The drug delivery system with "gatekeeper" is designed to achieve a stable entrapment state of the payload under normal physiological conditions through the gatekeepers. With tumor microenvironment or stimulation of exogenous factors, the gatekeeper is detached or altered to promote the responsive release of the drug. In this paper, we focus on applications of stimuli-responsive linkages and stimuli-responsive groups, and review research progresses of drug delivery system with "gatekeeper" developed over the past 10 years.

The incidence of thrombotic diseases has increased in the past decade, a factor endangering human health. Currently, antithrombotic drugs used in the clinic have side effects such as inducing bleeding. Data from clinical observation indicate that congenital deficiency of factor XI (FXI) gene decreases the incidence of stroke and deep venous thrombosis, without causing spontaneous bleeding. This unique property of FXI makes it a potential new target for antithrombotic drugs development. Many studies have focused on the discovery of novel inhibitors targeting FXI. This review summarizes the research progress in searching for the inhibitors against FXI.

Mutation and amplification of epidermal growth factor receptor (EGFR), one of the most important driver gene, are both reported to participate in the regulation of lung cancer development and progression. Here we investigated the effect and molecular mechanism of tripartite motif 25 (TRIM25) in the regulation of development of lung cancer. CCK-8 and Transwell assays were used to explore the tumor-promoting effect of TRIM25. Results showed that knockdown of TRIM25 significantly inhibited cell proliferation (34% inhibition rate) and invasion (42% inhibition rate). Gene set enrichment analysis (GSEA), Western blot and immunohistochemistry were adopted to detect the effect of TRIM25 on EGFR expression and its downstream signal activity. The results explained that TRIM25 not only up-regulated the expression level of EGFR, but also promoted EGFR signal activation. Co-immunoprecipitation, real-time PCR and cycloheximide (CHX) inhibit protein degradation assays were employed to explore the molecular mechanism of TRIM25 in regulating EGFR stability. Preliminary exploration results indicate that TRIM25 increases the expression level of EGFR and activates its downstream signaling activity through promoting K63-linked ubiquitination of EGFR. Restoration of EGFR expression rescues the phenotype of TRIM25 depletion. In A549 cells, overexpression of EGFR increased cell proliferation rate 1.5-fold and invasion rate 1.6-fold compared with knockdown of TRIM25 cells. Similarly, in H1975 cells, cell proliferation rate was enhanced 2-fold and invasion rate was improved 1.7-fold. These data suggest that TRIM25 promotes lung cancer development via maintaining EGFR stability and continuous EGFR signaling activation. The human lung cancer tissues were obtained from lung cancer patients at Cancer Hospital Chinese Academy of Medical Sciences. Informed consent was obtained from all participants in accordance with the Declaration of Helsinki. The study was approved by the Ethics Committee of the Cancer Hospital Chinese Academy of Medical Sciences.

Five alkaloids were isolated from a decoction of Uncaria rhynchophylla by a combination of various chromatographic techniques, including macroporous adsorbent resin, MCI resin, silica gel, Sephadex LH-20, and reversed phase HPLC. Their structures were characterized by comprehensive analyses of spectroscopic data as monoterpene indole alkaloids (+)-(7R)-3-oxo-7-hydroxy-3, 7-seco-dihydrorhynchohylline (1), (+)-(7S)-3-oxo-7-hydroxy-3, 7-seco-dihydrorhyncho-hylline (2), (+)-(7R)-3-oxo-7-hydroxy-3, 7-seco-rhynchohylline (3) and (+)-(7S)-3-oxo-7-hydroxy-3, 7-seco-rhynchohylline (4), and a β-carboline alkaloid 1, 2, 3, 4-tetrahydro-1-oxo-β-carboline (5). Among them, 1 and 2 are new compounds, 3 and 4 are new natural products that were semi-synthesized from isorhynchohylline with incorrect specific rotations, and 5 is isolated for the first time from the genus Uncaria.

This study was designed to investigate the effect on tumor growth inhibition activity of lizards (Gekkoswinhonis Guenther) with different extent of broiling. Samples were prepared by a traditional drying method combined with broiling on clay tiles. Four groups of samples were all dried before broiling. Group A was without broiling; group B was mildly broiled; group C was moderately broiled; and group D was heavily broiled. Crispiness was detected by the sizes of the generated fragments of different groups and crispiness increased with broiling. Sensory evaluation of vision and olfaction was performed, and scores were generated by evaluators. Moderately broiled group had the highest total score in sensory evaluation. Water content and content of water-soluble extracts were detected according to Chinese Pharmacopoeia. With the increasing broiling extent, content of water-soluble extracts increased while water content decreased. Soluble protein concentration was detected by bicinchoninic acid (BCA) kit and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) with the same crude drug content. Soluble protein concentration decreased with the increasing broiling extent. With equal loading of proteins at the same concentration, soluble protein diversity was detected by SDS-PAGE. Band difference was marked by red boxes. Soluble protein molecule weights showed significant difference with the increasing broiling extent. H₂₂ tumor-bearing mice model was established and used to detect tumor growth inhibition rate and immune organ index. Life quality of mice was evaluated. Mice treated with Gekkoswinhonis Guenther had better appetites and higher average weights compared with positive control group treated with fluorouracil (5-FU). Animal experiments were approved by the Ethics Committee of Beijing University of Chinese Medicine. Group A had the highest tumor growth inhibition rate (34.11%), followed by Group B (29.14%) and Group D (28.43%), Group C (21.98%) had the lowest tumor growth inhibition rate, but sensory evaluation was on the contrary. These results indicated that moderately broiling improved sensory evaluation but reduced the tumor growth inhibition activity of Gekkoswinhonis Guenther. The best tumor growth inhibition activity appeared when water content was 7.71%.

