Peihui Yang

Anti-tumor activity evaluation of novel chrysin–organogermanium(IV) complex in MCF-7 cells

Chrysin (5,7-dihydroxylflavone, Chry) is a natural product extracted from plants, honey, and propolis. In this work, a novel chrysin-organogermanium(IV) complex (Chry-Ge) with enhanced anticancer activities was synthesized, and its potential anticancer effects against cancer cells were measured using various methods. MTT results showed that Chry-Ge had significant inhibition effects on the proliferation of MCF-7, HepG2 and Colo205 human cancer cell lines in a dose-dependent manner while had little cytotoxic effects on MCF-10A human normal cells (MCF-10A cells) with the same treatment of Chry-Ge. These results suggested that Chry-Ge possessed enhanced anticancer effects and high selectivity between cancer cells and normal cells. The immuno-staining results showed that the nuclei of MCF-7 cells represented a total fragmented morphology and a disorganized cytoskeletal network in MCF-7 cells after Chry-Ge treatment. Besides, atomic force microscopy (AFM) was applied to detect the changes of ultrastructural and biomechanical properties of MCF-7 cellular membrane induced by Chry-Ge. The AFM data indicated that Chry-Ge treatment directly caused the decrease of cell rigidity and adhesion force of MCF-7 cells, suggesting that membrane toxicity might be one of the targets for Chry-Ge in MCF-7 cells. Moreover, the fluorescence-based flow cytometric analysis demonstrated that Chry-Ge could induce apoptosis in MCF-7 cells in ROS-dependent mitochondrial pathway. All results collectively showed that Chry-Ge could be as a promising anticancer drug for cancer therapy.

Gold nanoprobes-based resonance Rayleigh scattering assay platform: Sensitive cytosensing of breast cancer cells and facile monitoring of folate receptor expression

A rapid, facile assay for sensitive cytosensing of breast cancer cells should help to guide potential medical evaluation for breast cancer. Here, we report development of novel resonance Rayleigh scattering (RRS) cytosensor for cell recognitions and folate (FA) receptor expression analyses on living cells. Using FA-conjugated gold nanoparticles (FA-AuNPs) as nanoprobes, the constructed nanoprobes-assembled recognition interface could increase the binding capacity for cell recognition, amplify Au-aggregates-enhanced RRS signal, and then enhance the sensitivity for membrane antibody assay. FA-AuNPs-based RRS measurements enabled a distinct 34-times-enhancement in RRS intensities after incubation with human breast cancer cells, compared with normal cells. Receptor-targeted cytosensor was used to quantitatively detect human breast cancer MCF-7, liver cancer HepG2 and normal cells, which expressing different amount of FA receptor, respectively. The detection limit for MCF-7 cells was 12 cells/mL with good selectivity and reproducibility. Furthermore, the proposed cytosensor allowed for dynamic evaluation of FA receptor expression on different living cells after dihydroartemisinin stimulus. This assay platform shows the good potential for clinical diagnostics and antibody-targeted drug screening.

A label-free electrochemiluminescence cytosensors for specific detection of early apoptosis.

A novel electrochemiluminescence (ECL) cytosensors was developed for the detection of early apoptotic cells by the specific interaction between Annexin V and phosphatidylserine(PS) based on ECL signal of CdS-QDs. Immobilization of Annexin V on a L-cysteine-capped CdS-QDs/Polyaniline nanofibers (PANI-NF) resulted in the stable and high loading of Annexin V on the sensor surface and the possibility of sensitivity enhancement. Early apoptotic cells showed an increased exposure of PS on the cell membrane caused by physiological and pathological response reactions, leading to a strong interaction between the apoptotic cells and the sensor surface, which could be probed by the ECL. Using a real of early apoptotic HepG2 cell induced by resveratrol (RVL), the proposed novel strategy has demonstrated its simplicity, high sensitivity, good selectivity and high reproducibility and label-free capability which might hold a great potential for rapid detection of cell apoptosis and drug screening. The results from this approach have showed good agreement with those obtained using inverted microscope, flow cytometry(FCM) and Atomic force microscopy(AFM). The linear range for early apoptotic cells detection ranged from 500 to 1.0 × 10(6) cells mL(-1) with a detection limit of 500 cells mL(-1). The reported strategy has provided a promising platform for highly sensitive cytosensing and convenient screening of some clinically anticancer drugs.

Folate-Chitosan Nanoparticles Loaded with Ursolic Acid Confer Anti-Breast Cancer Activities in vitro and in vivo.

