Optimization of polyethylene terephthalate biodegradation using a self-assembled multi-enzyme cascade strategy.

Although many efforts have been devoted to the modification of polyethylene terephthalate (PET) hydrolases for improving the efficiency of PET degradation, the catalytic performance of these enzymes at near-ambient temperatures remains a challenge. Herein, a multi-enzyme cascade system (PT-EC) was developed and validated by assembling three well-developed PETases, PETaseEHA, Fast-PETase, and Z1-PETase, respectively, together with carboxylesterase TfCa, and hydrophobic binding module CBM3a using scaffold proteins. The resulting PT-ECEHA, PT-ECFPE, PT-ECZPE all demonstrated outstanding PET degradation efficacy. Notably, PT-ECEHA exhibited a 16.5-fold increase in product release compared to PETaseEHA, and PT-ECZPE yielded the highest amount of product. Subsequently, PT-ECs were displayed on the surface of Escherichia coli, respectively, and their degradation efficiency toward three PET types was investigated. The displayed PT-ECEHA exhibited a 20-fold increase in degradation efficiency with PET film compared to the surface-displayed PETaseEHA. Remarkably, an almost linear increase in product release was observed for the displayed PT-ECZPE over a one-week degradation period, reaching 11.56 ± 0.64 mM after 7 days. TfCaI69W/L281Y evolved using a docking-based virtual screening strategy showed a further 2.5-fold increase in the product release of PET degradation. Collectively, these advantages of PT-EC demonstrated the potential of a multi-enzyme cascade system for PET bio-cycling.

Sensitive detection of HSP70 using a current-amplified biosensor based on antibody-loaded PS-AuNPs@Cys/Au modified ITO chip.

A biosensing electrochemical platform for heat shock protein 70 (HSP70) has been developed by integrating a three-electrode indium tin oxide (ITO) on a chip. The platform includes modifications to the reference electrode and working electrode for the detection of HSP70. The new platform is constructed by assembly of HSP70 antibody on PS-AuNPs@Cys/Au indium tin oxide (ITO) electrode to create a high HSP70 sensitive surface. The PS-AuNPs@Cys/Au indium tin oxide (ITO) electrode is obtained by immersing the ITO electrode into the PS-AuNPs@Cys solution and performing constant potential deposition at -1.4 V (Ag/AgCl). The PS-AuNPs@Cys/Au film deposited on ITO glass provides a desirable substrate for the immobilization of the HSP70 antibody and improves the loading of antibody between PS-AuNPs@Cys/Au and the electrode resulting in a significant amplification. Under optimal conditions, the fabricated sensor demonstrates a linear range extending from 0.1 ng mL- 1 to 1000 ng mL- 1, with an impressive detection limit of 25.7 pg mL- 1 (S/N = 3). The developed immunoassay method successfully detected the HSP70 content in normal human blood samples and outperformed the ELISA method commonly used for clinical sample analysis.

Quantitative Analysis on Molecular Characteristics Evolution of Gastric Cancer Progression and Prognosis.

The dynamic changes of key biological characteristics from gastric low-grade intraepithelial neoplasia (LGIN) to high-grade intraepithelial neoplasia (HGIN) to early gastric cancer (EGC) are still unclear, which greatly affect the accurate diagnosis and treatment of EGC and prognosis evaluation of gastric cancer (GC). In this study, bioinformatics methods/tools are applied to quantitatively analyze molecular characteristics evolution of GC progression, and a prognosis model is constructed. This study finds that some dysregulated differentially expressed mRNAs (DEmRNAs) in the LGIN stage may continue to promote the occurrence and development of EGC. Among the LGIN, HGIN, and EGC stages, there are differences and relevance in the transcription expression patterns of DEmRNAs, and the activation related to immune cells is very different. The biological functions continuously changed during the progression from LGIN to HGIN to EGC. The COX model constructed based on the three EGC-related DEmRNAs has GC prognostic risk prediction ability. The evolution of biological characteristics during the development of EGC mined by the authors provides new insight into understanding the molecular mechanism of EGC occurrence and development. The three-gene prognostic risk model provides a new method for assisting GC clinical treatment decisions.

Understanding the experiences of patients with cancers in hospitals during COVID-19 pandemic in China: A qualitative research study.

AIM: To explore the experiences of patients with cancers in hospitals during the COVID-19 pandemic. DESIGN: A qualitative research study. METHODS: Using a phenomenological approach, we enrolled 22 patients with cancers in the Hunan Cancer Hospital from 20 February 2020 to 10 April 2020. The interviews were conducted face-to-face and were analysed by Colaizzi's 7-step method. This study aligns with the COREQ checklist. RESULTS: The experiences of patients with cancers in hospitals during the COVID-19 pandemic can be categorized into four major themes: (1) emotional changes; (2) delays in visiting hospital; (3) barriers to accessing medical care services, and (4) inconvenience related to logistics services.

