Youl-Hee Cho

Hanyang University, Ansan, Gyeonggi, South Korea

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Publications (16)35.97 Total impact

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    ABSTRACT: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
    ChemInform 01/2009; 40(25).
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    ABSTRACT: This study was aimed to elucidate the novel structure of HY253 isolated from the roots of Aralia continentalis and to evaluate its detailed mechanisms on apoptotic induction in HY253-treated HeLa cells. The structure of HY253 was elucidated based on the interpretation of the NMR spectra, as 7,8a-divinyl-2,4a,4b,5,6,7,8,8a,9,9a-decahydro-1H-fluorene-2,4a,4b,9a-tetraol. The TUNEL assay using flow cytometer revealed an appreciable apoptotic induction in HeLa cells treated with 100 microM of HY253 for 48 h. This apoptotic induction is associated with cytochrome c release from mitochondria, via up-regulation of pro-apoptotic Bcl-2 proteins, such as Bax and Bak, which, in turn, resulted in the activation of caspase-8, -9 and -3, and the cleavage of poly(ADP-ribose) polymerase (PARP).
    Bioorganic & medicinal chemistry letters 01/2009; 19(3):797-9. · 2.65 Impact Factor
  • ChemInform 01/2009; 40(26).
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    ABSTRACT: This study was aimed to elucidate the novel structure of HY251 isolated from the roots of Aralia continentalis and to evaluate its detailed inhibition mechanisms on cell cycle progression in HeLa cells. The structure of HY251 was elucidated based on the interpretation of the NMR spectra, as 3-propyl-2-vinyl-1,2,3,3a,3b,6,7,7a,8,8a-decahydrocyclopenta[a]indene-3,3a,7a,8a-tetraol. The flow cytometric analysis revealed an appreciable G(1) phase arrest in HeLa cells treated with 100 microM of HY251. This HY251-induced G(1) phase arrest is associated with decreased expression of cyclin D3 and up-regulation of p21(CIP1) and p27(KIP1), via p53 phosphorylation at Ser-15 by transcriptional up-regulation of ATM, which resulted in increased hypophosphorylated pRb in HeLa cells.
    Bioorganic & medicinal chemistry letters 12/2008; 19(3):959-61. · 2.65 Impact Factor
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    ABSTRACT: The cerebellum is involved in complex physiological functions including motor control, sensory perception, cognition, language, and emotion. Humans and animals with prion diseases are characterized clinically by ataxia, postural abnormalities and cognitive decline. Pathology in the cerebellum affected by prions includes spongiform degeneration, neuronal loss, and gliosis. To develop an in vitro model system for studying prion biology in cerebellar cells, we established and characterized an immortal cell line (CRBL) isolated from the cerebellum of mice lacking expression of a protein involved in cell cycle arrest. The characteristics of the cells include morphological heterogeneity, rapid proliferation, serum responsiveness during growth, and a change in the number of chromosomes. CRBL cells expressed both neuronal and glial cell markers as well as a considerable level of cellular prion protein, PrP(C). Upon in vitro infection, CRBL cells exhibited selective susceptibility to prions isolated from different sources. These cells chronically propagated prions from SMB cells. Strain-specific prion infection in CRBL cells was not due to instability of the cell line, allelic variance, or mutations in the PrP gene. Molecular properties of prions derived from SMB cells were maintained in the infected CRBL cells. Our results suggest that the specific interaction between a prion strain and hosts determined the selective susceptibility of CRBL cells, which reflects the conditions in vivo. In addition to the future studies revealing cellular and molecular mechanism involved in prion pathogenesis, CRBL cells will contribute to the studies dealing with prion strain properties and host susceptibilities.
    Brain Research 06/2008; 1208:170-80. · 2.88 Impact Factor
