Boosting ferroptosis and microtubule inhibition for antitumor therapy via a carrier-free supermolecule nanoreactor / 药物分析学报

Traditional microtubule inhibitors fail to significantly enhance the effect of colorectal cancer;hence,new and efficient strategies are necessary.In this study,a supramolecular nanoreactor(DOC@TA-Fe3+)based on tannic acid(TA),iron ion(Fe3+),and docetaxel(DOC)with microtubule inhibition,reactive oxygen species(ROS)generation,and glutathione peroxidase 4(GPX4)inhibition,is prepared for ferroptosis/apoptosis treatment.After internalization by CT26 cells,the DOC@TA-Fe3+nanoreactor escapes from the lysosomes to release payloads.The subsequent Fe3+/Fe2+conversion mediated by TA reducibility can trigger the Fenton reaction to enhance the ROS concentration.Additionally,Fe3+can consume gluta-thione to repress the activity of GPX4 to induce ferroptosis.Meanwhile,the released DOC controls microtubule dynamics to activate the apoptosis pathway.The superior in vivo antitumor efficacy of DOC@TA-Fe3+nanoreactor in terms of tumor growth inhibition and improved survival is verified in CT26 tumor-bearing mouse model.Therefore,the nanoreactor can act as an effective apoptosis and ferroptosis inducer for application in colorectal cancer therapy.

Self-assembling, pH-responsive nanoflowers for inhibiting PAD4 and neutrophil extracellular trap formation and improving the tumor immune microenvironment

Self-assembling carrier-free nanodrugs are attractive agents because they accumulate at tumor by an enhanced permeability and retention (EPR) effect without introduction of inactive substances, and some nanodrugs can alter the immune environment. We synthesized a peptidyl arginine deiminase 4 (PAD4) molecular inhibitor, ZD-E-1M. It could self-assembled into nanodrug ZD-E-1. Using confocal laser scanning microscopy, we observed its cellular colocalization, PAD4 activity and neutrophil extracellular traps (NETs) formation. The populations of immune cells and expression of immune-related proteins were determined by single-cell mass cytometry. ZD-E-1 formed nanoflowers in an acidic environment, whereas it formed nanospheres at pH 7.4. Accumulation of ZD-E-1 at tumor was pH-responsive because of its pH-dependent differences in the size and shape. It could enter the nucleus and bind to PAD4 to prolong the intracellular retention time. In mice, ZD-E-1 inhibited tumor growth and metastasis by inhibiting PAD4 activity and NETs formation. Besides, ZD-E-1 could regulate the ratio of immune cells in LLC tumor-bearing mice. Immunosuppressive proteins like LAG3 were suppressed, while IFN-γ and TNF-α as stimulators of tumor immune response were upregulated. Overall, ZD-E-1 is a self-assembling carrier-free nanodrug that responds to pH, inhibits PAD4 activity, blocks neutrophil extracellular traps formation, and improves the tumor immune microenvironment.

In vivo self-aggregation and efficient preparation of recombinant lichenase based on ferritin / 生物工程学报

Enzyme separation, purification, immobilization, and catalytic performance improvement have been the research hotspots and frontiers as well as the challenges in the field of biocatalysis. Thus, the development of novel methods for enzyme purification, immobilization, and improvement of their catalytic performance and storage are of great significance. Herein, ferritin was fused with the lichenase gene to achieve the purpose. The results showed that the fused gene was highly expressed in the cells of host strains, and that the resulted fusion proteins could self-aggregate into carrier-free active immobilized enzymes in vivo. Through low-speed centrifugation, the purity of the enzymes was up to > 90%, and the activity recovery was 61.1%. The activity of the enzymes after storage for 608 h was higher than the initial activity. After being used for 10 cycles, it still maintained 50.0% of the original activity. The insoluble active lichenase aggregates could spontaneously dissolve back into the buffer and formed the soluble polymeric lichenases with the diameter of about 12 nm. The specific activity of them was 12.09 times that of the free lichenase, while the catalytic efficiency was 7.11 times and the half-life at 50 ℃ was improved 11.09 folds. The results prove that the ferritin can be a versatile tag to trigger target enzyme self-aggregation and oligomerization in vivo, which can simplify the preparation of the target enzymes, improve their catalysis performance, and facilitate their storage.