Publications by authors named "Hoyun Lee"

Introduction: AMYPAD Diagnostic and Patient Management Study (DPMS) aims to investigate the clinical utility and cost-effectiveness of amyloid-PET in Europe. Here we present participants' baseline features and discuss the representativeness of the cohort.

Methods: Participants with subjective cognitive decline plus (SCD+), mild cognitive impairment (MCI), or dementia were recruited in eight European memory clinics from April 16, 2018, to October 30, 2020, and randomized into three arms: ARM1, early amyloid-PET; ARM2, late amyloid-PET; and ARM3, free-choice.

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Many agents targeting the colchicine binding site in tubulin have been developed as potential anticancer agents. However, none has successfully made it to the clinic, due mainly to dose limiting toxicities and the emergence of multi-drug resistance. Chalcones targeting tubulin have been proposed as a safe and effective alternative.

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Clostridioides difficile infection (CDI) is the primary cause of hospital-acquired diarrhea, and responsible for over 500,000 enteric infections a year in the United States alone. Although most patients with CDI are successfully treated with metronidazole or vancomycin, the high rate of recurrence is still a serious problem, in which case these antibiotics are usually not very effective. The primary objective of this research is to develop a potentially effective therapeutic agent against C.

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Cancer treatment remains unsatisfactory with high rates of recurrence and metastasis. Immunomodulatory agents capable of promoting cellular antitumor immunity while inhibiting the local immunosuppressive tumor microenvironment could greatly improve cancer treatment. We have developed a multi-targeted mannosylated cationic liposome delivery system containing muramyl dipeptide (DS) and low doses of the chemotherapeutic agent cytarabine (Ara-C).

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Natural products remain a viable source of novel therapeutics, and as detection and extraction techniques improve, we can identify more molecules from a broader set of plant tissues. The aim of this study was an investigation of the cytotoxic and anti-plasmodial activities of the methanol extract from Y.C.

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We previously found that the novel VR23 proteasome inhibitor not only possesses an effective antitumor activity without causing any ill effects to animals but also reduces side effects caused by a partner drug when used in combination. In this article, we report that VR23, unlike other proteasome inhibitors, exhibits potent anti-inflammatory activity. In the LPS-induced THP-1 monocyte model, VR23 downregulates proinflammatory cytokines IL-1β, TNF-α, IL-6, and IL-8 at a similar efficacy to dexamethasone.

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Purpose: Chloroquine has demonstrated anti-tumor activities through autophagy inhibition and cell cycle disruption. This study aimed to assess the effect of single-agent chloroquine on breast tumor cellular proliferation in a randomized, phase II, double-blind, placebo-controlled, pre-surgical window of opportunity trial.

Methods: Patients with newly diagnosed breast cancer were randomized 2:1 to chloroquine 500 mg daily or placebo for 2- to 6-weeks prior to their breast surgery.

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In an attempt to develop effective and potentially safe anticancer agents, thirty-six 4-aminoquinoline derived sulfonyl analogs were designed and synthesized using a hybrid pharmacophore approach. The cytotoxicity of these compounds was determined using three breast tumor cell lines (MDA-MB231, MDA-MB468 and MCF7) and two matching non-cancer breast epithelial cell lines (184B5 and MCF10A). Although most of the compounds were quite effective on the breast cancer cells, the compound 7-chloro-4-(4-(2,4-dinitrophenylsulfonyl)piperazin-1-yl)quinoline (13; VR23) emerged as potentially the most desirable one in this series of compounds.

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In an attempt to improve anti-breast cancer activity, a new series of 4-piperazinylquinoline derivatives based on the urea/thiourea scaffold were designed and synthesised by a pharmacophore hybrid approach. We then examined for their antiproliferative effects on three human breast tumor cell lines, MDA-MB231, MDA-MB468 and MCF7, and two non-cancer breast epithelial cell lines, 184B5 and MCF10A. Among those 26 novel compounds examined, 5, 9, 17, 18, 21, 23 and 29 showed significantly improved antiproliferative activity on breast cancer cells.

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Cancer immune therapy has recently shown tremendous promise to combat many different cancers. The microtubule is a well-defined and very effective cancer therapeutic target. Interestingly, several lines of evidence now suggest that microtubules are intimately connected to the body's immune responses.

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In an attempt to develop effective and safe anticancer agents, we designed, synthesized and examined 23 novel quinacrine (QC) derivatives by combining the 9-aminoacridine scaffold and the [1,3]thiazinan-4-ones group. Most of these hybrids showed strong anticancer activities, among which 3-(3-(6-chloro-2-methoxyacridin-9-ylamino)propyl)-2-(thiophen-2-yl)-1,3-thiazinan-4-one (25; VR151) effectively killed many different cancer cell types, including eight breast cancer cell lines with different genetic background, two prostate cancer and two lung cancer cell lines. In contrast, compound 25 is less effective against non-cancer cells, suggesting it may be less toxic to humans.