Random walks in time-varying networks with memory.

Random walks process on networks plays a fundamental role in understanding the importance of nodes and the similarity of them, which has been widely applied in PageRank, information retrieval, and community detection, etc. An individual's memory has been proved to be crucial to affect network evolution and dynamical processes unfolding on the network. In this work, we study the random-walk process on an extended activity-driven network model by taking account of an individual's memory. We analyze how an individual's memory affects random-walk process unfolding on the network when the timescales of the processes of the random walk and the network evolution are comparable. Under the constraints of long-time evolution, we derive analytical solutions for the distribution of walkers at the stationary state and the mean first-passage time of the random-walk process. We find that, compared with the memoryless activity-driven model, an individual's memory enhances the activity fluctuation and leads to the formation of small clusters of mutual contacts with high activity nodes, which reduces a node's capability of gathering walkers, especially for the nodes with large activity, and memory also delays the mean first-passage time. The results on real networks also support the theoretical analysis and numerical results with artificial networks.

Correction: Mechanosensitive caveolin-1 activation-induced PI3K/Akt/mTOR signaling pathway promotes breast cancer motility, invadopodia formation and metastasis in vivo.

[This corrects the article DOI: 10.18632/oncotarget.7583.].

MCP-1-induced ERK/GSK-3ß/Snail signaling facilitates the epithelial-mesenchymal transition and promotes the migration of MCF-7 human breast carcinoma cells.

Monocyte chemoattractant protein-1 (MCP-1) is a chemotactic cytokine that can bind to its receptor cysteine-cysteine chemokine receptor 2 (CCR2) and plays an important role in breast cancer cell metastasis. However, the molecular mechanisms underlying MCP-1-induced alterations in cellular functions during tumor progression are poorly understood. Here, we showed that MCP-1 stimulated the epithelial-mesenchymal transition (EMT) and induced the tumorigenesis of breast cancer cells by downregulating E-cadherin, upregulating vimentin and fibronectin, activating matrix metallopeptidase-2 (MMP-2), and promoting migration and invasion. Moreover, MCP-1 treatment reduced glycogen synthase kinase-3ß (GSK-3ß) activity via the MEK/ERK-mediated phosphorylation of serine-9 in MCF-7 cells. The inhibition of MEK/ERK by U0126 attenuated the MCP-1-induced phosphorylation of GSK-3ß and decreased the expression of Snail, an EMT-related transcription factor, leading to the inhibition of MCF-7 cell migration and invasion. Inactivation of GSK-3ß by LiCl (lithium chloride) treatment notably increased MMP-2 activity, vascular endothelial growth factor expression and EMT of MCF-7 cells. These findings revealed that MCP-1-induced EMT and migration are mediated by the ERK/GSK-3ß/Snail pathway, and identified a potential novel target for therapeutic intervention in breast cancer.

[Optical Analysis of the Interaction of Mercaptan Derivatives of Nanogold Particles with Carcinoembryonic Antigen].

