Pre- and post-irradiation mild hyperthermia enabled by NIR-II for sensitizing radiotherapy

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Oncology

Background:

• Hypoxia-induced radioresistance limits cancer radiotherapy effectiveness.
• Tumor hypoxia, insufficient DNA damage, and DNA repair mechanisms impede treatment outcomes.

Purpose of the Study:

• To develop a dual-hyperthermia strategy to potentiate radiotherapy.
• To overcome hypoxia-induced radioresistance and prevent irradiation-induced DNA damage repair.

Main Methods:

• Utilized PEGylated nanobipyramids (PNBys) as photo-transducers for controlled near-infrared laser-induced hyperthermia.
• Administered mild hyperthermia (MHt) both before and after radiotherapy.
• Evaluated PNBys' photothermal properties, including extinction coefficient and conversion efficiency.

Main Results:

• PNBys demonstrated efficient photothermal conversion in the NIR-II window.
• Pre-radiotherapy MHt improved tumor oxygenation and blood perfusion, increasing radiotherapy sensitivity.
• Post-radiotherapy MHt inhibited DNA damage repair, enhancing overall antitumor effects.
• The combined pre- and post-MHt strategy with radiotherapy showed superior efficacy in a murine model.

Conclusions:

• The dual-hyperthermia strategy using PNBys effectively potentiates radiotherapy by addressing tumor hypoxia and DNA repair.
• This approach offers a promising new avenue for improving cancer treatment efficacy beyond conventional radiotherapy or simple hyperthermia combinations.