Publications by authors named "Jeehun Park"

8 Publications

  • Page 1 of 1

Derivation of iPSC lines from two idiopathic ASD patients (OFi001-A, OFi002-A).

Stem Cell Res 2021 Aug 19;56:102510. Epub 2021 Aug 19.

Laboratory of Stem Cells and Organoids, OrganFactory Co., Ltd., Naesudong-ro, Seowon-gu, Cheongju-si, Chungcheongbuk-do 28864, Republic of Korea; Guangdong Provincial Key Laboratory of Large Animal Models for Biomedicine, Wuyi University, Jiangmen 529020, China. Electronic address:

Here we described two human induced pluripotent stem cell (hiPSC) lines from peripheral blood mononuclear cells (PBMCs) of idiopathic autism spectrum disorder (ASD) patients through forced expression of OCT4, SOX2, KLF4, and c-MYC. The hiPSC lines displayed morphology, gene expression patterns, and pluripotential differentiation potentials similar to those of human embryonic stem cells (hESCs). The hiPSC lines from idiopathic ASD patients might be useful to unveil the underlying mechanism of idiopathic ASD and finding its therapeutics.
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http://dx.doi.org/10.1016/j.scr.2021.102510DOI Listing
August 2021

Expansion of cytotoxic natural killer cells in multiple myeloma patients using K562 cells expressing OX40 ligand and membrane-bound IL-18 and IL-21.

Cancer Immunol Immunother 2021 Jul 20. Epub 2021 Jul 20.

Research Center for Cancer Immunotherapy, Gwangju, South Korea.

Background: Natural killer (NK) cell-based immunotherapy is a promising treatment approach for multiple myeloma (MM), but obtaining a sufficient number of activated NK cells remains challenging. Here, we report an improved method to generate ex vivo expanded NK (eNK) cells from MM patients based on genetic engineering of K562 cells to express OX40 ligand and membrane-bound (mb) IL-18 and IL-21.

Methods: K562-OX40L-mbIL-18/-21 cells were generated by transducing K562-OX40L cells with a lentiviral vector encoding mbIL-18 and mbIL-21, and these were used as feeder cells to expand NK cells from peripheral blood mononuclear cells of healthy donors (HDs) and MM patients in the presence of IL-2/IL-15. Purity, expansion rate, receptor expression, and functions of eNK cells were determined over four weeks of culture.

Results: NK cell expansion was enhanced by short exposure of soluble IL-18 and IL-21 with K562-OX40L cells. Co-culture of NK cells with K562-OX40L-mbIL-18/-21 cells resulted in remarkable expansion of NK cells from HDs (9,860-fold) and MM patients (4,929-fold) over the 28-day culture period. Moreover, eNK cells showed increased expression of major activation markers and enhanced cytotoxicity towards target K562, U266, and RPMI8226 cells.

Conclusions: Our data suggest that genetically engineered K562 cells expressing OX40L, mbIL-18, and mbIL-21 improve the expansion of NK cells, increase activation signals, and enhance their cytolytic activity towards MM cells.
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http://dx.doi.org/10.1007/s00262-021-02982-9DOI Listing
July 2021

Establishment of patient-derived organotypic tumor spheroid models for tumor microenvironment modeling.

Cancer Med 2021 Aug 9;10(16):5589-5598. Epub 2021 Jul 9.

Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.

Patient-derived cancer models that reconstitute the characteristics of the tumor microenvironment may facilitate efforts in precision immune-oncology and the discovery of effective anticancer therapies. Organoids that have recently emerged as robust preclinical models typically contain tumor epithelial cells and lack the native tumor immune microenvironment. A patient-derived organotypic tumor spheroid (PDOTS) is a novel and innovative ex vivo system that retains key features of the native tumor immune microenvironment. Here, we established and characterized a series of colorectal cancer PDOTS models for use as a preclinical platform for testing effective immunotherapy and its combinations with other drugs. Partially dissociated (> 100 μm in diameter) tumor tissues were embedded in Matrigel-containing organoid media and subsequently formed into organoid structures within 3 to 7 days of culture. The success rate of growing PDOTS from fresh tissues was ~86%. Morphological analysis showed that the PDOTSs varied in size and structure. Immunofluorescence and flow cytometry analysis revealed that the PDOTSs retained autologous tumor-infiltrating lymphoid cells and tumor-infiltrating lymphoid cells were continually decreased through serial passages. Notably, PDOTSs from tumors from a high-level microsatellite instability-harboring patient were sensitive to anti-PD-1 or anti-PD-L1 antibodies. Our results demonstrate that the PDOTS model in which the tumor immune microenvironment is preserved may represent an advantageous ex vivo system to develop effective immune therapeutics.
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http://dx.doi.org/10.1002/cam4.4114DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8366099PMC
August 2021

