Publications by authors named "Chaoquan Hu"

21 Publications

  • Page 1 of 1

A novel free-standing metal organic frameworks-derived cobalt sulfide polyhedron array for shuttle effect suppressive lithium-sulfur batteries.

Nanotechnology 2021 Nov 24. Epub 2021 Nov 24.

Chinese Academy of Sciences - Intelligent Machines Institute, Science Island 1130 M B, Hefei 230026, Hefei, 230031, CHINA.

Metal-organic-foams (MOFs)-derived nanostructures have received broad attention for secondary batteries. However, common strategies are focusing on the preparation of dispersive materials, which need complicated steps and some additives for making electrodes of batteries. Here, we develop a novel free-standing Co9S8 polyhedron array derived from ZIF-67, which grows on a three-dimensional carbon cloth for lithium-sulfur (Li-S) battery. The polar Co9S8 provides strong chemical binding to immobilize polysulfides, which enables efficiently suppressing of the shuttle effect. The free-standing [email protected] polyhedron array-based cathode exhibits ultrahigh capacity of 1079 mAh g-1 after cycling 100 times at 0.1C, and long cycling life of 500 cycles at 1C, recoverable rate-performance and good temperature tolerance. Furthermore, the adsorption energies towards polysulfides are investigated by using density functional theory (DFT) calculations, which display a strong binding with polysulfides.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1088/1361-6528/ac3ce5DOI Listing
November 2021

Electronic and lattice strain dual tailoring for boosting Pd electrocatalysis in oxygen reduction reaction.

iScience 2021 Nov 23;24(11):103332. Epub 2021 Oct 23.

State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China.

Deliberately optimizing the d-band position of an active component electronic and lattice strain tuning is an effective way to boost its catalytic performance. We herein demonstrate this concept by constructing core-shell [email protected] nanoparticles with NiPd alloy shells of only three atomic layers through combining an Au catalysis with the galvanic replacement reaction. The Au core with larger electronegativity modulates the Pd electronic configuration, while the Ni atoms alloyed in the ultrathin shells neutralize the lattice stretching in Pd shells exerted by Au cores, equipping the active Pd metal with a favorable d-band position for electrochemical oxygen reduction reaction in an alkaline medium, for which core-shell [email protected] nanoparticles with a Ni/Pd atomic ratio of 3/7 exhibit a half-wave potential of 0.92 V, specific activity of 3.7 mA cm, and mass activity of 0.65 A mg at 0.9 V, much better than most of the recently reported Pd-even Pt-based electrocatalysts.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.isci.2021.103332DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8586809PMC
November 2021

Catalytic Amination of Polylactic Acid to Alanine.

J Am Chem Soc 2021 Oct 30;143(40):16358-16363. Epub 2021 Sep 30.

Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, People's Republic of China.

In comparison to the traditional petroleum-based plastics, polylactic acid, the most popular biodegradable plastic, can be decomposed into carbon dioxide and water in the environment. However, the natural degradation of polylactic acid requires a substantial period of time and, more importantly, it is a carbon-emitting process. Therefore, it is highly desirable to develop a novel transformation process that can upcycle the plastic trash into value-added products, especially with high chemical selectivity. Here we demonstrate a one-pot catalytic method to convert polylactic acid into alanine by a simple ammonia solution treatment using a Ru/TiO catalyst. The process has a 77% yield of alanine at 140 °C, and an overall selectivity of 94% can be reached by recycling experiments. Importantly, no added hydrogen is used in this process. It has been verified that lactamide and ammonium lactate are the initial intermediates and that the dehydrogenation of ammonium lactate initiates the amination, while Ru nanoparticles are essential for the dehydrogenation/rehydrogenation and amination steps. The process demonstrated here could expand the application of polylactic acid waste and inspire new upcycling strategies for different plastic wastes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/jacs.1c08159DOI Listing
October 2021

Hydrolysis of waste polyethylene terephthalate catalyzed by easily recyclable terephthalic acid.

Waste Manag 2021 Nov 21;135:267-274. Epub 2021 Sep 21.

