Publications by authors named "Sujin Yun"

Background: Genetic alterations play a pivotal role in multiple myeloma (MM) development and therapeutic resistance. Traditionally, the genetic profiling of MM requires invasive bone marrow (BM) procedures; however, these procedures are associated with patient discomfort and cannot fully capture the spatial and temporal heterogeneity of the disease. Therefore, we investigated the clinical implications of liquid biopsy using targeted deep sequencing.

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Primary myelofibrosis (PMF) is a myeloid proliferative neoplasm (MPN) characterized by bone marrow (BM) fibrosis. Pre-fibrotic PMF (pre-PMF) progresses to overt PMF. Megakaryocytes (MKs) play a primary role in PMF; however, the functions of MK subsets and those of other hematopoietic cells during PMF progression remain unclarified.

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Dysregulation of epidermal growth factor receptor (EGFR) is one of the most common mechanisms associated with the pathogenesis of various cancers. Mitogen-inducible gene 6 [MIG6; also known as ERBB receptor feedback inhibitor 1 (ERRFI1)], identified as a feedback inhibitor of EGFR, negatively regulates EGFR by directly inhibiting its kinase activity and facilitating its internalization, subsequently leading to degradation. Despite its proposed role as an EGFR-dependent tumor suppressor, the functional consequences and clinical relevance in cancer etiology remain incompletely understood.

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Purpose: For precision medicine, exploration and monitoring of molecular biomarkers are essential. However, in advanced gastric cancer (GC) with visceral lesions, an invasive procedure cannot be performed repeatedly for the follow-up of molecular biomarkers.

Materials And Methods: To verify the clinical implication of serial liquid biopsies targeting circulating tumor DNA (ctDNA) on treatment response, we conducted targeted deep sequencing for serially collected ctDNA of 15 HER2-positive metastatic GC patients treated with anti-PD-1 inhibitor in combination with standard systemic treatment.

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GPR139 is a G-protein coupled receptor expressed in circumventricular regions of the habenula and septum. Amino acids L-tryptophan and L-phenylalanine have been shown to activate GPR139 at physiologically relevant concentrations. The aim of the present study was to investigate the role of GPR139 on sleep modulation using pharmacological and genetic (GPR139 knockout mice, KO) rodent models.

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The serine hydrolase monoacylglycerol lipase (MAGL) is the rate-limiting enzyme responsible for the degradation of the endocannabinoid 2-arachidonoylglycerol (2-AG) into arachidonic acid and glycerol. Inhibition of 2-AG degradation leads to elevation of 2-AG, the most abundant endogenous agonist of the cannabinoid receptors (CBs) CB1 and CB2. Activation of these receptors has demonstrated beneficial effects on mood, appetite, pain, and inflammation.

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Orexin neurons originating in the perifornical and lateral hypothalamic area are highly reactive to anxiogenic stimuli and have strong projections to anxiety and panic-associated circuitry. Recent studies support a role for the orexin system and in particular the orexin 1 receptor (OX1R) in coordinating an integrative stress response. However, no selective OX1R antagonist has been systematically tested in two preclinical models of using panicogenic stimuli that induce panic attack in the majority of people with panic disorder, namely an acute hypercapnia-panic provocation model and a model involving chronic inhibition of GABA synthesis in the perifornical hypothalamic area followed by intravenous sodium lactate infusion.

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Orexins peptides exert a prominent role in arousal-related processes including stress responding, by activating orexin-1 (OX1R) and orexin-2 (OX2R) receptors located widely throughout the brain. Stress or orexin administration stimulates hyperarousal, adrenocorticotropic hormone (ACTH) and corticosterone release, and selective OX1R blockade can attenuate several stress-induced behavioral and cardiovascular responses but not the hypothalamic-pituitary-adrenal (HPA) axis activation. As opposed to OX1R, OX2R are preferentially expressed in the paraventricular hypothalamic nucleus which is involved in the HPA axis regulation.

