Publications by authors named "Hyunsil Park"

The glucocorticoid receptor (GR) is an important anti-cancer target in lymphoid cancers but has been understudied in solid tumors like lung cancer, although glucocorticoids are often given with chemotherapy regimens to mitigate side effects. Here, we identify a dexamethasone-GR mediated anti-cancer response in a subset of aggressive non-small cell lung cancers (NSCLCs) that harbor Serine/Threonine Kinase 11 (STK11/LKB1) mutations. High tumor expression of carbamoyl phosphate synthase 1 (CPS1) was strongly linked to the presence of LKB1 mutations, was the best predictor of NSCLC dexamethasone (DEX) sensitivity ( < 10) but was not mechanistically involved in DEX sensitivity.

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Mutations in in non-small cell lung cancer (NSCLC) are associated with poor patient responses to immune checkpoint blockade (ICB), and introduction of a () mutation into murine lung adenocarcinomas driven by mutant and loss () resulted in an ICB refractory syngeneic tumor. Mechanistically this occurred because mutant NSCLCs lacked TCF1-expressing CD8 T cells, a phenotype recapitulated in human mutant NSCLCs. Systemic inhibition of Axl results in increased type I interferon secretion from dendritic cells that expanded tumor-associated TCF1PD-1CD8 T cells, restoring therapeutic response to PD-1 ICB in tumors.

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Although non-small cell lung cancer (NSCLC) patients benefit from standard taxane-platin chemotherapy, many relapse, developing drug resistance. We established preclinical taxane-platin-chemoresistance models and identified a 35-gene resistance signature, which was associated with poor recurrence-free survival in neoadjuvant-treated NSCLC patients and included upregulation of the JumonjiC lysine demethylase KDM3B. In fact, multi-drug-resistant cells progressively increased the expression of many JumonjiC demethylases, had altered histone methylation, and, importantly, showed hypersensitivity to JumonjiC inhibitors in vitro and in vivo.

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Unlabelled: Ionizing radiation (IR) is a key therapeutic regimen for many head and neck cancers (HNC). However, the 5-year overall survival rate for locally advanced HNCs is approximately 50% and better therapeutic efficacy is needed.

Nad(p)h: quinone oxidoreductase 1 (NQO1) is overexpressed in many cancers, and β-lapachone (β-lap), a unique NQO1 bioactivatable drug, exploits this enzyme to release massive reactive oxygen species (ROS) that synergize with IR to kill by programmed necrosis.

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Standard combined modality therapies for aerodigestive tract malignancies have suboptimal outcomes, and targeting cancer-specific molecular pathways in combination with radiation could improve the therapeutic ratio. Dysregulation of epigenetic modulators such as histone deacetylases (HDACs), and developmental morphogens such as the hedgehog (HH) pathway have been implicated in aerodigestive tumor progression and metastasis. We hypothesized that simultaneous targeting of HDACs and the HH-pathway mediator Smoothened (Smo) represents an opportunity to overcome therapeutic resistance in these cancers.

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Interleukin (IL) 21 plays a key role in the development of acute graft-versus-host disease (GVHD) after allogeneic bone marrow transplantation. Therapeutic manipulation of IL-21 activity may improve acute GVHD during the early-posttransplant period. We investigated the mechanisms regulating T- and B-cells during IL-21 blockade in acute GVHD.

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Systemic lupus erythematosus is characterized by the spontaneous production of IgG autoantibodies in patients and lupus-prone mice. In this study, we investigated the effect of the Sle1 lupus susceptibility locus on the peripheral development of 56R(+) anti-DNA transgenic B cells by tracking 56R(+) B cells in mice without (B6.56R) or with (B6.

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Establishment of mixed chimerism is an ideal approach to induce donor-specific tolerance while expanding its potential in various clinical settings. Despite the developments in partial conditioning regimens, improvements are still needed in reducing toxicity and bone marrow transplantation-related complications. Recently, cell-based therapies, including mesenchymal stem cells (MSCs), have been incorporated in establishing noncytoreductive mixed chimerism protocols; however, its efficacy is only partial and shows reversed immunosuppressive properties.