Nanjing IPE Institute of Green Manufacturing Industry, Nanjing, Jiangsu 211135, China; State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China. Electronic address:

Hydrolysis of polyethylene terephthalate (PET) is an efficient strategy for the depolymerization of waste PET to terephthalic acid (TPA), which can be used as a fundamental building block for the repolymerization of PET or for the synthesis of biodegradable plastics and metal-organic frameworks. However, most of the reported hydrolysis catalysts are strong acids or bases, which are soluble in reaction media and difficult to separate after the reaction, leading to high production costs and a profound influence on the environment. Herein, we propose the use of TPA, the basic unit of PET, as an acid catalyst to promote the hydrolysis of PET. Under optimized conditions, i.e., 2.5 g of PET, a TPA concentration of 0.1 g/mL, mass ratio PET:HO of 1:8, 220 °C of temperature, and 180 min of reaction time, a PET conversion of up to 100.0% and a TPA yield of 95.5% were achieved. Furthermore, the produced TPA exhibited a high purity of 99%, similar to that of fresh TPA, and was easily recoverable for PET hydrolysis without tedious workup and purification processes. More importantly, the hydrolysis efficiency was maintained over eight consecutive reaction cycles. Overall, this study provides a green, easy, and low-cost technology to recover and reuse TPA for waste PET hydrolysis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.wasman.2021.09.009DOI Listing
November 2021

A novel nanosphere-in-nanotube iron phosphide Li-ion battery anode displaying a long cycle life, recoverable rate-performance, and temperature tolerance.

Nanoscale 2021 Oct 1;13(37):15624-15630. Epub 2021 Oct 1.

National Laboratory of Solid State Microstructures, College of Engineering and Applied Sciences, Nanjing University, Nanjing, Jiangsu 210093, P. R. China.

Currently, non-ideal anodes restricts the development of long-term stable Li-ion batteries. Several currently available high-capacity anode candidates are suffering from a large volumetric change during charge and discharge and non-stable solid interphase formation. Here, we develop a novel nanosphere-confined one-dimensional yolk-shell anode taking iron phosphide (FeP) as a demonstrating case study. Multiple FeP nanospheres are encapsulated inside an FeP nanotube through a magnetic field-assisted and templated approach, forming a nanosphere-in-nanotube yolk-shell (NNYS) structure. After long-term 1000 cycles at 2 A g, the NNYS FeP anode shows a good capacity of 560 mA h g, and a coulombic efficiency of 99.8%. A recoverable rate-performance is also obtained after three rounds of tests. Furthermore, the capacities and coulombic efficiency remain stable at temperatures of -10 °C and 45 °C, respectively, indicating good potential for use under different conditions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/d1nr05294bDOI Listing
October 2021

A Polysulfides-Confined All-in-One Porous Microcapsule Lithium-Sulfur Battery Cathode.

Small 2021 Oct 12;17(41):e2103051. Epub 2021 Sep 12.

National Laboratory of Solid State Microstructures, College of Engineering and Applied Sciences, Nanjing University, Nanjing, Jiangsu, 210093, P. R. China.

Developing emerging materials for high energy-density lithium-sulfur (Li-S) batteries is of great significance to suppress the shuttle effect of polysulfides and to accommodate the volumetric change of sulfur. Here, a novel porous microcapsule system containing a carbon nanotubes/tin dioxide quantum dots/S (CNTs/QDs/S) composite core and a porous shell prepared through a liquid-driven coaxial microfluidic method as Li-S battery cathode is developed. The encapsulated CNTs in the microcapsules provide pathways for electron transport; SnO QDs on CNTs immobilize the polysulfides by strong adsorption, which is verified by using density functional theory calculations on binding energies. The porous shell of the microcapsule is beneficial for ion diffusion and electrolyte penetration. The void inside the microcapsule accommodates the volumetric change of sulfur. The Li-S battery based on the porous CNTs/QDs/S microcapsules displays a high capacity of 1025 mAh g after 100 cycles at 0.1 C. When the sulfur loading is 2.03 mg cm , the battery shows a stable cycling life of 700 cycles, a Coulombic efficiency exceeding 99.9%, a recoverable rate-performance during repeated tests, and a good temperature tolerance at both -5 and 45 °C, which indicates a potential for applications at different conditions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/smll.202103051DOI Listing
October 2021

Exosomal transfer of miR-106a-5p contributes to cisplatin resistance and tumorigenesis in nasopharyngeal carcinoma.

J Cell Mol Med 2021 10 1;25(19):9183-9198. Epub 2021 Sep 1.

Guizhou university medical college, Guiyang, China.

