Structure-Based Design of Anticancer Prodrug PABA/NO

Area of Science:

• Biochemistry
• Enzymology
• Medicinal Chemistry

Background:

• Glutathione S-transferase (GST) enzymes are crucial for detoxification.
• GSTpi is overexpressed in various cancers, offering a target for selective therapies.
• GSTalpha is the predominant isoform in the human liver.

Purpose of the Study:

• To detail the structure-based design of PABA/NO, a prodrug targeting GSTpi.
• To investigate molecular modeling and enzymatic characterization for prodrug development.
• To achieve selective drug delivery to GSTpi-overexpressing cancer cells.

Main Methods:

• Structure-based drug design utilizing ground-state and transition-state information of GST isozymes.
• Molecular modeling to understand enzyme-substrate interactions.
• Enzymatic characterization to assess prodrug activity and selectivity.

Main Results:

• PABA/NO was designed through structural modifications guided by isozyme-specific active site conformations.
• The prodrug selectively releases cytotoxic nitric oxide in GSTpi-overexpressing cancer cells.
• PABA/NO demonstrated in vitro and in vivo anticancer activity comparable to cisplatin.

Conclusions:

• Structure-based design, informed by mechanistic and structural insights of GST isozymes, is effective for developing targeted prodrugs.
• PABA/NO represents a promising strategy for selective cancer therapy.
• Understanding isozyme-specific transition states is key for optimizing prodrug selectivity.