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    ABSTRACT: Human embryonic stem (hES) cells can be guided to differentiate into ventral midbrain-type neural precursor (NP) cells that proliferate in vitro by specific mitogens. We investigated the potential of these NP cells derived from hES cells (hES-NP) for the large-scale generation of human dopamine (DA) neurons for functional analyses and therapeutic applications. To address this, hES-NP cells were expanded in vitro for 1.5 months with six passages, and their proliferation and differentiation properties determined over the NP passages. Interestingly, the total hES-NP cell number was increased by > 2 x 10(4)-folds over the in vitro period without alteration of phenotypic gene expression. They also sustained their differentiation capacity toward neuronal cells, exhibiting in vitro pre-synaptic DA neuronal functionality. Furthermore, the hES-NP cells can be cryopreserved without losing their proliferative and developmental potential. Upon transplantation into a Parkinson's disease rat model, the multi-passaged hES-NP cells survived, integrated into the host striatum, and differentiated toward the neuronal cells expressing DA phenotypes. A significant reduction in the amphetamine-induced rotation score of Parkinson's disease rats was observed by the cell transplantation. Taken together, these findings indicate that hES-NP cell expansion is exploitable for a large-scale generation of experimental and transplantable DA neurons of human-origin.
    Journal of Neurochemistry 12/2007; 103(4):1417-29. · 3.97 Impact Factor
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    ABSTRACT: To generate new scaffold candidates as highly selective and potent cyclin-dependent kinase (CDK) inhibitors, structure-based drug screening was performed utilizing 3D pharmacophore conformations of known potent inhibitors. As a result, CR229 (6-bromo-2,3,4,9-tetrahydro-carbolin-1-one) was generated as the hit-compound. A computational docking study using the X-ray crystallographic structure of CDK2 in complex with CR229 was evaluated. This predicted binding mode study of CR229 with CDK2 demonstrated that CR229 interacted effectively with the Leu83 and Glu81 residues in the ATP-binding pocket of CDK2 for the possible hydrogen bond formation. Furthermore, biochemical studies on inhibitory effects of CR229 on various kinases in the human cervical cancer HeLa cells demonstrated that CR229 was a potent inhibitor of CDK2 (IC50: 3 microM), CDK1 (IC50: 4.9 microM), and CDK4 (IC50: 3 microM), yet had much less inhibitory effect (IC50: >20 microM) on other kinases, such as casein kinase 2-1 (CK2- alpha1), protein kinase A (PKA), and protein kinase C (PKC). Accordingly, these data demonstrate that CR229 is a potent CDK inhibitor with anticancer efficacy.
    Journal of Microbiology and Biotechnology 11/2007; 17(10):1712-6. · 1.40 Impact Factor
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    ABSTRACT: In the course of screening for novel anticancer compounds, CR229 (6-Bromo-2,3,4,9-tetrahydro-carbolin-1-one), a novel derivative of beta-carbolin-1-one, was generated as a new scaffold candidate. For the first time, the authors demonstrate that CR229 inhibited the growth of HeLa cells by the induction of cell cycle arrest and apoptosis. Analysis of flow cytometry and western blots of HeLa cells treated with 2.5 microM CR229 revealed an appreciable cell cycle arrest in the G1, G2/M phase and apoptotic induction via the p53-dependent pathway. Furthermore, the release of cytochrome c from mitochondria was detected using confocal microscopy in HeLa cells treated with CR229. Accordingly, these data demonstrate that the anticancer activity of CR229 is associated with: (i) the down-regulation of cyclins and cyclin-dependent kinase; (ii) the induction of p53, p21, and p16; and (iii) the activation of caspase-3.
    Cancer Science 10/2007; 98(9):1402-7. · 3.48 Impact Factor
