Construction of Near-Infrared Probes with Remarkable Large Stokes Shift Based on a Novel Purine Platform for the Visualization of mtG4 Upregulation during Mitochondrial Disorder in Somatic Cells and Human Sperms.

G-quadruplex structures within the nuclear genome (nG4) is an important regulatory factor, while the function of G4 in the mitochondrial genome (mtG4) still needs to be explored, especially in human sperms. To gain a better understanding of the relationship between mtG4 and mitochondrial function, it is crucial to develop excellent probes that can selectively visualize and track mtG4 in both somatic cells and sperms. Herein, based on our previous research on purine frameworks, we attempted for the first time to extend the conjugated structure from the C-8 site of purine skeleton and discovered that the purine derivative modified by the C-8 aldehyde group is an ideal platform for constructing near-infrared probes with extremely large Stokes shift (>220 nm). Compared with the compound substituted with methylpyridine (PAP), the molecule substituted with methylthiazole orange (PATO) showed better G4 recognition ability, including longer emission (∼720 nm), more significant fluorescent enhancement (∼67-fold), lower background, and excellent photostability. PATO exhibited a sensitive response to mtG4 variation in both somatic cells and human sperms. Most importantly, PATO helped us to discover that mtG4 was significantly increased in cells with mitochondrial respiratory chain damage caused by complex I inhibitors (6-OHDA and rotenone), as well as in human sperms that suffer from oxidative stress. Altogether, our study not only provides a novel ideal molecular platform for constructing high-performance probes but also develops an effective tool for studying the relationship between mtG4 and mitochondrial function in both somatic cells and human sperms.

Neuroprotective Effects of Oligosaccharides From Periplaneta Americana on Parkinson's Disease Models In Vitro and In Vivo.

Parkinson's disease (PD) is one of the neurodegenerative diseases that is characterized by obvious motor and some nonmotor symptoms. Various therapeutics failed in the effective treatment of PD because of impaired neurological function in the brain and various complications. Periplaneta Americana oligosaccharides (OPA), the main active ingredients extracted from the medicine residues of Periplaneta Americana (P. Americana), have been reported to exert anti-inflammatory effects. The purpose of this study was to evaluate the possible mechanisms of OPA against 1-methyl-4-phenylpyridinium (MPP+)-induced apotosis in SH-SY5Y cells and its potential neuroprotective effects in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD subacute model mice. The data demonstrated that OPA significantly reversed the MPP+-induced decrease in SH-SY5Y cell viability, reduced the proportion of apoptotic cells, and protected SH-SY5Y cells from apoptosis in a dose-dependent manner by regulating the expression of apoptosis-related genes. Furthermore, OPA also alleviated the motor dysfunction of PD model mice, prevented the loss of tyrosine hydroxylase positive cells, suppressed the apoptosis of substantia nigra cells, and improved the dysbiosis of gut microbiota in vivo, suggesting that OPA demonstrated a significantly neuroprotective effect on PD model mice. These results indicated that OPA might be the possibility of PD therapeutics with economic utility and high safety.

Identification of Potential Inhibitors Against the TGF-ß/BMPs-Activin Receptor- like Kinase 1 Signal Pathway.

INTRODUCTION: In many diseased states, especially fibrosis and cancer, TGF-ß family members are overexpressed and the outcome of signaling is diverted toward disease progression. As the result of activin receptor-like kinase 1 (ALK1) plays a key role in TGF-ß signaling, discovering inhibitors of ALK1 to block TGF-ß signaling for a therapeutic benefit has become an effective strategy. METHODS: In this work, ZINC15894217 and ZINC12404282 were identified as potential ALK1 inhibitors using molecular docking, molecular dynamics simulation and MM/PBSA calculations studies. The analysis of energy decomposition found that Val208, Val216, Lys229, Gly283, Arg334 and Leu337 acted as crucial residues for ligand binding and system stabilizing. RESULTS: In addition, these compounds displayed excellent pharmacological and structural properties, which can be further evaluated through in vitro and in vivo experiments for the inhibition of ALK1 to be developed as drugs against fibrosis and tumor. CONCLUSION: Overall, our study illustrated a time- and cost-effective computer aided drug design procedure to identify potential ALK1 inhibitors. It would provide useful information for further development of ALK1 inhibitors to improve disease related to TGF-ß signal pathway.

