Multi-Stimuli-Induced Mechanical Bending and Reversible Fluorescence Switching in a Single Organic Crystal.

Fluorescent single crystals that respond to multiple external stimuli are of great interest in molecular machines, sensors, and displays. The integration of photo- or acid-induced fluorescence enhancement and bending in one organic crystal, however, has not been reported yet. Herein, we report the interesting plastic photomechanical bending and switching on of the fluorescence of an azine crystal in a single-crystal transformation, due to extended π-conjugation and molecular slippage. Moreover, the fluorescent plastic bending driven by multiple volatile acid vapors was firstly observed, and attributed to the synergistic effect of push-pull electronic structure and hydrogen bonding. The single crystal also shows high elasticity under external force. In addition, reversible fluorescence switching can be triggered by grinding and solvent fuming, as well as by the adsorption and desorption of HCl vapor. The integration of plastic, elastic bending and switch-on fluorescence into one single crystal provides a new strategy for next-generation smart materials.

Endogenous and exogenous galectin-3 promote the adhesion of tumor cells with low expression of MUC1 to HUVECs through upregulation of N-cadherin and CD44.

Tumor cell-endothelial adhesion is one of the key steps in tumor cell haematogenous dissemination in metastasis and was previously shown to be mediated by interaction of galectin-3 with the transmembrane mucin protein MUC1. In this study, the effect of exogenous as well as endogenous galectin-3 on adhesion of two cell lines (low MUC1-expressing human prostate cancer PC-3M cells and non-small-cell lung cancer A549 cells) to monolayer of umbilical vein endothelial cells (HUVECs) was investigated. We found that suppression of endogenous galectin-3 expression reduced tumor cell adhesion to HUVECs and also decreased cell invasion and migration. Exogenous galectin-3 promoted tumor cell adhesion to HUVECs by entering cells. Both exogenous and endogenous galectin-3 upregulated the expression of ß-catenin and increased ß-catenin nuclear accumulation, and subsequently upregulated the expression of N-cadherin and CD44. We deduced that both exogenous as well as endogenous galectin-3 promoted low MUC1-expressing cancer cell adhesion to HUVECs by increasing the expression of N-cadherin and CD44 via an increase of nuclear ß-catenin accumulation. These results were confirmed further by using a ß-catenin/TCF transcriptional activity inhibitor, N-cadherin or CD44 siRNAs. Taken together, our results suggest a new molecular mechanism of galectin-3-mediated cell adhesion in cancer metastasis.

Metformin incombination with curcumin inhibits the growth, metastasis, and angiogenesis of hepatocellular carcinoma in vitro and in vivo.

Hepatocellular carcinoma (HCC) has poor prognosis due to the advanced disease stages by the time it is diagnosed, high recurrence rates and metastasis. In the present study, we investigated the effects of metformin (a safe anti-diabetic drug) and curcumin (a turmeric polyphenol extracted from rhizome of Curcuma longa Linn.) on proliferation, apoptosis, invasion, metastasis, and angiogenesis of HCC in vitro and in vivo. It was found that co-treatment of metformin and curcumin could not only induce tumor cells into apoptosis through activating the mitochondria pathways, but also suppress the invasion, metastasis of HCC cells and angiogenesis of HUVECs. These effects were associated with downregulation of the expression of MMP2/9, VEGF, and VEGFR-2, up-regulation of PTEN, P53 and suppression of PI3K/Akt/mTOR/NF-κB and EGFR/STAT3 signaling. Co-administration of metformin and curcumin significantly inhibited HCC tumor growth than administration with metformin or curcumin alone in a xenograft mouse model. Thus, metformin and curcumin in combination showed a better anti-tumor effects in hepatoma cells than either metformin or curcumin presence alone and might represent an effective therapeutic strategy for HCC treatment.

Discovery and Characterization of 4-Hydroxy-2-pyridone Derivative Sambutoxin as a Potent and Promising Anticancer Drug Candidate: Activity and Molecular Mechanism.

