Publications by authors named "Okhee Kim"

While methyl-tertiary butyl ether (MTBE) remains the sole clinical topical agent for gallstone dissolution, its utility is limited due to side effects, largely stemming from its relatively low boiling point (55°C). In this study, we introduced 2-methoxy-6-methylpyridine (MMP), a novel gallstone-dissolving compound featuring an aromatic moiety and a substantially higher boiling point (156°C), designed to mitigate these side effects. We conducted a comprehensive evaluation of the efficacy and potential toxicities of MMP compared to MTBE using both in vitro and in vivo models.

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  • Recent advancements in nanomedicine have shown that exosome-based therapies could be effective for targeted cancer treatment, particularly in colon cancer.
  • A study explored the effectiveness of siPIN1-loaded exosomes that target a specific ligand (sAPRIL) in cancer models, demonstrating that these engineered exosomes have enhanced anticancer properties.
  • Results indicated that the tEx[p] group, which had the siPIN1 RNA loaded, significantly reduced tumor size and growth compared to other treatments, suggesting a promising new strategy for colon cancer therapy.
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Objectives: This study assessed the anticancer potential of genetically modified exosomes engineered to express CD133-binding peptides on their surface and carry PD-L1 siRNA for the treatment of murine model of metastatic pancreatic cancer.

Methods: CD133-targeting exosomes (tEx) were generated by harvesting conditioned media from adipose-derived stem cells (ASCs) that had undergone transformation using pDisplay vectors encoding CD133-binding peptide sequences. Subsequently, siPD-L1-loaded CD133-targeting Exosomes, referred to as tEx(s), were created by incorporating PD-L1 siRNA into the tEx using Exofect kit.

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The type 2 scavenger receptor CD36 functions not only as a long chain fatty acid transporter, but also as a pro-inflammatory mediator. Ceramide is the simple N-acylated form of sphingosine and exerts distinct biological activity depending on its acyl chain length. Six ceramide synthases (CerS) in mammals determine the chain length of ceramide species, and CerS6 mainly produces C16-ceramide.

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Elevated metastasis-associated in colon cancer 1 (MACC1) expression in colorectal cancer patients, and high transmembrane 4 L6 family member 5 (TM4SF5) protein expressed on various solid tumors' surface, are linked to aggressive cancer behavior and progression. In this study, adipose-derived stem cells (ASCs) were engineered to produce exosomes (Ex) that target the TM4SF5 protein on tumors. Moreover, MACC1-targeting microRNA was encapsulated within the Ex, resulting in TM4SF5-targeting Ex (MACC1-suppressing miRNA; miR-143).

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  • The study investigates genetically engineered exosomes for targeted drug delivery in gastric cancer treatment by using adipose-derived stem cells that express a specific peptide for improved targeting.
  • The engineered exosomes encapsulated an anticancer drug, 17-DMAG, which showed significantly better targeting and effectiveness in reducing tumor size and growth in mouse models compared to other formulations.
  • Mechanistic studies indicated that the 17-DMAG-loaded exosomes promoted cell death through specific protein regulation and had minimal effects on antioxidant enzyme levels, highlighting their therapeutic potential and reduced side effects in gastric cancer treatment.
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Background: Inflammatory bowel disease (IBD) is a chronic inflammatory condition of the gastrointestinal tract, with tumor necrosis factor (TNF)-α playing a key role in its pathogenesis. Etanercept, a decoy receptor for TNF, is used to treat inflammatory conditions. The secretome derived from adipose-derived stem cells (ASCs) has anti-inflammatory effects, making it a promising therapeutic option for IBD.

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Recently, artificial exosomes have been developed to overcome the challenges of natural exosomes, such as production scalability and stability. In the production of artificial exosomes, the incorporation of membrane proteins into lipid nanostructures is emerging as a notable approach for enhancing biocompatibility and treatment efficacy. This study focuses on incorporating HEK293T cell-derived membrane proteins into liposomes to create membrane-protein-bound liposomes (MPLCs), with the goal of improving their effectiveness as anticancer therapeutics.

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Purpose: Liver fibrosis is a critical health issue with limited treatment options. This study investigates the potential of PGC-Sec, a secretome derived from peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α)-overexpressing adipose-derived stem cells (ASCs), as a novel therapeutic strategy for liver fibrosis.

Methods: Upon achieving a cellular confluence of 70%-80%, ASCs were transfected with pcDNA-PGC-1α.

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Insulin resistance is a major contributor to the pathogenesis of several human diseases, including type 2 diabetes, hypertension, and hyperlipidemia. Notably, insulin resistance and hypertension share common abnormalities, including increased oxidative stress, inflammation, and organelle dysfunction. Recently, we showed that excess intracellular Ca, a known pathogenic factor in hypertension, acts as a critical negative regulator of insulin signaling by forming Ca-phosphoinositides that prevent the membrane localization of AKT, a key serine/threonine kinase signaling molecule.

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Tranilast, an anti-allergic drug used in the treatment of bronchial asthma, was identified as an inhibitor of the transcription factor Forkhead box O-1 (FoxO-1) by high throughput chemical library screening in the present study. Based on FoxO-1's role in apoptotic cell death and differentiation, we examined the effect of tranilast on palmitic acid (PA)-induced cell damage in INS-1 cells. Tranilast substantially inhibited lipoapoptosis and restored glucose-stimulated insulin secretion under high PA exposure.

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Background: Hypoxic preconditioning (HP) is a stem cell preconditioning modality designed to augment the therapeutic effects of mesenchymal stem cells (MSCs). Although autophagy is expected to play a role in HP, very little is known regarding the relationship between HP and autophagy.