Multifunctional gold nanoparticles as smart nanovehicles with enhanced tumour-targeting abilities for intracellular pH mapping and in vivo MR/fluorescence imaging.

A number of multimodal agents have been developed for tumour imaging and diagnosis, but most of them cannot be used to study the detailed physiological or pathological changes in living cells at the same time. Herein, a series of pH-responsive magnetic resonance and fluorescence imaging (MRI/FI) dual-modal "nanovehicles" are developed and tested. These new dual-modal materials allow for intercellular pH sensing, and those with units that are dually sensitive towards both acidic and basic environments have the ability for intracellular pH mapping and can be used to quantify pH at the cellular level. In addition, detailed pH changes in organelles (including lysosomes and mitochondria) can be investigated at the same time. On the other hand, with the tumour-targeting peptide (cRGD)-modified dual-modal nanovehicles, in vivo tumour MR and fluorescence imaging, which is suitable for cancer diagnosis, can be achieved. Moreover, it has been proved that these materials can pass through the blood brain barrier (BBB). By combining the above mentioned promising properties, these novel multifunctional "nanovehicles" may provide a new method for studying the role of pH during cancer diagnosis and treatment.

Metabolic gene NR4A1 as a potential therapeutic target for non-smoking female non-small cell lung cancer patients.

BACKGROUND: Although cigarette smoking is considered one of the key risk factors for lung cancer, 15% of male patients and 53% of female patients with lung cancer are non-smokers. Metabolic changes are critical features of cancer. Therapeutic target identification from a metabolic perspective in non-small cell lung cancer (NSCLC) tissue of female non-smokers has long been ignored. RESULTS: Based on microarray data retrieved from Affymetrix expression arrays E-GEOD-19804, we found that the downregulated genes in non-smoking female NSCLC patients tended to participate in protein/amino acid and lipid metabolism, while upregulated genes were more involved in protein/amino acid and carbohydrate metabolism. Combining nutrient metabolic co-expression, protein-protein interaction network construction and overall survival assessment, we identified NR4A1 and TIE1 as potential therapeutic targets for NSCLC in female non-smokers. To accelerate the drug development for non-smoking female NSCLC patients, we identified nilotinib as a potential agonist targeting NR4A1 encoded protein by molecular docking and molecular dynamic stimulation. We also show that nilotinib inhibited proliferation and induced senescence of cells in non-smoking female NSCLC patients in vitro. CONCLUSIONS: These results not only uncover nutrient metabolic characteristics in non-smoking female NSCLC patients, but also provide a new paradigm for identifying new targets and drugs for novel therapy for such patients.

Structure-based discovery of new maternal embryonic leucine zipper kinase inhibitors.

Maternal embryonic leucine zipper kinase (MELK), a serine/threonine protein kinase, has oncogenic properties and plays a key functional role in various cancer cells. Although MELK may not be a cancer addiction target, the development of specific MELK inhibitors would provide useful chemical tools for synthetic lethal investigation. Herein, we identified several hit compounds using a customized structure-based virtual screening, among which compounds 4 and 16 showed the most potent inhibition to MELK with IC50 values of 3.52 µM and 178.3 nM, respectively. In vitro cell-based assays revealed that 16 has no effect on the growth of various types of cancer cells, but has the potential to inhibit cancer cell migration and invasion. Western blotting analyses revealed that 16 suppresses the phosphorylation of focal adhesion kinase (FAK), a downstream molecule of MELK, which is a key kinase in regulating cancer cell migration and invasion.

In silico identification of potential inhibitors targeting Streptococcus mutans sortase A.