Fabrication of 2D and 3D Cell Cluster Arrays Using a Cell-Friendly Photoresist.

ACS Biomater Sci Eng 2021 07 14;7(7):3082-3087. Epub 2021 Jun 14.

Research Institute of Advanced Materials (RIAM), Seoul National University, 1, Gwanak-ro, Seoul 08826, South Korea.

Cells in 3D behave differently than cells in 2D. We develop a new method for the fabrication of 2D and 3D cell cluster arrays on an identical substrate using a cell-friendly photoresist, which enables comparative study between cells in 2D and 3D cell clusters. The fabricated cell cluster arrays maintain their structure up to 3 days with good viability. Using this method, 2D and 3D cancer cell clusters with comparable sizes are fabricated, and natural killer (NK) cell cytotoxicity assays are performed to assess how dimensionality of cancer cell clusters influence their susceptibility to immune cell-mediated killing.
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http://dx.doi.org/10.1021/acsbiomaterials.1c00655DOI Listing
July 2021

Multifunctional Microparticles with Stimulation and Sensing Capabilities for Facile NK Cell Activity Assay.

ACS Sens 2021 03 19;6(3):693-697. Epub 2021 Feb 19.

Research Institute of Advanced Materials (RIAM), Seoul National University, Seoul, 08826, South Korea.

Natural killer (NK) cells are a subset of innate lymphoid cells playing an important role in immune surveillance and early defense against infection and cancer. They recognize and directly kill infected or transformed cells. At the same time, they produce various cytokines and chemokines to regulate other immune cells. NK cell activity can be a useful marker for health screenings because impaired NK cell functions may indicate a more susceptible environment for infection or tumor development. Currently, most NK cell activity assays are focused on measuring either cytokine secretion, in particular, interferon γ (IFN-γ), or cytotoxicity against target cells such as K562, thus only providing partial information on NK cell activity. In order to develop a comprehensive test for measuring NK cell function, cytotoxicity and cytokine secretion ability should be measured simultaneously. In addition, current NK cell assays are performed by stimulating NK cells with cocktails of cytokines, antibody-coated beads, or live target cells. In this study, we developed multifunctional microparticles for NK cell activity assay (MNAs) that allow simultaneous stimulation and sensing various NK cell activities, including cytokine secretion and cytotoxicity. The surfaces of MNAs are decorated with multiple functional biomolecules, including antibodies that stimulate NK cells by engaging NK cell activating receptors, antibodies that can capture cytokines secreted by NK cells, and a peptide sensor that reacts with granzyme B, a key molecule released by NK cells for cytotoxicity. The performances of MNAs are assessed using flow cytometry and live cell imaging. NK cell activity is measured by simply mixing MNAs with NK cells and performing flow cytometry, and the results are comparable to those measured by standard NK cell activity assays.
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http://dx.doi.org/10.1021/acssensors.0c02138DOI Listing
March 2021

A Flow Cytometry-Based Whole Blood Natural Killer Cell Cytotoxicity Assay Using Overnight Cytokine Activation.

Front Immunol 2020 14;11:1851. Epub 2020 Aug 14.

Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul, South Korea.

