Influence of ligand coordination mode on DNA interaction and cytotoxic investigations of cyclometalated platinum(II) complexes with bisphosphine ligands

A series of cyclometalated platinum(II) complexes including [Pt(bhq)(dppm)]Cl ( C 1 ), [Pt(bhq)(dppa)]Cl ( C 2 ), [Pt 2 (Cl) 2 (ppy) 2 (μ-dppm)] ( D 1 ) and [Pt 2 (Cl) 2 (bhq) 2 (μ-dppa)] ( D 2 ) which ppy, dppm, dppa, and bhq are 2-phenylpyridinate, bis(diphenylphosphino)methane, bis(diphenylphosphino)amine and benzo[ h ]quinoline, respectively, were used to study their interactions with ct-DNA. The interaction mode and the binding properties of these platinum(II) complexes to ct-DNA, were investigated by common methods such as UV–vis absorption, the fluorescence quenching studies (incomplete quenching) with ethidium bromide and Hoechst 33258, viscosity measurement in physiological conditions, and molecular docking modeling. The results of these studies, suggest non/partial intercalative interaction or minor-groove binding with ct-DNA. In order to determine the potential antiproliferative and cytotoxic activity of four Pt(II) complexes with C^N/bisphosphine as the non-leaving groups, the MTT assay was carried out on breast adenocarcinoma (MCF-7), non-small cell lung carcinoma (A549), and mouse fibroblast (L-929) cell lines Platinum(II) cyclometallated complexes had potent cytotoxicity towards the A549 and MCF-7 cancer cells, with C 2 demonstrating effective cytotoxicity in both cancer cell lines. The cytotoxic effects of the Pt(II) complexes were further investigated through MTT assay, apoptosis evaluation, and cell cycle analysis to elucidate their anticancer potential.