Nasopharyngeal carcinoma (NPC), a subclass of cancers of the neck and head, is a predominant cause of cancer-associated death worldwide. Hence, there is a critical need for research into NPC-related treatment strategies. Cisplatin is a promising therapy option for NPCs and other cancers that is frequently utilized. Some patients acquire resistance to cisplatin therapy, which complicates the successful use of cisplatin treatment in NPCs. Although exosomal transfer of oncogenic miRNAs has been shown to improve recipient cell proliferation, metastasis and chemoresistance, the molecular mechanism behind this effect on NPC has yet to be fully understood. Exosomal microRNAs (miRNAs) from cisplatin-resistant cells were identified as significant mediators of chemoresistance in NPC cells in this investigation. Initially, we found that exosomal miR-106a-5p levels in the serum of chemoresistant and last-cycle patients were greater than in that of non-resistant and first-cycle patients. Also, exosomal miR-106a-5p enhanced the proliferative ability of NPC cells. Mechanistically, exosomal miR-106a-5p targets ARNT2, which further activates AKT phosphorylation, and thus promotes NPC cell proliferation, decreases apoptosis and in turn regulates tumorigenesis. We found similar results using in vivo NPC models, where exosomal miR-106a-5p through regulation of ARNT2 (aryl hydrocarbon receptor nuclear translocator 2) promoted tumorigenesis. Taken together, these findings indicate that exosomal miR-106a-5p could be a promising diagnostic biomarker and drug target for patients with NPC.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/jcmm.16801DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8500979PMC
October 2021

Benzenesulfonic acid-based hydrotropic system for achieving lignocellulose separation and utilization under mild conditions.

Bioresour Technol 2021 Oct 4;337:125379. Epub 2021 Jun 4.

Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing 210037, China; International Innovation Center for Forest Chemicals and Materials, Nanjing Forestry University, Nanjing 210037, China; State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan 250353. Electronic address:

Developing low-cost and sustainable fractionation technology is the key to achieve the maximal utilization of lignocellulosic biomass. This study reported benzenesulfonic acid (BA) as a green hydrotrope for efficient lignocellulose conversion into two fractions at atmospheric pressure: (1) a primarily cellulosic solid residue that can be utilized to produce high-value building blocks (lignocellulosic nanomaterials or sugars), and (2) the collected spent acid liquor that can be diluted with anti-solvent to easily obtain lignin nanoparticles. BA hydrotropic method exhibited greater reaction selectivity to solubilize lignin, where approximately 80% lignin were removed at only 80 °C in 20 min. The lower lignin content substrates resulted in relatively higher enzymatic hydrolysis efficiency of 80% and less entangled lignocellulosic nanofibrils (LCNF). Furthermore, the separated lignin particles size can be easily adjusted by the initial acid concentration. Overall, this work presented a promising and simple technology in achieving lignocellulose separation and utilization under mild conditions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.biortech.2021.125379DOI Listing
October 2021

Nanocapillarity and Nanoconfinement Effects of Pipet-like [email protected] Nanotubes for Highly Efficient Electrocatalytic CO Reduction.

Nano Lett 2021 Mar 12;21(6):2650-2657. Epub 2021 Mar 12.

MOE Key Laboratory of Mesoscopic Chemistry, MOE Key Laboratory of High Performance Polymer Materials and Technology, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.

Electrocatalytic CO reduction reaction is regarded as an intriguing route for producing renewable chemicals and fuels, but its development is limited by the lack of highly efficient and stable electrocatalysts. Herein, we propose the pipet-like bismuth (Bi) nanorods semifilled in nitrogen-doped carbon nanotubes ([email protected]) for highly selective electrocatalytic CO reduction. Benefited from the prominent capillary and confinement effects, the [email protected] act as nanoscale conveyors that can significantly facilitate the mass transport, adsorption,and concentration of reactants onto the active sites, realizing rapid reaction kinetics and low cathodic polarization. The spatial encapsulation and separation by the NCNT shells prevents the self-aggregation and surface oxidation of Bi-NRs, increasing the dispersity and stability of the electrocatalyst. As a result, the [email protected] exhibit high activity and durable catalytic stability for CO-to-formate conversion over a wide potential range. The Faradaic efficiency for formate production reaches 90.9% at a moderate applied potential of -0.9 V vs reversible hydrogen electrode (RHE).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.nanolett.1c00390DOI Listing
March 2021

Drug resistance‑related sunitinib sequestration in autophagolysosomes of endothelial cells.

Int J Oncol 2020 Jan 26;56(1):113-122. Epub 2019 Nov 26.