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    ABSTRACT: Chromosome microdissection and the reverse FISH technique is one of the most useful methods for the identification of structurally abnormal chromosomes. In particular, the laser microbeam microdissection (LMM) method allows rapid isolation of a target chromosome or a specific region of chromosomes without damage of genetic materials and contamination. Isolated chromosomes were directly amplified by the degenerate oligonucleotide-primed polymerase chain reaction (DOP-PCR), and then the FISH probes labeled with spectrum green- or spectrum red-dUTP were generated by nick-translation. Whole chromosome painting (WCP) probes were successfully generated from only 5 copies of the chromosome. With this method, we produced 24 WCP probes for each human chromosome. We also tried to characterize a marker chromosome, which seemed to be originated from chromosome 11 on conventional banding technique. The marker chromosomes were isolated by the LMM method and analyzed by reverse FISH. We elucidated that the marker chromosome was originated from the short arm of chromosome 5 (5p11-->pter). A fully automated and computer-controlled LMM method is a very simple laboratory procedure, and enables rapid and precise characterization of various chromosome abnormalities.
    Journal of Microbiology and Biotechnology 07/2007; 17(7):1079-82. · 1.40 Impact Factor
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    ABSTRACT: We report on a de novo centric fission of chromosome 11 in a healthy female referred for chromosome analysis due to recurrent miscarriages. Both fission products were mitotically stable. This centric fission of chromosome 11 appears to have no clinical significance for this patient other than recurrent miscarriages.
    Journal of Korean Medical Science 03/2007; 22(1):146-8. · 1.25 Impact Factor
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    ABSTRACT: Genetic factors make a significant contribution to the determination of human personality traits. We aimed to investigate the possible relationship between dopamine receptor D2 (DRD2) TaqI A polymorphism and the reward-related personality traits as measured by the Carver and White Behavioral Inhibition System/Behavioral Approach System (BIS/BAS) scales and Cloninger's Temperament and Character Inventory (TCI). The sample consisted of 267 female healthy Korean unrelated university students (age: 23.12 +/- 3.22 years) and they filled out the BIS/BAS scales and the TCI. Genomic DNA was isolated from whole blood and genotyped with the fluorescence polarization detection method. The effect of the independent variables (DRD2 genotypes) on the dependent variables were analyzed by multivariate and subsequent univariate ANOVA. We found significant associations between the A1 allele of the DRD2 TaqI A polymorphism and a high BAS-RR score (reward responsiveness). No significant association was observed between DRD2 polymorphisms and other factors of the BIS/BAS scales and TCI. These findings suggest the notion that DRD2 TaqI A polymorphism contributes to high reward sensitivity, which measures anticipation and positive response towards reward.
    Neuropsychobiology 02/2007; 56(2-3):146-51. · 2.37 Impact Factor
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    ABSTRACT: The purpose of the present study was to investigate the mechanisms involved in the antiproliferative and apoptotic effects of MCS-C2, a novel analog of the pyrrolo[2,3-d]pyrimidine nucleoside toyocamycin and sangivamycin, in human prostate cancer LNCaP cells. MCS-C2, a selective inhibitor of cyclin-dependent kinase, was found to inhibit cell growth in a time- and dose-dependent manner, and inhibit cell cycle progression by inducing the arrest of the G1 phase and apoptosis in LNCaP cells. When treated with 3 microM MCS-C2, inhibited proliferation associated with apoptotic induction was found in the LNCaP cells in a concentration and time-dependent manner, and nuclear DAPI staining revealed the typical nuclear features of apoptosis. Furthermore, MCS-C2 induced cell cycle arrest in the G1 phase through the upregulated phosphorylation of the p53 protein at Ser-15 and activation of its downstream target gene p21WAF1/CIP1. Accordingly, these results suggest that MCS-C2 inhibits the proliferation of LNCaP cells by way of G1-phase arrest and apoptosis in association with the regulation of multiple molecules in the cell cycle progression.
    Cancer Science 06/2006; 97(5):430-6. · 3.48 Impact Factor
