Natural killer (NK) cells, as an essential part of innate immunity, can directly identify and kill tumor cells after being activated by the synergistic action of surface inhibitory receptors and activated receptors. It can secrete cytokines to recruit dendritic cells (DCs), induce DCs maturation and enhance adaptive immune response. It can target cancer stem cells (CSCs) and circulating tumor cells (CTCs) to inhibit cancer metastasis. NK cells have a unique inflammatory tendency, which can respond to cytokines and chemokines released from tumor sites and migrate to tumor sites, making them occupy an important advantage in cancer targeted therapy. The research on cancer targeted therapy of NK cells as drug delivery carriers, NK cell membrane-coated biomimetic nanoparticles, and NK cell extracellular vesicles (NKEVs) has attracted more and more attention. The article will focus on the mechanism of NK cells inhibiting cancer, and summarize the research progress of cancer targeted therapy of NK cells.

Vaccination is an effective way to reduce the morbidity and mortality of infectious diseases. As a needle-free transcutaneous immunization (NF-TCI) vaccination technology, microneedles (MNs), composed of multiple micro-needles orderly attached to a substrate, can overcome the problems of low immune efficiency, poor compliance and waste of resources that exists in the conventional vaccination by injection, thus becoming a research hotspot in biomedicine. The microneedle vaccine can directly break through the stratum corneum barrier of the skin without touching nerves and blood vessels in the dermis, and effectively delivers the vaccine to the immune cells in the skin tissue to initiate the immune response of the body, thus triggering strong humoral and cellular immune processes. Vaccine delivery via the MNs system possesses the advantages of high safety, satisfying immune effect and practical economy, and shows great prospect in the prevention and treatment of infectious diseases and antineoplastic therapy. This article reviews the development background of MNs in transcutaneous immunization, the types of vaccine delivery, the factors affecting the immune effect, the problems to be solved and development direction in the future.

During fluorescence-guided cancer surgery, ultra-pH sensitive (UPS) fluorescent nanoprobes has multiple advantages such as real-time imaging procedures, ultra-high imaging sensitivity as well as broad tumor detection specificity. UPS nanoprobes stay at "OFF" state at higher pH and turn into "ON" state at lower pH with emission of strong fluorescence. Moreover, the transition pH points (transition pH point, pH_t) can be precisely controlled by structural-based strategy. One of the previously-reported UPS nanoprobes showed good imaging effect. However, it is still not clear about the effect of pH_t on cancer imaging efficiency of UPS nanoprobes and to further identify the optimal UPS. In this study, we synthesized a series of UPS nanoprobes with pH_t at 4.5, 6.2, 6.6, 7.8 by adjusting the hydrophobic blocks of UPS polymers. Each nanoprobe showed excellent stability in "OFF" state by dynamic light scattering and uniform morphology observed by transmission electron microscopy. In vitro imaging characterized the ultra-pH sensitive fluorescence transition of each probe. In vivo imaging results identified two UPS nanoprobes (NP-6.2 and NP-6.6) with superior tumor imaging effect. All animal experiments in this study were approved by the Animal Ethics Committee of Peking University Health Science Center and were strictly followed by the welfare regulations of laboratory animals of Peking University Health Science Center. Therefore, this study has explored the effect of pH_t on the cancer imaging efficiency of UPS nanoprobes and provides a new idea for design of the other cancer microenvironment-responsive polymers.

The dense extracellular matrix (ECM) of the tumor severely limits the deep penetration of nanomedicine and weakens its anti-tumor effect. Based on this, the yeast vesicle biomimetic nanomedicine with active deep penetration ability of tumor tissue was designed and developed for enhanced tumor therapy. Results of characterization showed that the yeast cell vesicles (YCV) displayed a spherical morphology with diameter of around 100 nm and was well dispersed. Then the chemotherapeutic drug doxorubicin (DOX) was selected as a model drug, and DOX was loaded into YCV to obtain YCV/DOX through electrostatic interaction, the encapsulation efficiencies of DOX were calculated as 82.5%. The drug release profile of YCV/DOX implied that DOX release showed a manner of pH-dependent, it may be that pH has affected the electrostatic effect of YCV and DOX. Compared with liposomes (Lipo), in vitro cell experiments showed that YCV from natural sources had stronger permeability in three-dimensional multicellular spheres. It is speculated that the mechanism may be good deformation capacity of YCV. A 4T1 xenograft tumor model was established to evaluate the therapeutic efficacy of YCV/DOX. The results suggested that YCV/DOX has stronger tumor tissue penetration ability and could effectively inhibit the tumor growth. All animal experiments were performed in line with national regulations and approved by the Animal Experiments Ethical Committee of Zhengzhou University. This study brings new ideas for the development of biomimetic nanomedicine to overcome the ECM of solid tumors.