Urate transporter 1 (URAT1) is a validated target for the treatment of hyperuricemia. Based on the structure of URC-102, which is currently under a phase Ⅱ clinical trial, fourteen novel analogs were designed and synthesized. Among them, four compounds (9b, 9c, 10e and 10g) exhibited substantial inhibitory effect against URAT1. The most active compound 9b showed an IC₅₀ value of 0.061 μmol·L^-1, which is significantly more potent than Lesinurad and Benzbromarone. Preliminary SAR was drawn, providing clues for further structural optimization.

Alzheimer's disease (AD) is characterized clinically as irreversible cognitive dysfunction. Although a significant progress has been made in the study of AD pathogenesis, the effective measures to block AD progress have not been satisfactory. Abnormal autophagy is thought to be involved in the pathogenesis of AD, and regulation of autophagy may become a new strategy for AD treatment. Some medicines, which regulate autophagy by mTOR-dependent and independent (Bcl-2/Beclin-1, GSK-3β, and p-AKT) pathways, have shown excellent effects in alleviating AD symptoms. In addition, certain compounds extracted from plants have also been reported to regulate autophagy and prevent AD progression through multiple pathways and multiple targets. This article reviews the recent advances in the regulation of autophagy and AD treatment. It provides a new theoretical basis for clinical treatment of AD.

CAT3 is a promising anti-brain tumor agent that has significant anti-tumor activity on Daoy or U87MG orthotopic xenograft in nude mice. This study was carried out to investigate the metabolic profiles of CAT3 in mouse/dog/human blood and microsome as well as in humanized recombinant enzymes. All animal care and experimental procedures were reviewed and approved by the Animal Ethics Committee of Chinese Academy of Medical Sciences. Our findings showed that CAT3 could be hydrolyzed to active metabolite PF403 by carboxylesterase, butyrylcholinesterase and serine hydrolase in mouse/dog/human blood. PF403 could be further metabolized to M1 oxidative dehydration product, M2 double oxidation dehydration product, M3 methylation oxidative dehydration product, M4 oxidation product and M5 demethylation product, which were mainly catalyzed by CYP1A2, 1A1, 2C9 and 3A4, and slightly by CYP2B6, 2C8, 2C19 and 2D6. Besides oxidative metabolism, PF403 also was transformed into glucuronylation metabolites GLU-PF403 by Phase Ⅱ enzymes UGT1A1, 1A3 and 1A9. Taken together, the metabolism of CAT3 was a multiple enzyme catalytic reaction. These results could provide valuable information for potential enzyme-mediated DDI in clinic studies.

The grading and quality analysis methods for different commercial Glycyrrhiza Polygalae Radix slices were established. The qualities of different grade samples were analyzed and compared, in order to provide useful information for the formulation of the grading standards of Glycyrrhiza Polygalae Radix slices. A total of 34 batches of Glycyrrhiza Polygalae Radix slice samples collected from 12 companies were divided into two grades:first-grade (diameter ≥ 3.0 mm) and second-grade (diameter < 3.0 mm). Thin-layer chromatography (TLC), multi-component content determination and fingerprint analysis were used to analyze the qualities of different grades of Glycyrrhiza Polygalae Radix slices, and the fingerprints were statistically analyzed using partial least squares-discriminant analysis (PLS-DA) and orthogonal partial least squares-discriminant analysis (OPLS-DA). The results showed that the established TLC method can simultaneously identify three major types of components, including sugar esters, xanthones, and saponins in Glycyrrhiza Polygalae Radix slices, and has obvious advantage compared to the existing methods for its rich information, low cost, and easy or safe operation. The multi-component determination showed that the contents of three index components (polygalaxanthone Ⅲ, 3, 6'-disinapoyl sucrose and tenuifolin) in the first-grade products of Glycyrrhiza Polygalae Radix slices were lower than those in the second-grade products. The results of PLS-DA and OPLS-DA indicated significant differences were observed between the first-grade and second-grade products, with sibiricose A5, sibiricose A6, polygalaxanthone Ⅲ, 3, 6'-disinapoyl sucrose and tenuifoliside A being identifies as the major differentiate markers.

This paper summarizes research progresses of Chinese scholars in the field of drug metabolism and pharmacokinetics (DMPK) in 2018. Chinese scholars focused on drug metabolizing enzymes and transporters, and carried out studies on the mechanisms of drug metabolism and transport of active molecules. Topics of research included regulatory mechanisms of drug metabolizing enzymes or transporters, and their implications in drug development and disease etiology or progression. Here, we summarized studies on drug toxicity based on drug metabolism or transport, rational drug use in the clinic, drug metabolism mediated by intestinal flora, metabolism of traditional Chinese medicines, and new technologies or models in DMPK. In recent years, the research focus of drug metabolism in China has transformed from serving for new drug discovery and rational use, to innovation driven and mechanism oriented research. The domestic research topics and technology utilization are gradually aligning with the international conventions.