Intracellular Delivery of Stabilized Peptide Blocking MTDH-SND1 Interaction for Breast Cancer Suppression.

Triple-negative breast cancer is one of the most prevalent malignant cancers worldwide. Disrupting the MTDH-SND1 protein-protein interaction has recently been shown to be a promising strategy for breast cancer therapy. In this work, a novel potent stabilized peptide with a stronger binding affinity was obtained through rational structure-based optimization. Furthermore, a sulfonium-based peptide delivery system was established to improve the cell penetration and antitumor effects of stabilized peptides in metastatic breast cancer. Our study further broadens the in vivo applications of the stabilized peptides for blocking MTDH-SND1 interaction and provides promising opportunities for breast cancer therapy.

Machine-learning-assisted single-vessel analysis of nanoparticle permeability in tumour vasculatures.

The central dogma that nanoparticle delivery to tumours requires enhanced leakiness of vasculatures is a topic of debate. To address this, we propose a single-vessel quantitative analysis method by taking advantage of protein-based nanoprobes and image-segmentation-based machine learning (nano-ISML). Using nano-ISML, >67,000 individual blood vessels from 32 tumour models were quantified, revealing highly heterogenous vascular permeability of protein-based nanoparticles. There was a >13-fold difference in the percentage of high-permeability vessels in different tumours and >100-fold penetration ability in vessels with the highest permeability compared with vessels with the lowest permeability. Our data suggest passive extravasation and transendothelial transport were the dominant mechanisms for high- and low-permeability tumour vessels, respectively. To exemplify the nano-ISML-assisted rational design of nanomedicines, genetically tailored protein nanoparticles with improved transendothelial transport in low-permeability tumours were developed. Our study delineates the heterogeneity of tumour vascular permeability and defines a direction for the rational design of next-generation anticancer nanomedicines.

Screening of Protein-Based Ultrasmall Nanozymes for Building Cell-Mimicking Catalytic Vesicles.

Enzymes are an important component for bottom-up building of synthetic/artificial cells. Nanozymes are nanomaterials with intrinsic enzyme-like properties, however, the construction of synthetic cells using nanozymes is difficult owing to their high surface energy or large size. Herein, the authors show a protein-based general platform that biomimetically integrates various ultrasmall metal nanozymes into protein shells. Specifically, eight metal-based ultrasmall nano-particles/clusters are in situ incorporated into ferritin nanocages that are self-assembled by 24 subunits of ferritin heavy chain. As a nanozyme generator, such a platform is suitable for screening the desired enzyme-like activities, including peroxidase (POD), oxidase (OXD), catalase (CAT) and superoxide dismutase (SOD). After screening, it is found that Ru intrinsically possesses the highest POD-like and CAT-like activities, while Mn and Pt show the highest OXD-like and SOD-like activities, respectively. Additionally, the inducers/inhibitors of various nanozymes are screened from more than 50 compounds to improve or inhibit their enzyme-like activities. Based on the screened nanozymes and their inhibitors, a proof-of-conceptually constructs cell-mimicking catalytic vesicles to mimic or modulate the events of redox homeostasis in living cells. This study offers a type of artificial metalloenzyme based on nanotechnology and shows a choice for bottom-up enzyme-based synthetic cell systems in a fully synthetic manner.

Modular Assembly of Tumor-Penetrating and Oligomeric Nanozyme Based on Intrinsically Self-Assembling Protein Nanocages.

Biomimetic design of nanomaterials with enzyme-like characteristics has emerged as a promising method for the generation of novel therapeutics. However, synthesis of nanomaterials while maintaining a high degree of control over both geometry and valency poses a prominent challenge. Herein, the authors introduce a nanomaterial-based synthetic biology strategy for accurate and quantitative tailoring of high-ordered nanostructures that uses a "bottom-up" hierarchical incorporation of protein building blocks. The assembled nano-oligomers possessed tunable protein motifs and multivalent binding domains, which facilitated prolonged blood circulation time, accumulation within tumor cells through direct targeting of cell receptors, and deep tumor tissue penetration via a transcytosis mechanism. Using these protein/protein nano-oligomers as scaffolds, the authors created a new series of artificial nano-scaled metalloenzymes (nanozymes) by the in situ incorporation of metal nanoclusters within the cavity of the protein nanocages. Nanozymes were capable of mimicking peroxidase-like activity and generated cytotoxic free radicals. Compared to nanozyme alone, the systemic delivery of oligomeric nanozymes demonstrated significantly enhanced therapeutic and anti-tumor benefits. This study shows a new insight into nanotechnology by taking advantage of synthetic biotechnology.

Biomimetic Design of Mitochondria-Targeted Hybrid Nanozymes as Superoxide Scavengers.

Development of enzyme mimics for the scavenging of excessive mitochondrial superoxide (O2 •- ) can serve as an effective strategy in the treatment of many diseases. Here, protein reconstruction technology and nanotechnology is taken advantage of to biomimetically create an artificial hybrid nanozyme. These nanozymes consist of ferritin-heavy-chain-based protein as the enzyme scaffold and a metal nanoparticle core as the enzyme active center. This artificial cascade nanozyme possesses superoxide dismutase- and catalase-like activities and also targets mitochondria by overcoming multiple biological barriers. Using cardiac ischemia-reperfusion animal models, the protective advantages of the hybrid nanozymes are demonstrated in vivo during mitochondrial oxidative injury and in the recovery of heart functionality following infarction via systemic delivery and localized release from adhesive hydrogels (i.e., cardiac patch), respectively. This study illustrates a de novo design strategy in the development of enzyme mimics and provides a promising therapeutic option for alleviating oxidative damage in regenerative medicine.