Jeong-hyuk Ahn

Metastasis is a major cause of therapeutic failure in ovarian cancer. To elucidate molecular mechanisms of ovarian cancer metastasis, we previously established a metastatic xenograft mouse model using human ovarian carcinoma SK-OV-3 cells. Using gene expression profiling, we found that γ-aminobutyric acid (GABA)A receptor π subunit (GABRP) expression was upregulated (44-fold) in metastatic tissues from our xenograft mice compared with SK-OV-3 cells. Importantly, GABRP knockdown diminished the mi

The Swedish mutation (K595N/M596L) of amyloid precursor protein (APP-swe) has been known to increase abnormal cleavage of cellular APP by Beta-secretase (BACE), which causes tau protein hyperphosphorylation and early-onset Alzheimer’s disease (AD). Here, we analyzed the effect of APP-swe in global gene expression using deep transcriptome sequencing technique. We found 283 genes were down-regulated and 348genes were up-regulated in APP-swe expressing H4-swe cells compared to H4 wild-type cells fr

Purpose: Both genetic and epigenetic alterations can lead to abnormal expressionof metastasis-regulating genes in tumor cells. Recent studies suggest that aberrantepigenetic alterations, followed by differential gene expression, leads to an aggressive cancer cell phenotype. We examined epigenetically regulated genes that are involved in ovarian cancer metastasis. Materials and Methods: We developedSK-OV-3 human ovarian carcinoma cell xenografts in mice. We comparedthe mRNA expression and DNA met

Overexpression of amyloid precursor protein with the Swedish mutation causes abnormal hyperphosphorylationof the microtubule-associated protein tau. Hyperphosphorylated isoforms of tau are majorcomponents of neurofibrillary tangles, which are histopathological hallmarks of Alzheimer’s disease. Protein phosphatase 2A (PP2A), a major tau protein phosphatase, consists of a structural A subunit,catalytic C subunit, and a variety of regulatory B subunits. The B subunits have been reported tomodulate

Purpose: Recent discoveries suggest that aberrant DNA methylation provides cancercells with advanced metastatic properties. However, the precise regulatory mechanismscontrolling metastasis genes and their role in metastatic transformation are largely unknown. To address epigenetically-regulated gene products involved in ovarian cancer metastasis, we examined the mechanisms regulating mucin 13 (MUC13) expression and its influence on aggressive behaviors of ovarian malignancies. Materials and Meth

To characterize the biochemical properties of the PP2A regulatory B subunit, PPP2R5D, we analyzed its phosphorylation sites, stoichiometry and effect on holoenzyme activity. PPP2R5D was phosphorylated on Ser-53, Ser-68, Ser-81, and Ser-566 by protein kinase A, and mutations at all four of these sites abolished any significant phosphorylation in vitro. In HEK293cells, however, the Ser-566 was the major phosphorylation site after PKA activation by forskolin, with marginal phosphorylation on Ser-81

Aging is a major risk factor for common neurodegenerative diseases. Although multiple molecular, cellular, structural, and functional changes occur in the brain during aging, the involvement of caveolin-2 (Cav-2) in brain ageing remains unknown. We investigated Cav-2 expression in brains of aged mice and its effects on endothelial cells. The human umbilical vein endothelial cells (HUVECs) showed decreased THP-1 adhesion and infiltration when treated with Cav-2 siRNA compared to control siRNA. In

Purpose: Ovarian cancer (OC) is the most fatal of gynecological malignancies with a high rate of recurrence. We aimed to evaluatethe expression of solute carrier family 6, member 12 (SLC6A12) and methylation of its promoter CpG sites in a xenograft mousemodel of metastatic OC, and to investigate the regulatory mechanisms that promote aggressive properties during OC progression. Materials and Methods: Expression of SLC6A12 mRNA was determined by reverse-transcription quantitative polymerase chain

Purpose Glioblastoma multiforme (GBM) is the most common adult primary intracranial tumor. The remarkable features of GBM include central necrosis. MicroRNAs (miRNAs) have been considered as diagnostic/prognostic biomarkers for many cancers, including glioblastoma. However, the effect of necrosis on the miRNA expression profile and predicted miRNA-mRNA regulatory information remain unclear. The purpose of this study is to examine the effect of necrotic cells on the modulation of miRNA and mRNA e

Although cisplatin is one of the most effective antitumor drugs for ovarian cancer, the emergence of chemoresistance to cisplatin in over 80% of initially responsive patients is a major barrier to successful therapy. The precise mechanisms underlying the development of cisplatin resistance are not fully understood, but alteration of DNA methylation associated with aberrant gene silencing may play a role. To identify epigenetically regulated genes directly associated with ovarian cancer cisplatin

Vitrification approaches for the cryopreservation of human periodontal ligament (PDL) cells have not yet been successfully standardized, although vitrification has been widely used in various cells and tissues. The aims of this study were to examine whether vitrification approaches could be used for the cryopreservation of human PDL cells and to establish the most suitable vitrification formula for tooth cryopreservation. Human PDL cells were cryopreserved with 4 solutions: VS1, 20% (v/v) ethyle