National Institute of Health and Medical Research, Medical Research Unit 942/Paris University 7 and 13, Avicenne Hospital, 93000 Bobigny, France.

Our previous study demonstrated that the tyrosine kinase receptor inhibitor sunitinib induces acquired drug resistance in endothelial cells. The present study explored the role of lysosomal sequestration of sunitinib in the acquisition of drug resistance in human microcapillary endothelial HMEC‑1 cells. Resistance was induced by escalating concentrations of sunitinib and a shift in IC50 from 12.8 to >20 µM was detected. The results of time‑lapse fluorescence microscopy illustrated an instantaneous emergence of fluorescent vesicles in living cells once sunitinib was added. Most of these vesicles emerged in the juxtanuclear area, and exhibited the characteristics of growing autophagosomes and lysosomes. The vesicles were identified as autophagosomes and lysosomes because they co‑located with the lysosomal tracers Lyso‑ER and Lyso‑NIR, and the protein markers lysosomal‑associated membrane protein 1 (LAMP‑1) and microtubule‑associated protein 1A/1B‑light chain 3 (LC3). The results of western blotting demonstrated that sunitinib induced upregulation of LAMP‑1 and LC3‑II, and downregulation of sequestosome 1/p62, indicating the activation of autophagy. Bafilomycin A1, which suppresses lysosomal acidification, completely blocked sunitinib sequestration; however, chloroquine, which blocks lysosomal fusion with autophagosomes, exhibited no effect. Notably, bafilomycin A1 and chloroquine significantly counterbalanced HMEC‑1 drug‑resistance. These results provided evidence for autophagy‑flux‑associated sunitinib lysosomal sequestration in endothelial cells, leading to isolation of the drug from the cytoplasm; a key process involved in the development of drug resistance during antiangiogenic therapy. These data supported the notion that inhibiting autophagy may be a potential strategy to prevent drug sequestration and resistance to antiangiogenic therapy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3892/ijo.2019.4924DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6910192PMC
January 2020

Drug-resistant endothelial cells facilitate progression, EMT and chemoresistance in nasopharyngeal carcinoma via exosomes.

Cell Signal 2019 11 5;63:109385. Epub 2019 Aug 5.

Department of Oncology, Guizhou Provincial People's Hospital, Guizhou Cancer Center, Guiyang, Guizhou, China. Electronic address:

Recent antitumor drug development has included investigation of a wide variety of anti-angiogenesis therapies. Because cancer cells in tumors require new blood vessels to grow and spread, they stimulate capillary proliferation from existing vessels as well as new vessel formation from endothelial precursor cells. Our previous findings suggested that drug resistance in mouse endothelial cells supported tumor growth, but the relationship between endothelial cells (ECs) and nasopharyngeal carcinoma (NPC) cells remained unclear. Exosomes are small membrane vesicles that are released by several cell types, including human microvascular ECs (HMECs). Exosomes carrying membrane and cytoplasmic constituents have been described as participants in a novel mechanism of cell-to-cell communication. In the present study, we investigated the mechanisms underlying the interactions between HMECs and NPC cells. We found that drug-resistant HMECs secreted small heterogeneous 40-100 nm vesicles, defined as exosomes. Co-incubation of NPC cells with doxorubicin-resistant (R-DOX) HMEC-derived exosomes resulted in promotion of their proliferation, migration, and chemoresistance, as well as changes in the expression of epithelial-mesenchymal transition (EMT) markers. These effects were significantly inhibited by treatment with GW4869 (an exosome inhibitor). We also found that GW4869 inhibited the stimulation of drug-resistant HMECs on NPC progression by modulating EMT in vivo. These data suggest that exosomes participate in a novel mechanism by which drug-resistant ECs enhance NPC progression.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.cellsig.2019.109385DOI Listing
November 2019

Hydrogen Diffusion Guided Design of Pt-Based Alloys for Inhibition of Butadiene Over-Hydrogenation.

Chemphyschem 2019 07 21;20(14):1804-1811. Epub 2019 Jun 21.

College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China.

Alloying Pt with other metals is an effective strategy to tune its performance towards selective hydrogenation reactions. Herein, we have demonstrated a process to screen Pt-based alloys for inhibition of butadiene over-hydrogenation with a model comprising isolated single atoms (ISA) embedded into Pt(111). DFT calculations reveal that the diffusion energy barrier of H co-adsorbed with 1-butene is a key parameter for the screening. The output from the ISA model was validated by testing several typical Pt-based alloys towards butadiene hydrogenation. Furthermore, an unexpected higher selectivity to cis-2-butene compared to the trans isomer and 1-butene over the PtZn alloy was explored employing the ISA model.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/cphc.201900380DOI Listing
July 2019

New design for highly durable infrared-reflective coatings.

