Publications by authors named "Hyun-kyung Choi"

We present a CuAAC (Copper-Catalyzed Azide-Alkyne Cycloaddition) reaction protocol designed for the visualization of mRNA. To achieve this, we synthesized stable mRNA molecules incorporating the modified nucleoside analog, EU, a crucial element for fluorophore attachment. Leveraging this modified mRNA, we successfully executed the CuAAC reaction, wherein the pro-fluorophore, coumarin, was conjugated to EU on the mRNA through our meticulously designed CuAAC process.

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We exploited bacterial infection assays using the fruit fly to identify anti-infective compounds that abrogate the pathological consequences in the infected hosts. Here, we demonstrated that a pyridine-3--sulfonylpiperidine derivative () protects from the acute infections caused by bacterial pathogens including . did not inhibit the growth of in vitro, but inhibited the production of secreted toxins such as pyocyanin and hydrogen cyanide, while enhancing the production of pyoverdine and pyochelin, indicative of iron deprivation.

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Background: New ceramide (CER) NPs were prepared by linking fatty acids derived from oils of Korean traditional plants to phytosphingosine (PHS). The oils of Korean traditional plants were extracted from the seeds of Panax ginseng, Camellia sinensis, Glycine max napjakong, Glycine max seoritae, and Camellia japonica as sources of diverse fatty acids.

Aims: The aim of this study was to investigate signaling bioactivities of HP-C.

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Our previous work demonstrated that ()--benzyl-6-(2-(3, 4-dihydroxybenzylidene) hydrazinyl)--methylpyridine-3-sulfonamide (BHMPS), a novel synthetic inhibitor of Rab27aSlp(s) interaction, suppresses tumor cell invasion and metastasis. Here, we aimed to further investigate the mechanisms of action and biological significance of BHMPS. BHMPS decreased the expression of epithelial-mesenchymal transition transcription factors through inhibition of focal adhesion kinase and c-Jun N-terminal kinase activation, thereby reducing the migration and invasion of breast cancer.

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Article Synopsis
  • Antipathogenic strategies focus on targeting specific virulence pathways in bacteria that are not essential for their growth, aiming to reduce the chances of developing drug resistance.
  • This study identifies a novel chemical compound that targets OxyR, a key peroxide sensor in pathogenic bacteria, through computer-based screening and molecular docking techniques.
  • The promising compound (compound 1) inhibits OxyR's function without harming bacterial growth or viability and shows selective antibacterial effects against specific bacterial infections, suggesting a new approach to treat Gram-negative infections with lower risk of resistance.
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The primitive state (stemness) of mesenchymal stromal cells (MSCs) is responsible for supporting the function of tissue-specific stem cells to regenerate damaged tissues. However, molecular mechanisms regulating the stemness of MSCs remain unknown. In this study, we found that the primitive state of MSCs is hierarchically regulated by the expression levels of the chromatin remodeling complex, CHD1, with CHD1 expression levels higher in the undifferentiated state, and decreasing upon MSC differentiation.

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Background/aim: FMS-like tyrosine kinase 3 (FLT3) is a class III receptor tyrosine kinase involved in signal transduction underlying survival, proliferation, and differentiation of hematopoietic cells. An internal tandem duplication (ITD) in FLT3 in the juxtamembrane domain is a common mutation causing human acute myeloid leukemia (AML) and activates constitutive signaling.

Materials And Methods: We evaluated the novel FLT3 inhibitor 5-(4-fluorophenyl)-N-(naphthalen-1-yl)oxazol-2-amine (AIU2008) for the treatment of AML.

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Background Local tumor progression (LTP) is associated with poorer survival in patients undergoing radiofrequency ablation (RFA) for colorectal liver metastasis (CLM). An algorithmic strategy to predict LTP may help in selection of patients who would benefit most from RFA for CLM. Purpose To estimate local tumor progression-free survival (LTPFS) following RFA of CLM and develop an algorithmic strategy based on clinical variables.