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    ABSTRACT: In the course of screening for a novel inhibitor of cyclin-dependent kinase (CDK), HY52 (C17H30O2N2; molecular weight 294) was isolated from the leaves of Pata de Vaca (Bauhinia forficata). The growth of HeLa cells was inhibited in a dose-dependent manner when treated with 0.07 to 0.41 mM of HY52 for 24 h (IC50:0.11 mM). Furthermore, HY52 showed the selective inhibitory activity on CDC2 kinase purified using immunoprecipitation with an IC 50 value of 0.45 mM. A flow cytometric analysis of the HeLa cells treated with HY52 revealed an appreciable cell-cycle arrest in the G1 phase. Moreover, a TUNEL assay exhibited the apoptotic induction of HeLa cells treated with HY52. To obtain further information on the cell-cycle arrest induced by HY52, the expression of certain cell-cycle-associated proteins was examined using a Western blot analysis. The results revealed that HY52 was found to inhibit the proliferation of HeLa cells through inducing a G1-phase arrest by inhibiting pRb phosphorylation via an up-regulation of p21WAF1/CIP1 and p27KIP1, and G2/M-phase arrest by down-regulation of CDC2, cyclin A, and cyclin B1.
    Cancer Letters 03/2006; 233(1):89-97. · 4.26 Impact Factor
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    ABSTRACT: The purpose of the present study was to investigate the anti-proliferative and apoptotic effects of MCS-C2, a novel synthetic analogue of the pyrrolo[2,3-d]pyrimidine nucleoside toyocamycin and sangivamycin, in human promyelocytic leukemia (HL-60) cells. When treated with 5 microM MCS-C2, inhibited proliferation associated with apoptotic induction was found in the HL-60 cells in a concentration-dependent and time-dependent manner, plus nuclear DAPI staining revealed the typical nuclear features of apoptosis. However, MCS-C2 showed almost no antiproliferative effect and no apoptotic induction in normal lymphocyte cells used as a control when compared with those in HL-60 cancer cells. Moreover, a flow cytometric analysis of the HL-60 cells using FITC-dUTP and propidium iodide (PI) showed that the apoptotic cell population increased gradually from <1% at 0 h to 34% at 12 h after exposure to 5 microM MCS-C2. This apoptotic induction was associated with the cleavage of Bid and a release of cytochrome c from mitochondria into the cytosol, followed by the activation of caspase-3 and inactivation of poly(ADP-ribose) polymerase (PARP). However, there was no significant change in any other mitochondrial membrane proteins, such as Bcl-2 and Bax. Consequently, the current findings suggest that the mitochondrial pathway was primarily involved in the MCS-C2-induced apoptosis in the human promyelocytic leukemia HL-60 cells.
    Cancer Letters 07/2005; 223(2):239-47. · 4.26 Impact Factor
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    ABSTRACT: Previous reports on the analysis of the human monoblastic cell line U937 had described several sublines containing unidentified rearrangements and marker chromosomes. In order to determine the true nature of the rearrangements, conventional banding analysis was carried out with various combinations of molecular cytogenetic techniques: comparative genomic hybridization, fluorescence in situ hybridization (FISH) with whole chromosome painting probes, and microdissection and reverse painting FISH. The origins of the marker chromosomes were identified and the composite karyotype is described.
    Cancer Genetics and Cytogenetics 10/2002; 137(2):124-32. · 1.93 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Previous reports on the analysis of the human monoblastic cell line U937 had described several sublines containing unidentified rearrangements and marker chromosomes. In order to determine the true nature of the rearrangements, conventional banding analysis was carried out with various combinations of molecular cytogenetic techniques: comparative genomic hybridization, fluorescence in situ hybridization (FISH) with whole chromosome painting probes, and microdissection and reverse painting FISH. The origins of the marker chromosomes were identified and the composite karyotype is described.
    Cancer Genetics and Cytogenetics - CANCER GENET CYTOGENET. 01/2002; 137(2):124-132.

Publication Stats

122 Citations
35.97 Total Impact Points

Institutions

  • 2002–2009
    • Hanyang University
      • Major in Medical Genetics
      Ansan, Gyeonggi, South Korea
  • 2005–2008
    • Hanyang University Medical Center
      Sŏul, Seoul, South Korea