While radiotherapy (RT) is commonly used in clinics for cancer treatment, the therapeutic efficiency is not satisfactory owing to the existence of the hypoxic tumor microenvironment which seriously affects the efficiency of RT. Herein, we design polyethylene glycol (PEG)-modified reduced nano-graphene oxide-manganese dioxide (rGO-MnO-PEG) nanocomposites to trigger oxygen generation from HO to reduce the tumor hypoxic microenvironments. We use the radioisotope, I labeled rGO-MnO-PEG nanocomposites as therapeutic agents for in vivo tumor radioisotope therapy (RIT), achieving excellent tumor killing and further enhancing the therapeutic efficiency of RIT. More importantly, the dissolution of MnO under acidic conditions and the redox process during the catalytic pathway of HO decomposition in the cellular microenvironment direct to the production of an enormous amount of Mn which has been used as a contrast agent for magnetic resonance imaging (MRI). Our proposed work provides a strategy to trigger oxygen formation via an internal stimulus to enhance imaging-guided RIT efficiency.

Yeast has been increasingly used as a host for the expression of enzymes. Compared to other expression systems, the yeast expression system has many advantages including its suitability for large-scale fermentation and its ability to modify enzymes. When expressed in yeast, many recombinant enzymes are N-glycosylated, and this may play an important role in their activity, thermostability and secretion. Although the mechanism underlying this process is not clear, the regulation of N-glycosylation by introducing or eliminating N-glycosylation at specific sites has developed into an important strategy for improving the production or catalytic properties of recombinant enzymes. In this review, we summarize the recent advances in understanding the effects of N-glycosylation on the expression and characteristics of recombinant enzymes, and discuss novel strategies for regulating N-glycosylation in yeast. We hope that this review will help improve the understanding of the expression and the catalytic properties of N-glycosylated proteins.

Radionuclides for cancer theranostic have confronted problems such as limitation in real-time visualization and unsatisfied therapeutic effect sacrificed by the nonspecific distribution. Nanoscale metal-organic frameworks (nMOFs) have been widely used...