Methods And Results: The adipose-derived stem cell (ASC)-secretome obtained under normoxia (NCM) and ASC-secretome obtained under HP (HCM) were obtained by culturing ASCs for 24 h under normoxic (21% partial pressure of O) and hypoxic (1% partial pressure of O) conditions, respectively.

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To explore extracellular vesicle microRNAs (EV miRNAs) and their target mRNAs in relation to diabetic kidney disease (DKD), we performed paired plasma and urinary EV small RNA sequencing (n = 18) in patients with type 2 diabetes and DKD (n = 5) and healthy subjects (n = 4) and metabolic network analyses using our own miRNA and public mRNA datasets. We found 13 common differentially expressed EV miRNAs in both fluids and 17 target mRNAs, including RRM2, NT5E, and UGDH. Because succinate dehydrogenase B was suggested to interact with proteins encoded by these three genes, we measured urinary succinate and adenosine in a validation study (n = 194).

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Apoptotic cells are rapidly engulfed and removed by phagocytes after displaying cell surface eat-me signals. Among many phospholipids, only phosphatidylserine (PS) is known to act as an eat-me signal on apoptotic cells. Using unbiased proteomics, we identified externalized phosphatidylinositides (PIPs) as apoptotic eat-me signals recognized by CD14 phagocytes.

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  • Amyloid-β (Aβ) buildup in the hippocampus is linked to Alzheimer's disease, resulting from the breakdown of a precursor protein by secretases, but the exact causes are still unclear.* -
  • Research showed that rats on high-phytate diets had increased Aβ accumulation and neuron death in the hippocampus, possibly due to activation of the amyloidogenic pathway.* -
  • The study also found that parathyroid hormone affects the production of Aβ and its precursor proteins by intervening in calcium and phosphate balance, suggesting that diet-induced disruptions in these minerals may heighten Alzheimer's risk.*
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Purpose: Survivin is a typical antiapoptotic protein. It is copiously expressed during human fetal development but is infrequently present in adult tissues. In this experiment, we researched the treatment effect of the secretome that adipose-derived stem cells (ASCs) transfected with survivin.

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  • Research is focused on enhancing Pt-based catalysts for better performance and durability in energy conversion systems, especially in fuel cells.
  • While efforts are made to increase the electroactive surface area and activity for oxygen reduction reactions (ORR), most findings are limited to laboratory setups (like rotating disk electrodes) rather than practical applications in full-cell systems.
  • The review aims to compare catalyst performance in laboratory vs. real-world fuel cells, address durability issues, and provide new strategic design ideas for improving full-cell device efficiency.
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BACKGROUNDMolecular characterization in pediatric papillary thyroid cancer (PTC), distinct from adult PTC, is important for developing molecularly targeted therapies for progressive radioiodine-refractory (131I-refractory) PTC.METHODSPTC samples from 106 pediatric patients (age range: 4.3-19.

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Purpose: mTORC1 and mTORC2 inhibition by Ku-0063794 could confer profound anticancer effects against cancer cells because it eliminates feedback activation of Akt. Herein, we aimed to determine anticancer effects of docetaxel and Ku-0063794, individually or in combination, against breast cancer cells, especially triple-negative breast cancer (TNBC) cells.

Materials And Methods: MCF-7 breast cancer and MDA-MB-231 TNBC cell lines for in vitro studies and mouse xenograft model for in vivo studies were used to investigate the effect of docetaxel, Ku-0063794, or their combination.

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It is challenging to overcome the low response rate of everolimus in the treatment of patients with hepatocellular carcinoma (HCC). To overcome this challenge, we combined everolimus with Ku0063794, the inhibitor of mTORC1 and mTORC2, to achieve higher anticancer effects. However, the precise mechanism for the synergistic effects is not clearly understood yet.

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Background: Di-2-ethylhexyl phthalate (DEHP) is known to disrupt thyroid hormonal status. However, the underlying molecular mechanism of this disruption is unclear. Therefore, we investigated the direct effects of DEHP on the thyroid gland.

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Mesenchymal stem cells (MSCs) have the function of repairing damaged tissue, which is known to be mediated by the secretome, the collection of secretory materials shed from MSCs. Adjusting the culture conditions of MSCs can lead to a significant difference in the composition of the secretome. It was hypothesized that pre‑sensitization of MSCs with specific disease‑causing agents could harness MSCs to release the therapeutic materials specialized for the disease.

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Currently, there is no appropriate treatment option for patients with sorafenib-resistant hepatocellular carcinoma (HCC). Meanwhile, pronounced anticancer activities of newly-developed mitochondria-accumulating self-assembly peptides (Mito-FF) have been demonstrated. This study intended to determine the anticancer effects of Mito-FF against sorafenib-resistant Huh7 (Huh7-R) cells.

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Several studies have indicated that cholestatic liver damage involves mitochondria dysfunction. However, the precise mechanism by which hydrophobic bile salts cause mitochondrial dysfunction is not clear. In this study, we intended to determine the pathogenesis of cholestatic liver injury associated with peroxisome proliferator-activated receptor-γ co-activator 1α (PGC-1α).

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Here, we provide the possibility of a novel chemotherapeutic agent against gastric cancer cells, comprising the combination of 5-fluorouracil (5-FU) and a mitochondria-targeting self-assembly peptide, which is a phenylalanine dipeptide with triphenyl phosphonium (Mito-FF). The anticancer effects and mechanisms of 5-FU and Mito-FF, individually or in combination, were compared through both and models of gastric cancer. Our experiments consistently demonstrated that the 5-FU and Mito-FF combination therapy was superior to monotherapy with either, as manifested by both higher reduction of proliferation as well as an induction of apoptotic cell death.

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