Anticancer effect of organotin complexes derived from 2,6-naphthalenedicarboxylic acid by enhancing the ROS generation

Abstract

Enhancing ROS generation is crucial for anti-metastasis and anti-proliferation effects in anticancer chemotherapeutics. Herein, five organotin complexes [(Ph3Sn)2L] (1) [(R3Sn)2L]n (R = Et 2, R = n-Bu 3), [(n-Bu3Sn)2L(4,4′-bpe)]n (4), [(n-Bu3Sn)2L(4,4′-bipy)]n (5) were synthesized based on appropriate organotin precursors, 2,6-naphthalenedicarboxylic acid (H2L) and auxiliary ligand (4,4′-bipy = 4,4′-bipyridine, 4,4′-bpe = 1,2-di(4-pyridyl)ethylene). It was found that complex 1 exhibits a tetra-coordinated monomeric structure, complexes 2 and 3 show the 2D coordination polymer, and complexes 4 and 5 display the 1D chain with the central tin atoms as all penta-coordinated. These complexes showed high anti-tumor activity in vitro against four cancer cells (A549, HCT116, HepG-2 and HeLa), with IC50 values changed from 0.34±0.01 μM to 25.54 ± 1.55 μM. Additionally, complex 1 could be effective in inhibiting HepG-2 cell migration. Simultaneously, anticancer mechanism studies show that complex 1 induces excessive ROS production in HepG-2 cells, which in turn leads to the occurrence of ROS-induced downstream events, followed by the disintegration of the redox balance, depolarization of mitochondrial membrane potential, nucleus damage and ultimately apoptosis. This work suggests that enhancing the ability of organotin complexes to generate reactive oxygen species and disrupt intracellular redox balance may be a promising anticancer strategy.