Engineered bacterium-metal-organic framework biohybrids for boosting radiotherapy with multiple effects.

Hypoxia and lactate-overexpressed tumor microenvironment always lead to poor therapeutic effect of radiotherapy. Here, platinum nanoparticles-embellished hafnium metal-organic framework (Hf-MOF-Pt NPs) were elaborately integrated with Shewanella oneidensis MR-1 (SO) to construct an engineered biohybrid platform (SO@Hf-MOF-Pt) for enhancing radiotherapy. Benefiting from the tumor-targeting and metabolic respiration characteristics of SO, SO@Hf-MOF-Pt could enrich in tumor sites and continuously metabolize the overexpressed lactate, which specifically downregulated the expression of hypoxia-inducible factor (HIF-1α), thereby relieving the radiosuppressive tumor microenvironment to some extent. Moreover, SO@Hf-MOF-Pt would react with tumor-overexpressed hydrogen peroxide (HO) to generate oxygen (O) and further inhibit the expression of HIF-1α, resulting in the downregulation of lactate dehydrogenase (LDHA) and subsequently reducing the lactate production. Under these multiple cascaded effects, the radiosuppressive tumor microenvironment was significantly reshaped, thus potentiating the radiosentization of SO@Hf-MOF-Pt and remarkably amplifying the therapeutic outcomes of radiotherapy. The designed biohybrid SO@Hf-MOF-Pt represented promising prospects in sensitizing radiotherapy via bacterium-based metabolic regulation.