Sambutoxin, a representative derivative of 4-hydroxy-2-pyridone, was isolated from Hericium alpestre for the first time in this study. The possible correlation between the sambutoxin-induced suppression of tumor growth and its influence on cell-cycle arrest and apoptosis was investigated. The effects of sambutoxin on reactive oxygen species (ROS) production, DNA damage, mitochondrial transmembrane potential, cell apoptosis, and the expression of related proteins were evaluated. An in vitro cell viability study demonstrated that sambutoxin could inhibit the proliferation of various cancer cells. Treatment with sambutoxin induced the production of ROS, which caused DNA damage. Furthermore, the subsequent sambutoxin-induced activation of ATM and Chk2 resulted in G2/M arrest, accompanied by decreased expression of cdc25C, cdc2, and cyclin B1. Sambutoxin induced apoptosis by activating the mitochondrial apoptosis pathway through an increased Bax/Bcl-2 ratio, loss of mitochondrial membrane potential (ΔΨm), cytochrome (Cyt) c release, caspase-9 and caspase-3 activation, and poly(ADP-ribose) polymerase (PARP) degradation. The ROS elevation induced the sustained phosphorylation of c-Jun N-terminal kinase (JNK), while SP600125, a JNK inhibitor, nearly completely reversed sambutoxin-induced apoptosis. Accordingly, an in vivo study showed that sambutoxin exhibited potential antitumor activity in a BALB/c nude mouse xenograft model without significant systemic toxicity. Moreover, the expression changes in proteins related to the G2/M phase, DNA damage, and apoptosis in vivo were consistent with those in vitro. Importantly, sambutoxin has remarkable antiproliferative effects and is a promising anticarcinogen candidate for cancer treatment.

Research progress on the role of PDGF/PDGFR in type 2 diabetes.

Platelet-derived growth factors (PDGFs) are basic proteins stored in the α granules of platelets. PDGFs and their receptors (PDGFRs) are widely expressed in platelets, fibroblasts, vascular endothelial cells, platelets, pericytes, smooth muscle cells and tumor cells. The activation of PDGFR plays a number of critical roles in physiological functions and diseases, including normal embryonic development, cellular differentiation, and responses to tissue damage. In recent years, emerging experimental evidence has shown that activation of the PDGF/PDGFR pathway is involved in the development of diabetes and its complications, such as atherosclerosis, diabetic foot ulcers, diabetic nephropathy, and retinopathy. Research on targeting PDGF/PDGFR as a treatment has also made great progress. In this mini-review, we summarized the role of PDGF in diabetes, as well as the research progress on targeted diabetes therapy, which provides a new strategy for the treatment of type 2 diabetes.

The role of ß-catenin in cardiac diseases.

The Wnt/ß-catenin signaling pathway is a classical Wnt pathway that regulates the stability and nuclear localization of ß-catenin and plays an important role in adult heart development and cardiac tissue homeostasis. In recent years, an increasing number of researchers have implicated the dysregulation of this signaling pathway in a variety of cardiac diseases, such as myocardial infarction, arrhythmias, arrhythmogenic cardiomyopathy, diabetic cardiomyopathies, and myocardial hypertrophy. The morbidity and mortality of cardiac diseases are increasing, which brings great challenges to clinical treatment and seriously affects patient health. Thus, understanding the biological roles of the Wnt/ß-catenin pathway in these diseases may be essential for cardiac disease treatment and diagnosis to improve patient quality of life. In this review, we summarize current research on the roles of ß-catenin in human cardiac diseases and potential inhibitors of Wnt/ß-catenin, which may provide new strategies for cardiac disease therapies.

Dual-Stimulus-Driven Dynamically Controllable [3]Rotaxane with Tunable Organic Room-Temperature Phosphorescence.

A dual-stimulus-driven stiff-stilbene-based dynamic [3]rotaxane has been facilely developed using the threading-stoppering strategy and exhibits reversible shuttling motions and bidirectional rotations upon encountering acid-base and distinct light stimulations, respectively. Herein, the two dibenzo-24-crown-8 macrocycles can undergo reversible switching motion between two different stations along the axle suffered from acid-base stimulation, and simultaneously, the two rotaxanes can also perform cis-trans rotations upon irradiation with distinct light. In other words, the constructed rotaxanes can conduct two modes of regular motions without interference. Interestingly, reciprocating switching motion of the rings along the axle enabled the rotaxanes to exhibit controllable and reversible photoisomerization speed, conversion yield, and quantum yield. Crucially, these rotaxanes also manifest adjustable solid-state organic room-temperature phosphorescence (RTP) and photoluminescence stimulated by dual factors (acid-base and diverse light), which are further applied in information encryption and anticounterfeiting. The presented study provides an instructive way for precisely boosting photoisomerization performances and the fabrication of dual-stimuli-induced molecular machines with functions of two-mode mechanical motions and controllable pure organic RTP switches.