Ursolic acid (UA) has proved to have broad-spectrum anti-tumor effects, but its poor water solubility and incompetent targeting property largely limit its clinical application and efficiency. Here, we synthesized a nanoparticle-based drug carrier composed of chitosan, UA and folate (FA-CS-UA-NPs) and demonstrated that FA-CS-UA-NPs could effectively diminish off-target effects and increase local drug concentrations of UA. Using MCF-7 cells as in vitro model for anti-cancer mechanistic studies, we found that FA-CS-UA-NPs could be easily internalized by cancer cells through a folate receptor-mediated endocytic pathway. FA-CS-UA-NPs entered into lysosome, destructed the permeability of lysosomal membrane, and then got released from lysosomes. Subsequently, FA-CS-UA-NPs localized into mitochondria but not nuclei. The prolonged retention of FA-CS-UA-NPs in mitochondria induced overproduction of ROS and destruction of mitochondrial membrane potential, and resulted in the irreversible apoptosis in cancer cells. In vivo experiments showed that FA-CS-UA-NPs could significantly reduce breast cancer burden in MCF-7 xenograft mouse model. These results suggested that FA-CS-UA-NPs could further be explored as an anti-cancer drug candidate and that our approach might provide a platform to develop novel anti-cancer drug delivery system.

An efficient nanomaterial-based electrochemical biosensor for sensitive recognition of drug-resistant leukemia cells

A novel electrochemical cytosensor was developed for the fast and high-sensitivity recognition of drug-resistant leukemia K562/ADM cells based on the P-glycoprotein (P-gp) expression level on a cell membrane. The nanocomposite interface of the gold nanoparticles/polyaniline nanofibers (AuNPs/PANI-NF) was chosen to design the biosensor for electrochemical detection. Au/PANI-NF-based cytosensors coated with anti-P-glycoprotein (anti-P-gp) molecules could provide a biomimetic interface for the immunosensing of cell surface P-glycoprotein, and thus could capture the over-expression P-gp cells. Transmission electron microscopy (TEM) indicated that the gold nanoparticles were uniformly anchored along the structure of the PANI-NF surface, displaying fibrillar morphology with a diameter of ∼70 nm, and atomic force microscopy (AFM) further presented the morphology of the nanocomposite film. Owing to the high affinity of anti-P-gp for leukemia K562/ADM cells of the propounded sensing platform, the proposed biosensor exhibited excellent analytical performance for leukemia K562/ADM cells, ranging from 1.6 × 10(2) to 1.6 × 10(6) cells per mL with a detection limit of 80 cells per mL. Recovery experiments indicated that the sensitivity reported here is suitable for practical application. The cell surface P-gp expression level was analysed by flow cytometric experiments, which confirmed the above recognized result. This strategy is also a cost-effective and convenient operation, implying great promise for the sensitive recognition of cancer cells and cell surface receptors; thus, it is helpful in cancer diagnosis.

Synthesis and synergetic effects of chrysin-organogermanium (IV) complex as potential anti-oxidant.

Organogermanium(IV) (Ge) is considered to play an important role in the anti-oxidative activities of some Chinese medicines. Here, a new chrysin-organogermanium (Chry-Ge) complex was synthesized and investigated for its potential biological activities. The radicals-sensitive Ge-O bond was introduced to Chry-Ge complex to enhance bioactivities of organic Ge or Chry. Results showed that Chry-Ge complex possessed great anti-oxidative activities, showing stronger hydroxyl scavenging effects than their corresponding ligands. We also demonstrated Chry-Ge complex inhibited ROS-dependent oxidative damage in cells. Moreover, the morphological and biophysical recoveries in oxidation-damaged cells induced by Chry-Ge complex were characterized by atomic force microscopy. All these results collectively suggested that Chry-Ge complex has synergetic effect for radicals scavenging and could be served as promising pharmacologically active agent against anti-oxidative treatment.

Single molecule force spectroscopy for in-situ probing oridonin inhibited ROS-mediated EGF-EGFR interactions in living KYSE-150 cells

