Photosynthetic microorganisms coupled photodynamic therapy for enhanced antitumor immune effect.

Wang, Haoran; Liu, Honghui; Guo, Yunfei; Zai, Wenjing; Li, Xianghui; Xiong, Wei; Zhao, Xiaozhi; Yao, Yingfang et al. · Bioact Mater · 2022

basic_science · Level V

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Abstract

The ideal photodynamic therapy (PDT) should effectively remove the primary tumor, and produce a stronger immune memory effect to inhibit the tumor recurrence and tumor metastasis. However, limited by the hypoxic and immunosuppressive microenvironment, the PDT efficiency is apparently low. Here, <i>Chlorella (Chl.)</i> is exploited to enhance local effect by producing oxygen to reverse hypoxia, and release adjuvants to reverse immunosuppressive microenvironment to enhance abscopal effect afterwards. Results from different animal models indicated that <i>Chl.</i> could enhance local effect and PDT related immune response. Ultimately, <i>Chl.</i> coupled PDT elicited anti-tumor effects toward established primary tumors (inhibition rate: 90%) and abscopal tumors (75%), controlled the challenged tumors (100%) and alleviated metastatic tumors (90%). This <i>Chl.</i> coupled PDT strategy can also produce a stronger anti-tumor immune memory effect. Overall, this <i>Chl.</i> coupled PDT strategy generates enhanced local tumor killing, boosts PDT-induced immune responses and promotes anti-tumor immune memory effect, which may be a great progress for realizing systemic effect of PDT.