Synthesis, characterization and biological evaluation of a cobalt(II) complex with 5-chloro-8-hydroxyquinoline as anticancer agent.

A new cobalt(II) complex ( 1) of 5-chloro-8-hydroxyquinoline was prepared and structurally characterized using , electrospray ionization , elemental analysis, single-crystal X-ray diffraction as well as powder X-ray diffraction. Its biological activities including DNA binding and anticancer activity were investigated. The DNA binding study of complex 1 suggested that it interacted with calf thymus DNA mainly via an intercalative binding mode. The in vitro anticancer activity of complex 1 was screened against a series of tumor cell lines as well as the normal liver cell line HL-7702 using MTT assay. complex 1 showed much higher cytotoxicity than corresponding metal salt and ligand towards the five tested tumor cell lines, in which T-24 was the most sensitive tumor cell line towards 1, with IC50 value of 7.04 ± 0.06 μM. complex 1 was found to greatly induce cell cycle arrest in T-24 cells at S phase, and consequently to induce cell apoptosis in a dose-dependent mode suggested by cell apoptosis analysis via Hoechst 33258 and acridine orange/ethidium bromide staining assays. The cell apoptosis mechanism of 1 was studied targeting the mitochondrion-mediated pathway, since the apoptotic mechanism in the T-24 cells treated by 1 was investigated by (ROS) detection, intracellular calcium concentration measurement and caspase-9/3 activity assay. The results suggested that the cell apoptosis induced by 1 was closely related to the loss of mitochondrial membrane potential, ROS production and enhancement of intracellular [Ca2+], which would trigger the caspase-9/3 activation via a mitochondrial dysfunction pathway. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]