Shenyang Pharmaceutical University

autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field.

SARS-CoV-2 has caused tens of thousands of infections and more than one thousand deaths. There are currently no registered therapies for treating coronavirus infections. Because of time consuming process of new drug development, drug repositioning may be the only solution to the epidemic of sudden infectious diseases. We systematically analyzed all the proteins encoded by SARS-CoV-2 genes, compared them with proteins from other coronaviruses, predicted their structures, and built 19 structures that could be done by homology modeling. By performing target-based virtual ligand screening, a total of 21 targets (including two human targets) were screened against compound libraries including ZINC drug database and our own database of natural products. Structure and screening results of important targets such as 3-chymotrypsin-like protease (3CLpro), Spike, RNA-dependent RNA polymerase (RdRp), and papain like protease (PLpro) were discussed in detail. In addition, a database of 78 commonly used anti-viral drugs including those currently on the market and undergoing clinical trials for SARS-CoV-2 was constructed. Possible targets of these compounds and potential drugs acting on a certain target were predicted. This study will provide new lead compounds and targets for further in vitro and in vivo studies of SARS-CoV-2, new insights for those drugs currently ongoing clinical studies, and also possible new strategies for drug repositioning to treat SARS-CoV-2 infections.

Phospholipids have the characteristics of excellent biocompatibility and a especial amphiphilicity. These unique properties make phospholipids most appropriate to be employed as important pharmaceutical excipients and they have a very wide range of applications in drug delivery systems. The aim of this review is to summarize phospholipids and some of their related applications in drug delivery systems, and highlight the relationship between the properties and applications, and the effect of the species of phospholipids on the efficiency of drug delivery. We refer to some relevant literatures, starting from the structures, main sources and properties of phospholipids to introduce their applications in drug delivery systems. The present article focuses on introducing five types of carriers based on phospholipids, including liposomes, intravenous lipid emulsions, micelles, drug-phospholipids complexes and cochleates.

Flavonoids, a class of polyphenol secondary metabolites, are presented broadly in plants and diets. They are believed to have various bioactive effects including anti-viral, antiinflammatory, cardioprotective, anti-diabetic, anti-cancer, anti-aging, etc. Their basic structures consist of C6-C3-C6 rings with different substitution patterns to produce a series of subclass compounds, and correlations between chemical structures and bioactivities have been studied before. Given their poor bioavailability, however, information about associations between structure and biological fate is limited and urgently needed. This review therefore attempts to bring some order into relationships between structure, activity as well as pharmacokinetics of bioactive flavonoids.

Nanoparticles have many potential applications in tumor therapy. Systemically administered nanoparticles should remain in circulation for a long time to increase their accumulation in targeted tissues before being cleared by the reticuloendothelial system, and be effectively internalized by the targeted cells, which can be influenced significantly by the physicochemical characteristics of nanoparticles, such as particle size, surface properties, and particle shape. This review highlights the impact of the main affects of physicochemical properties on nanoparticle transport behavior in blood, their uptake and clearance by macrophages and their consequent biodistribution, as well as their interaction with targeted cells.

Drug delivery systems (DDS) are defined as methods by which drugs are delivered to desired tissues, organs, cells and subcellular organs for drug release and absorption through a variety of drug carriers. Its usual purpose to improve the pharmacological activities of therapeutic drugs and to overcome problems such as limited solubility, drug aggregation, low bioavailability, poor biodistribution, lack of selectivity, or to reduce the side effects of therapeutic drugs. During 2015-2018, significant progress in the research on drug delivery systems has been achieved along with advances in related fields, such as pharmaceutical sciences, material sciences and biomedical sciences. This review provides a concise overview of current progress in this research area through its focus on the delivery strategies, construction techniques and specific examples. It is a valuable reference for pharmaceutical scientists who want to learn more about the design of drug delivery systems.