Light Sci Appl 2018 6;7:17175. Epub 2018 Apr 6.

State Key Laboratory of Superhard Materials, Key Laboratory of Automobile Materials of MOE, and School of Materials Science and Engineering, Jilin University, Changchun 130012, China.

The fundamental challenge in designing durable infrared-reflective coatings is achieving the ideal combination of both high reflectivity and durability. Satisfying these competing demands is traditionally achieved by deposition of durable layers on highly reflective metals. We overturn the traditional logic of 'first reflectivity and then durability' and propose an alternative of 'first durability and then reflectivity': First, a transition-metal compound is selected as a durable base; then its reflectivity is improved by incorporating silver/gold to form an alloy or by overcoating a multilayer stack. Two validation experiments prove that the new strategy works extremely well: the coatings thus obtained have infrared reflectivities close to that of aluminum, and their hardness and acid and salt corrosion resistances are 27-50, 400-1 500 and 7 500-25 000 times that of aluminum. The traditional mirror coating (e.g., Al/SiO films) is more suitable for moderate environments, while our mirror coating that was obtained by the new strategy (e.g., an Ag-doped hafnium nitride film) is more suitable for harsh environments, such as ones with dust, windblown sand, moisture, acid rain or salt fog. This work opens up new opportunities for highly durable infrared-reflective coatings and rejuvenates the study of transition metal compounds in a completely new area of optics.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/lsa.2017.175DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6060051PMC
April 2018

miR-29c regulates resistance to paclitaxel in nasopharyngeal cancer by targeting ITGB1.

Exp Cell Res 2019 05 16;378(1):1-10. Epub 2019 Feb 16.

Department of Oncology, Guizhou Provincial People's Hospital, Guiyang, Guizhou, China. Electronic address:

Paclitaxel (Taxol) is an anticancer taxane drug commonly used in the treatment of nasopharyngeal carcinoma (NPC). However, resistance to paclitaxel is a major difficulty in developing an effective therapy against NPC. MicroRNAs (miRNAs) are known to regulate genes that are involved in drug resistance. We assessed the effects of miR-29c, an miRNA identified in a genome-wide study of Taxol resistance, on genes associated with resistance in NPC cells. We established Taxol resistance in two human NPC cell lines, SUNE-1 and C666-1 (SUNE-1-Taxol and C666-1-Taxol) and found that miR-29c was downregulated and integrin beta-1 (ITGB1) was upregulated in Taxol-resistant NPC cells compared with parental NPC cells. Further investigations using a TUNEL assay and BAX/BCL-2 ratio, found that overexpression of miR-29c and knockdown of ITGB1 can resensitize drug-resistant NPC cells to Taxol and promote apoptosis. In addition, a dual-luciferase reporter assay indicated that ITGB1 is the target of miR-29c. Furthermore, silencing miR-29c markedly increased Taxol-resistant NPC tumor growth in a nude mouse xenograft model while knockdown of ITGB1 reversed this result. Overall, these data demonstrate that miR-29c regulates resistance to Taxol in NPC by targeting ITGB1. Our research indicates that miR-29c may have potential use in Taxol-resistant NPC therapy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.yexcr.2019.02.012DOI Listing
May 2019

MicroRNA-29c Increases the Chemosensitivity of Pancreatic Cancer Cells by Inhibiting USP22 Mediated Autophagy.

Cell Physiol Biochem 2018 22;47(2):747-758. Epub 2018 May 22.

Department of Oncology, Guizhou Provincial People's Hospital, Guiyang, China.

Background/aims: Pancreatic cancer (PC) is an aggressive malignancy with a poor survival rate. Despite advances in the treatment of PC, the efficacy of therapy is limited by the development of chemoresistance. Here, we examined the role of microRNA-29c (miR-29c) and the involvement of autophagy and apoptosis in the chemoresistance of PC cells in vivo and in vitro.

