Publications by authors named "Nguyen Hoa Hong"

7 Publications

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A Selective Inhibitor of Ubiquitin-Specific Protease 4 Suppresses Colorectal Cancer Progression by Regulating β-Catenin Signaling.

Cell Physiol Biochem 2019 ;53(1):157-171

Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea.

Background/aims: Dysregulation of deubiquitinating enzymes (DUBs), which regulate the stability of key proteins, has been implicated in many human diseases, including cancers. Thus, DUBs can be considered as potential therapeutic targets for many diseases. Among them, USP4 has been proposed as a promising target for colon cancer drugs since USP4 controls the stability of β-catenin, a key factor in the Wnt signaling involved in the tumorigenesis of colorectal cancer. However, developing potential DUB inhibitors has been hindered because many DUBs harbor similar active site structures and show broad substrate specificities.

Methods: By performing in vitro deubiquitinating activity assays using a chemical library, we identified several potential DUB inhibitors. Among them, only neutral red (NR) showed selective inhibitory activity on USP4 in a cell-based assay system. In colon cancer cells, NR affected the protein stability of β-catenin, as shown by immunoblotting, and it affected the target gene expression of β-catenin, as shown by quantitative real-time PCR. NR's potential as an anticancer drug was further estimated by colony formation and cell migration assays and by using a mouse xenograft model.

Results: We identified NR as an uncompetitive inhibitor of USP4 and validated its effects in colorectal cancer. NR-treated cells showed decreased β-catenin stability and reduced expression of β-catenin target genes. Additionally, treating colon cancer cells with NR significantly reduced colony formation and cell migration, and injecting NR into a mouse xenograft model reduced the tumor volume.

Conclusion: The current results suggest that NR could be developed as an anticancer drug targeting USP4, and they support the possibility of developing specific DUB inhibitors as therapeutic agents.
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http://dx.doi.org/10.33594/000000127DOI Listing
July 2019

Toxicity and T₂-Weighted Magnetic Resonance Imaging Potentials of Holmium Oxide Nanoparticles.

Nanomaterials (Basel) 2017 Aug 7;7(8). Epub 2017 Aug 7.

Department of Physics and Astronomy, Seoul National University, Seoul 08826, Korea.

In recent years, paramagnetic nanoparticles (NPs) have been widely used for magnetic resonance imaging (MRI). This paper reports the fabrication and toxicity evaluation of polyethylene glycol (PEG)-functionalized holmium oxide (Ho₂O₃) NPs for potential ₂-weighted MRI applications. Various characterization techniques were used to examine the morphology, structure and chemical properties of the prepared PEG-Ho₂O₃ NPs. MRI relaxivity measurements revealed that PEG-Ho₂O₃ NPs could generate a strong negative contrast in ₂-weighted MRI. The pilot cytotoxicity experiments showed that the prepared PEG-Ho₂O₃ NPs are biocompatible at concentrations less than 16 μg/mL. Overall, the prepared PEG-Ho₂O₃ NPs have potential applications for ₂-weighted MRI imaging.
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http://dx.doi.org/10.3390/nano7080216DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5575698PMC
August 2017

Thickness Dependence Magnetization in Laser Ablated Ni-Cu-Zn Ferrite Nanostructured Thin Films.

J Nanosci Nanotechnol 2016 Jan;16(1):811-5

Ni₀.₅Cu₀.₃Zn₀.₂Fe₂O₄ thin films with thickness ranging from 25 nm to 500 nm were grown on Si substrate using pulsed laser deposition technique and their structural and magnetic properties were investigated. From the atomic force microscopy (AFM) analysis, it is observed that the film roughness (Ra) depends strongly on the thickness of the fabricated film. The magnetizations of the thin films were found to decrease when the film thickness increases. The thinner films showed a larger magnetization than the thick films. All the films showed a blocking temperature indicating their superparamagnetic behavior.
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http://dx.doi.org/10.1166/jnn.2016.10881DOI Listing
January 2016

The origin of magnetism in transition metal-doped ZrO2 thin films: experiment and theory.