Effects of 2,2',4'-trihydroxychalcone on the proliferation, metastasis and apoptosis of A549 human lung cancer cells.

The aim of the present study was to evaluate the antitumor effects of 2,2',4'-trihydroxychalcone (7a) on the A549 human lung cancer cell line. A549 cells were treated with different concentrations of 7a for different time periods. Cells without 7a were used as the negative control group. Cell proliferation, invasion, vasculogenic mimicry (VM) formation, heterogeneous adhesion and apoptosis were measured using Cell Counting Kit-8, Transwell invasion, VM, adhesion and flow cytometric assays, respectively. In addition, the expression of related proteins was determined using western blot analysis or ELISA. The present study found that 7a had a significant inhibitory effect on the survival rate of the A549 lung cancer cells but almost no effect on BEAS-2B human lung epithelial cells or human venous endothelial cells. The migration rate, VM length, invasion rate and heterogeneous adhesion number of cells treated with 7a significantly decreased as the concentration increased, while the apoptosis rate increased. Western blot analysis showed that 7a treatment significantly increased the expression levels of E-cadherin, cleaved poly (ADP-ribose) polymerase, Bax and caspase-3 and simultaneously decreased the expression levels of metalloproteinase-2/9, Bcl-2, phosphorylated (p)-PI3K, p-AKT, p-mTOR, vascular endothelial growth factor (VEGF), E-selectin and N-cadherin. At the same time, the ELISA results showed that the level of the pro-angiogenic factor VEGF in the culture media was reduced in the presence of 7a. In addition, 7a could also reduce the nuclear NF-κB protein expression, which could inhibit the gene transcription of tumor apoptosis and metastasis-related proteins. Therefore, 7a may exert inhibitory effects on A549 cells by inhibiting cell proliferation, migration, VM formation and heterogeneous adhesion, as well as by inducing apoptosis through the suppression of the PI3K/AKT/NF-κB signaling pathway; these findings suggested that 7a may be a promising agent for the treatment of lung cancer.

Research progress on the role of gal-3 in cardio/cerebrovascular diseases.

Galectin-3 (gal-3), a member of the galectin family, is a glycoprotein with high affinity for ß-galactoside. Gal-3 is a cytoplasmically synthesized protein that can shuttle between the cytoplasm and nucleus and can even be transported to the membrane and secreted into the extracellular environment. Cardio/cerebrovascular diseases generally refer to ischemic or hemorrhagic diseases occurring in the heart, brain and systemic tissues, which are characterized by high morbidity, high disability rates and high mortality rates. To date, considerable research has demonstrated that gal-3 expression is aberrantly increased and plays important roles in cardio/cerebrovascular diseases, such as acute ischemic stroke (AIS), myocardial fibrosis, acute coronary syndrome (ACS), and heart failure (HF). Hence, understanding the biological roles of gal-3 in these diseases may be essential for cardio/cerebrovascular disease treatment and diagnosis to improve patient quality of life. In this review, we summarize current research on the roles of gal-3 in human cardiovascular diseases and potential inhibitors of gal-3, which may provide new strategies for disease therapies.

Light driven molecular lock comprises a Ru(bpy)2(hpip) complex and cucurbit[8]uril.

Here, complex 1 ([Ru(bpy)2(hpip)]2+-MV2+) and CB[8] can form a stable 1 : 1 inclusion complex in aqueous solution, resembling a U-shaped conformation. Upon light irradiation, two complex 1 were reversibly locked through the formation of a MV˙+ radical dimer that is stabilized in the cavity of CB[8] with Ru complexes as blockers, in which complex 1 was transformed from a U-shaped conformation to a interlocked complex. This study provided a feasible strategy for the fabrication of a photo-driven supramolecular machine resembling a "lock".

The roles of galectins in hepatic diseases.

