Publications by authors named "Je-Won Ryu"

Introduction: Humanized mouse models to recapitulate human biological systems still have limitations, such as the onset of lethal graft-versus-host disease (GvHD), a variable success rate, and the low accessibility of total body irradiation (TBI). Recently, mice modified with the CD47-SIRPA axis have been studied to improve humanized mouse models. However, such trials have been rarely applied in NOD mice.

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Background: Tumor-derived exosomes are critical elements of the cell-cell communication response to various stimuli. This study aims to reveal that the histone deacetylase 5 (HDAC5) and p53 interaction upon radiation in hepatocellular carcinoma intricately regulates the secretion and composition of exosomes.

Methods: We observed that HDAC5 and p53 expression were significantly increased by 2 Gy and 4 Gy radiation exposure in HCC.

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Damage to normal tissue can occur over a long period after cancer radiotherapy. Free radical by radiation can initiate or accelerate chronic inflammation, which can lead to atherosclerosis. However, the underlying mechanisms remain unclear.

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Purpose: This study evaluates the oncogenic role of PIBF1 in triple-negative breast cancer (TNBC). TNBC is considered to have a poorer prognosis than other types of breast cancer and is associated with high risk of recurrence and distant metastasis. Currently, there are no effective therapies for the TNBC patients with distant metastasis due to the lack of targeted therapeutic options.

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In the event of a mass casualty radiation scenario, biodosimetry has the potential to quantify individual exposures for triaging and providing dose-appropriate medical intervention. Structural maintenance of chromosomes 1 (SMC1) is phosphorylated in response to ionizing radiation. The goal of this study was to develop a new biodosimetry method using SMC1 phosphorylation as a measure of exposure to radiation.

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Aim: We investigated the therapeutic effects of a mitogen-activated protein (MEK) inhibitor, selumetinib, in a hepatic melanoma metastasis model and studied its possible mechanism of action.

Materials And Methods: Melanoma cell lines were exposed to selumetinib under different experimental conditions. We established a mouse model of liver metastasis and treated mice orally with vehicle or selumetinib and then evaluated metastasis progress.

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Article Synopsis
  • EGF signaling previously thought to promote cancer cell growth instead inhibits proliferation and promotes cell death in non-small cell lung cancer (NSCLC) cells like A549.
  • Increased expression of redox factor-1 (Ref-1) and its interaction with EGR1 leads to higher levels of PTEN, which inhibits the Akt pathway and encourages apoptosis and autophagy.
  • EGF's effects are linked to changes in purinergic receptor activity and require NADPH oxidase function, suggesting a complex mechanism behind EGF's role in NSCLC cell regulation.
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Glucose-6-phosphate dehydrogenase (G6PD), a rate-limiting enzyme of the pentose phosphate pathway, plays important roles in redox regulation and de novo lipogenesis. It was recently demonstrated that aberrant upregulation of G6PD in obese adipose tissue mediates insulin resistance as a result of imbalanced energy metabolism and oxidative stress. It remains elusive, however, whether inhibition of G6PD in vivo may relieve obesity-induced insulin resistance.

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Radiation-induced fibrosis (RIF) is one of the most common late complications of radiation therapy. We found that α-lipoic acid (α-LA) effectively prevents RIF. In RIF a mouse model, leg contracture assay was used to test the in vivo efficacy of α-LA.

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The CCR2 antagonist is a receptor antagonist for monocyte chemoattractant protein-1 and is known to be a potential anti-inflammatory therapeutic agent. Recently used optimized labeling techniques for superparamagnetic iron oxide, macrophage homing, and recruitment toward the infection site can be observed on in vivo MRI. This study details the effect of the CCR2 antagonist on the macrophage migration and the feasibility of in vivo MRI for assessing the inhibition of chemotactic activity by the CCR2 antagonist.

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Objective: Adiponectin is an important adipocytokine that improves insulin action and reduces atherosclerotic processes. The plasma adiponectin level is paradoxically reduced in obese individuals, but the underlying mechanism is unknown. This study was undertaken to test the hypothesis that mitochondrial function is linked to adiponectin synthesis in adipocytes.

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AMP-activated protein kinase (AMPK) functions as a fuel sensor in the cell and is activated when cellular energy is depleted. Here we report that alpha-lipoic acid (alpha-LA), a cofactor of mitochondrial enzymes, decreases hypothalamic AMPK activity and causes profound weight loss in rodents by reducing food intake and enhancing energy expenditure. Activation of hypothalamic AMPK reverses the effects of alpha-LA on food intake and energy expenditure.

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Ghrelin, a stomach-derived hormone, induces adiposity when administered to rodents. Because ghrelin receptor is abundantly expressed in adipose tissue, we investigated the role of ghrelin in adipocyte biology. We observed ghrelin receptor expression in 3T3-L1 preadipocytes and adipocytes.

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Objective: Uncoupling protein 2 (UCP2) belongs to the mitochondrial anion carrier family and regulates production of reactive oxygen species in macrophages. Previous studies have shown that selective genetic disruption of UCP2 in bone marrow cells results in excess accumulation of monocytes/macrophages in the vascular wall of hypercholesterolemic low-density lipoprotein receptor-deficient (LDLR-/-) mice. Here we investigated whether UCP2 regulates expression of genes involved in monocyte recruitment.

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We found that UCP-1 and UCP-3 mRNA expression levels and the UCP-1 protein content in brown adipose tissue (BAT) were reduced in prediabetic OLETF rats than the lean LETO rats. Administration of dehydroepiandrosterone (DHEA) for 17 days induced remarkable weight loss, which was in part attributed to an enhanced utilization of ingested energy. DHEA administration significantly increased the levels of BAT UCP-1 and UCP-3 mRNA expression.

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