Synthesis, characterization and the anticancer activity of six lanthanides(III) complexes with 5,7-dihalogenated-8-quinolinol and 2,2′-bipyridine derivatives

Six new lanthanide(III) complexes, namely [Gd-III(QL1)(3)(BL1)] (Gd1), [Gd-III(QL1)(3)(BL2)] (Gd2), [Lu-III(QL2)(2)(BL3)(NO3)] (Lu1), [Lu-III(QL2)(2)(BL2)(NO3)] (Lu2), [Yb-III(QL3)(2)(BL2)(NO3)] (Yb1), and [Yb-III(QL4)(2)(BL2)(NO3)] (Yb2) coordinated with 5,7-dibromo-8-quinolinol (H-QL1), 5,5 '-dimethyl-2,2 '-bipyridyl (BL1), 4,4 '-di-tert-butyl-2,2 '-bipyridine (BL2), 5,7-dibromo-2-methylquinolin-8-ol (H-QL2), 2,2 '-bipyridine (BL3), 5,7-dichloro-8-hydroxyquinoline (H-QL3), and 5,7-dichloro-8-hydroxy-2-methylquinoline (H-QL4), were prepared. The Ln(III)complexesGd1,Gd2,Lu1,Lu2,Yb1andYb2showed high cytotoxicity toward cervical (HeLa), ovarian (SK-OV-3) and lung (NCI-H460) cancer cells with IC(50)values from 0.18 +/- 0.14 to 8.02 +/- 1.71 mu M. In addition,Yb1andYb2impaired mitochondrial functions, decreased mitochondrial membrane potential, and altered the levels of mitochondrial related-proteins. The apoptosis-inducing capability was in the order ofYb2 > Yb1. Such observed differences in biological activities could be caused by the electronic effect of the methyl group of H-QL4 inYb2.