Mixed‐Ligand Mononuclear Copper(II) Complex: Crystal Structure and Anticancer Activity

A novel copper(II) complex with mixed ligands including β‐(3‐formyl‐5‐methyl‐2‐hydroxy‐benzylidene)amino]propionic acid anion and 1,10′‐phenanthroline was synthesized, and its crystal structure was thoroughly characterized. It exerted excellent inducing apoptosis, anti‐angiogenesis and antiproliferative properties in vitro. The complex can bind human serum albumin (HSA) at physiological pH conditions. Remarkably, it can induce formation of the mixed parallel/antiparallel G‐quadruplex structures in the G‐rich sequence of the proximal vascular endothelial growth factor (VEGF) promoter, and stabilize these G‐quadruplex structures, which provide an opportunity for anti‐angiogenesis chemotherapeutics. Furthermore, the complex showed a strong uptake, and exhibited multiple anticancer functions by inhibiting the expression of p‐Akt and p‐Erk1/2 proteins and by upregulating the levels of reactive oxygen species (ROS). Because of the reported results, this new copper(II) complex qualifies itself as a potential anticancer drug candidate.