China has developed nano-enzymes for the treatment of tumors
- May 05, 2018 -

A few days ago, Nature Communications magazine published the latest research results on the nanoparticle-catalyzed treatment of tumors, which was jointly completed by the Gaolizeng Group of the School of Medicine of Yangzhou University and the research group of the Institute of Biophysics of the Chinese Academy of Sciences. This study demonstrates for the first time that by regulating the in vivo activity of the nanozyme multi-enzyme system, tumor metabolites can be catalyzed as toxic substances, enabling specific killing of tumors. According to reports, this research is the first time that nanozymes are used directly in tumor therapy.

The research team designed a new type of carbon-nitrogen nano-enzymes with multiple enzymatic activities and used ferritin navigation to achieve precise delivery of nano-enzymes and regulation of enzymatic activity in vivo. It uses tumor-specific metabolites to exert specificity on tumors. The effective killing effect establishes a new strategy of nano-enzyme targeted catalysis for tumor treatment, providing new ideas and techniques for cancer treatment.

According to reports, tumor metabolism has different characteristics from normal cells, and how to use tumor metabolites to develop a therapeutic strategy that “does one's way, but also makes it happen” is a new field of cancer biological therapy. Since hydrogen peroxide can be catalyzed by peroxidase to generate cytotoxic free radicals, peroxidases are expected to develop new drugs for tumors. However, natural enzymes tend to have poor stability and are easily inactivated in a complex in vivo environment, and their use is limited. The researchers in this work have taken a different path and explored the application of nanozymes with both enzyme catalytic activity and nanomaterial stability in this strategy.

The researchers first designed and synthesized novel nanozymes with four enzymes: oxidase, peroxidase, catalase and superoxide dismutase. This multienzyme activity of nanozymes is achieved by doping nitrogen into the mesoporous carbon spheres. How to accurately deliver the nanozyme to tumor cells and specifically activate the oxidase and peroxidase activities that produce active oxygen free radicals is the key to determine whether carbon nanospheres can be applied to tumor treatment.

The researchers used ferritin to modify the novel carbon-nitrogen nanozymes and verified that ferritin-modified carbon-nitrogen nanozymes can specifically recognize tumor cells and locate them in lysosomes that have an acidic environment inside tumor cells. Oxidase and peroxidase are specifically activated, which catalyzes the production of highly toxic reactive oxygen species by oxygen and hydrogen peroxide in tumors, thereby achieving specific killing of tumor cells. Animal tumor-bearing experiments showed that ferritin-carbon-nitrogen nanozyme can significantly inhibit tumor growth.