The occurrence of antibiotics and antibiotic resistance genes (ARGs) was quantified in water and sediment samples collected from a 72 km stretch of the Haihe River, China. Tetracycline resistance genes (tetW, tetQ, tetO, tetT, tetM, tetB, and tetS) were not detected by quantitative PCR in many samples. In contrast, sul1 and sul2 (coding for sulfonamide resistance) were present at relatively high concentrations in all (38) samples. The highest ARG concentrations detected were (7.8 ± 1.0) × 10(9) copies/g for sul1 and (1.7 ± 0.2) × 10(11) copies/g for sul2, in sediment samples collected during the summer. The corresponding total bacterial concentration (quantified with a universal 16S-rDNA probe) was (3.3 ± 0.4) × 10(12) cells/g. Sul1 and sul2 concentrations in sediments were 120-2000 times higher than that in water, indicating that sediments are an important ARG reservoir in the Haihe River. Statistical analysis indicated a positive correlation between the relative abundance of these ARGs (i.e., sul1/16S-rDNA and sul2/16S-rDNA) and the total concentration of sulfamethoxazole, sulfadiazine, plus sulfachlororyridazine, suggesting that sulfonamides exerted selective pressure for these ARGs. A class 1 integron was implicated in the propagation of sul1. Overall, the widespread distribution of sulfonamide ARGs underscores the need to better understand and mitigate their propagation in the environment and the associated risks to public health.

A unique biomimetic drug-delivery system composed of 4T1-breast-cancer-cell membranes and paclitaxel-loaded polymeric nanoparticles (PPNs) (cell-membrane-coated PPNs), demonstrates superior interactions to its source tumor cells and elongated blood circulation, and displays highly cell-specific targeting of the homotypic primary tumor and metastases, with successful inhibition of the growth and lung metastasis of the breast cancer cells. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but are not copy-edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Nanomedicines employ multiple endocytic pathways to enter cells. Their following fate is interesting, but it is not sufficient understood currently. This review introduces the endocytic pathways, presents new technologies to confirm the specific endocytic pathways and discusses factors for pathway selection. In addition, some intriguing implication about nanomedicine design based on endocytosis will also be discussed at the end. This review may provide new thoughts for the design of novel multifunctional nanomedicines.

Chemoimmunotherapy is reported to activate a robust T cell antitumor immune response by triggering immunogenic cell death (ICD), which has initiated a number of clinical trials. However, current chemoimmunotherapy is restricted to a small fraction of patients due to low drug delivery efficacy and immunosuppression within the tumor microenvironment. A tumor microenvironment-activatable prodrug vesicle for cancer chemoimmunotherapy using ICD is herein reported. The prodrug vesicles are engineered by integrating an oxaliplatin (OXA) prodrug and PEGylated photosensitizer (PS) into a single nanoplatform, which show tumor-specific accumulation, activation, and deep penetration in response to the tumoral acidic and enzymatic microenvironment. It is demonstrated that codelivery of OXA prodrug and PS can trigger ICD of the tumor cells by immunogenic cells killing. The combination of prodrug vesicle-induced ICD with Î ± CD47-mediated CD47 blockade further facilitates dendritic cell (DC) maturation, promotes antigen presentation by DCs, and eventually propagates the antitumor immunity of ICD. CD47 blockade and ICD induction efficiently inhibit the growth of both primary and abscopal tumors, suppress tumor metastasis, and prevent tumor recurrence. Collectively, these results imply that boosting antitumor immunity using ICD induction and suppressing tumor immune evasion via CD47 blockade might be promising for improved cancer chemoimmunotherapy.

The direct nucleic acid repair dioxygenase FTO is an enzyme that demethylates N(6)-methyladenosine (m(6)A) residues in mRNA in vitro and inside cells. FTO is the first RNA demethylase discovered that also serves a major regulatory function in mammals. Together with structure-based virtual screening and biochemical analyses, we report the first identification of several small-molecule inhibitors of human FTO demethylase. The most potent compound, the natural product rhein, which is neither a structural mimic of 2-oxoglutarate nor a chelator of metal ion, competitively binds to the FTO active site in vitro. Rhein also exhibits good inhibitory activity on m(6)A demethylation inside cells. These studies shed light on the development of powerful probes and new therapies for use in RNA biology and drug discovery.

Chemotherapeutic efficacy can be greatly improved by developing nanoparticulate drug delivery systems (nano-DDS) with high drug loading capacity and smart stimulus-triggered drug release in tumor cells. Herein, we report a novel redox dual-responsive prodrug-nanosystem self-assembled by hydrophobic small-molecule conjugates of paclitaxel (PTX) and oleic acid (OA). Thioether linked conjugates (PTX-S-OA) and dithioether inserted conjugates (PTX-2S-OA) are designed to respond to the redox-heterogeneity in tumor. Dithioether has been reported to show redox dual-responsiveness, but we find that PTX-S-OA exhibits superior redox sensitivity over PTX-2S-OA, achieving more rapid and selective release of free PTX from the prodrug nanoassemblies triggered by redox stimuli. PEGylated PTX-S-OA nanoassemblies, with impressively high drug loading (57.4%), exhibit potent antitumor activity in a human epidermoid carcinoma xenograft. This novel prodrug-nanosystem addresses concerns related to the low drug loading and inefficient drug release from hydrophobic prodrugs of PTX, and provides possibilities for the development of redox dual-sensitive conjugates or polymers for efficient anticancer drug delivery.

