Protein binding and anticancer activity of two newly synthesized Schiff base platinum (II) complexes: A theoretical and experimental study

Platinum-based complexes are effective chemotherapeutics which are applied in chemotherapy regimens to treat cancer. The present study is designed to investigate the interaction of new Schiff base-platinum complexes named Pt-246 and Pt-247 with human serum albumin (HSA) via spectroscopy techniques, molecular docking studies, and molecular dynamics (MD) simulations. Also, the toxicity effects of platinum complexes were studied on two cancer cell lines, HCT116 and MCF7 by MTT assay. The thermodynamic characteristics of the interaction between Pt-complexes and HSA were examined through fluorescence spectroscopy. According to the fluorescence analysis, the quenching mechanisms of Pt-246 and Pt-247 with HSA can be attributed to the dynamic model. Circular dichroism (CD) spectroscopy results indicated that the ordered secondary structure of HSA can be altered by the Pt-complexes. According to the docking study, the main interactions of Pt-246 and Pt-247 complexes with HSA were van der Waals, as well as hydrophobic and hydrogen bonding interactions. MD simulations revealed that the main interactions between HSA protein and ligands can be attributed to van der Waals forces. The Coulomb energy in HSA:Pt-247 was almost twice as large as in HSA:Pt-246, indicating that Pt-247 formed a far more stable complex. The IC50 values of Pt-246-treated MCF7 and HCT116 cell lines were determined 58.52 & PLUSMN; 1.19 (P-value 0.0001) and 42.68 & PLUSMN; 1.6 (P-value 0.054), respectively. On the other hand, the IC50 values of Pt247-treated MCF7 and HCT116 cell lines were calculated 52.98 & PLUSMN; 3.2 (P-value 0.038) and 31.7 & PLUSMN; 1 (P-value 0.001), respectively. The current study concluded that Schiff base ligands can be employed in designing potential Pt-based complexes as therapeutic products with anti-cancer activities.

Automated summary

The present study investigated the interaction of new Schiff base-platinum complexes with human serum albumin and their toxicity effects on cancer cell lines. Fluorescence and circular dichroism spectroscopy revealed the quenching mechanisms and structural changes of the albumin caused by the complexes. Molecular docking and molecular dynamics simulations identified the main interactions between the complexes and albumin. The IC50 values of the complexes on the cancer cell lines demonstrated their anti-cancer activities.