Verbenone-Based Selenophene Derivatives as Potential Anti-cancer Agents: Synthesis and Biological Evaluation in 2D and 3D A549 Cell Models

Abstract

Natural-product-inspired scaffolds remain a valuable source of novel anticancer agents. In this study, a series of verbenone-selenophene hybrids (2A-2U) were rationally designed. Their antiproliferative activities were evaluated in vitro against human cancer cells, with A549 non-small cell lung cancer cells as the primary model and LO2 normal hepatic cells as a reference for toxicity. Structure-activity relationship analysis revealed that both the electronic nature and positional pattern of aryl substituents strongly influenced potency: ortho-substituted derivatives and parabromo substitution conferred the greatest activity, identifying compound 2R (4-Br) as the most promising hit (IC₅₀ ≈ 9 μM in A549 cells) with relatively low toxicity toward LO2 cells. Mechanistic studies demonstrated that 2R significantly inhibited A549 cell proliferation by inducing a marked, concentration-dependent G0/G1 cell-cycle arrest and promoting apoptotic cell death. Furthermore, 2R caused a pronounced loss of mitochondrial membrane potential (ΔΨm) and triggered a concentration-dependent accumulation of intracellular reactive oxygen species (ROS). In addition, target prediction and molecular docking analysis suggested that 2OBJ and 2WD9 as putative molecular targets. In a three-dimensional tumor spheroid model, 2R effectively penetrated the spheroids and induced robust cell death in a dose-dependent manner. Collectively, these findings indicate that verbenone-selenophene derivative 2R represents a promising lead for further development as a novel anticancer candidate.