Methods: We employed qRT-PCR, western blot and immunofluorescence to examine the expression level of miR-29c, USP22 and autophagy relative protein. In addition, we used MTT assay to detect cell proliferation and transwell assay to measure migration and invasiveness. The apoptosis was determined using annexin V-FITC/PI apoptosis detection kit by flow cytometry. Luciferase reporter assays confirmed the relationship between USP22 and miR-29c.

Results: miR-29c overexpression in the PC cell line PANC-1 enhanced the effect of gemcitabine on decreasing cell viability and inducing apoptosis and inhibited autophagy, as shown by western blotting, immunofluorescence staining, colony formation assays, and flow cytometry. Ubiquitin specific peptidase (USP)-22, a deubiquitinating enzyme known to induce autophagy and promote PC cell survival, was identified as a direct target of miR-29c. USP22 knockdown experiments indicated that USP22 suppresses gemcitabine-induced apoptosis by promoting autophagy, thereby increasing the chemoresistance of PC cells. Luciferase reporter assays confirmed that USP22 is a direct target of miR-29c. A xenograft mouse model demonstrated that miR-29c increases the chemosensitivity of PC in vivo by downregulating USP22, leading to the inhibition of autophagy and induction of apoptosis.

Conclusions: Taken together, these findings reveal a potential mechanism underlying the chemoresistance of PC cells mediated by the regulation of USP22-mediated autophagy by miR-29c, suggesting potential targets and therapeutic strategies in PC.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1159/000490027DOI Listing
July 2018

Highly hard yet toughened bcc-W coating by doping unexpectedly low B content.

Sci Rep 2017 08 24;7(1):9353. Epub 2017 Aug 24.

State Key Laboratory of Superhard Materials, Department of Materials Science, Key Laboratory of Automobile Materials, MOE, and Jilin University, Changchun, 130012, People's Republic of China.

Either hardness or toughness has been the core interest in scientific exploration and technological pursuit for a long time. However, it is still a big challenge to enhance the hardness and toughness at the same time, since the improvement of one side is always at the expense of the other one. Here, we have succeeded in dealing with this pair of conflict based on tungsten (W) coating by doping boron (B) via magnetron co-sputtering. The results reveal that the introduction of low concentrations of B (6.3 at. %), in the doping regime, leads to the formation of W(B) supersaturated solid solution with refined grains. Meanwhile, the doping-induced higher compressive stress, higher H/E and denser microstructure result in a surprising combination of improved hardness (2 × larger than pure W) and superior toughness (higher crack formation threshold compared to pure W). We believe this is an innovative sight to design new generation of transition-metal-based multifunctional coatings. Besides, our results are applicable for industrial application because it can be realized by simple manufacturing approaches, e.g. magnetron sputtering technology.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-017-09807-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5571190PMC
August 2017

Cross-drug resistance to sunitinib induced by doxorubicin in endothelial cells.

Oncol Lett 2015 Mar 22;9(3):1287-1292. Epub 2014 Dec 22.

Laboratory of MERCI (EA 3829), Faculty of Medicine and Pharmacy, University of Rouen, Rouen 76183, France.

Multiple drug resistance remains an unsolved problem in cancer therapy. A previous study has demonstrated that the chemotherapeutic drug doxorubicin (Dox) induced upregulation of P-glycoprotein in endothelial cells, resulting in a 20-fold increase in drug resistance and reduced efficiency of doxorubicin treatment in a mouse tumor model. In the present study, the cross-resistance and sensitivity of HMECd1 and HMECd2 established cell lines to anti-angiogenic drugs, particularly sunitinib, was explored. The results revealed that Dox treatment induced a significant increase in the breast cancer resistance protein (ABCG2) gene transcription and protein expression. This increase gave rise to a 4- to 5-fold increase in the half maximal inhibitory concentration of the HMECd1 and HMECd2 cells in response to sunitinib treatment . Functionally, the role of ABCG2 in the resistance to sunitinib was confirmed by the use of the ABCG2 inhibitors fumitremorgin C and diethylstilbestrol, which blocked cell resistance. The present study indicates that endothelial cells exhibit cross-resistance between cytotoxic drugs and anti-angiogenic drugs. This suggests that multiple drug resistance induced by chemotherapy in endothelial cells may affect the efficiency of anti-angiogenic drugs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3892/ol.2014.2819DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4315062PMC
March 2015

Induction of multiple drug resistance in HMEC-1 endothelial cells after long-term exposure to sunitinib.

Onco Targets Ther 2014 4;7:2249-55. Epub 2014 Dec 4.