The non-specific accumulation and release of drugs are the main factors affecting the therapeutic effect as well as causing toxic side effects of chemotherapeutic drugs. Nowadays, the application of nanotechnology and responsive drug release is an important strategy to improve the tumor-specific accumulation of drugs and reduce their side effects. In this study, an α-enolase targeted peptide (ETP)-modified polyethylene glycol poly-lysine block copolymer loaded with oxaliplatin prodrug was synthesized first, and then, polymer-coating Fe₃O₄ nanoparticles were prepared by phase transfer dialysis method to improve the blood circulation stability and tumor targeting of oxaliplatin. At the same time, the physicochemical properties, reductant-responsive drug release, cellular uptake, tumor targeting and other biological functions of ETP modified oxaliplatin-loaded Fe₃O₄ nanoparticles were studied in vitro and in vivo. First, the results of reductant-triggered drug release study showed that the drug-loaded nanoparticles could achieve rapid release of more than 80% of the prototype oxaliplatin within 3 h under the reduction conditions simulating the tumor cytoplasmic microenvironment. Secondly, the results of flow cytometry showed that the modification of ETP could increase the ratio of cellular uptake of drug-loaded nanoparticles in tumor cells, and the way that drug-loaded nanoparticles endocytosed by tumor cells were mainly through the energy-dependent and receptor protein and fossin-mediated endocytosis pathway. The animal procedures were approved by the Institutional Animal Care and Use Committee of School of Pharmacy of Fudan University. Moreover, the results of pharmacokinetic experiment showed that the area under the curve (AUC_0-∞) of oxaliplatin could be significantly increased by nano-formulation which was about 5 times than that of free oxaliplatin. Besides, the pharmacokinetic results also showed that the drug-loaded Fe₃O₄ nanoparticles constructed by covalent linkage and chelation had good overall stability in vivo. Finally, the in vivo imaging results showed that ETP modification could increase tumor accumulation of drug-loaded nanoparticles, which would be conducive to the efficacy of oxaliplatin in tumor lesions. In summary, the oxaliplatin-loaded Fe₃O₄ nanoparticles with the capability of reductant-responsive drug release have good drug release characteristics, blood circulation stability and tumor targeting ability, and have the potential to improve the anti-tumor therapeutic effect of oxaliplatin.

Photothermal therapy (PTT) is a highly effective anti-tumor method. However, when laser radiation was used to ablate tumors, it usually triggers a series of inflammatory reactions, promoting the further development of tumors and affecting the effect of anti-tumor therapy. Therefore, it is an effective method to improve the anti-tumor effect by suppressing the inflammatory response through the precise targeted delivery of anti-inflammatory drug while realizing the photothermal treatment of tumors. To this end, the redox-responsive linker 3, 3'-dithiodipropionic acid was used to bond the classic hydrophobic anti-inflammatory drug 18β-glycyrrhetinic acid (18β-GA) and the hydrophilic fragment methoxy-polyethylene glycol (mPEG-NH₂) to obtain redox-responsive amphiphilic polymer PEG-DA-GA in this study. Then, photothermal agent IR-780 was encapsulated to prepare redox-responsive polymer micelle PDG/IR-780 NPs. The PDG/IR-780 NPs exhibited uniform particle size of 80.2±5.3 nm and the polydispersity index (PDI) was 0.215±0.079. All animal experiments followed the ethical requirements formulated by the Ethics Committee of Sichuan University. The results showed that PDG/IR-780 NPs could respond to the abundant glutathione (GSH) in tumor cells to promote the disintegration of nanoparticle and the release of 18β-GA, thus significantly improved the killing efficiency on 4T1 cells, when compared with the non-redox-responsive control PSG/IR-780 NPs. When the concentration of 18β-GA was 50 μg·mL^-1, the cell viability of 4T1 cells in the PDG/IR-780 NPs group was only (19.29±1.80)%, which was significantly lower than the result of in PSG/IR-780 NPs group (29.30±1.37)%. The results of frozen sections of tumor tissues showed that the designed PDG NPs can promote the tumor-targeted distribution of drugs compared with the free drug group. Eventually, PDG/IR-780 NPs achieved wonderful anti-tumor efficacy on 4T1 triple-negative breast cancer model, revealing the new possibility of the combined therapy strategy of photothermal and anti-inflammatory therapy.

Huang-Qin is a traditional Chinese medicine with antiviral, antioxidant, and anti-inflammatory activities. Its major bioactive compounds are diverse flavone O-glucuronides and glucosides. Although three flavonoid O-glycosyltransferases have been identified from S. baicalensis, this information is not sufficient to elucidate the structural diversity of flavonoid glycosides. In this study, nine glycosyltransferase candidate genes were discovered from S. baicalensis by BLAST analysis and their functions were characterized after heterologous expression. Three new flavone O-glycosyltransferases were able to catalyze the formation of major compounds in S. baicalensis, including baicalin and wogonoside. These enzymes could also utilize exogenous flavones as sugar acceptors. This work further elucidates biosynthetic pathways for Scutellaria flavonoid O-glycosides.