Disulfide bonds have been widely used to develop reduction-responsive drug-delivery systems (DDS) for cancer therapy. We propose that disulfide bonds might be also used as an oxidation-responsive linkage just like thioether bonds, which can be oxidized to hydrophilic sulfoxide or sulphone in the presence of oxidation stimuli. To test our hypothesis, we design three novel paclitaxel-citronellol conjugates linked via different lengths of disulfide-bond-containing carbon chain. The prodrugs can self-assemble into uniform-size nanoparticles with impressively high drug loading (>55%). As expected, the disulfide-bond-bridged prodrug nanoparticles show redox dual-responsive drug release. More interestingly, the position of disulfide bonds in the carbon chain linkage has profound impacts on the redox dual responsiveness, thereby affecting the drug release, cytotoxicity, pharmacokinetics, biodistribution, and in vivo antitumor efficacy of prodrug nanoassemblies. The redox dual-responsive mechanism is elucidated, and how the position of disulfide bonds in the carbon chain affects the redox dual responsiveness and antitumor efficiency of prodrug nanoassemblies is also clarified. Our findings give new insight into the stimuli responsiveness of disulfide bonds and provide a good foundation for the development of novel redox dual-responsive DDS for cancer therapy.

The combination of a chemotherapeutic drug with a multidrug resistance (MDR) modulator has emerged as a promising strategy for treating MDR cancer. To ensure two drugs could be simultaneously delivered to tumor region at the optimum ratio, and the MDR modulator could be released earlier and faster than the chemotherapeutic drug to inactivate P-glycoprotein (P-gp) and subsequently inhibit the pumping out of the chemotherapeutic drug, a smart pH-sensitive polymeric micelles system with high drug loading and precise drug ratio was designed and prepared by conjugating doxorubicin (DOX) to poly(styrene-co-maleic anhydride) (SMA) derivative with adipic dihydrazide (ADH) through a acid-cleavable hydrazone bond, and then encapsulating disulfiram (DSF), a P-gp inhibitor as well as an apoptosis inducer, into the micelles formed by the self-assembly of SMA-ADH-DOX (SAD) conjugate. The pH-sensitive polymeric micelles system enabled a temporal release of two drugs: encapsulated DSF was released fast to inhibit the activity of P-gp and restore cell apoptotic signaling pathways, while conjugated DOX was released in a sustained and pH-dependent manner and highly accumulated in drug resistant cells to exert therapeutic effect, due to the inactivation of P-gp by DSF. The smart co-delivery system was very effective in enhancing the cytotoxicity by increasing the intracellular accumulation of DOX and promoting the apoptotic response, and showed the most effective inhibitory effect on the growth of drug-resistant breast cancer xenografts as compared to other combinations of both drugs. In a word, this smart co-delivery system has significant promise for the clinical therapy of MDR cancer.

NF-kappaB is a central transcriptional factor and a pleiotropic regulator of many genes involved in immunological responses. During the screening of a plant extract library of traditional Chinese herbal medicines, we found that NF-kappaB activity was potently inhibited by andrographolide (Andro), an abundant component of the plant Andrographis that has been commonly used as a folk remedy for alleviation of inflammatory disorders in Asia for millennia. Mechanistically, it formed a covalent adduct with reduced cysteine (62) of p50, thus blocking the binding of NF-kappaB oligonucleotide to nuclear proteins. Andro suppressed the activation of NF-kappaB in stimulated endothelial cells, which reduced the expression of cell adhesion molecule E-selectin and prevented E-selectin-mediated leukocyte adhesion under flow. It also abrogated the cytokine- and endotoxin-induced peritoneal deposition of neutrophils, attenuated septic shock, and prevented allergic lung inflammation in vivo. Notably, it had no suppressive effect on IkappaBalpha degradation, p50 and p65 nuclear translocation, or cell growth rates. Our results thus reveal a unique pharmacological mechanism of Andro's protective anti-inflammatory actions.

