Biomedical subjects

Pyung-Keun Myung

Publications and source records attributed to Pyung-Keun Myung.

4 recordsLinked to original sources

PubMed2006

Proteomic analysis and the antimetastatic effect of N-(4-methyl)phenyl-O-(4-methoxy) phenyl-thionocarbamate-induced apoptosis in human melanoma SK-MEL-28 cells.

We employed human SK-MEL-28 cells as a model system to identify cellular proteins that accompany N-(4-methyl)phenyl-O-(4-methoxy)phenyl-thionocarbamate (MMTC)-induced apoptosis based on a proteomic approach. Cell viability tests revealed that SK-MEL-28 skin cancer cells underwent more cell death than normal HaCaT cells in a dose-dependent manner after treatment with MMTC. Two-dimensional electrophoresis in conjunction with matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry analysis or computer matching with a protein database further revealed that the MMTC-induced apoptosis is accompanied by increased levels of caspase-1, checkpoint suppressor-1, caspase-4, NF-kappaB inhibitor, AP-2, c-Jun-N-terminal kinase, melanoma inhibitor, granzyme K, G1/S specific cyclin D3, cystein rich protein, Ras-related protein Rab-37 or Ras-related protein Rab-13, and reduced levels of EMS (oncogene), ATP synthase, tyrosine-phosphatase, Cdc25c, 14-3-3 protein or specific structure of nuclear receptor. The migration suppressing effect of MMTC on SK-MEL-28 cell was tested. MMTC suppressed the metastasis of SK-MEL-8 cells. It was also identified that MMTC had little angiogenic effect because it did not suppress the proliferation of HUVEC cell line. These results suggest that MMTC is a novel chemotherapeutic and metastatic agents against the SK-MEL-28 human melanoma cell line.

Antineoplastic Agents↗

PubMed2005

Stage-dependent gene expression profiles during natural killer cell development.

Natural killer (NK) cells develop from hematopoietic stem cells (HSCs) in the bone marrow. To understand the molecular regulation of NK cell development, serial analysis of gene expression (SAGE) was applied to HSCs, NK precursor (pNK) cells, and mature NK cells (mNK) cultured without or with OP9 stromal cells. From 170,464 total individual tags from four SAGE libraries, 35,385 unique genes were identified. A set of genes was expressed in a stage-specific manner: 15 genes in HSCs, 30 genes in pNK cells, and 27 genes in mNK cells. Among them, lipoprotein lipase induced NK cell maturation and cytotoxic activity. Identification of genome-wide profiles of gene expression in different stages of NK cell development affords us a fundamental basis for defining the molecular network during NK cell development.

Animals↗

PubMed2005

E7-expressing HaCaT keratinocyte cells are resistant to oxidative stress-induced cell death via the induction of catalase.

Cervical carcinoma is one of the most prevalent cancers in women worldwide, and human papillomavirus (HPV) type 16 is the most common agent linked to human cervical carcinoma. In order to identify various relevant factors affected by the E7 oncogene, we established a stable cell line, which constitutively expressed E7 using the HaCaT human keratinocyte cell line. The increased expression and activity of catalase in the E7-expressing HaCaT cells (HaCaT/E7) were verified via matrix-assisted laser desorption/ionization-time of flight, Western blot, and reverse transcription-polymerase chain reaction analyses. The regulation of catalase by E7 was investigated by the detection of catalase promoter activity. E7 enhanced the activities of both the catalase promoter and nuclear factor-kappaB, one of the major transcription factors regulating the expression of the catalase gene. HaCaT/E7 cells produced lower quantities of intracellular reactive oxygen species (ROS), and appeared to be more resistant to H(2)O(2)-induced cell death. Moreover, in order to test the specific effects of E7 on catalase induction, the HaCaT/E7 cells were transiently transfected with E7 antisense vector, resulting in reductions in both the expression and activity of catalase, and a recovery of intracellular ROS levels, thus resulting in recovered sensitivity to H(2)O(2)-induced cell death. These results suggest that the HPV 16 E7 oncogene induces higher resistance to ROS-induced cell injury in the E7-infected cells, probably via the modulation of several anti-oxidant enzymes, including catalase.

Blotting, Western↗

PubMed2004

Epitope analysis of PPARgamma monoclonal antibody Pgamma48.34A and its application for screening PPARgamma ligands.

Peroxisome proliferator-activated receptors (PPARs) are transcription factors that directly modulate gene expression by binding to specific ligands. It has been established that PPARgamma ligands play an essential role in obesity, diabetes, and inflammation. Recently, a great deal of research has focused on the screening of PPARgamma ligands. In this study, both a human peroxisome proliferator-activated receptors gamma2 (PPARgamma2) recombinant protein and a specific monoclonal antibody against PPARgamma2 were produced in order to screen PPARgamma ligands. Analysis of deletion mutants revealed that monoclonal anti-PPARgamma antibody Pgamma48.34A possesses an antigenic determinant in the N-terminal region (31-84 a.a) of human PPARgamma2. The results of Western blot testing revealed that Pgamma48.34A recognized both glutathione S-transferase (GST)- and his-tagged human and mouse PPARgamma recombinant proteins and also identified PPARgamma in adipocytes and mouse tissues. Compared to some commercially available antibodies, this antibody does not bind with skimmed milk or BSA and exhibits a higher degree of specificity. An in vitro binding assay revealed that PPARgamma2 was bound to steroid receptor coactivator-1 (SRC-1) in a dose-responsive manner in the presence of indomethacin, and Pr48.34A was able to detect PPARgamma in a complex consisting of PPARgamma and SRC-1. Using Pgamma48.34A antibody, an enzyme-linked immunosorbent assay (ELISA) system based on the binding between fPPARgamma2 and SRC-1 has been optimized to screen new PPARgamma ligands. This new antibody, Pgamma48.34A, exhibits higher degrees of both specificity and sensitivity against PPARgamma than do other commercial anti-PPARgamma antibody, and may constitute a profound contribution to the screening of PPARgamma ligands as well as the functional study of PPARgamma.

Animals↗