Publications by authors named "Yhun Y Sheen"

Radio-resistance resulting from radiotherapy-induced fibrosis is a major clinical obstacle in breast cancer treatment because it typically leads to cancer recurrence, treatment failure, and patient death. Transforming growth factor-β (TGF-β) is a key signal messenger in fibrosis, which plays an important role in radiation-induced fibrosis and cancer stem cell (CSC) development, may be mediated through the generation of oxidative stress. This study was conducted to confirm the efficacy of vactosertib, a TGF-β/ALK5 inhibitor, as a potent inhibitor in radiation-induced oxidative stress generation, fibrosis and CSC development.

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Globalization of the pharmaceutical industry has continued over the past few decades, and various regulatory authorities have put considerable effort into harmonizing and standardizing drug regulations. However, the regulatory practices of each regulatory authority, in addition to local differences in ethnic, social, and cultural backgrounds, create discrepancies in risk/benefit assessments, regulatory decisions, and drug label information in various countries. This study examines discrepancies in the label information for direct oral anticoagulants approved in the US, Europe, Korea, and Japan and reviews the causes of those discrepancies, focusing on regulatory practices.

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Background/aims: Hypoxia is an environmental factor that aggravates liver fibrosis. HIF1α activates hepatic stellate cells (HSCs) and increases transforming growth factor-β (TGF-β) signaling and the epithelial mesenchymal transition (EMT), accelerating the progression of fibrosis. We evaluated the anti-fibrotic therapeutic potential of a small-molecule inhibitor of TGF-β type I receptor kinase, EW-7197, on HIF1α-derived TGF-β signaling in cholestatic liver fibrosis.

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Recent strategies for treating CML patients have focused on investigating new combinations of tyrosine kinase inhibitors (TKIs) as well as identifying novel translational research agents that can eradicate CML leukemia-initiating cells (CML-LICs). However, little is known about the therapeutic benefits such CML-LIC targeting therapies might bring to CML patients. In this study, we investigated the therapeutic potential of EW-7197, an orally bioavailable transforming growth factor-β signaling inhibitor which has recently been approved as an Investigational New Drug (NIH, USA), to suppress CML-LICs in vivo.

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To further optimize a clinical candidate 5 (EW-7197), a series of 5-(3-, 4-, or 5-fluoro-substituted-6-methylpyridin-2-yl)-4-([1,2,4]triazolo[1,5-a]pyridin-6-yl)imidazoles 19a-l have been synthesized and evaluated for their TGF-β type I receptor kinase (ALK5) and p38α MAP kinase inhibitory activity in an enzyme assay. The 5-(5-fluoro-substituted-6-methylpyridin-2-yl)-4-([1,2,4]triazolo[1,5-a]pyridin-6-yl)imidazoles 19h-l displayed the similar level of potency to that of 5 against both ALK5 (IC50=7.68-13.

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Distant relapse after chemotherapy is an important clinical issue for treating breast cancer patients and results from the development of cancer stem-like cells (CSCs) during chemotherapy. Here we report that blocking epithelial-to-mesenchymal transition (EMT) suppresses paclitaxel-induced CSCs properties by using a MDA-MB-231-xenografted mice model (in vivo), and breast cancer cell lines (in vitro). Paclitaxel, one of the cytotoxic taxane-drugs such as docetaxel, increases mesenchymal markers (Vimentin and Fibronectin) and decreases an epithelial marker (Zo-1).

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Fibrosis is an inherent response to chronic damage upon immense apoptosis or necrosis. Transforming growth factor-beta1 (TGF-β1) signaling plays a key role in the fibrotic response to chronic liver injury. To develop anti-fibrotic therapeutics, we synthesized a novel small-molecule inhibitor of the TGF-β type I receptor kinase (ALK5), EW-7197, and evaluated its therapeutic potential in carbon tetrachloride (CCl4) mouse, bile duct ligation (BDL) rat, bleomycin (BLM) mouse, and unilateral ureteral obstruction (UUO) mouse models.

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TGF-β signaling plays an important role in breast cancer progression and metastasis. Epithelial-mesenchymal transition (EMT) is an important step in the progression of solid tumors to metastatic disease. We previously reported that IN-1130, a novel transforming growth factor-β type I receptor kinase (ALK5) inhibitor, suppressed renal fibrosis in obstructive nephropathy (Moon et al.

