Synthesis of a platinum(II) complex with 2-(4-methoxy-phenyl) imidazo [4,5-f]-[1,10] phenanthrolin and study of its antitumor activity

•One platinum(II) complex with phenanthrolin derivative was synthesized.•The platinum(II) complex exhibited selective cytotoxicity toward tumor cells.•Its antitumor activity was achieved via inhibiting telomerase activity.•Its mechanism is interaction c-myc quadruplex and activation of caspase-3/9.

A new platinum(II) complex of [PtII(L) (pn)]Cl·2H2O (1) (pn = 1,3-propanediamine) with 2-(4-methoxy-phenyl)imidazo [4,5-f]-[1,10]phenanthrolin (H-L) was synthesized and characterized. In complex 1, the platinum adopts a four-coordinated square planar geometry. Complex 1 exhibited selective cytotoxicity against NCI–H460, BEL-7402, SK-OV-3, SK-OV-3/DDP and HeLa cell lines with IC50 values in the micromolar range (9.7–35.8 μM), but low cytotoxicity toward normal human liver HL-7702 cells. Complex 1 caused HeLa cell cycle arrest at S phase and it induced HeLa apoptosis by the activation of caspase-3/9. Various experiments showed that complex 1 preferred to bind with G-quadruplex in c-myc. Taken together, we found that complex 1 exerted its antitumor activity mainly via inhibiting telomerase by interaction with c-myc quadruplex and activation of caspase-3/9.

Graphical abstractOne platinum(II) complex with phenanthrolin derivative was synthesized. It exhibited selective cytotoxicity toward tumor cells achieved via inhibiting telomerase activity by interaction c-myc quadruplex and activation of caspase-3/9.Figure optionsDownload full-size imageDownload as PowerPoint slide