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Agents targeting colchicine-binding pocket usually show a minimal drug-resistance issue, albeit often associated with high toxicity. Chalcone-based compounds, which may bind to colchicine-binding site, are found in many edible fruits, suggesting that they can be effective drugs with less toxicity. Therefore, we synthesized and examined 24 quinolone chalcone compounds, from which we identified ((E)-3-(3-(2-Methoxyphenyl)-3-oxoprop-1-enyl) quinolin-2(1H)-one) (CTR-17) and ((E)-6-Methoxy-3-(3-(2-methoxyphenyl)-3-oxoprop-1-enyl) quinolin-2(1H)-one) (CTR-20) as promising leads.

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Extracts from the tubers of Stephania venosa (Blum) Spreng growing in Vietnam significantly inhibited cell proliferation against a number of cancer cells including HeLa, MDA-MB231 and MCF-7 cells. A bioassay-guided fractionation led to the isolation of four aporphine and one tetrahydroprotoberberine alkaloids: dehydrocrebanine 1, tetrahydropalmatine 2, stephanine 3, crebanine 4 and O-methylbulbocapnine 5. The characterization of these compounds was based on MS, NMR and published data.

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Both quinacrine, which contains a 9-aminoacridine scaffold, and thiazolidin-4-one are promising anticancer leads. In an attempt to develop effective and potentially safe anticancer agents, we synthesized 23 novel hybrid compounds by linking the main structural unit of the 9-aminoacridine ring with the thiazolidin-4-one ring system, followed by examination of their anticancer effects against three human breast tumor cell lines and matching non-cancer cells. Most of the hybrid compounds showed good activities, and many of them possessed the preferential killing property against cancer over non-cancer cells.

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The co-regulation of DNA replication and gene transcription is still poorly understood. To gain a better understanding of this important control mechanism, we examined the DNA replication and transcription using the Dbf4 origin-promoter and Dbf4 pseudogene models. We found that origin firing and Dbf4 transcription activity were inversely regulated in a cell cycle-dependent manner.

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To maintain genetic stability, the entire mammalian genome must replicate only once per cell cycle. This is largely achieved by strictly regulating the stepwise formation of the pre-replication complex (pre-RC), followed by the activation of individual origins of DNA replication by Cdc7/Dbf4 kinase. However, the mechanism how Cdc7 itself is regulated in the context of cell cycle progression is poorly understood.

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A series of 25 novel quinolino-stilbene derivatives were designed, synthesized and evaluated for their potential as anticancer agents. Three of them not only displayed quite potent antiproliferative activity with IC50 values<4μM but also showed approximately twofold selectivity against cancer cells, compared to non-cancerous cells. Three other compounds exhibited comparatively good activity with IC50 values in the range of 4-10μM, and the rest was moderately active or inactive.

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The proteasome is clinically validated as a target for cancer therapeutics. However, proteasome-inhibitory agents that are cancer selective have yet to be developed. In this study, we report the identification of a safe and effective proteasome inhibitor with selective anticancer properties.

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Chloroquine (CQ) has a broad spectrum of pharmacological activities including anticancer and anti-inflammatory, in addition to its well-known antimalarial activity. This very useful property of CQ may be rendered through a variety of different molecular and cellular mechanisms, including the induction of apoptosis, necrosis and lysosomal dysfunction. CQ alone may not be as effective as many well-known anticancer drugs; however, it often shows synergisticts when combined with other anticancer agents, without causing substantial ill-effects.

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Here we reported our investigation, as part of our drug repositioning effort, on anti-Toxoplasma properties of newly synthesized quinoline compounds. A collection of 4-aminoquinoline and 4-piperazinylquinoline analogs have recently been synthesized for use in cancer chemotherapy. Some analogs were able to outperform chloroquine, a quinoline derivative drug which is commonly used in the treatment of malaria and other parasitic infections.

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In an attempt to develop effective anticancer therapeutics, a new series of heteroaryl chalcone compounds were designed, synthesized, and examined for their antiproliferative effects on two breast cancer cell lines and one matching non-cancer breast cell line. The structure-activity relationship (SAR) analysis suggested that the compounds derived from thiophene chalcones (6-17) exhibited generally better antiproliferative activity than those derived from bioisoteric replacement of furan chalcones (18-29) on MDA-MB231 breast cancer cells. In contrast, the compounds derived from furan chalcones showed generally better antiproliferative activity on MDA-MB468 breast cancer cells.

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Background: Akt/PKB is a promising anticancer therapeutic target, since abnormally elevated Akt activity is directly correlated to tumor development, progression, poor prognosis and resistance to cancer therapies. Currently, the unique role of each Akt isoform and their relevance to human breast cancer are poorly understood.

Methodology/principal Findings: We previously found that Akt1, 2 and 3 are localized at specific subcellular compartments (the cytoplasm, mitochondria and nucleus, respectively), raising the possibility that each isoform may have unique functions and employ different regulation mechanisms.

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