Dental caries is one of the most common chronic diseases and is caused by acid fermentation of bacteria adhered to the teeth. Streptococcus mutans (S. mutans) utilizes sortase A (SrtA) to anchor surface proteins to the cell wall and forms a biofilm to facilitate its adhesion to the tooth surface. Some plant natural products, especially several flavonoids, are effective inhibitors of SrtA. However, given the limited number of inhibitors and the development of drug resistance, the discovery of new inhibitors is urgent. Here, the high-throughput virtual screening approach was performed to identify new potential inhibitors of S. mutans SrtA. Two libraries were used for screening, and nine compounds that had the lowest scores were chosen for further molecular dynamics simulation, binding free energy analysis and absorption, distribution, metabolism, excretion and toxicity (ADMET) properties analysis. The results revealed that several similar compounds composed of benzofuran, thiadiazole and pyrrole, which exhibited good affinities and appropriate pharmacokinetic parameters, were potential inhibitors to impede the catalysis of SrtA. In addition, the carbonyl of these compounds can have a key role in the inhibition mechanism. These findings can provide a new strategy for microbial infection disease therapy.

Identification of Novel Pathways in Plant Lectin-Induced Cancer Cell Apoptosis.

Plant lectins have been investigated to elucidate their complicated mechanisms due to their remarkable anticancer activities. Although plant lectins seems promising as a potential anticancer agent for further preclinical and clinical uses, further research is still urgently needed and should include more focus on molecular mechanisms. Herein, a Naïve Bayesian model was developed to predict the protein-protein interaction (PPI), and thus construct the global human PPI network. Moreover, multiple sources of biological data, such as smallest shared biological process (SSBP), domain-domain interaction (DDI), gene co-expression profiles and cross-species interolog mapping were integrated to build the core apoptotic PPI network. In addition, we further modified it into a plant lectin-induced apoptotic cell death context. Then, we identified 22 apoptotic hub proteins in mesothelioma cells according to their different microarray expressions. Subsequently, we used combinational methods to predict microRNAs (miRNAs) which could negatively regulate the abovementioned hub proteins. Together, we demonstrated the ability of our Naïve Bayesian model-based network for identifying novel plant lectin-treated cancer cell apoptotic pathways. These findings may provide new clues concerning plant lectins as potential apoptotic inducers for cancer drug discovery.

In silico identification of novel kinase inhibitors by targeting B-Raf(v660e) from natural products database.

The Ras/Raf/MEK/ERK (MAPK) signaling pathway has gained much attention from scientific community for therapeutic intervention in the past decades, specifically in oncology. Notably, a most prevalent B-Raf(v600e) mutant in Raf kinase family exhibits elevated kinase activity and results in constitutive activation of the MAPK pathway, thus making it a promising drug target for cancer therapy. Herein, virtual screening is applied to identify its potential inhibitors. Following the 25 ns molecular dynamic (MD) simulations, ZINC38541768, ZINC38541767, and ZINC12496469 are identified as B-Raf(v600e) potential inhibitors in a DFG-in conformation. Furthermore, according to the molecular mechanics/generalized born surface area (MM/GBSA) method, these three small molecules exhibit similar and good binding affinity toward B-Raf(v600e) (-38.76 kcal mol(-1), -42.60 kcal mol(-1), and -39.04 kcal mol(-1)). At the same time, several critical residues, such as I463, V471 in the P-loop, and DFG motif residue D594 within the A-loop, are also well clarified. All these results may not only indicate some future applications of inhibitors targeting B-Raf(v600e), but also benefit B-Raf(v600e) harboring cancer patients.

Antiviral and antitumor activities of the lectin extracted from Aspidistra elatior.