Measurement of natural killer (NK) cell function has important clinical utility in several diseases. Although the flow cytometry (FC)-based 4-h NK cytotoxicity assay using peripheral blood mononuclear cells (PBMCs) in the clinical laboratory has been used for this purpose, this assay requires large amounts of blood and a rapid PBMC isolation step. Here, we developed an FC-based overnight NK cytotoxicity assay using whole blood (WB), and applied it to patients with liver diseases. Peripheral blood of healthy volunteers ( = 28) and patients with liver diseases, including hepatocellular carcinoma ( = 19) and liver cirrhosis ( = 7), was analyzed for complete blood count, absolute NK cell count, and NK cell activity (NKA). NKA was evaluated in three assay types: an FC-based overnight WB NK cytotoxicity assay using carboxyfluorescein diacetate succinimidyl ester-labeled K562 cells in the presence of various cytokine combinations [including interleukin (IL)-2, IL-18, and IL-21], an FC-based 4-h PBMC NK cytotoxicity assay, and an FC-based CD107a degranulation assay using WB and PBMCs. Optimal cytokine combinations for NK cell activation in WB were determined (IL-2/IL-18, IL-2/IL-21, and IL-2/IL-18/IL-21). A good correlation was observed between WB and PBMC NK cytotoxicity assays; absolute NK cell counts were better correlated with the WB NK cytotoxicity assay than with the PBMC NK cytotoxicity assay. This WB NK cytotoxicity assay showed that patients with liver diseases had significantly lower NK cytotoxicity than healthy volunteers, under stimulation with various cytokines ( < 0.001). The proposed FC-based overnight WB NK cytotoxicity assay correlates well with the conventional 4-h PBMC NK cytotoxicity assay, demonstrating future potential as a supportive assay for clinical laboratory research and observational studies.
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http://dx.doi.org/10.3389/fimmu.2020.01851DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7457041PMC
April 2021

In Situ Subcellular Detachment of Cells Using a Cell-Friendly Photoresist and Spatially Modulated Light.

Adv Sci (Weinh) 2019 Jul 17;6(14):1900566. Epub 2019 May 17.

Department of Materials Science and Engineering Seoul National University 1 Gwanak-ro Gwanak-gu Seoul 08826 South Korea.

Dynamic adhesion and detachment of subcellular regions occur during cell migration, thus a technique allowing precise control of subcellular detachment of cells will be useful for cell migration study. Previous methods for cell detachment were developed either for harvesting cells or cell sheets attached on surfaces with low resolution patterning capability, or for detaching subcellular regions located on predefined electrodes. In this paper, a method that allows in situ subcellular detachment of cells with ≈1.5 µm critical feature size while observing cells under a fluorescence microscope is introduced using a cell-friendly photoresist and spatially modulated light. Using this method, a single cell, regions in cell sheets, and a single focal adhesion complex within a cell are successfully detached. Furthermore, different subcellular regions of migrating cells are detached and changes in cell polarity and migration direction are quantitatively analyzed. This method will be useful for many applications in cell detachment, in particular when subcellular resolution is required.
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http://dx.doi.org/10.1002/advs.201900566DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6661940PMC
July 2019

Roles of endothelial A-type lamins in migration of T cells on and under endothelial layers.

Sci Rep 2016 Mar 21;6:23412. Epub 2016 Mar 21.

Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH) San 31, Hyoja-dong, Nam-Gu, Pohang, Gyeongbuk, 790-784, Korea.

Stiff nuclei in cell-dense microenvironments may serve as distinct biomechanical cues for cell migration, but such a possibility has not been tested experimentally. As a first step addressing this question, we altered nuclear stiffness of endothelial cells (ECs) by reducing the expression of A-type lamins using siRNA, and investigated the migration of T cells on and under EC layers. While most T cells crawling on control EC layers avoided crossing over EC nuclei, a significantly higher fraction of T cells on EC layers with reduced expression of A-type lamins crossed over EC nuclei. This result suggests that stiff EC nuclei underlying T cells may serve as "duro-repulsive" cues to direct T cell migration toward less stiff EC cytoplasm. During subendothelial migration under EC layers with reduced expression of A-type lamins, T cells made prolonged contact and substantially deformed EC nuclei, resulting in reduced speed and directional persistence. This result suggests that EC nuclear stiffness promotes fast and directionally persistent subendothelial migration of T cells by allowing minimum interaction between T cells and EC nuclei.
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http://dx.doi.org/10.1038/srep23412DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4800500PMC
March 2016
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