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Advanced tumors produce an excessive amount of transforming growth factor β (TGFβ), which promotes tumor progression at late stages of malignancy. The purpose of this study was to develop anti-TGFβ therapeutics for cancer. We synthesized a novel small-molecule TGFβ receptor I kinase (activin receptor-like kinase 5) inhibitor termed N-[[4-([1,2,4]triazolo[1,5-a]pyridin-6-yl)-5-(6-methylpyridin-2-yl)-1H-imidazol-2-yl]methyl]-2-fluoroaniline (EW-7197), and we investigated its potential antimetastatic efficacy in mouse mammary tumor virus (MMTV)/c-Neu mice and 4T1 orthotopic-grafted mice.

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A series of 2-substituted-4-([1,2,4]triazolo[1,5-a]pyridin-6-yl)-5-(6-methylpyridin-2-yl)imidazoles was synthesized and evaluated to optimize a prototype inhibitor of TGF-β type I receptor kinase (ALK5), 6. Combination of replacement of a quinoxalin-6-yl moiety of 6 with a [1,2,4]triazolo[1,5-a]pyridin-6-yl moiety, insertion of a methyleneamino linker, and a o-F substituent in the phenyl ring markedly increased ALK5 inhibitory activity, kinase selectivity, and oral bioavailability. The 12b (EW-7197) inhibited ALK5 with IC50 value of 0.

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Article Synopsis
  • A series of imidazole and pyrazole compounds were synthesized and tested for their ability to inhibit the ALK5 enzyme.
  • The most effective compound, pyrazole derivative 21b, demonstrated an IC50 value of 0.018 μM and achieved 95% inhibition in a luciferase reporter assay.
  • Docking analysis indicated that 21b fits perfectly into the ATP binding site of ALK5, forming multiple hydrogen bonds, and also showed a high selectivity index against p38α MAP kinase.
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TGF-β pathway is being extensively evaluated as a potential therapeutic target. The transforming growth factor-β (TGF-β) signaling pathway has the dual role in both tumor suppression and tumor promotion. To design cancer therapeutics successfully, it is important to understand TGF-β related functional contexts.

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Amyloid β (Αβ) has been reported to be responsible for the functional and structural abnormalities of Alzheimer's disease (AD) through the induction of oxidative stress. The aim of this study was to determine whether or not treatment of transgenic (Tg) mice with green tea catechin (GTC), a radical scavenger, improves AD phenotypes. To test this, 7-month-old Tg mice were treated with a low (1 mg) or high (10 mg) dose of GTC for 6 months.

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High aldehyde dehydrogenase (ALDH) activity has been recognized as a marker of cancer stem cells (CSCs) in breast cancer. In this study, we examined whether inhibition of ALDH activity suppresses stem-like cell properties in a 4T1 syngeneic mouse model of breast cancer. We found that ALDH-positive 4T1 cells showed stem cell-like properties in vitro and in vivo.

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A series of 2-benzylamino-4(5)-(6-methylpyridin-2-yl)-5(4)-([1,2,4]triazolo[1,5-a]pyridin-6-yl)thiazoles 12a-ab, 13a, 13b, and 18a-d has been synthesized and evaluated for their ALK5 inhibitory activity in an enzyme assay and in a cell-based luciferase reporter assay. The N-(3-fluorobenzyl)-4-(6-methylpyridin-2-yl)-5-([1,2,4]triazolo[1,5-a]pyridin-6-yl)thiazol-2-amine (12b) inhibited ALK5 phosphorylation with an IC(50) value of 7.01 nM and showed 61% inhibition at 30 nM in a luciferase reporter assay using HaCaT cells permanently transfected with p3TP-luc reporter construct.

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Objectives: In recent years, a number of structurally diverse Histone deacetylase (HDAC) inhibitors have been identified and these HDAC inhibitors induce growth arrest, differentiation and/or apoptosis of cancer cells in vitro and in vivo. This study aimed at investigating the anti-tumor activity of newly synthesized HDAC inhibitor, 3-(4-dimethylamino phenyl)-N-hydroxy-2-propenamide (IN-2001) using human breast cancer cells.

Methods: We have synthesized a new HDAC inhibitor, IN-2001, and cell proliferation inhibition assay with this chemical in estrogen receptor-positive human breast cancer MCF-7 cells.

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In recent years, inhibition of HDACs has emerged as a potential strategy to reverse aberrant epigenetic changes associated with cancer, and several classes of HDAC inhibitors have been found to have potent and specific anticancer activities in preclinical studies. But their precise mechanism of action has not been elucidated. In this study, a novel synthetic inhibitor of HDAC, 3-(4-dimethylamino phenyl)-N-hydroxy-2-propenamide [IN-2001] was examined for its antitumor activity and the underlying molecular mechanisms of any such activity on human breast cancer cell lines.