Graphical abstract Figure. No Caption available. ABSTRACT As the active anticancer component of Rabdosia Rubescens, oridonin has been proved to show strong anticancer activity in cancer cells, which is also found to be closely related to its specific inhibition effects on the EGFR tyrosine kinase activity. In this study, atomic force microscopy based single molecule force spectroscopy (AFM‐SMFS) was used for real‐time and in‐situ detection of EGF‐EGFR interactions in living esophageal cancer KYSE‐150 cells to evaluate the anticancer activity of oridonin for the first time. Oridonin was found to induce apoptosis and also reduce EGFR expression in KYSE‐150 cells. AFM‐SMFS results demonstrated that oridonin could inhibit the binding between EGF and EGFR in KYSE‐150 cells by decreasing the unbinding force and binding probability for EGF‐EGFR complexes, which was further proved to be closely associated with the intracellular ROS level. More precise mechanism studies based on AFM‐SMFS demonstrated that oridonin treatment could decrease the energy barrier width, increase the dissociation off rate constant and decrease the activation energy of EGF‐EGFR complexes in ROS dependent way, suggesting oridonin as a strong anticancer agent targeting EGF‐EGFR interactions in cancer cells through ROS dependent mechanism. Our results not only suggested oridonin as a strong anticancer agent targeting EGF‐EGFR interactions in ROS dependent mechanism, but also highlighted AFM‐SMFS as a powerful technique for pharmacodynamic studies by detecting ligand‐receptor interactions, which was also expected to be developed into a promising tool for the screening and mechanism studies of drugs.

Hydroxyl radical scavenging mechanism of human erythrocytes by quercetin–germanium (IV) complex

Quercetin is a popular flavonoid in plant foods, herbs, and dietary supplement. Germanium, a kind of trace elements, can enhance the body immunity. This study investigated the hydroxyl-radical-scavenging mechanism of the quercertin-germanium (IV) (Qu-Ge) complex to human erythrocytes, especially the effects on ultrastructure and mechanical properties of cell membrane, plasma membrane potential and intracellular free Ca(2+) concentration. Results showed that QuGe(2), a kind of the Qu-Ge complex, could reduce the oxidative damage of erythrocytes, change the cell-surface morphology, and partly recover the disruption of plasma membrane potential and intracellular free Ca(2+) level. Atomic force microscopy (AFM) was used to characterize the changes of the cell morphology, cell-membrane ultrastructure and biophysical properties at nanoscalar level. QuGe(2) has triggered the antioxidative factor to inhibit cellular damage. These results can improve the understanding of hydroxyl-radical-scavenging mechanism of human erythrocytes induced by the Qu-Ge complex, which can be potentially developed as a new antioxidant for treatment of oxidative damage.

A sensitive electrochemiluminescence cytosensor for quantitative evaluation of epidermal growth factor receptor expressed on cell surfaces.

A sensitive electrochemiluminescence (ECL) strategy for evaluating the epidermal growth factor receptor (EGFR) expression level on cell surfaces was designed by integrating the specific recognition of EGFR expressed on MCF-7 cell surfaces with an epidermal growth factor (EGF)-funtionalized CdS quantum dots (CdSQDs)-capped magnetic bead (MB) probe. The high sensitivity of ECL probe of EGF-funtionalized CdSQD-capped-MB was used for competitive recognition with EGFR expressed on cell surfaces with recombinant EGFR protein. The changes of ECL intensity depended on both the cell number and the expression level of EGFR receptor on cell surfaces. A wide linear response to cells ranging from 80 to 4×10(6)cellsmL(-1) with a detection limit of 40cellsmL(-1) was obtained. The EGF-cytosensor was used to evaluate EGFR expression levels on MCF-7 cells, and the average number of EGFR receptor on single MCF-7 cells was 1.35×10(5) with the relative standard deviation of 4.3%. This strategy was further used for in-situ and real-time evaluating EGFR receptor expressed on cell surfaces in response to drugs stimulation at different concentration and incubation time. The proposed method provided potential applications in the detection of receptors on cancer cells and anticancer drugs screening.

Construction of An Electrochemical Cytosensor Based on Polyaniline Nanofiber/Gold Nanoparticle Interface and Application to Detection of Cancer Cells

Abstract Polyaniline nanofibers (PANI-NF) were first synthesized with diameters of approximately 60–80 nm. PANI-NF/gold nanoparticle (PANI-NF/AuNP) nanocomposite was then fabricated through a simple electrostatic reaction between the positive charges on the surface of PANI-NF and the negatively charged AuNPs. Thereafter, a novel electrochemical cytosensor was designed by the self-assembly of folate on PANI-NF/AuNP nanocomposite film. An electrochemical impedance method was used to detect cancer cells based on the specific interaction between the folate receptor on cancer cell membranes and folate immobilized on PANI-NF/AuNP surface. Experimental results showed that the PANI-NF/AuNP cytosensor specifically recognized cancer cells, such as HeLa cells, which was reflected by the change in electrode impedance after attachment of the cancer cells. The linear detection range was from 1.0 × 104 to 6.4 × 106 cells mL−1, and the detection limit was 2000 cells mL−1. This cytosensor has several advantages, such as easy construction, short response time, high sensitivity, easy regeneration, good stability, and freedom of additional labeling, which can be thus used for a highly sensitive detection of cancer cells.