Hepatic diseases include all diseases that occur in the liver, including hepatitis, cirrhosis, hepatocellular carcinoma, etc. Hepatic diseases worldwide are characterized by high incidences of digestive system diseases, which present with subtle symptoms, are difficult to treat and have high mortality. Galectins are ß-galactoside-binding proteins that have been found to be aberrantly expressed during hepatic disease progression. An increasing number of studies have shown that abnormal expression of galectins is extensively involved in hepatic diseases, such as hepatocellular carcinoma (HCC), liver cirrhosis, hepatitis and liver fibrosis. Galectins function as intracellular and extracellular hepatic disease regulators mainly through the binding of their carbohydrate recognition domain to glycoconjugates expressed in hepatocytes. In this review, we summarize current research on the various roles of galectins in cirrhosis, hepatitis, liver fibrosis and HCC, which may provide a preliminary theoretical basis for the exploration of new targets for the treatment of hepatic diseases.

Aberrant N-cadherin expression in cancer.

Neural (N)-cadherin is a calcium-dependent single-chain transmembrane glycoprotein that mediates homotypic and heterotypic cell-cell adhesion. As an important member of the cadherin family, N-cadherin plays an important role in the developmental and functional regulation of the nervous system, brain, heart, skeletal muscles, blood vessels and hematopoietic microenvironment. However, aberrant expression of N-cadherin has been found in many cancers, such as lung cancer, breast cancer, prostate cancer and squamous cell carcinoma. It is increasingly recognized that aberrant expression of N-cadherin is closely related to aspects of malignant tumor progression in humans, such as transformation, adhesion, apoptosis, angiogenesis, invasion and metastasis, suggesting that N-cadherin can be a therapeutic target for tumor invasion and metastasis. This minireview summarizes the diverse roles of N-cadherin in cancer progression and the regulatory factors that affect the expression of N-cadherin in cancer, findings that increase our awareness of the importance of developing new therapeutic agents targeting N-cadherin.

Reversible switching of a supramolecular morphology driven by an amphiphilic bistable [2]rotaxane.

An acid/base responsive amphiphilic [2]rotaxane switch containing a hydrophilic macrocycle component and a hydrophobic terminal bulky group was prepared and characterized. The morphology of the supramolecular assemblies formed by the rotaxanes could be switched between spherical vesicles and worm-like micelles using acid/base stimuli, as confirmed by transmission electron microscopy (TEM).

Determination of brusatol in plasma and tissues by LC-MS method and its application to a pharmacokinetic and distribution study in mice.

OBJECTIVES: The quassinoid brusatol, which can be isolated from Brucea javanica (L.) Merr., becomes popularly studied because of its anti-tumor activity. In order to further investigate brusatol and extend its applications, a sensitive analytical method for determination of brusatol in biological samples is essential. However, few methods had been reported until now. In this study, a highly sensitive and reproducible LC-MS method for simultaneous quantification of brusatol in mouse plasma and tissues was developed and validated. METHOD: Plasma samples and tissue homogenate were extracted with diethyl ether after addition of the internal standard solution(IS). The supernatant was blown to dryness with nitrogen and residual was reconstituted with 100µl of methanol. The separation was performed on an Intersil ODS-3 column and gradient elution was conducted with the mobile phase of water and methanol (0-5min 47:53, 5-5.5min 47:53-10:90, 5.5-9min 10:90, posttime 4min 47:53) at a flow rate of 0.8mL/min. Quantification was performed in the selected ion monitoring (SIM) mode at m/z 543.2 for brusatol and 220.0 for IS (ornidazole). The method was validated by analyzing quality control plasma and tissue homogenate samples, and was applied to analyze samples obtained from mice after injections of brusatol via the tail vein. RESULTS: With ornidazole as the internal standard, calibration curve of the method ranged from 10 to 320ng/ml for plasma and 10-240ng/ml for tissues. Recovery rate of brusatol from plasma and tissues were between 71.09%-94.91%. Relative standard deviation (RSD) for inter- and intra-day precision was less than 15%, and the accuracy was between 96.1%-111.8%. The pharmacokinetics and distribution study of brusatol in mice after three single doses via the tail vein were carried out based on this method. The concentration of brusatol in plasma decreased rapidly and a more than 10 fold concentration of brusatol was found as compared to that in other tissues. CONCLUSIONS: This is the first reported LC-MS method for detecting brusatol in tissues and can accurately determine the concentrations of these compounds in plasma and different tissues. Further research on the metabolism of brusatol in vivo is still needed.

The anti-inflammatory effects of Morin hydrate in atherosclerosis is associated with autophagy induction through cAMP signaling.