J Phys Condens Matter 2013 Oct 4;25(43):436003. Epub 2013 Oct 4.

Department of Physics and Astronomy, Seoul National University, Gwanak-gu, Seoul 151-747, Korea.

We have investigated the magnetic properties of Fe/Co/Ni-doped ZrO2 laser ablated thin films in comparison with the known results of Mn-doped ZrO2, which is thought to be a promising material for spintronics applications. It is found that doping with a transition metal can induce room temperature ferromagnetism in 'fake' diamond. Theoretical analysis based on density functional theory confirms the experimental measurements, by revealing that the magnetic moments of Mn- and Ni-doped ZrO2 thin films are much larger than that of Fe- or Co-doped ZrO2 thin films. Most importantly, our calculations confirm that Mn- and Ni-doped ZrO2 show a ferromagnetic ground state in comparison to Co- and Fe-doped ZrO2, which favor an antiferromagnetic ground state.
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http://dx.doi.org/10.1088/0953-8984/25/43/436003DOI Listing
October 2013

Mesoporous silica with fibrous morphology: a multifunctional core-shell platform for biomedical applications.

Nanotechnology 2013 Aug 30;24(34):345603. Epub 2013 Jul 30.

Department of Physics and Astronomy, Seoul National University, Gwanak-gu, Seoul 151-747, Korea.

Multifunctional mesoporous silica nanocomposites are attractive carriers for targeted drug delivery in nanomedicine. Although promising developments have been made in the fabrication of multifunctional mesoporous silica nanocomposites, the design and mass production of novel multifunctional carriers are still challenging. This paper reports the facile one-pot fabrication of a multifunctional inorganic composite composed of superparamagnetic Fe3O4 nanoparticles and coated dye-functionalized mesoporous silica with a high specific surface area. The resulting composite particles had a tunable particle size, special open pore channels with high specific surface area, which is quite favorable for drug loading and release properties, as well as luminescent and superparamagnetic properties suitable for targeted drug delivery and tracking. This composite exhibited low toxicity, suggesting potential biomedical applications.
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http://dx.doi.org/10.1088/0957-4484/24/34/345603DOI Listing
August 2013

Room temperature ferromagnetism with large magnetic moment at low field in rare-earth-doped BiFeO₃ thin films.

J Phys Condens Matter 2013 May 25;25(20):206003. Epub 2013 Apr 25.

Nanomagnetism Laboratory, Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea.

Thin films of rare earth (RE)-doped BiFeO3 (where RE=Sm, Ho, Pr and Nd) were grown on LaAlO3 substrates by using the pulsed laser deposition technique. All the films show a single phase of rhombohedral structure with space group R3c. The saturated magnetization in the Ho- and Sm-doped films is much larger than the values reported in the literature, and is observed at quite a low field of 0.2 T. For Ho and Sm doping, the magnetization increases as the film becomes thinner, suggesting that the observed magnetism is mostly due to a surface effect. In the case of Nd doping, even though the thin film has a large magnetic moment, the mechanism seems to be different.
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http://dx.doi.org/10.1088/0953-8984/25/20/206003DOI Listing
May 2013

Magnetism in V-doped ZnO thin films.

J Phys Condens Matter 2005 Jan 10;17(1):199-204. Epub 2004 Dec 10.

Laboratoire LEMA, UMR 6157 CNRS/CEA, Université F Rabelais, Parc de Grandmont, 37200 Tours, France.

Ferromagnetism at room temperature, along with a spin-glass-like behaviour at low temperatures, has been observed in laser ablated V-doped ZnO thin films. It is found that V atoms were well substituted for Zn atoms and resulted in a very uniform distribution among the ZnO matrices.
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http://dx.doi.org/10.1088/0953-8984/17/1/018DOI Listing
January 2005