Lectins, a group of highly diverse proteins of non-immune origin and are ubiquitously distributed in plants, animals and fungi, have multiple significant biological functions, such as anti-fungal, anti-viral and, most notably, anti-tumor activities. A lectin was purified from the rhizomes of Aspidistra elatior Blume, named A. elatior lectin (AEL). In vitro experiments showed that the minimum inhibitory concentrations of AEL against the vesicular stomatitis virus, Coxsackie virus B4, and respiratory syncytial virus were all the same at about 4 µg/mL. However, AEL was ineffective against the Sindbis virus and reovirus-1. AEL also showed significant in vitro antiproliferative activity towards Bre-04, Lu-04, HepG2, and Pro-01 tumor cell lines by increasing the proportion of their sub-G1 phase. However, AEL failed to restrict the proliferation of the HeLa cell line. Western blotting indicated that AEL induced the upregulation of cell cycle-related proteins p53 and p21. The molecular basis and species-specific effectiveness of the anti-proliferative and anti-viral potential of AEL are discussed.

Mangiferin facilitates islet regeneration and ß-cell proliferation through upregulation of cell cycle and ß-cell regeneration regulators.

Mangiferin, a xanthonoid found in plants including mangoes and iris unguicularis, was suggested in previous studies to have anti-hyperglycemic function, though the underlying mechanisms are largely unknown. This study was designed to determine the therapeutic effect of mangiferin by the regeneration of ß-cells in mice following 70% partial pancreatectomy (PPx), and to explore the mechanisms of mangiferin-induced ß-cell proliferation. For this purpose, adult C57BL/6J mice after 7-14 days post-PPx, or a sham operation were subjected to mangiferin (30 and 90 mg/kg body weight) or control solvent injection. Mangiferin-treated mice exhibited an improved glycemia and glucose tolerance, increased serum insulin levels, enhanced ß-cell hyperplasia, elevated ß-cell proliferation and reduced ß-cell apoptosis. Further dissection at the molecular level showed several key regulators of cell cycle, such as cyclin D1, D2 and cyclin-dependent kinase 4 (Cdk4) were significantly up-regulated in mangiferin-treated mice. In addition, critical genes related to ß-cell regeneration, such as pancreatic and duodenal homeobox 1 (PDX-1), neurogenin 3 (Ngn3), glucose transporter 2 (GLUT-2), Forkhead box protein O1 (Foxo-1), and glucokinase (GCK), were found to be promoted by mangiferin at both the mRNA and protein expression level. Thus, mangiferin administration markedly facilitates ß-cell proliferation and islet regeneration, likely by regulating essential genes in the cell cycle and the process of islet regeneration. These effects therefore suggest that mangiferin bears a therapeutic potential in preventing and/or treating the diabetes.

In silico identification of novel kinase inhibitors targeting wild-type and T315I mutant ABL1 from FDA-approved drugs.

The constitutively active fusion protein BCR-ABL1 is the major cause of chronic myeloid leukemia (CML), and selective inhibition of ABL1 is a promising approach for the treatment of CML. Reported drugs worked well in clinical practice, such as imatinib, dasatinib, nilotinib and bosutinib. However, resistance arises due to ABL1 mutation in patients, especially the T315I gate-keeper mutation. Thus, wide spectrum drugs targeting ABL1 are urgently needed. In order to screen potential drugs targeting wild-type ABL1 and T315I mutant ABL1, 1408 FDA approved small molecule drugs were subjected to molecular docking. With subsequent molecular dynamic (MD) simulation and MM/GBSA binding free energy calculation and energy decomposition, we identified chlorhexidine and sorafenib as potential "new use" drugs targeting wild-type ABL1, while nicergoline and plerixafor targeted T315I ABL1. Meanwhile, we also found that residues located in the ATP-binding site and A-loop motif played key roles in drug discovery towards ABL1. These findings may not only serve as a paradigm for the repositioning of existing approved drugs, but also instill new vitality to ABL1-targeted anti-CML therapeutics.

The receptor binding domain of MERS-CoV: the dawn of vaccine and treatment development.