To explore the effect of tanshinone IIA (TanIIA) on the occurrence and development of breast cancer, we employed the mouse mammary tumor virus-polyomavirus middle T antigen (MMTV-PyMT) transgenic mice as a spontaneous breast cancer mouse model. Animal welfare and experimental procedures were in accordance with the regulations of the Animal Ethics Committee of Nanjing University of Chinese Medicine. The animals were divided into control group, low-dose TanIIA treatment group (30 mg·kg^-1·day^-1), and high-dose TanIIA treatment group (60 mg·kg^-1·day^-1). The treatment was administered orally and daily for 5 weeks. The mice were sacrificed after final treatment. Mammary gland and lung were collected for histopathology studies. We evaluated the chemoprophylaxis effect of TanIIA on breast cancer in mice according to the pathological characteristics of breast cancer at different stages of development. Immunofluorescence staining were employed for blood vessel analysis. The expression levels of E-cadherin, proliferating nuclear antigen (PCNA), and oncogene c-Myc were detected by immunohistochemistry. Flow cytometry was used to analyze cell cycle and Cytoscape was used to construct drug-disease protein-protein interaction (PPI) network. Our results showed that TanIIA inhibits breast tumor progression by delaying malignancy from adenoma to early carcinoma, and inhibits blood vessel formation during tumor development. TanIIA (60 mg·kg^-1·day^-1) inhibits the expression levels of PCNA and c-Myc, upregulates the expression of E-cadherin. In addition, cell cycle experiments showed that the cell cycle of PyMT primary mammary cells in the high-dose TanIIA group was arrested in the G0/G1 phase. Our study demonstrated that TanIIA can significantly inhibit breast tumor progression in MMTV-PyMT mouse model, which may be related to the inhibition of angiogenic switch and cell cycle arrest.

Compound reserpine and triamterene tablets (CRTT), a compound antihypertensive drug developed by Chinese scientists, is still widely used in clinical practice. However, the mechanisms by which CRTT treats hypertension remain to be fully understood. This study used network pharmacology to analyze CRTT's antihypertensive mechanisms with in vitro experiments. The targets of the four chemical components of CRTT were collected from the Swiss Target Prediction database; 1 828 protein targets related to hypertension were collected from the Therapeutic Target Database (TTD) and Online Mendelian Inheritance in Man (OMIM) database. The CRTT-hypertension network model was constructed using a search tool for recurring instances of neighbouring genes (STRING). Gene ontology (GO) and pathway enrichment analysis of targets of interest was conducted with the Metascape database. In the in vitro study, human umbilical vein endothelial cells (HUVEC) and vascular smooth muscle cells (VSMC) were treated with 1 μmol·L^-1 angiotensin Ⅱ (AngⅡ) and CRTT was administered at concentrations of 0.01, 0.1, and 1 μmol·L^-1. Changes in the phosphatidylinositol-3-kinase/protein serine threonine kinase/endothelial nitric oxide synthase (PI3K/Akt/eNOS) pathway in HUVEC and the cyclic guanosine monophosphate/cGMP-dependent protein kinase (cGMP/PKG) pathway in VSMC were determined by Western blot. Network pharmacological analysis revealed that the antihypertensive effect of CRTT is closely associated with biological pathways such as vascular tone regulation, adrenergic receptor activation, protein kinase activity and signaling pathways such as the cGMP/PKG signaling pathway, vascular smooth muscle contraction, neuroactive ligand-receptor interaction, adrenergic signaling in cardiomyocytes and calcium signaling pathways. The in vitro study confirmed that CRTT increased the levels of phosphorylated phosphatidylinositol-3-kinase (p-PI3K), phosphorylated protein serine threonine kinase (p-Akt), phosphorylated endothelial nitric oxide synthase (p-eNOS) in HUVEC and the levels of eNOS, phosphorylated vasodilator-stimulated phosphoprotein (p-VASP), and PKG in VSMC through multiple targets and pathways. These results suggest that the activation of PI3K/Akt/eNOS pathway and endothelial-dependent NO/cGMP signaling may be involved in the CRTT-mediated hypotensive effect.

In this study, exosomes were extracted from human malignant melanoma cell A375. Folic acid (FA) receptor was used as target and triptolide (TPL) was used as model drug to prepare exosome targeted drug delivery system, FA-Exo/TPL. The physicochemical properties and antitumor effect were evaluated in vivo and in vitro. Gradient centrifugation method was applied to collect exosomes. Then, exosome was modified with FA for loading TPL. The particle sizes of the FA-Exo/TPL were about 100 nm with a double-layer membrane structure like a tray. It is characteristic of high encapsulation efficiency and drug loading. In vitro experiments showed that FA-Exo/TPL could be effectively uptaken by A375 cells, thus significantly inhibiting proliferation and promoting apoptosis the cells. In vivo experiment results showed that FA-Exo/TPL could effectively inhibit the growth of tumor tissue, prolong the model mice life cycle, and significantly reduce the systemic toxicity of the free drug, playing a synergistic and toxic role. Animal welfare and experimental procedures follow the regulations of the Animal Ethics Committee of Fudan University Shanghai Cancer Center. This study provides a new strategies and methods for the preparation of TPL against malignant melanoma.