H₂S-Releasing Polymer Micelles for Studying Selective Cell Toxicity

Area of Science:

• Biomaterials Science
• Chemical Biology
• Cancer Research

Background:

• Hydrogen sulfide (H2S) is a gasotransmitter with significant physiological roles.
• Controlled H2S delivery is challenging due to rapid release from inorganic sources, leading to conflicting data on its effects.
• Amphiphilic block copolymers offer a platform for controlled drug delivery.

Purpose of the Study:

• To synthesize and characterize S-aroylthiooxime (SATO) functionalized amphiphilic block copolymer micelles for sustained H2S release.
• To investigate the H2S release kinetics from SATO micelles in response to cysteine.
• To compare the cellular cytotoxicity of sustained H2S release from micelles versus single-dose H2S administration in colon cancer cells.

Main Methods:

• Preparation and characterization of SATO-functionalized amphiphilic block copolymer micelles.
• Kinetics study of H2S release from micelles triggered by cysteine.
• In vitro cytotoxicity assays using HCT116 colon cancer cells and NIH/3T3 fibroblasts.
• Comparison of cellular responses to micelles, Na2S, GYY4137, and small molecule SATO.

Main Results:

• SATO-functionalized micelles demonstrated sustained H2S release with a half-life of 3.3 hours.
• The micelles significantly reduced the survival of HCT116 colon cancer cells.
• Cancer cell death was more pronounced with sustained H2S release from micelles compared to single-dose Na2S or GYY4137.
• SATO micelles showed selective toxicity towards cancer cells, with minimal impact on normal fibroblasts.

Conclusions:

• SATO-functionalized micelles provide a promising platform for controlled H2S delivery.
• Sustained H2S release kinetics are critical for enhancing anticancer efficacy.
• This approach offers potential for selective cancer therapy with reduced side effects.