Gold nanoparticles (AuNPs) have been the subject of intense research for use in biomedicine over the past couple of decades. AuNPs, also referred to as colloidal gold, possess some astounding optical and physical properties that have earned them a prime spot among the new promising tools for medical applications. Today, AuNPs are offered to provide the clinical laboratory with more sensitive, faster, and simpler assays, which are also cost-effective. AuNPs can be used to develop point-of- care tests and novel testing strategies such as in drug targeting, disease detection, molecular recognition, and biological labels. The typical structure of AuNPs is spherical nano-sized gold particles, but they can also be composed of a thin gold shell surrounding a dielectric core, such as silica (gold nanoshells). their size range from 0.8 to 250 nm and are characterized by high absorption coefficients. AuNPs have some unique optical properties, such as enhanced absorption and scattering, where the absorption cross-section of AuNPs is 4~5 orders of magnitude greater than that of rhodamine 6G. When AuNPs aggregate, interaction of locally adjacent AuNPs (plasmon-plasmon interaction) shifts their color to blue. Thus, the binding of AuNP-labeled entities to their respective target would lead to aggregation of the nanoparticles and a detectable shift in the optical signal. The strong absorption of AuNPs can also be used in colorimetric detection of analytes by measuring changes in the refractive index of the AuNP's environment caused by adsorption of the target analytes. However, a large number of surface atoms of nanoparticles have huge surplus bonding ability, because of surface effect of gold nanoparticles, result in reuniting and sinking among the nanoparticles which make them unstable. In order to detect traces of carcinoembryonic antigen, one of the tumor targets, a new kind of gold nanoparticle with hyperchormic effect and fluorescence sensitization effect material needs to be prepared. In this paper, novel mercaptan derivative of nanogold particles are prepared and studied using transmission electron microscopy (TEM), ultra-violet-visible absorption spectra (UV-Vis), fluorescence emission (FE) spectrum and infrared spectrum (IR) methods. The UV-Vis and FE results show the presence of new ligands mercaptan, more electrons from the orbit of ligand which can excite to the central ion related orbits and increase fluorescence of gold. Fluorescence sensitization effect was observed when mercaptan derivatives of nanogold interacted with carcinoembryonic antigen (CEA) and no fluorescence sensitization effect was found when nanogold interacted with carcinoembryonic antigen (CEA). The study of CEA hyperchromic mechanism of mercaptan derivatives nanogold and the CEA by the method of infrared spectrum, shows that the randomized OH bonds in the Au-protein interaction, showed more on the outside of the plane of bending vibration after the interaction with the mercaptan derivative nanogold, making the energy transfer from mercaptan derivatives nanogold to protein easy; leading to its fluorescence sensitization effect.

Folate-Functionalized Magnetic-Mesoporous Silica Nanoparticles for Drug/Gene Codelivery To Potentiate the Antitumor Efficacy.

An appropriate codelivery system for chemotherapeutic agents and nucleic acid drugs will provide a more efficacious approach for the treatment of cancer. Combining gene therapy with chemotherapeutics in a single delivery system is more effective than individual delivery systems carrying either gene or drug. In this work, we developed folate (FA) receptor targeted magnetic-mesoporous silica nanoparticles for the codelivery of VEGF shRNA and doxorubicin (DOX) (denoted as M-MSN(DOX)/PEI-FA/VEGF shRNA). Our data showed that M-MSN(DOX)/PEI-FA could strongly condense VEGF shRNA at weight ratios of 30:1, and possesses higher stability against DNase I digestion and sodium heparin. In vitro antitumor activity assays revealed that HeLa cell growth was significantly inhibited. The intracellular accumulation of DOX by confocal microscopy and fluorescence spectrophotometry showed that M-MSN(DOX)/PEI-FA were more easily taken up than nontargeted M-MSN(DOX). Quantitative PCR and ELISA data revealed that M-MSN/PEI-FA/VEGF shRNA induced a significant decrease in VEGF expression as compared to cells treated with either the control or other complexes. The invasion and migration phenotypes of the HUVECs were significantly decrease after coculture with MSN/PEI-FA/VEGF shRNA nanocomplexes-treated HeLa cells. The approach provides a potential strategy to treat cancer by a singular nanoparticle delivery system.

Notch-1 signaling activates NF-κB in human breast carcinoma MDA-MB-231 cells via PP2A-dependent AKT pathway.

Breast cancer has a high incidence in the world and is becoming a leading cause of death in female patients due to its high metastatic ability. High expression of Notch-1 and its ligand Jagged-1 correlates with poor prognosis in breast cancer. Our previous work has shown that Notch-1 signaling pathway upregulates NF-κB transcriptional activity and induces the adhesion, migration and invasion of human breast cancer cell line MDA-MB-231. However, the role of Notch-1 in NF-κB activation is still poorly understood. Here, we aim to understand the exact mechanism that Notch-1 regulates NF-κB activity. In MDA-MB-231 cells where Notch-1 is constitutively activated, the phosphorylation of p85 and AKT (Tyr308/Ser473) is upregulated, indicating PI3K/AKT pathway is activated. Notch-1 activation caused the increase of PP2A phosphorylation at Tyr307, indicating Notch-1 inhibits PP2A activity. NF-κB transcriptional activity was evaluated by dual-luciferase reporter assay, and the results showed that, while silencing of Notch-1, PP2A activity was upregulated and NF-κB activity was downregulated, whereas PP2A inhibitor okadaic acid (OA) restored NF-κB activity. Immunofluorescence and Western blots showed that OA treatment antagonized the decrease of p65 nuclear translocation caused by Notch-1 silencing. Moreover, OA treatment also upregulated MMP-2, MMP-9 and VEGF mRNA expression levels, indicating OA rescues Notch-1 silencing that caused low cell invasion. Taken together, our results suggest that Notch-1-activating PI3K/AKT/NF-κB pathway is PP2A dependent; PP2A may be a potential therapeutic target in breast cancer.