MERCI (EA 3829), Faculté de Médecine et de Pharmacie, Université de Rouen, Rouen, France.

Multiple drug resistance is still an unsolved problem in cancer therapy. Our previous study demonstrated that the chemotherapeutic drug doxorubicin (Dox) induced upregulation of P-glycoprotein (P-gp) in endothelial cells, resulting in a 20-fold increase in drug resistance and reduced efficiency of Dox treatment in a mice tumor model. In this study, we exposed human microvascular endothelial cells (HMEC-1) to sunitinib, a tyrosine kinase receptor inhibitor, to induce drug resistance. The results show that sunitinib treatment induced multiple drug resistance in these cells. They became resistant not only to sunitinib but also to Dox, paclitaxel, and vinblastine. Significant increases in P-gp (9.3-fold), ABCG2 (breast cancer resistance protein, 1.9-fold), and multidrug resistance-associated protein 1 (2.7-fold) gene transcription were found by quantitative polymerase chain reaction quantification, and their protein expression was confirmed by Western blot. These increases gave rise to an approximately five-fold increase in half maximal inhibitory concentration in these cells in response to sunitinib treatment in vitro. The inhibitors of adenosine triphosphate-binding cassette transporters did not reverse the drug resistance in sunitinib-resistant HMEC-1 cells, assumedly because of a blockage of the pump function caused by sunitinib. Our study indicates that the antiangiogenic drug sunitinib induces multiple drug resistance in endothelial cells. The induction of adenosine triphosphate-binding cassette transporters seems not to be responsible for observed multiple drug resistance, and the underlying mechanisms remain unknown.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2147/OTT.S67251DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4262216PMC
January 2015

Induction of acquired drug resistance in endothelial cells and its involvement in anticancer therapy.

J Hematol Oncol 2013 Jul 9;6:49. Epub 2013 Jul 9.

Background: Multidrug resistance (MDR) is one of the major problems in the treatment of cancer. Overcoming it is therefore expected to improve clinical outcomes for cancer patients. MDR is usually characterized by overexpression of ABC (ATP-binding cassette) protein transporters such as P-gp, MRP1, and ABCG2. Though the importance of ABC transporters for cancer cells is recognized, few studies have looked at its implications for the endothelial cells that are essential to tumor angiogenesis. This study investigated the expression and functions of these ABC transporters in endothelial cells in vitro and their potential contribution to cancer growth in mice.

Methods: Human micro vessel endothelial cells (HMEC-1) and human umbilical vein endothelial cells (HUVEC) were exposed to increasing doses of Doxorubicin (Dox) to induce ABC gene expression. Cell viability was then quantified by (3)H-thymidine and MTS assay. Flow cytometry, qPCR, and western blot were used to detect mRNA and the protein expression of P-gp, MRP1, and ABCG2. The intracellular accumulation of Rhodamine 123 (Rho) was used to evaluate drug efflux function and the inhibitors for P-gp, ABCG2, and MRP1 were used to verify their respective roles in vitro. In an attempt to evaluate drug resistance in endothelial cells in vivo, athymic mice were treated with Dox for 15 days before a MDA-MB-435 tumor graft to observe subsequent changes in the inhibition curves of tumor growth in response to Dox treatment. Furthermore, endothelial cells from multiple sites in these mice were also isolated to estimate their P-gp expression by flow cytometry.

Results: Drug resistance in HMEC-1 and HUVEC was successfully induced by the addition of Dox to the culture media. Two stabilized subcell lines of HMEC1 (HMECd1 and HMECd2) showed 15- and 24-fold increases in resistance. Tests also showed that these induced endothelial cells were cross-resistant to the structurally unrelated drugs Daunorubicin, Vinblastine, and Etoposide. P-gp protein levels increased four and six fold in HMECd1 and HMECd2 as revealed by western blot. The qPCR demonstrated 3.4- and 7.2-fold increases in P-gp, and a slight increase in ABCG2, gene expression. The Rho accumulation within these cells was inversely correlated with the expression levels of P-gp. The inhibitors of P-gp, but not of ABCG2 or MRP1, were able to block the induced endothelial cell resistance to Dox. Furthermore, we also showed that injecting Dox into healthy mice induced an increase in P-gp expression in endothelial cells. Using these pretreated mice in a tumor growth experiment, we observed a dramatic diminution in the therapeutic efficiency of Dox treatment, suggesting implications for drug resistance in mice endothelial cells supporting tumor growth.

