Publications by authors named "Myung Gu Jung"

Liver damage upon exposure to ionizing radiation, whether accidental or because of therapy can contribute to liver dysfunction. Currently, radiation therapy is used for various cancers including hepatocellular carcinoma; however, the treatment dose is limited by poor liver tolerance to radiation. Furthermore, reliable biomarkers to predict liver damage and associated side-effects are unavailable.

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Overexpression of NQO1 is associated with poor prognosis in human cancers including breast, colon, cervix, lung and pancreas. Yet, the molecular mechanisms underlying the pro-tumorigenic capacities of NQO1 have not been fully elucidated. Here we show a previously undescribed function for NQO1 in stabilizing HIF-1α, a master transcription factor of oxygen homeostasis that has been implicated in the survival, proliferation and malignant progression of cancers.

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Radiation-induced lung injury (RILI) involves pneumonitis and fibrosis, and results in pulmonary dysfunction. Moreover, RILI can be a fatal complication of thoracic radiotherapy. The present study investigated the protective effect of geranylgeranlyacetone (GGA), an inducer of heat shock protein (HSP)70, on RILI using a C57BL/6 mouse model of RILI developing 6 months subsequent to exposure to 12.

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Radiation enteropathy is a common complication in cancer patients. The aim of this study was to investigate whether radiation-induced intestinal injury could be alleviated by coniferyl aldehyde (CA), an HSF1-inducing agent that increases cellular HSP70 expression. We systemically administered CA to mice with radiation enteropathy following abdominal irradiation (IR) to demonstrate the protective effects of CA against radiation-induced gastrointestinal injury.

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Although multiple studies have revealed that gallic acid plays an important role in the inhibition of malignant transformation, cancer development, and inflammation, the molecular mechanism of gallic acid in inflammatory diseases is still unclear. In this study, we identified gallic acid from Rosa rugosa as a histone acetyltransferase (HAT) inhibitor with global specificity for the majority of HAT enzymes, but with no activity toward epigenetic enzymes including sirtuin (silent mating type information regulation 2 homologue) 1 (S. cerevisiae), histone deacetylase, and histone methyltransferase.

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Because the p300/CBP-mediated hyperacetylation of RelA (p65) is critical for nuclear factor-kappaB (NF-kappaB) activation, the attenuation of p65 acetylation is a potential molecular target for the prevention of chronic inflammation. During our ongoing screening study to identify natural compounds with histone acetyltransferase inhibitor (HATi) activity, we identified epigallocatechin-3-gallate (EGCG) as a novel HATi with global specificity for the majority of HAT enzymes but with no activity toward epigenetic enzymes including HDAC, SIRT1, and HMTase. At a dose of 100 micromol/L, EGCG abrogates p300-induced p65 acetylation in vitro and in vivo, increases the level of cytosolic IkappaBalpha, and suppresses tumor necrosis factor alpha (TNFalpha)-induced NF-kappaB activation.

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Ethnopharmacological Relevance: Rosa rugosa Thunb. (Rosaceae) has been traditionally used for treatments of diabetes, chronic inflammatory diseases, pain, and anticancer in Korea.

Aim Of Study: We investigate the inhibitory effect of histone acetyltransferase activity from the methanol extract of stems of Rosa rugosa on androgen receptor-mediated transcriptional regulation.

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Histone acetylation depends on the activity of two enzyme families, histone acetyltransferase (HAT) and deacetylase (HDAC). In this study, we screened various plant extracts to find potent HAT inhibitors. Hot water extracts of allspice inhibited HAT activity, especially p300 and CBP (40% at 100 microg/ml).

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