Mechanosensitive caveolin-1 activation-induced PI3K/Akt/mTOR signaling pathway promotes breast cancer motility, invadopodia formation and metastasis in vivo.

Cancer cells are subjected to fluid shear stress during passage through the venous and lymphatic system. Caveolin-1 (Cav-1), a principal structural component of caveolar membrane domains, contributes to cancer development but its mechanobiological roles under low shear stress (LSS) conditions remain largely unknown. Here, we identified Cav-1 is mechanosensitive to LSS exposure, and its activation-induced PI3K/Akt/mTOR signaling promotes motility, invadopodia formation and metastasis of breast carcinoma MDA-MB-231 cells. Application of LSS (1.8 and 4.0 dynes/cm2) to MDA-MB-231 cells significantly increased the cell motility, invadopodia formation, MT1-MMP expression, ECM degradation, and also induced a sustained activation of Cav-1 and PI3K/Akt/mTOR signaling cascades. Methyl-ß-cyclodextrin-caused caveolae destruction markedly decreased LSS-induced activation of both Cav-1 and PI3K/Akt/mTOR, leading to suppress MT1-MMP expression, inhibit invadopodia formation and ECM degradation, suggesting that caveolae integrity also involved in metastasis. Immunocytochemical assay showed that LSS induces the Cav-1 clustering in lipid rafts and co-localization of Cav-1 and MT1-MMP on invadopodia. Immunofluorescence confocal analysis demonstrated that Cav-1 activation were required for the acquisition of a polarized phenotype in MDA-MB-231 cells. Finally, Cav-1 knockdown significantly suppressed tumor colonization in the lungs and distant metastases in animal models. Our findings highlight the importance of Cav-1 in hematogenous metastasis, and provide new insights into the underlying mechanisms of mechanotransduction induced by LSS.

Essential oils from Inula japonica and Angelicae dahuricae enhance sensitivity of MCF-7/ADR breast cancer cells to doxorubicin via multiple mechanisms.

ETHNOPHARMACOLOGICAL RELEVANCE: Angelicae dahurica (Hoffm.) Benth. & Hook.f.ex Franch. & Sav combined with Pueraria and Gastrodia elata Bl. combined with Inula japonica Thunb. are widely used in herb-pairs of traditional chinese medicine. Previous studies have shown that Angelicae dahuricae essential oil (ADO) enhanced puerarin internalization into ABCB1-overexpressed Caco-2 cells. These findings suggest the possibility that essential oils may enhance the absorption via certain mechanisms related to ABCB1 and reverse multidrug resistance (MDR). AIM OF THE STUDY: ADO and essential oils from Inula japonica (IJO) may reverse ABCB1-mediated MDR, but this ability has not been investigated in detail in the well-established cancer cell lines. In this study, the underlying molecular mechanisms were further investigated to examine how IJO and ADO reverse MDR in the resistant human breast cancer cell line of MCF-7/ADR. Also this work may help uncover the conceivable compatibility mechanisms of above herb-pairs involved in ABCB1. MATERIALS AND METHODS: The MDR human breast cancer MCF-7/ADR cells were treated with IJO, its sesquiterpene component isoalantolactone (ISO) or ADOat non- cytotoxic concentrations. The MDR ability was examined by measuring the sensitivity to doxorubicin (DOX), DOX accumulation and efflux, ABCB1 ATPase activity, ABCB1 expression, membrane fluidity, and stability and localization of lipid rafts and caveolae. Finally, the molecular modeling was performed to postulate how ISO interacts with ABCB1. RESULTS: Treating MCF-7/ADR cells with IJ oil, ISO or AD oil reversed MDR 2- to 3-fold, without affecting the sensitivity of the non-MDR parental cell line. Mechanistic studies showed that these oils down-regulated mRNA and protein expression of ABCB1, and reduced the stability of lipid rafts in the cell membrane, which has previously been shown to reduce ABCB1-mediated transport. On the other hand, IJO, ISO and ADO did not inhibit ABCB1 ATPase activity, and fluorescence polarization experiments showed that low concentrations of the oils did not appear to alter membrane fluidity, unlike some MDR-reversing agents, ISO showed a higher docking score than verapamil but lower than dofequidar and tariquidar. CONCLUSIONS: Our results suggest that IJO, ISO and ADO could reverse MDR by down-regulating ABCB1 expression and reducing lipid raft stability. These findings may be useful for developing safer and effective MDR reversal agents and also help find out the compatibility mechanisms.