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Members of the α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionic acid (AMPA) subtype of ionotropic glutamate receptors mediate the majority of fast synaptic transmission within the mammalian brain and spinal cord, representing attractive targets for therapeutic intervention. Here, we describe novel AMPA receptor modulators that require the presence of the accessory protein CACNG8, also known as transmembrane AMPA receptor regulatory protein γ8 (TARP-γ8). Using calcium flux, radioligand binding, and electrophysiological assays of wild-type and mutant forms of TARP-γ8, we demonstrate that these compounds possess a novel mechanism of action consistent with a partial disruption of the interaction between the TARP and the pore-forming subunit of the channel.

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GPR139 is an orphan G-protein-coupled receptor expressed in the central nervous system. To identify its physiologic ligand, we measured GPR139 receptor activity from recombinant cells after treatment with amino acids, orphan ligands, serum, and tissue extracts. GPR139 activity was measured using guanosine 5'-O-(3-[(35)S]thio)-triphosphate binding, calcium mobilization, and extracellular signal-regulated kinases phosphorylation assays.

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Dual orexin receptor antagonists have been shown to promote sleep in various species, including humans. Emerging research indicates that selective orexin-2 receptor (OX2R) antagonists may offer specificity and a more adequate sleep profile by preserving normal sleep architecture. Here, we characterized JNJ-42847922 ([5-(4,6-dimethyl-pyrimidin-2-yl)-hexahydro-pyrrolo[3,4-c]pyrrol-2-yl]-(2-fluoro-6-[1,2,3]triazol-2-yl-phenyl)-methanone), a high-affinity/potent OX2R antagonist.

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The preclinical characterization of novel octahydropyrrolo[3,4-c]pyrroles that are potent and selective orexin-2 antagonists is described. Optimization of physicochemical and DMPK properties led to the discovery of compounds with tissue distribution and duration of action suitable for evaluation in the treatment of primary insomnia. These selective orexin-2 antagonists are proven to promote sleep in rats, and this work ultimately led to the identification of a compound that progressed into human clinical trials for the treatment of primary insomnia.

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Previously we have shown that human abdominal adipose derived-stem cells (ADSCs) could aggregate during the high-density culture in the presence of human serum (HS). In the present study, we observed that human cord blood serum (CBS) and follicular fluid (HFF) also induced aggregation. Similarly, porcine serum could induce aggregation whereas bovine and sheep sera induced little aggregation.

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Recent reports have illustrated a reciprocal relationship between circadian rhythm disruption and mood disorders. The 5-HT7 receptor may provide a crucial link between the two sides of this equation since the receptor plays a critical role in sleep, depression, and circadian rhythm regulation. To further define the role of the 5-HT7 receptor as a potential pharmacotherapy to correct circadian rhythm disruptions, the current study utilized the selective 5-HT7 antagonist JNJ-18038683 (10 mg/kg) in three different circadian paradigms.

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Orexins (OXs) are peptides produced by perifornical (PeF) and lateral hypothalamic neurons that exert a prominent role in arousal-related processes, including stress. A critical role for the orexin-1 receptor (OX1R) in complex emotional behavior is emerging, such as overactivation of the OX1R pathway being associated with panic or anxiety states. Here we characterize a brain-penetrant, selective, and high-affinity OX1R antagonist, compound 56 [N-({3-[(3-ethoxy-6-methylpyridin-2-yl)carbonyl]-3-azabicyclo[4.

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Therapeutic drugs for cognitive and psychiatric disorders are often characterized by their molecular mechanism of action. Here we demonstrate a new approach to elucidate drug action on large-scale neuronal activity by tracking somatic calcium dynamics in hundreds of CA1 hippocampal neurons of pharmacologically manipulated behaving mice. We used an adeno-associated viral vector to express the calcium sensor GCaMP3 in CA1 pyramidal cells under control of the CaMKII promoter and a miniaturized microscope to observe cellular dynamics.

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In accordance with the prominent role of orexins in the maintenance of wakefulness via activation of orexin-1 (OX1R) and orexin-2 (OX2R) receptors, various dual OX1/2R antagonists have been shown to promote sleep in animals and humans. While selective blockade of OX2R seems to be sufficient to initiate and prolong sleep, the beneficial effect of additional inhibition of OX1R remains controversial. The relative contribution of OX1R and OX2R to the sleep effects induced by a dual OX1/2R antagonist was further investigated in the rat, and specifically on rapid eye movement (REM) sleep since a deficiency of the orexin system is associated with narcolepsy/cataplexy based on clinical and pre-clinical data.