SCOPE: Although the previous trials of inflammation have indicated that morin hydrate (MO) hold considerable promise, understanding the distinct mechanism of MO against inflammation remains a challenge. METHODS AND RESULTS: This study investigated the effect of MO in atherosclerosis in ApoE-/- mice and underlying cell signaling of MO effect in inflammation in human umbilical vein endothelial cells (HUVECs). Administration of MO significantly reduced serum lipid level, inflammatory cytokines (TNF-α and ICAM-1), and atherosclerotic plaque formation in vivo. MO presence attenuated the expression of TNF-α-induced inflammatory cytokines (ICAM-1, COX-2, and MMP-9), and remarkably enhanced microtubule associated protein 1 light chain 3 beta 2 (MAP1LC3B2) expression and sequestosome 1 (SQSTM1/p62) degradation in HUVECs. These MO effects were significantly prevented by the presence of autophagic inhibitors, 3-methyladenine (3-MA), or chloroquine (CQ), as well as siRNA suppression of ATG5 and BECN1. MO increased intracellular cAMP levels and activated cAMP-PKA-AMPK-SIRT1 signaling in vivo and in vitro. These changes resulted in increased expression of autophagy-related protein MAP1LC3B2 and decreased secretion of inflammatory cytokines (ICAM-1, COX-2, and MMP-9). CONCLUSION: Our results suggest that anti-AS and anti-inflammatory effects of MO are largely associated with its induction of autophagy through stimulation of cAMP-PKA-AMPK-SIRT1 signaling pathway.

The role of galectin-4 in physiology and diseases.

Galectin-4, a tandem repeat member of the ß-galactoside-binding proteins, possesses two carbohydrate-recognition domains (CRD) in a single peptide chain. This lectin is mostly expressed in epithelial cells of the intestinal tract and secreted to the extracellular. The two domains have 40% similarity in amino acid sequence, but distinctly binding to various ligands. Just because the two domains bind to different ligands simultaneously, galectin-4 can be a crosslinker and crucial regulator in a large number of biological processes. Recent evidence shows that galectin-4 plays an important role in lipid raft stabilization, protein apical trafficking, cell adhesion, wound healing, intestinal inflammation, tumor progression, etc. This article reviews the physiological and pathological features of galectin-4 and its important role in such processes.

Photo-powered stretchable nano-containers based on well-defined vesicles formed by an overcrowded alkene switch.

A novel photo-responsive nano-container was successfully constructed based on well-defined vesicles formed by an amphiphilic overcrowded alkene switch. The nano-container could adjust its inner volume in reversible photo/heat controlled mode, which could show potential in remote drug delivery systems.

A fluorescent bistable [2]rotaxane molecular switch on SiO2 nanoparticles.

A fluorescent bistable [2]rotaxane terminated with an alkyne functional group was constructed and immobilized onto the surface of SiO2 nanoparticles through click reaction. The shuttling motion of the macrocycle component between two different stations was driven by external acid-base stimuli both in solution and on SiO2 nanoparticles, accompanied by visual fluorescence changes.

A switchable bis-branched [1]rotaxane featuring dual-mode molecular motions and tunable molecular aggregation.

A multifunctional bis-branched [1]rotaxane containing a perylene bisimide (PBI) core and two identical bistable[1]rotaxane arms terminated with ferrocene units was prepared and characterized by (1)H NMR, (13)C NMR, and 2D ROESY NMR spectroscopies and by HR-ESI spectrometry. The system is shown to possess several key features: (1) In acetone solution, external acid-base stimuli can result in relative mechanical movements of its ring and thread, which can induce extension and contraction movements of the whole system accompanied by a rotational movement of the ferrocene units, thus realizing dual-mode molecular motions, and the optimized conformations at different states are obtained through molecular dynamics simulations employing the general Amber force field. (2) The introduction of PBI enables the system fluorescence encoding through distance-dependent photoinduced electron transfer process from the ferrocene units to the PBI fluorophore. (3) The addition of Zn(2+) can increase the degree of aggregation of the system, while adding base hinders aggregation because of the movement of the macrocycle. The tunable aggregated nanostructural morphologies of [1]rotaxane were examined by scanning electron microscopy. These results can pave the way to achieve precise control of integrated and coupling nanomechanical motions at a single-molecule level and provide more insight into controlling the aggregate behavior of switchable mechanically interlocked molecules.