan M, Zhang LY - Acta Pharmacol. Sin. (2014)

Bottom Line: Among the 7000 compounds, 4 hits (XHN22, XHN26, XHN27 and triptoquinone A) were found to inhibit aromatase with IC50 values of 1.60±0.07, 2.76±0.24, 0.81±0.08 and 45.8±11.3 μmol /L, respectively.Moreover, the most potent hit XHN27 at 10 and 50 μmol/L inhibited the proliferation of T47D cells by 45.3% and 35.2%, respectively.The docking study revealed that XHN27 docked within the active site of aromatase and might form a hydrogen bond and had a π-cation interaction with amino acid residues of the protein.

View Article: PubMed Central - PubMed

Affiliation: Jiangsu Center for Drug Screening, China Pharmaceutical University, Nanjing 210009, China.

ABSTRACT

Aim: Aromatase is an important target for drugs to treat hormone-dependent diseases, including breast cancer. The aim of this study was to develop a homogeneous time-resolved fluorescence (HTRF) aromatase assay suitable for high-throughput screening (HTS).

Methods: A 384-well aromatase HTRF assay was established, and used to screen about 7000 compounds from a compound library. Anti-proliferation activity of the hit was evaluated using alamarBlue(R) assay in a hormone-dependent breast cancer cell line T47D. Molecular docking was conducted to elucidate the binding mode of the hit using the Discovery Studio program.

Results: The Z' value and signal to background (S/B) ratio were 0.74 and 5.4, respectively. Among the 7000 compounds, 4 hits (XHN22, XHN26, XHN27 and triptoquinone A) were found to inhibit aromatase with IC50 values of 1.60±0.07, 2.76±0.24, 0.81±0.08 and 45.8±11.3 μmol /L, respectively. The hits XHN22, XHN26 and XHN27 shared the same chemical scaffold of 4-imidazolyl quinoline. Moreover, the most potent hit XHN27 at 10 and 50 μmol/L inhibited the proliferation of T47D cells by 45.3% and 35.2%, respectively. The docking study revealed that XHN27 docked within the active site of aromatase and might form a hydrogen bond and had a π-cation interaction with amino acid residues of the protein.

Conclusion: XHN27, an imidazolyl quinoline derivative of flavonoid, is a potent aromatase inhibitor with anti-proliferation activity against breast cancer in vitro. The established assay can be used in HTS for discovering novel aromatase inhibitor.

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Related in: MedlinePlus

π–π stacking interactions of the compounds letrozole (A), BCA (B), and XHN27 (C) with the side chains of amino acid residues of aromatase.
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fig8: π–π stacking interactions of the compounds letrozole (A), BCA (B), and XHN27 (C) with the side chains of amino acid residues of aromatase.

Mentions: The 22-nitrile and 20-nitrile of letrozole form two hydrogen bonds with the hydroxyl of Ser 478 and the amide of Met 374, respectively (Figure 7A). Unlike the binding mode of Δ4A with the Fe atom of the heme group, the triazole of letrozole forms a π–π stacking interaction with the porphyrin ring and a π-cation interaction with the Fe atom (Figure 8A), which may explain its affinity for the enzyme. Furthermore, one of the benzonitrile groups extended into the access channel that links the active site to the outer surface. Thus, letrozole would tightly bind in the pocket instead of Δ4A.


Discovery of novel aromatase inhibitors using a homogeneous time-resolved fluorescence assay.

Ji JZ, Lao KJ, Hu J, Pang T, Jiang ZZ, Yuan HL, Miao JS, Chen X, Ning SS, Xiang H, Guo YM, Yan M, Zhang LY - Acta Pharmacol. Sin. (2014)

π–π stacking interactions of the compounds letrozole (A), BCA (B), and XHN27 (C) with the side chains of amino acid residues of aromatase.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4125720&req=5

fig8: π–π stacking interactions of the compounds letrozole (A), BCA (B), and XHN27 (C) with the side chains of amino acid residues of aromatase.
Mentions: The 22-nitrile and 20-nitrile of letrozole form two hydrogen bonds with the hydroxyl of Ser 478 and the amide of Met 374, respectively (Figure 7A). Unlike the binding mode of Δ4A with the Fe atom of the heme group, the triazole of letrozole forms a π–π stacking interaction with the porphyrin ring and a π-cation interaction with the Fe atom (Figure 8A), which may explain its affinity for the enzyme. Furthermore, one of the benzonitrile groups extended into the access channel that links the active site to the outer surface. Thus, letrozole would tightly bind in the pocket instead of Δ4A.

Bottom Line: Among the 7000 compounds, 4 hits (XHN22, XHN26, XHN27 and triptoquinone A) were found to inhibit aromatase with IC50 values of 1.60±0.07, 2.76±0.24, 0.81±0.08 and 45.8±11.3 μmol /L, respectively.Moreover, the most potent hit XHN27 at 10 and 50 μmol/L inhibited the proliferation of T47D cells by 45.3% and 35.2%, respectively.The docking study revealed that XHN27 docked within the active site of aromatase and might form a hydrogen bond and had a π-cation interaction with amino acid residues of the protein.

View Article: PubMed Central - PubMed

Affiliation: Jiangsu Center for Drug Screening, China Pharmaceutical University, Nanjing 210009, China.

ABSTRACT

Aim: Aromatase is an important target for drugs to treat hormone-dependent diseases, including breast cancer. The aim of this study was to develop a homogeneous time-resolved fluorescence (HTRF) aromatase assay suitable for high-throughput screening (HTS).

Methods: A 384-well aromatase HTRF assay was established, and used to screen about 7000 compounds from a compound library. Anti-proliferation activity of the hit was evaluated using alamarBlue(R) assay in a hormone-dependent breast cancer cell line T47D. Molecular docking was conducted to elucidate the binding mode of the hit using the Discovery Studio program.

Results: The Z' value and signal to background (S/B) ratio were 0.74 and 5.4, respectively. Among the 7000 compounds, 4 hits (XHN22, XHN26, XHN27 and triptoquinone A) were found to inhibit aromatase with IC50 values of 1.60±0.07, 2.76±0.24, 0.81±0.08 and 45.8±11.3 μmol /L, respectively. The hits XHN22, XHN26 and XHN27 shared the same chemical scaffold of 4-imidazolyl quinoline. Moreover, the most potent hit XHN27 at 10 and 50 μmol/L inhibited the proliferation of T47D cells by 45.3% and 35.2%, respectively. The docking study revealed that XHN27 docked within the active site of aromatase and might form a hydrogen bond and had a π-cation interaction with amino acid residues of the protein.

Conclusion: XHN27, an imidazolyl quinoline derivative of flavonoid, is a potent aromatase inhibitor with anti-proliferation activity against breast cancer in vitro. The established assay can be used in HTS for discovering novel aromatase inhibitor.

Show MeSH
Related in: MedlinePlus