The newly emerged Middle East respiratory syndrome coronavirus (MERS-CoV) is becoming another "SARS-like" threat to the world. It has an extremely high death rate (∼50%) as there is no vaccine or efficient therapeutics. The identification of the structures of both the MERS-CoV receptor binding domain (RBD) and its complex with dipeptidyl peptidase 4 (DPP4), raises the hope of alleviating this currently severe situation. In this review, we examined the molecular basis of the RBD-receptor interaction to outline why/how could we use MERS-CoV RBD to develop vaccines and antiviral drugs.

Green tea catechins: a fresh flavor to anticancer therapy.

Green tea catechins have been extensively studied for their cancer preventive effects. Accumulating evidence has shown that green tea catechins, like (-)-epigallocatechin-3-gallate, have strong anti-oxidant activity and affect several signal transduction pathways relevant to cancer development. Here, we review the biological properties of green tea catechins and the molecular mechanisms of their anticancer effects, including the suppression of cancer cell proliferation, induction of apoptosis, and inhibition of tumor metastasis and angiogenesis. We summarize the efficacy of a single catechin and the synergetic effects of multiple catechins. We also discuss the enhanced anticancer effects of green tea catechins when they are combined with anticancer drugs. The information present in this review might promote the development of strategy for the co-administration of green tea catechins with other anticancer drugs to increase the potency of currently available anticancer medicine. This new strategy should in turn lower the cytotoxicity and cost of anticancer treatment.

Isochaetomium A2, a new bis(naphthodihydropyran-4-one) with antimicrobial and immunological activities from fungus Chaetomium microcephalum.

Isochaetomium A2 (1), a new bis(naphthodihydropyran-4-one), along with chaetochromins A (2) and B (3), was isolated from the solid-state fermented rice culture of Chaetomium microcephalum. The structure of compound 1 was elucidated on the basis of 1D and 2D NMR spectral data, and the relative configuration was confirmed by CD spectrum. Compounds 1-3 possessed significant antimicrobial activity against Escherichia coli 1.044, Staphylococcus aureus 1.252, and Bacillus subtilis 1.079. Moreover, compounds 1-3 showed obvious inhibitory effects on mouse spleen cell proliferation with successive IC50 values of 0.52, 0.19, and 0.24 µM.

Antitumor effects of concanavalin A and Sophora flavescens lectin in vitro and in vivo.

AIM: Proteins with legume lectin domains are known to possess a wide range of biological functions. Here, the antitumor effects of two representative legume lectins, concanavalin A (ConA) and Sophora flavescens lectin (SFL), on human breast carcinoma cells were investigated in vitro and in vivo. METHODS: Human breast carcinoma MCF-7 cells and human normal mammary epithelial MCF-10A cells were examined. Cell viability was detected using WST-1 and CCK-8 assays. Cell apoptosis was analyzed with Hoechst 33258 staining. Cell cycle was investigated using flow cytometry. The expression of relevant proteins was measured using Western blotting. Breast carcinoma MCF-7 bearing nude mice were used to study the antitumor effects in vivo. The mice were injected with ConA (40 mg/kg, ip) and SFL (55 mg/kg, ip) daily for 14 d. RESULTS: ConA and SFL inhibited the growth of MCF-7 cells in dose- and time-dependent manners (IC50 values were 15 and 20 µg/mL, respectively). Both ConA and SFL induced apoptotic morphology in MCF-7 cells without affecting MCF-10A cells. ConA and SFL dose-dependently increased the sub-G1 proportion in MCF-7 cells, while SFL also triggered the G2/M phase cell cycle arrest. Both ConA and SFL dose-dependently increased the activities of caspase-3 and caspase-9 and release of cytochrome C from mitochondria into cytoplasm, up-regulated Bax and Bid, and down-regulated Bcl-2 and Bcl-XL in MCF-7 cells. ConA reduced NF-κB, ERK, and JNK levels, and increased p53 and p21 levels, while SFL caused similar changes in NF-κB, ERK, p53, and p21 levels, but did not affect JNK expression. Administration of ConA and SFL significantly decreased the subcutaneous tumor mass volume and weight in MCF-7 bearing nude mice. CONCLUSION: ConA and SFL exert anti-tumor actions against human breast carcinoma MCF-7 cells both in vitro and in vivo.