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To identify specific biomarkers generated upon exposure of L5178Y mouse lymphoma cells to carcinogens, 2-DE and MALDI-TOF MS analysis were conducted using the cellular proteome of L5178Y cells that had been treated with the known carcinogens, 1,2-dibromoethane and O-nitrotoluene and the noncarcinogens, emodin and D-mannitol. Eight protein spots that showed a greater than 1.5-fold increase or decrease in intensity following carcinogen treatment compared with treatment with noncarcinogens were selected.

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1,2-Dibromoethane and glycidol are well known genotoxic carcinogens, which have been widely used in industry. To identify a specific biomarker for these carcinogens in cells, the cellular proteome of L5178Y mouse lymphoma cells treated with these compounds was analyzed by 2-dimensional gel electrophoresis (2-DE) and MALDI-TOF mass spectrometry (MS). Of 50 protein spots showing a greater than 1.

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Histone deacetylases (HDACs) are enzymes involved in the remodelling of chromatin, and have a key role in the epigenetic regulation of gene expression. Histone deacetylase (HDAC) inhibitors are emerging as an exciting new class of potential anti-cancer agents. In recent years, a number of structurally diverse HDAC inhibitors have been identified and these HDAC inhibitors induce growth arrest, differentiation and/or apoptosis of cancer cells in vitro and in vivo.

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Article Synopsis
  • A range of 1-substituted-3-(6-methylpyridin-2-yl)-4-([1,2,4]triazolo[1,5-a]pyridin-6-yl)pyrazoles has been synthesized and tested for their ability to inhibit the ALK5 enzyme.
  • Compound 14n demonstrated strong inhibitory effectiveness with an IC(50) value of 0.57 nM, making it a potent candidate.
  • Additionally, it achieved 94% inhibition in a luciferase reporter assay in specific cell lines, indicating high potential for further research and development.
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Recently, researchers are actively pursuing efforts to develop potent and selective ALK5 (TβRI) kinase inhibitors for clinical development. In this study, the authors examined a novel small molecule inhibitor of ALK5, 3-((4-([1,2,4]triazolo[1,5-a]pyridin-6-yl)-5-(6-methylpyridin-2-yl)-1H-imidazol-2-yl)methylamino)benzonitrile (EW-7195) to determine if it has potential for cancer treatment. The inhibitory effects of EW-7195 on TGF-β-induced Smad signaling and epithelial-to-mesenchymal transition (EMT) were investigated in mammary epithelial cells using luciferase reporter assays, immunoblotting, confocal microscopy and wound healing assays.

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Recently, small molecule inhibitors of transforming growth factorβ (TGF-β) type I receptor kinase ⁄ activin receptor-like kinase-5 (ALK5) have been developed to target TGF-β signalling as a therapeutic strategy for combating cancer. In the present study, the authors examined a novel small molecule inhibitor of ALK5, 3-((5- ([1,2,4]triazolo[1,5-a]pyridin-6-yl)-4-(6-methylpyridin-2-yl)thiazol-2-ylamino)methyl)benzonitrile (EW-7203) in breast cancer cells to determine if it has potential for cancer treatment. The inhibitory effects of EW-7203 on TGF-β-induced Smad signalling and epithelial- to-mesenchymal transition (EMT) were investigated in mammary epithelial cells using luciferase reporter assays, immunoblotting, confocal microscopy and wound healing assays.

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Article Synopsis
  • A series of novel compounds, specifically 1-substituted-3(5)-(6-methylpyridin-2-yl)-4-(quinoxalin-6-yl)pyrazoles, were synthesized and tested for their ability to inhibit ALK5 activity.
  • The compound 2-[3-(6-methylpyridin-2-yl)-4-(quinoxalin-6-yl)-1H-pyrazol-1-yl]-N-phenylethanethioamide (18a) demonstrated a strong inhibitory effect, with an IC(50) value of 0.013 μM.
  • Additionally, it achieved 80% inhibition at a concentration of 0.1 μM in
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A series of 1-substituted-3(5)-(6-methylpyridin-2-yl)-4-(quinolin-6-yl)pyrazoles 14a-e, 15a-e, 17a-c, and 18a-d have been synthesized and evaluated for their ALK5 inhibitory activity in an enzyme assay and in a cell-based luciferase reporter assay. The 6-quinolinyl pyrazole analogue 14b inhibited ALK5 phosphorylation with IC(50) value of 0.022 μM and showed 84% inhibition at 0.

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