Structure-activity relationships and docking studies of synthetic 2-arylindole derivatives determined with aromatase and quinone reductase 1

摘要

In our ongoing effort of discovering anticancer and chemopreventive agents, a series of 2-arylindole derivatives were synthesized and evaluated toward aromatase and quinone reductase 1 (QR1). Biological evaluation revealed that several compounds (e.g., >2d, IC50 = 1.61 μM; >21, IC50 = 3.05 μM; and >27, IC50 = 3.34 μM) showed aromatase inhibitory activity with half maximal inhibitory concentration (IC50) values in the low micromolar concentrations. With regard to the QR1 induction activity, >11 exhibited the highest QR1 induction ratio (IR) with a low concentration to double activity (CD) value (IR = 8.34, CD = 2.75 μM), while >7 showed the most potent CD value of 1.12 μM. A dual acting compound >24 showed aromatase inhibition (IC50 = 9.00 μM) as well as QR1 induction (CD = 5.76 μM) activities. Computational docking studies using CDOCKER (Discovery Studio 3.5) provided insight in regard to the potential binding modes of 2-arylindoles within the aromatase active site. Predominantly, the 2-arylindoles preferred binding with the 2-aryl group toward a small hydrophobic pocket within the active site. The C-5 electron withdrawing group on indole was predicted to have an important role and formed a hydrogen bond with Ser478 (OH). Alternatively, meta-pyridyl analogs may orient with the pyridyl 3′-nitrogen coordinating with the heme group.