Conclusions: ABC transporter expression can be induced in endothelial cells in vitro. This study also indicates that P-gp plays an important role in the acquisition of resistance to Dox in endothelial cells and that this reduces the efficiency of chemotherapy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/1756-8722-6-49DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3717049PMC
July 2013

Opposite regulation by PI3K/Akt and MAPK/ERK pathways of tissue factor expression, cell-associated procoagulant activity and invasiveness in MDA-MB-231 cells.

J Hematol Oncol 2012 Jul 11;5:16. Epub 2012 Jul 11.

INSERM, U728, F-75010 Paris, France.

Background: Tissue factor (TF), an initiator of blood coagulation, participates in cancer progression and metastasis. We recently found that inhibition of MAPK/ERK upregulated both full length TF (flTF) and soluble isoform TF (asTF) gene expression and cell-associated TF activity in breast cancer MDA-MB-231 cells. We explored the possible mechanisms, especially the possible interaction with EGFR and PI3K/Akt pathways.

Methods: A plasmid containing TF promoter -2174 ~ +128 plus luciferase reporter gene was introduced into MDA-MB-231 cells to evaluate TF promoter activity. In order to study the interaction of these pathways, ERK inhibitor (PD98059), PI3K inhibitors (LY294002, wortmannin), Akt inhibitor (A6730), and EGFR inhibitor (erlotinib) as well as the corresponding siRNAs were used to treat MDA-MB-231 cells, and ovarian cancer OVCAR-3 and SKOV-3 cells. Quantitative PCR and western blot were used to determine TF expression. One stage clotting assays were used to measure pro-coagulation activity of the MDA-MB-231 cells.

Results: We show that PI3K inhibitors LY294002, wortmannin and A6730 significantly inhibited TF promoter activity, and reduced TF mRNA and protein levels due to the inhibition of Akt phosphorylation. In contrast, ERK inhibitor PD98059 and ERK siRNA enhanced TF promoter activity by 2.5 fold and induced an increase in TF mRNA and protein levels in a dose dependent manner in these cells. The PI3K/Akt pathway was shown to be involved in PD98059-induced TF expression because the induction was inhibited by PI3K/Akt inhibitors. Most interestingly, the EGFR inhibitor erlotinib and EGFR siRNA also significantly suppressed PD98059- or ERK siRNA-induced TF promoter activity and TF protein expression. Similar results were found with ovarian cancer cells SKOV-3 and OVCAR-3. Furthermore, in MDA-MB-231, mRNA levels of asTF were regulated in a similar way to that of TF in response to the cell treatment.

Conclusions: This study showed a regulatory mechanism in which MAPK/ERK signals inhibit EGFR/PI3K/Akt-mediated TF expression in breast cancer MDA-MB-231 cells. The same regulation was observed in ovarian cancer OVCAR-3 and SKOV-3 cells. Interestingly, we observed that both flTF and asTF could be regulated in a parallel manner in MDA-MB-231. As the PI3K/Akt pathway and EGFR regulate TF expression in cancer cells, targeting these signaling components is expected to potentially inhibit TF expression-associated tumor progression.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/1756-8722-5-16DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3394220PMC
July 2012

Effects of the chemical bonding on the optical and mechanical properties for germanium carbide films used as antireflection and protection coating of ZnS windows.

J Phys Condens Matter 2006 May 13;18(17):4231-41. Epub 2006 Apr 13.

Department of Materials Science and Key Laboratory of Automobile Materials of MOE, Jilin University, Changchun 130012, People's Republic of China.

Germanium carbide (Ge(1-x)C(x)) films have been prepared by RF reactive sputtering a pure Ge(111) target at different flow rate ratios of CH(4)/(CH(4)+Ar) in a CH(4)/Ar mixture discharge, and it has been found that the composition, chemical bonding, optical and mechanical properties of Ge(1-x)C(x) films are remarkably influenced by the flow rate ratio of CH(4)/(CH(4)+Ar). The effects of the chemical bonding on the optical and mechanical properties of the Ge(1-x)C(x) films have been explored. In addition, an antireflection Ge(1-x)C(x) double-layer coating deposited on both sides of the ZnS substrate wafer has been developed for application as an infrared window. It is shown that the transmittance in the wavelength region between 8 and 12 µm and the hardness of the ZnS substrate have been significantly improved by the double-layer coating.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1088/0953-8984/18/17/011DOI Listing
May 2006
-->