To prolong the circulation time of drug, PEGylation has been widely used via the enhanced permeability and retention (EPR) effect, thereby providing new hope for better treatment. However, PEGylation also brings the "PEG dilemma", which is difficult for the cellular absorption of drugs and subsequent endosomal escape. As a result, the activity of drugs is inevitably lost after PEG modification. To achieve successful drug delivery for effective treatment, the crucial issue associated with the use of PEG-lipids, that is, "PEG dilemma" must be addressed. In this paper, we introduced the development and application of nanocarriers with cleavable PEGylation, and discussed various strategies for overcoming the PEG dilemma. Compared to the traditional ones, the vehicle systems with different environmental-sensitive PEG-lipids were discussed, which cleavage can be achieved in response to the intracellular as well as the tumor microenvironment. This smart cleavable PEGylation provides us an efficient strategy to overcome "PEG dilemma", thereby may be a good candidate for the cancer treatment in future.

Withanolides are a group of naturally occurring C28 steroids built on an ergostane skeleton functionalized at carbons 1, 22 and 26, commonly known as the withanolide skeleton. Over the period of August 1996 to March 2010, 360 new naturally occurring withanolides were isolated and identified. This review provides a comprehensive summary of the structural classification and distribution of these new compounds. The diverse biological and pharmacological activities of natural withanolides are also discussed based on their structural features. A total of 211 references are cited in this review.

The cell-specific targeting drug delivery and controlled release of drug at the cancer cells are still the main challenges for anti-breast cancer metastasis therapy. Herein, the authors first report a biomimetic drug delivery system composed of doxorubicin (DOX)-loaded gold nanocages (AuNs) as the inner cores and 4T1 cancer cell membranes (CMVs) as the outer shells (coated surface of DOX-incorporated AuNs (CDAuNs)). The CDAuNs, perfectly utilizing the natural cancer cell membranes with the homotypic targeting and hyperthermia-responsive ability to cap the DAuNs with the photothermal property, can realize the selective targeting of the homotypic tumor cells, hyperthermia-triggered drug release under the near-infrared laser irradiation, and the combination of chemo/photothermal therapy. The CDAuNs exhibit a stimuli-release of DOX under the hyperthermia and a high cell-specific targeting of the 4T1 cells in vitro. Moreover, the excellent combinational therapy with about 98.9% and 98.5% inhibiting rates of the tumor volume and metastatic nodules is observed in the 4T1 orthotopic mammary tumor models. As a result, CDAuNs can be a promising nanodelivery system for the future therapy of breast cancer.

Antibody-drug conjugates (ADCs) are gradually revolutionizing clinical cancer therapy. The antibody-drug conjugate linker molecule determines both the efficacy and the adverse effects, and so has a major influence on the fate of ADCs. An ideal linker should be stable in the circulatory system and release the cytotoxic payload specifically in the tumor. However, existing linkers often release payloads nonspecifically and inevitably lead to off-target toxicity. This defect is becoming an increasingly important factor that restricts the development of ADCs. The pursuit of ADCs with optimal therapeutic windows has resulted in remarkable progress in the discovery and development of novel linkers. The present review summarizes the advance of the chemical trigger, linker‒antibody attachment and linker‒payload attachment over the last 5 years, and describes the ADMET properties of ADCs. This work also helps clarify future developmental directions for the linkers.

Cancer is a disease caused by the accumulation of genetic and epigenetic changes in two types of genes: tumor suppressor genes (TSGs) and proto-oncogenes. Extensive research has been conducted over the last few decades to elucidate the role of TSGs in cancer development. In cancer, loss of TSG function occurs via the deletion or inactivation of two alleles, according to Knudson's two-hit model hypothesis. It has become clear that mutations in TSGs are recessive at the level of an individual cell; therefore, a single mutation in a TSG is not sufficient to cause carcinogenesis. However, many studies have identified candidate TSGs that do not conform with this standard definition, including genes inactivated by epigenetic silencing rather than by deletion. In addition, proteasomal degradation by ubiquitination, abnormal cellular localization, and transcriptional regulation are also involved in the inactivation of TSGs. This review incorporates these novel additional mechanisms of TSG inactivation into the existing two-hit model and proposes a revised multiple-hit model that will enable the identification of novel TSGs that can be used as prognostic and predictive biomarkers of cancer.