Synthesis and in vitro biological evaluation of three 4′-(4-methoxyphenyl)-2,2′:6′,2″-terpyridine iridium(III) complexes as new telomerase inhibitors

• Published in: European journal of medicinal chemistry 2018-01, Vol.143, p.1387-1395
• Main Authors: Qin, Qi-Pin, Meng, Ting, Tan, Ming-Xiong, Liu, Yan-Cheng, Luo, Xu-Jian, Zou, Bi-Qun, Liang, Hong
• Format: Article
• Language: English
• Subjects: 4′-substituted-2,2′:6′,2″-terpyridine; Antitumor activity; Cell apoptosis; Iridium(III) complexes; Telomerase activity
• ISSN: 0223-5234; 1768-3254
• DOI: 10.1016/j.ejmech.2017.10.035

There iridium(III) complexes, [Ir(3-MeO-Phtpy)Cl3] (1), [Ir(2-MeO-Phtpy)Cl3] (2) and [Ir(4-MeO-Phtpy)Cl3] (3) with 4′-(3-methoxyphenyl)-2,2′:6′,2″-terpyridine (3-MeO-Phtpy), 4′-(2-methoxyphenyl)-2,2′:6′,2″-terpyridine (2-MeO-Phtpy) and 4′-(4-methoxyphenyl)-2,2′:6′,2″-terpyridine (4-MeO-Phtpy) as ligands, respectively, were synthesized and evaluated for their antiproliferative activities. In these complexes, the iridium(III) center adopts a six-coordinate distorted octahedral geometry. Among them, complex 1 exhibited the most potent activity, with IC50 values of 3.19–27.77 μM against four cancer cell lines (BEL-7404, Hep-G2, NCI-H460 and MGC80-3 cells). Cellular mechanism studies suggested that complexes 1–3 directly targeted c-myc promoter elements and inhibited the telomerase activity. In addition, complexes 1–3 may trigger cell apoptosis via a mitochondrial dysfunction pathway. We postulated that the difference in the in vitro antitumor activities of complexes 1–3 is mainly dependent on the position of the methoxy group on the phenyl ring of the iridium ligand. 1–3 directly targeted c-myc promoter elements and inhibited the telomerase activity. In addition, 1–3 may trigger cell apoptosis via a mitochondrial dysfunction pathway. [Display omitted] •There iridium(III) complexes with terpyridine ligands were synthesized and characterized.•Complexes 1–3 directly targeted c-myc promoter elements and inhibited the telomerase activity.•1–3 may trigger cell apoptosis via a mitochondrial dysfunction pathway.