Yeonsun Hong

Development of Computer-Aided Inspection System with CMM for Integrated Mold Manufacturing

An interactive and integrated inspection system has been developed for molds having sculptured surfaces with some basic features, such as; holes, slots and bosses. Features to be inspected can be chosen in the CAD environment. Then the inspection planning is to be done for each feature, respectively. For the accurate measurement of sculptured surfaces, the distribution of measurement paints can be controlled to be uniform, curvature dependent or hybrid of the two. The output of the planning is the machine code for a specific CMM having CNC capability. The measured data are to be transferred back to the CAD system, compensated by the form error calculation, and the evaluated errors are displayed graphically. High degree of CAD/CAM/CA. integration is demonstrated by implementing the developed system to real molds.

Identification of Novel ROS Inducers: Quinone Derivatives Tethered to Long Hydrocarbon Chains

We performed the first synthesis of the 17-carbon chain-tethered quinone moiety 22 (SAN5201) of irisferin A, a natural product exhibiting anticancer activity, and its derivatives. We found that 22 is a potent ROS inducer and cytotoxic agent. Compound 25 (SAN7401), the hydroquinone form of 22, induced a significant release of intracellular ROS and apoptosis (EC50 = 1.3-2.6 μM) in cancer cell lines, including A549 and HCT-116. Compared with the activity of a well-known ROS inducer, piperlongumine, 22 and 25 showed stronger cytotoxicity and higher selectivity over noncancerous cells. Another hydroquinone tethering 12-carbon chain, 26 (SAN4601), generated reduced levels of ROS but showed more potent cytotoxicity (EC50 = 0.8-1.6 μM) in cancer cells, although it lacked selectivity over noncancerous cells, implying that the naturally occurring 17-carbon chain is also crucial for ROS production and a selective anticancer effect. Both 25 and 26 displayed strong, equipotent activities against vemurafenib-resistant SK-Mel2 melanoma cells and p53-deficient H1299 lung cancer cells as well, demonstrating their broad therapeutic potential as anticancer agents.

Cancer-derived exosomes as a delivery platform of CRISPR/Cas9 confer cancer cell tropism-dependent targeting

ABSTRACT An intracellular delivery system for CRISPR/Cas9 is crucial for its application as a therapeutic genome editing technology in a broad range of diseases. Current vehicles carrying CRISPR/Cas9 limit in vivo delivery because of low tolerance and immunogenicity; thus, the in vivo delivery of genome editing remains challenging. Here, we report that cancer‐derived exosomes function as natural carriers that can efficiently deliver CRISPR/Cas9 plasmids to cancer. Compared to epithelial cell‐derived exosomes, cancer‐derived exosomes provide potential vehicles for effective in vivo delivery via selective accumulation in ovarian cancer tumors of SKOV3 xenograft mice, most likely because of their cell tropism. CRISPR/Cas9‐loaded exosomes can suppress expression of poly (ADP‐ribose) polymerase‐1 (PARP‐1), resulting in the induction of apoptosis in ovarian cancer. Furthermore, the inhibition of PARP‐1 by CRISPR/Cas9‐mediated genome editing enhances the chemosensitivity to cisplatin, showing synergistic cytotoxicity. Based on these results, tumor‐derived exosomes may be very promising for cancer therapeutics in the future. Graphical abstract Figure. No caption available.

Ferritin nanocage with intrinsically disordered proteins and affibody: A platform for tumor targeting with extended pharmacokinetics

ABSTRACT Ferritin nanocages are of particular interest as a novel platform for drug and vaccine delivery, diagnosis, biomineralization scaffold and more, due to their perfect and complex symmetry, ideal physical properties, high biocompatibility, low toxicity profiles as well as easy manipulation by genetic or chemical strategies. However, a short half‐life is still a hurdle for the translation of ferritin‐based nanomedicines into the clinic. Here, we developed a series of rationally designed long circulating ferritin nanocages (LCFNs) with ‘Intrinsically Disordered Proteins (IDP)’ as a stealth layer for extending the half‐life of ferritin nanocages. Through predictions with 3D modelling, the LCFNs were designed, generated and their pharmacokinetic parameters including half‐life, clearance rate, mean residence time, and more, were evaluated by qualitative and quantitative analysis. LCFNs have a tenfold increased half‐life and overall improved pharmacokinetic parameters compared to wild‐type ferritin nanocages (wtFN), corresponding to the low binding against bone marrow‐derived macrophages (BMDMs) and endothelial cells. Subsequently, a tumor targeting moiety, epidermal growth factor receptor (EGFR)‐targeting affibody peptide, was fused to LCFNs for evaluating their potential as a theragnostic platform. The tumor targeting‐LCFNs successfully accumulated to the tumor tissue, by efficient targeting via active and passive properties, and also the shielding effect of IDP in vivo. This strategy can be applied to other protein‐based nanocages for further progressing their use in the field of nanomedicine. Graphical abstract Long circulating ferritin nanocages are designed by 3D modelling. Modified by intrinsically disordered protein (IDP) clouds, this novel biocompatible nanocage platform can be applied in the field of nanomedicine. Figure. No caption available.