Photosensitizer-assembled PEGylated graphene-copper sulfide nanohybrids as a synergistic near-infrared phototherapeutic agent.

OBJECTIVES: Stimulative nanostructures play a crucial role in developing the smart nanomedicine for high therapeutic efficacy with minimum adverse effects. Herein, a near-infrared (NIR) light-responsive nanohybrids p-nanographene oxide (GO)-copper sulfide (CuS)/indocyanine green (ICG) comprised of GO, CuS nanoparticles and photosensitizer ICG was fabricated to couple the photothermal property of CuS and photodynamic effect of ICG in one system in order to achieve the synergistic phototherapy. METHODS: pGO-CuS/ICG was constructed by self-assembling ICG on pGO-CuS nanostructure. Its physicochemical, photothermal and photodynamic properties were studied by spectroscopic methods. The in vitro cellular uptake, cytotoxicity, the single/combined photothermal therapeutic (PTT) and photodynamic therapeutic (PDT) effects were investigated with biological techniques. RESULTS: pGO-CuS/ICG exhibited high efficacy of photothermal conversation and singlet oxygen generation under NIR laser excitation. It entered into the target cancer cells probably via passive transmembrane pathway and exerted obvious PTT and PDT effect against the tumor cells upon irradiation with the respective 940 and 808 nm lasers. In particular, the tremendous synergistic efficacy of PDT and PTT had been demonstrated by tuning the NIR laser combined irradiation. CONCLUSIONS: This study promises the future applications of pGO-CuS/ICG as a NIR light activable theranostic nanodrug for deep-seated cancer noninvasive phototherapy.

A molecule-imprinted polyaniline membrane modified on carbon fiber for detection of glycine.

A layer of L-glycine-molecule-imprinted polyaniline (LMIP-PANI) polymer film has been modified on a carbon fiber electrode for the determination of L-glycine standard samples and L-glycine in cerebrospinal fluid of wistar mice. It has been found that a linear relationship exists between current and concentration for the glycine standard samples in the range of 0-12 µM by using the LMIP-PANI-modified carbon fiber electrode as a sensor. However, there is no any relationship between current and concentration for the carbon fiber electrode modified with no-glycine-molecule-imprinted polyaniline (NIP-PANI). The MIP-PANI- and NIP-PANI-modified carbon fiber films have been characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and electrochemistry methods. The investigation shows that the MIP-PANI-imprinted carbon fiber electrode will have a potential application in in-situ monitoring neurotransmitter due to its easy fabrication, low cost, bio-compatibility and flexibility.

Complex thiolated mannose/quinone film modified on EQCM/Au electrode for recognizing specific carbohydrate-proteins.

A complex thiolated mannose (TM)/quinone functionalised polythiophene (QFPT) thin film was modified on EQCM/Au electrode for recognition of specific carbohydrate-proteins. Different lectins such as those from Sambucus nigra (elder berry), Arachis hypogaea (peanut), Ulex europaeus (gorse, furze), Triticum vulgaris and Concanavalin A (ConA) was used for probes to evaluate bio-sensing performance of the TM/QFPT film. A specific response was observed for ConA from lectins when using the TM/QFPT film as sensing material and employing either elelctrochemical or the QCM method. No response was detected between thiolated mannose and other lectins. The linear relationship between current and ConA concentration is in the range of 0.5-17.5 nM by the elelctrochemical method and the linear relationship between frequency change and ConA concentration is in the range of 0.5-4.5 nM by the QCM method. This shows that the TM/QFPT-modified EQCM biosensor presents a paralleled determination by using electrochemical and the QCM method. The elelctrochemical method of the biosensor can be applicable in a large concentration range and its frequency change can be more precise.

[Preparation of fluoridated hydroxyapatite coatings on titanium by electrolytic deposition and its FTIR characteristics].

Fluoridated hydroxyapatite coatings (FHAP) were prepared on titanium substrate by electrochemical deposition technique containing Ca2+, PO4(3-), and F(-) ions. The deposition was all conducted at a constant current of 0.9 mA for 60 min at 60 degrees C. The as-prepared coatings were examined by scanning electron microscope (SEM), energy-dispersive Xray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR) and Xray diffraction (XRD) tests. The results indicate that the FHAP cryatals take the morphology of nanoscale-rodlike cone rather than the micron-daisy petal, and the composite coating becomes more compact. The FTIR test indicates that the symmetry of stretching and bending vibration modes of hydroxyl changed, simulated body fluid immersion test proved that the FHAP coating had induced carbonate-apatite formation, indicating that the composite coating possesses excellent biocompatibility.