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Internal tandem duplication (ITD) of FMS-like tyrosine kinase 3 (FLT3) is the most common mutation in patients with acute myeloid leukemia (AML). FLT3-ITD induces constitutive activation of FLT3, causing an abnormally rapid proliferation of cancer cells. In this study, we identified novel FLT3 inhibitors and investigated 5-(4-fluorophenyl)--phenyloxazol-2-amine (compound ; ) as candidates for the treatment of AML.

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β-Lactam antibiotics are the most commonly prescribed antibiotics worldwide; however, antimicrobial resistance (AMR) is a global challenge. The β-lactam resistance in Gram-negative bacteria is due to the production of β-lactamases, including extended-spectrum β-lactamases, metallo-β-lactamases, and carbapenem-hydrolyzing class D β-lactamases. To restore the efficacy of BLAs, the most successful strategy is to use them in combination with β-lactamase inhibitors (BLI).

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We previously reported on a poly (ADP-ribose) polymerase (PARP) 1/2 inhibitor -(3-(hydroxycarbamoyl)phenyl)carboxamide (designated KJ-28d), which increased the death of human ovarian cancer -deficient SNU-251 cells. In the present study, we further investigated the antitumor activities of KJ-28d in -proficient non-small cell lung cancer (NSCLC) cells to expand the use of PARP inhibitors. KJ-28d significantly inhibited the growth of NSCLC cells in vitro and , and induced DNA damage and reactive oxygen species in A549 and H1299 cells.

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Article Synopsis
  • Class III receptor tyrosine kinase (RTK) inhibitors like AIU2001 have been identified as potential treatments for lung cancer, specifically targeting proteins like FLT3 and c-KIT that are not well studied in this context.
  • AIU2001 not only inhibits these RTKs but also shows effectiveness in reducing the growth of non-small cell lung cancer (NSCLC) cells by causing DNA damage and inducing cell cycle arrest.
  • The combination of AIU2001 with poly (ADP-ribose) polymerase (PARP) inhibitors or radiation therapy enhances its anti-tumor effects by further suppressing DNA repair mechanisms, suggesting its promise as a therapeutic strategy for NSCLC.
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  • Structural reflective colors using Fabry-Perot (F-P) cavities are popular for applications like decoration, displays, and imaging, but existing designs struggle with low color purity and vividness due to narrow absorption bands.
  • A new approach introduces a solution-processed, F-P ultra-broadband light absorber made from a high lossy nanoporous material to enhance vivid color generation.
  • This innovative absorber achieves up to 98% maximum absorption intensity and expands the bandwidth by 300 nm, making it suitable for high-resolution displays and anticounterfeiting devices, offering flexibility through inkjet printing technology.
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Ceramide NP is known to be the most abundant class of 12 ceramide (CER) families that form a permeability barrier in the human skin barrier. However, not many studies have been reported on the regulation of the biosynthesis of ceramide NP. Recently, it has been reported that phytosphingosine (PHS) treatment in the cultured keratinocytes (KC) notably increased the content of ceramide NP.

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(CC) is widely used in Asian countries to treat inflammatory diseases. We investigated the anti-inflammatory activity of the aqueous fraction separated from CC extract and of berberine, its key bioactive component, in human keratinocytes and the possible molecular mechanisms underlying this. Treating HaCaT keratinocytic cells with heat-killed induced nitric oxide and proinflammatory cytokine (, tumor necrosis factor-α, interleukin (IL)-1β, and IL-8) production and their mRNA expression; these effects were suppressed by pretreatment with the aqueous fraction or berberine, which also suppressed the phosphorylation of ERK, JNK, and p38 kinases and the nuclear expression of nuclear factor (NF)-κB p65 in -stimulated cells.

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Phytosphingosine (PHS) is a sphingoid that is a key component of phytoceramides NP, AP and EOP. PHS has been known to have anti-inflammation and antimicrobial activities and to stimulate epidermal differentiation. In addition, it is reported that PHS treatment notably increased phytoceramide content in keratinocytes.