Combined Rho-kinase inhibition and immunogenic cell death triggers and propagates immunity against cancer

Activation of T cell immune response is critical for the therapeutic efficacy of cancer immunotherapy. Current immunotherapies have shown remarkable clinical success against several cancers; however, significant responses remain restricted to a minority of patients. Here, we show a therapeutic strategy that combines enhancing the phagocytic activity of antigen-presenting cells with immunogenic cell death to trigger efficient antitumour immunity. Rho-kinase (ROCK) blockade increases cancer cell phagocytosis and induces antitumour immunity through enhancement of T cell priming by dendritic cells (DCs), leading to suppression of tumour growth in syngeneic tumour models. Combining ROCK blockade with immunogenic chemotherapy leads to increased DC maturation and synergistic CD8+ cytotoxic T cell priming and infiltration into tumours. This therapeutic strategy effectively suppresses tumour growth and improves overall survival in a genetic mouse mammary tumour virus/Neu tumour model. Collectively, these results suggest that boosting intrinsic cancer immunity using immunogenic killing and enhanced phagocytosis is a promising therapeutic strategy for cancer immunotherapy.Activation of an immune response is critical for the efficacy of cancer therapies. Here, the authors show that combination of ROCK inhibitor with chemotherapeutics that induce immunogenic cell death of cancer cells leads to increased dendritic cells’ maturation and synergistic CD8+ cytotoxic T cell priming and infiltration into the tumours, leading to suppressed tumour growth and improved overall survival in syngeneic and genetically engineered tumour models.

Extracellular vesicles as a platform for membrane-associated therapeutic protein delivery

ABSTRACT Membrane proteins are of great research interest, particularly because they are rich in targets for therapeutic application. The suitability of various membrane proteins as targets for therapeutic formulations, such as drugs or antibodies, has been studied in preclinical and clinical studies. For therapeutic application, however, a protein must be expressed and purified in as close to its native conformation as possible. This has proven difficult for membrane proteins, as their native conformation requires the association with an appropriate cellular membrane. One solution to this problem is to use extracellular vesicles as a display platform. Exosomes and microvesicles are membranous extracellular vesicles that are released from most cells. Their membranes may provide a favourable microenvironment for membrane proteins to take on their proper conformation, activity, and membrane distribution; moreover, membrane proteins can cluster into microdomains on the surface of extracellular vesicles following their biogenesis. In this review, we survey the state-of-the-art of extracellular vesicle (exosome and small-sized microvesicle)-based therapeutics, evaluate the current biological understanding of these formulations, and forecast the technical advances that will be needed to continue driving the development of membrane protein therapeutics.

Comparison of exosomes and ferritin protein nanocages for the delivery of membrane protein therapeutics

ABSTRACT Exosomes are small membrane vesicles secreted by most cell types that play an important role in intercellular communication. Due to the characteristic of transferring their biomacromolecules, exosomes have potential as a new alternative for delivering protein therapeutics. Here, we investigate whether exosomes provide crucial advantages over other nanoparticles, in particular protein nanocage formulations, as a delivery system for membrane protein therapeutics. We characterized membrane‐scaffold–based exosomes and protein‐scaffold–based ferritin nanocages, both harboring SIRP&agr; (signal regulatory protein &agr;), an antagonist of CD47 on tumor cells. The efficacy of these two systems in delivering protein therapeutics was compared by testing their ability to enhance phagocytosis of tumor cells by bone‐marrow–derived macrophages and subsequent inhibition of in vivo tumor growth. These analyses allowed us to comprehensively conclude that the therapeutic index of exosome‐mediated CD47 blockade against tumor growth inhibition was higher than that of the same dose of ferritin‐SIRP&agr;. The results of this analysis reveal the importance of the unique characteristics of exosomes, in particular their membrane scaffold, in improving therapeutic protein delivery compared with protein‐scaffold–based nanocages.