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In oral tolerance, locally instigated tolerance in the gut propagate to systemic tolerance. In order to investigate the mechanism, we analyzed indoleamine 2,3-dioxygenase (IDO) expression in splenic dendritic cell (DC) subsets and tested whether DCs suppress collagen-induced arthritis (CIA) by inducing regulatory T cells (Tregs). The proportion of IDO-expressing cells was higher in the CD11b(+) subset of splenic DCs from orally tolerized CIA mice.

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Maintaining an appropriate balance between subsets of CD4(+) helper T cells and T regulatory cells (Tregs) is a critical process in immune homeostasis and a protective mechanism against autoimmunity and inflammation. To identify the role of vitamin A-related compounds, we investigated the regulation of interleukin (IL)-17-producing helper T cells (Th17 cells) and Tregs treated with all-trans-retinal (retinal). CD4(+)T cells or total cells from the spleens of C57BL/6 mice were stimulated under Treg-polarizing (anti-CD3/CD28 and TGF-β) or Th17-polarizing (anti-CD3/CD28, TGF-β, and IL-6) conditions in the presence or absence of retinal.

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Catheters are implanted into the peritoneal cavity during the process of peritoneal dialysis. Though these catheters may be effective and beneficial, the impact of catheters on the immune system is poorly understood. Catheters and other devices implanted in the peritoneal cavity elicit a foreign body reaction.

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Objective: Bone marrow-derived mesenchymal stem cells (MSCs) can prevent various autoimmune diseases. We examined the therapeutic potential of transforming growth factor β (TGFβ)-transduced MSCs in experimental autoimmune arthritis, using an accepted animal model of collagen-induced arthritis (CIA).

Methods: DBA/1J mice with CIA were treated with syngeneic TGFβ-induced MSCs, whereas control mice received either vehicle or MSCs alone.

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Grape seed proanthocyanidin extract (GSPE), which is the antioxidant derived from grape seeds, has been reported to possess a variety of potent properties. We have previously shown that GSPE attenuates collagen-induced arthritis. However the mechanism by which GSPE regulates the immune response remains unclear, although it may involve effects on the regulation of pathogenic T cells in autoimmune arthritis.

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Background/aims: The bone marrow functions not only as the primary B-lymphocyte-producing organ but also as a secondary lymphoid organ for CD4 and CD8 cell responses and a site of preferential homing and persistence for memory T cells. Bone marrow T (BM-T) cells are distinguished from peripheral blood T cells by surface phenotype, cytokine secretion profile, and immune functions. In this study, we evaluated the alloreactive potential of donor lymphocyte infusion (DLI) using BM-T cells in mixed chimerism compared to that using spleen T (SP-T) cells.

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N-tosyl-l-phenylalanine chloromethyl ketone (TPCK) is known to inhibit NF-kappaB activation and the expression of inflammation mediators in cultured cells. We measured the potential of TPCK to inhibit the pathogenesis of collagen-induced arthritis by blocking NF-kappaB activation. Arthritis was induced in DBA/1J mice by the injection of bovine type II collagen in adjuvant on days 0 and 14.

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Introduction: The present study was devised to understand the role of systemic indoleamine 2,3-dioxygenase (IDO) in the tolerance induction for orally tolerized mice in collagen-induced arthritis (CIA). We examined whether IDO-expressing dendritic cells (DCs) are involved in the generation of CD4+CD25+ regulatory T cells during the induction of oral tolerance in a murine CIA model.

Methods: Type II collagen was fed six times to DBA/1 mice beginning 2 weeks before immunization, and the effect on arthritis was assessed.

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To investigate the role of CD8alpha(+) DCs in the development of collagen-induced arthritis (CIA). The immunogenic properties of CD8alpha(+) and CD8alpha(-) DC subsets were investigated by mixed-lymphocyte reaction and cytokine enzyme-linked immunoassay. CII-pulsed CD8alpha(+) DCs or CD8alpha(-) DCs with CD4(+) T cells from CIA mice were adoptively transferred onto the hind footpad of DBA mice.

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