Regulating the Tumor Microbiome through Near-Infrared-III Light-Excited Photosynthesis

Area of Science:

• Biomedical Engineering
• Cancer Therapy
• Microbiome Research

Background:

• Tumor microbiomes significantly influence cancer progression and metastasis.
• Targeting the tumor microbiome presents a promising therapeutic strategy.
• Tumor microenvironments often exhibit hypoxia, impacting treatment efficacy.

Purpose of the Study:

• To investigate a biohybrid system for regulating tumor microbiomes using 1550 nm light.
• To assess the potential of this biohybrid in inhibiting tumor growth and modulating the tumor microenvironment.
• To explore the immunomodulatory effects and long-lasting immune memory induced by the therapy.

Main Methods:

• Development of a biohybrid by arming microalga *Chlorella* with Er-based core-shell upconversion nanoparticles.
• Utilizing 1550 nm light excitation to trigger oxygenic photosynthesis in the biohybrid.
• Evaluating the biohybrid's effect on tumor hypoxia, microbiome composition, tumor growth, and immune response in vivo.

Main Results:

• The biohybrid successfully performed oxygenic photosynthesis under 1550 nm light, alleviating tumor hypoxia.
• Significant changes in the tumor microbiome were observed, leading to marked tumor growth inhibition.
• The therapy demonstrated efficacy against deep-seated tumors due to the penetration of 1550 nm light.
• Immune activation was observed, converting "cold" tumors to "hot" tumors and establishing immune memory.

Conclusions:

• The developed biohybrid offers a novel therapeutic strategy for cancer by regulating the tumor microbiome.
• This approach effectively inhibits tumor growth, particularly deep-seated tumors, through hypoxia alleviation and immune modulation.
• The therapy induces a potent and lasting anti-tumor immune response.