Structural Insight of the Anticancer Properties of Doxazosin on Overexpressing EGFR/HER2 Cell Lines

Abstract

The selective α1-adrenergic receptor antagonist doxazosin is used for the treatment of hypertension. More recently, an experimental report demonstrated that this compound exhibits antiproliferative activity in breast cancer cell lines with similar inhibitory activity to gefitinib, a selective inhibitor of EGFR in the active state (EGFRAC). This experimental study provided evidence that doxazosin can be employed as an anticancer compound, however, the structural basis for its inhibitory properties is poorly understood at the atomic level. To gain insight about this molecule, molecular dynamics (MD) simulation with the molecular mechanics generalized Born surface area (MMGBSA) approach was employed to explore the structural and energetic features that guide the inhibitory properties of doxazosin and gefitinib in overexpressing EGFR/HER2 cell lines. Our result suggest that doxazosin exerts its inhibitory properties in breast cancer cell lines by targeting EGFR/HER2 but mainly HER2 in the inactive state (HER2IN), whereas gefitinib by targeting mainly EGFRAC, in line with previous literature. Decomposition of the binding affinity into individual contributions of HER2IN-doxazosin and EGFRAC-gefitinib systems detected hot spot residues but also showed polar interactions of Met801/Met793 with the quinazoline ring of both compounds. Principal component (PC) analysis revealed that the molecular recognition of the HER2IN-doxazosin system was linked to conformational changes but EGFRAC-gefitinib was not.