Quinolyl-Based PGM Metallarectangles: Antiproliferative Activity, DNA and BSA Protein Interactions, and a Molecular Docking Perspective.

The increased success of small metal-containing molecules as pharmaceutical agents has prompted investigations into the pharmacological activity of a different class of metal-based compounds; supramolecular coordination complexes (SCCs). Such complexes have been extensively investigated for their anticancer activity, with many displaying activities comparable or superior to available clinical chemotherapeutic drugs. Here, we evaluated a series of quinoline-containing binuclear complexes and metallarectangles for their in vitro anticancer activity in the hormone receptor positive MCF-7 and triple negative MDA-MB-231 breast cancer cell lines. The preliminary cytotoxic screen, in the MCF-7 cell line, revealed that the ligand (7-chloro-4-(pyridin-4-yl)quinoline, L) and metallarectangle [{Ir(μ-Cl)(Cp*)}4 (μ-L)2 ](OTf)4 display superior activity to cisplatin, while [{Ru(p-cymene)}4 (μ-η2 -η2 -C2 O4 )2 (μ-L)2 ](OTf)4 was more potent than cisplatin in the triple-negative MDA-MD-231 cell line. Upon evaluation in a multidose screen, ligand L and metallarectangle [{Ir(μ-Cl)(Cp*)}4 (μ-L)2 ](OTf)4 displayed antiproliferative activity almost two-fold greater than cisplatin in the MCF-7 cell line, while [{Ru(p-cymene)}4 (μ-η2 -η2 -C2 O4 )2 (μ-L)2 ](OTf)4 was over two-times more active than cisplatin in the MDA-MB-231 cell line. Additionally, using the non-tumorigenic MCF-12 A breast epithelial cell line, the compounds demonstrate increased selectivity toward breast cancer cells over non-tumorigenic cells. Furthermore, investigations into the interactions of ligand L and selected complexes with calf thymus DNA (CT-DNA) and bovine serum albumin (BSA) indicate favourable binding.