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Human serum (HS) has been reported to induce aggregation of human eyelid adipose-derived stem cells (HEACs) during high-density culture in vitro. The present study focused on the role of cell adhesion molecules and gelatinases during HS-induced aggregation of HEACs. HS-induced aggregation occurred between 9-15 days of culture.

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Fetal bovine serum (FBS) is the most frequently used serum for the cultivation of mammalian cells. However, since animal-derived materials might not be appropriate due to safety issues, allogeneic human serum (HS) has been used to replace FBS, particularly for the culture of human cells. While there has been a debate about the advantages of HS, its precise effect on human adult stem cells have not been clarified.

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Objective: Tributyltin (TBT), an endocrine disrupting chemical, has been reported to decrease ovarian function by causing apoptosis in the ovary, but the mechanism is not fully understood. Therefore, we examined whether TBT increases the expression of adipogenesis-related genes in the ovary and the increased expression of these genes is associated with apoptosis induction.

Methods: Three-week-old Sprague-Dawley rats were orally administered TBT (1 or 10 mg/kg body weight) or sesame oil as a control for 7 days.

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An antibody simultaneously targeting epidermal growth factor receptor (EGFR) and vascular endothelial growth factor (VEGF), two major tumor growth-driving machineries, may provide a novel effective strategy for optimizing tumor targeting and maximizing potential clinical benefits. Human domain antibodies selected against VEGF and EGFR were formatted into a fully human dual-targeting IgG (DT-IgG) to directly target both antigens in a single molecule. We evaluated the efficacy of DT-IgG in comparison with bevacizumab and cetuximab alone and in combination in the lung cancer cell line A549 (low EGFR expression and KRAS mutant) and the head and neck squamous cell carcinoma (HNSCC) cell line Tu212 (high EGFR expression and KRAS wild type) in vitro and in vivo.

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Purpose: DT-IgG is a fully humanized dual-target therapeutic antibody being developed to simultaneously target epidermal growth factor receptor (EGFR) and vascular endothelial growth factor (VEGF), important signaling molecules for tumor growth. The antitumor pharmacodynamics (PD) of DT-IgG was studied in nude mice bearing human tumor xenografts with different EGFR and VEGF expressions and K-ras oncogene status and compared with bevacizumab, cetuximab and bevacizumab + cetuximab.

Methods: Mice bearing human oral squamous cell carcinoma (Tu212), lung adenocarcinoma (A549), or colon cancer (GEO) subcutaneous xenografts were administered with the antibodies intraperitoneally (i.

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Glucocorticoid (GC) hormones, increased in response to stress, can cause neuronal loss. We tested the effect of GC hormone on cell viability of neural SHSY-5Y cells and protective effects of ginsenoside Rb1 and Rg3 on the action of GC. We treated SHSY-5Y cells with increasing concentrations of synthetic GC dexamethasone (DEX; 10, 25, 50, and 100 nM) for 24 and 48 h, and then determined cell viability by using MTT assay.

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Prolonged stress results in elevation of glucocorticoid (GC) hormones, which can have deleterious effects in the brain. The hippocampus, which has a high concentration of glucocorticoid receptors, is especially vulnerable to increasing levels of GCs. GCs have been suggested to endanger hippocampal neurons by exacerbating the excitotoxic glutamate-calcium-reactive oxygen species (ROS) cascade.

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Neuroanatomical studies have shown relaxin-3 neurons, primarily found in the rodent nucleus incertus (NI), project widely into a large number of areas expressing the relaxin-3 receptor (RXFP3), and these data suggest relaxin-3/RXFP3 signaling modulates sensory, emotional, and neuroendocrine processing. The similar distribution of this receptor-ligand pair in the rat, mouse, and monkey brain suggests that experimental findings obtained in lower species will translate to higher species. A role for relaxin-3 and RXFP3 in modulating stress responses is strongly suggested by the expression of corticotropin-releasing factor R1 (CRF-R1) by NI cells, increased relaxin-3 expression in the NI after stress or CRF injection, and hormonal responses to intracerebroventricular (i.

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