Anti-inflammatory phenanthrene derivatives from stems of Dendrobium denneanum.

Cultivated Dendrobium denneanum has been substituted for other endangered Dendrobium species in recent years, but there have been few studies regarding either its chemical constituents or pharmacological effects. In this study, three phenanthrene glycosides, three 9,10-dihydrophenanthrenes, two 9,10-dihydrophenanthrenes glycosides, and four known phenanthrene derivatives, were isolated from the stems of D. denneanum. Their structures were elucidated on the basis of MS and NMR spectroscopic data. Ten compounds were found to inhibit nitric oxide (NO) production in lipopolysaccharide (LPS)-activated mouse macrophage RAW264.7 cells with IC50 values of 0.7-41.5 µM, and exhibited no cytotoxicity in RAW264.7, HeLa, or HepG2 cells. Additionally, it was found that 2,5-dihydroxy-4-methoxy-phenanthrene 2-O-ß-d-glucopyranoside, and 5-methoxy-2,4,7,9S-tetrahydroxy-9,10-dihydrophenanthrene suppressed LPS-induced expression of inducible NO synthase (iNOS) inhibited phosphorylation of p38, JNK as well as mitogen-activated protein kinase (MAPK), and inhibitory kappa B-α (IκBα). This indicated that both compounds exert anti-inflammatory effects by inhibiting MAPKs and nuclear factor κB (NF-κB) pathways.

Modeling, docking and dynamics simulations of a non-specific lipid transfer protein from Peganum harmala L.

Non-specific lipid transfer proteins (ns-LTPs), ubiquitously found in various types of plants, have been well-known to transfer amphiphilic lipids and promote the lipid exchange between mitochondria and microbody. In this study, an in silico analysis was proposed to study ns-LTP in Peganum harmala L., which may belong to ns-LTP1 family, aiming at constructing its three-dimensional structure. Moreover, we adopted MEGA to analyze ns-LTPs and other species phylogenetically, which brought out an initial sequence alignment of ns-LTPs. In addition, we used molecular docking and molecular dynamics simulations to further investigate the affinities and stabilities of ns-LTP with several ligands complexes. Taken together, our results about ns-LTPs and their ligand-binding activities can provide a better understanding of the lipid-protein interactions, indicating some future applications of ns-LTP-mediated transport.

A systems biology analysis of autophagy in cancer therapy.

Autophagy, which degrades redundant or damaged cellular constituents, is intricately relevant to a variety of human diseases, most notably cancer. Autophagy exerts distinct effects on cancer initiation and progression, due to the intrinsic overlapping of autophagic and cancer signalling pathways. However, due to the complexity of cancer as a systemic disease, the fate of cancer cells is not decided by any one signalling pathway. Numerous autophagic inter-connectivity and cross-talk pathways need to be further clarified at a systems level. In this review, we propose a systems biology perspective for the comprehensive analysis of the autophagy-cancer network, focusing on systems biology analysis in autophagy and cancer therapy. Together, these analyses may not only improve our understanding on autophagy-cancer relationships, but also facilitate cancer drug discovery.

Autophagy modulation as a target for anticancer drug discovery.

Autophagy, an evolutionarily conserved catabolic process involving the engulfment and degradation of non-essential or abnormal cellular organelles and proteins, is crucial for homeostatic maintenance in living cells. This highly regulated, multi-step process has been implicated in diverse diseases including cancer. Autophagy can function as either a promoter or a suppressor of cancer, which makes it a promising and challenging therapeutic target. Herein, we overview the regulatory mechanisms and dual roles of autophagy in cancer. We also describe some of the representative agents that exert their anticancer effects by regulating autophagy. Additionally, some emerging strategies aimed at modulating autophagy are discussed as having the potential for future anticancer drug discovery. In summary, these findings will provide valuable information to better utilize autophagy in the future development of anticancer therapeutics that meet clinical requirements.