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Ex-vivo expanded mesenchymal stromal cells (MSCs) are increasingly used for paracrine support of hematopoietic stem cell (HSC) regeneration, but inconsistent outcomes have hindered ongoing clinical trials. Here, we show that significant heterogeneity in the niche activity of MSCs is created during their culture in various serum-supplemented media. The MSCs cultured under stimulatory or non-stimulatory culture conditions exhibited differences in colony forming unit-fibroblast contents, expression levels of cross-talk molecules (Jagged-1 and CXCL-12) and their support for HSC self-renewal.

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In this study, a reliable method for the quantitation of (E)-N-benzyl-6-[2-(3, 4-dihydroxy benzylidene)hydrazinyl]-N-methylpyridine-3-sulfonamide (JW-55) in rat plasma was developed and validated using high-performance liquid chromatography. Plasma samples were deproteinized; sildenafil was used as an internal standard. Chromatographic separation was achieved using a reversed-phase C column.

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To identify novel small molecules that induce selective cancer cell death, we screened a chemical library containing 1040 compounds in HT29 colon cancer and CCD18-Co normal colon cells, using a phenotypic cell-based viability assay system with the Cell Counting Kit-8 (CCK-8). We discovered a novel anthraquinone derivative, N-(4-[{(9,10-dioxo-9,10-dihydro-1-anthracenyl)sulfonyl}amino]phenyl)-N-methylacetamide (IMP1338), which was cytotoxic against the human colon cancer cells tested. The MTT cell viability assay showed that treatment with IMP1338 selectively inhibited HCT116, HCT116 p53(-/-), HT29, and A549 cancer cell proliferation compared to that of Beas2B normal epithelial cells.

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Conjugation between various small fluorophores and specific ligands has become one of the main strategies for bioimaging in disease diagnosis, medicinal chemistry, immunology, and fluorescence-guided surgery, etc. Herein, we present our review of recent studies relating to molecular fluorescent imaging techniques for various cancers in cell-based and animal-based models. Various organic fluorophores, especially near-infrared (NIR) probes, have been employed with specific ligands.

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Rab GTPases regulate various types of intracellular membrane trafficking in all eukaryotes. Since Rab27a and its multiple effectors are involved in exocytosis of lysosome-related organelles and play a major role in malignancy, compounds targeting Rab27a could be likely used to inhibit invasive growth and tumor metastasis. Thus, we designed and synthesized several compounds based on the previously reported Rab27a-targeting synthetic compounds identified by virtual screening, and investigated their anti-metastatic effects in MDA-MB231 and A375 cells.

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Mesenchymal stromal cells (MSCs) have been extensively utilized for various cell therapeutic trials, but the signals regulating their stromal function remain largely unclear. Here, we show that canonical Wnt signals distinctively regulate MSCs in a biphasic manner depending on signal intensity, i.e.

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Objectives: To compare the effectiveness of transarterial chemoembolization (TACE) and radiofrequency ablation (RFA) for treating small (≤2 cm) hepatocellular carcinomas (HCCs).

Methods: This retrospective study consisted of 287 patients (mean age, 57.1 years; age range, 29-84 years; 221 men, 66 women; 73.

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With the increasing use of culture-expanded mesenchymal stromal cells (MSCs) for cell therapies, factors that regulate the cellular characteristics of MSCs have been of major interest. Oxygen concentration has been shown to influence the functions of MSCs, as well as other normal and malignant stem cells. However, the underlying mechanisms of hypoxic responses and the precise role of hypoxia-inducible factor-1α (Hif-1α), the master regulatory protein of hypoxia, in MSCs remain unclear, due to the limited span of Hif-1α stabilization and the complex network of hypoxic responses.

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Forceful contractions of neck and jaw muscles have consistently been shown to modulate tinnitus and can be used to screen patients who are responsive to somatic stimulation and, therefore, optimal candidates for somatosensory-based treatment. To identify the factors associated with somatic modulation of tinnitus, 163 patients underwent 19 neck and jaw maneuvers after an extensive physiological and audiological profile was compiled. Overall, tinnitus was modulated in 57.

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