Exploring anticancer efficiency of mitochondria-targeted cyclometalated iridium(III) complexes

Abstract We prepared and characterized new iridium(III) complexes: [Ir(N C)2(MPPIP)](PF6) (N-C = 2-phenylpyridine 1a; benzo[h]quinolone 1b; 1-phenylisoquinolone, 1c, MPPIP = 2-(4-(4′-methylpiperazin-yl)phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline). MTT (MTT = 3-(4,5-dimethylthiazole-2-yl)-2,5-biphenyl tetrazolium bromide) method was used to assay anticancer activities of the complexes 1a-1c toward SGC-7901, HeLa, A549, BEL-7402, mouse embryonic fibroblast NIH3T3 cell lines. Complexes 1a, 1b, 1c are sensitive to A549 cells and display a relatively low IC50 value of 5.4 ± 0.3, 4.2 ± 0.03 and 3.8 ± 0.2 μM, respectively. The apoptotic efficiency was investigated and the number of apoptotic cells induced by 1a, 1b and 1c is 9.92%, 11.30% and 16.00%. The complexes are able to increase intracellular ROS content and lessen the mitochondrial membrane potential. Besides, anti-tumor activity in vivo reveals that complex 1c exhibits moderate effect on inhibiting the tumor growth, and complex 1c has no influence on liver, brain, kidney, lung and heart.