Improving the Therapeutic Efficiency of Hypoxic-Activated Prodrugs by Enhancing Hypoxia in Solid Tumors.

The low sensitivity of hypoxic regions in solid tumors to radiotherapy and chemotherapy remains a major obstacle to cancer treatment. By taking advantage of hypoxic-activated prodrugs, tirapazamine (TPZ), generating cytotoxic reductive products and the glucose oxidase (GO _x )-based glucose oxidation reaction, we designed a nanodrug-loading system that combined TPZ-induced chemotherapy with GO _x -mediated cancer-orchestrated starvation therapy and cancer oxidation therapy. In this work, we first prepared mesoporous silica (MSN) loaded with TPZ. Then, in order to prevent the leakage of TPZ in advance, the surface was coated with a layer of carMOF formed by Fe ³⁺ and carbenicillin (car), and GO _x was adsorbed on the outermost layer to form the final nanosystem MSN-TPZ@carMOF-GO _x (MT@c-G). GO _x could effectively consume oxygen and catalyzed glucose into gluconic acid and hydrogen peroxide. First, the generated gluconic acid lowered the pH of tumor tissues, promoted the decomposition of carMOF, and released TPZ. Second, oxygen consumption could improve the degree of hypoxia in tumor tissues, so that enhanced the activity of TPZ. Furthermore, GO _x could generate cancer-orchestrated starvation/oxidation therapy. Therefore, our study provided a new strategy that TPZ combined with GO _x achieved starvation/oxidation/chemotherapy for enhancing anticancer effects in hypoxic regions.