Inner and outer complexes of Pt-coordination compounds with DNA probed by SERS spectroscopy

Area of Science:

• Biophysical Chemistry
• Molecular Biology
• Materials Science

Background:

• Platinum-based compounds are crucial in cancer chemotherapy.
• Understanding platinum-DNA interactions is key to developing more effective treatments.
• Surface-enhanced Raman scattering (SERS) offers high sensitivity for molecular studies.

Purpose of the Study:

• To investigate the interfacial behavior of DNA modified by platinum coordination compounds using SERS.
• To differentiate the binding modes of antitumoral active and inactive platinum complexes with DNA.
• To correlate stereochemical configurations with biological activity.

Main Methods:

• Utilized SERS spectroscopy to analyze DNA-platinum adducts.
• Studied the adsorption behavior of DNA modified by cis-diamminedichloroplatinum(II) (cis-DDP) and [Pt(dien)Cl]Cl.
• Compared the interfacial interactions of two distinct platinum coordination compounds.

Main Results:

• Observed different adsorption behaviors for DNA modified by cis-DDP and [Pt-(dien)Cl]Cl.
• Deduced two stereochemical configurations of platinum-DNA complexes based on adsorption patterns.
• cis-DDP, an active anticancer agent, favors inner complex formation with DNA.
• [Pt-(dien)Cl]Cl, an inactive compound, forms an outer complex with DNA.

Conclusions:

• SERS spectroscopy effectively distinguishes between different platinum-DNA complex configurations.
• The binding mode (inner vs. outer complex) correlates with the antitumoral activity of platinum compounds.
• These findings provide insights into the mechanism of action for platinum-based anticancer drugs.