Glutathione depletion and dual-model oxygen balance disruption for photodynamic therapy enhancement

Area of Science:

• Biomedical Engineering
• Nanomedicine
• Photodynamic Therapy

Background:

• Tumor microenvironment presents challenges to photodynamic therapy (PDT) due to hypoxia and high glutathione (GSH) levels.
• These factors limit the generation of cytotoxic singlet oxygen (¹O₂) and overall PDT effectiveness.
• Developing strategies to overcome these limitations is crucial for advancing PDT in cancer treatment.

Purpose of the Study:

• To design and evaluate a dual-strategy approach for enhancing PDT efficacy.
• To address tumor hypoxia and reduce GSH levels using perfluorocarbon nanoliposomes (FI@Lip) and S-nitrosated human serum albumin (HSA-SNO).
• To investigate the synergistic effects of oxygen supply and GSH depletion on ¹O₂ generation and therapeutic outcome.

Main Methods:

• Development of perfluorocarbon nanoliposomes (FI@Lip) for oxygen delivery.
• Co-formulation with S-nitrosated human serum albumin (HSA-SNO) as a biocompatible nitric oxide donor and GSH scavenger.
• In vitro assessment of oxygen release, GSH depletion, nitric oxide generation, and ¹O₂ production under near-infrared (NIR) laser irradiation.
• Evaluation of the combined system's impact on intracellular hypoxia and PDT-induced cytotoxicity.

Main Results:

• FI@Lip effectively dissolved oxygen, enhancing ¹O₂ generation upon NIR irradiation.
• HSA-SNO co-delivery led to significant GSH depletion, restoring ¹O₂ levels and releasing NO.
• The combined FI@Lip and HSA-SNO strategy effectively alleviated intracellular hypoxia and decreased GSH, leading to increased ¹O₂ production and enhanced PDT effects.
• Nitric oxide release inhibited mitochondrial respiration, further contributing to tumor cell damage.

Conclusions:

• The combination of FI@Lip and HSA-SNO presents a promising synergistic strategy to overcome tumor microenvironment barriers in PDT.
• This approach enhances ¹O₂ generation by addressing hypoxia and depleting GSH, while NO release adds a complementary anti-tumor mechanism.
• The findings offer valuable insights for designing next-generation PDT strategies with improved clinical potential.