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1.  Sensitization of Chemo-Resistant Human Chronic Myeloid Leukemia Stem-Like Cells to Hsp90 Inhibitor by SIRT1 Inhibition 
Development of effective therapeutic strategies to eliminate cancer stem-like cells (CSCs), which play a major role in drug resistance and disease recurrence, is critical to improve cancer treatment outcomes. The current investigation was undertaken to examine the effectiveness of the combination treatment of Hsp90 inhibitor and SIRT1 inhibitor in inhibiting the growth of chemo-resistant stem-like cells isolated from human chronic myeloid leukemia K562 cells. Inhibition of SIRT1 by use of SIRT1 siRNA or SIRT1 inhibitors (amurensin G and EX527) effectively potentiated sensitivity of Hsp90 inhibitors (17-AAG and AUY922) in CD44high K562 stem-like cells expressing high levels of CSC-related molecules including Oct4, CD34, β-catenin, c-Myc, mutant p53 (mut p53), BCRP and P-glycoprotein (P-gp) as well as CD44. SIRT1 depletion caused significant down-regulation of heat shock factor 1 (HSF1)/heat shock proteins (Hsps) as well as these CSC-related molecules, which led to the sensitization of CD44high K562 cells to Hsp90 inhibitor by SIRT1 inhibitor. Moreover, 17-AAG-mediated activation of HSF1/Hsps and P-gp-mediated efflux, major causes of Hsp90 inhibitor resistance, was suppressed by SIRT1 inhibitor in K562-CD44high cells. Our data suggest that combined treatment with Hsp90 inhibitor and SIRT1 inhibitor could be an effective therapeutic approach to target CSCs that are resistant to current therapies.
PMCID: PMC4495410  PMID: 26157347
Hsp90 inhibitor; K562; CD44; SIRT1 inhibitor; multidrug resistance; cancer stem-like cells
2.  Heterologous Reconstitution of Omega-3 Polyunsaturated Fatty Acids in Arabidopsis 
BioMed Research International  2015;2015:768478.
Reconstitution of nonnative, very-long-chain polyunsaturated fatty acid (VLC-PUFA) biosynthetic pathways in Arabidopsis thaliana was undertaken. The introduction of three primary biosynthetic activities to cells requires the stable coexpression of multiple proteins within the same cell. Herein, we report that C22 VLC-PUFAs were synthesized from C18 precursors by reactions catalyzed by Δ6-desaturase, an ELOVL5-like enzyme involved in VLC-PUFA elongation, and Δ5-desaturase. Coexpression of the corresponding genes (McD6DES, AsELOVL5, and PtD5DES) under the control of the seed-specific vicilin promoter resulted in production of docosapentaenoic acid (22:5 n-3) and docosatetraenoic acid (22:4 n-6) as well as eicosapentaenoic acid (20:5 n-3) and arachidonic acid (20:4 n-6) in Arabidopsis seeds. The contributions of the transgenic enzymes and endogenous fatty acid metabolism were determined. Specifically, the reasonable synthesis of omega-3 stearidonic acid (18:4 n-3) could be a useful tool to obtain a sustainable system for the production of omega-3 fatty acids in seeds of a transgenic T3 line 63-1. The results indicated that coexpression of the three proteins was stable. Therefore, this study suggests that metabolic engineering of oilseed crops to produce VLC-PUFAs is feasible.
PMCID: PMC4538586  PMID: 26339641
4.  Bone Marrow Flow Cytometry in Staging of Patients With B-cell Non-Hodgkin Lymphoma 
Annals of Laboratory Medicine  2015;35(2):187-193.
Bone marrow biopsies are routinely performed for staging patients with B-cell non-Hodgkin lymphoma (NHL). In addition to histomorphological studies, ancillary tools may be needed for accurate diagnosis. We investigated the clinical utility of multiparameter flow cytometric examination of bone marrow aspirates.
A total of 248 bone marrow specimens from 232 patients diagnosed with B-cell NHL were examined. Monoclonal antibodies directed against CD19, CD20, CD10 (or CD5), and κ and λ immunoglobulins were used. Multi-stage sequential gating was performed to select specific cells of interest, and the results were compared with bone marrow histology.
The concordance rate between histomorphology and flow cytometry was 91.5% (n=227). Eight cases (3.2%) were detected by flow cytometry alone and were missed by histomorphology analysis, and 6 of these 8 cases showed minimal bone marrow involvement (0.09-2.2%). The diagnosis in these cases included large cell lymphoma (n=3), mantle cell lymphoma (n=3), and mucosa-associated lymphoid tissue (MALT) lymphoma (n=2). Thirteen cases were histopathologically positive and immunophenotypically negative, and the diagnoses in these cases included diffuse large cell lymphoma (n=7), T-cell/histiocyte-rich large B-cell lymphoma (n=2), anaplastic lymphoma kinase (ALK)-positive large B-cell lymphoma (n=1), follicular lymphoma (n=1), MALT lymphoma (n=1), and unclassifiable lymphoma (n=1).
Multi-color flow cytometry can be a useful method for assessing bone marrow in staging NHL and also plays a complementary role, especially in detecting small numbers of lymphoma cells.
PMCID: PMC4330167  PMID: 25729719
Bone marrow; Immunophenotyping; Flow cytometry; Non-Hodgkin lymphoma
7.  Metastatic colon cancer cell populations contain more cancer stem-like cells with a higher susceptibility to natural killer cell-mediated lysis compared with primary colon cancer cells 
Oncology Letters  2015;9(4):1641-1646.
In the present study, the soft agar clonogenicity and the susceptibility of clonogenic cancer cells to natural killer (NK) cells were compared between primary colon cancer cells (KM12C) and metastatic colon cancer cells (KM12L4a and KM12SM) to determine whether the metastatic cancer cells consisted of more cancer stem-like cells and were resistant to NK cell-mediated lysis. The majority of colon cancer cells were positive for putative cancer stem cell markers, including CD44, CD133 and EpCAM, with the exception of KM12C cells, of which only ~55% were positive for CD133. In addition, the expression levels of sex determining region Y-box 2, Nanog and octamer-binding transcription factor 4, which are essential for maintaining self-renewal, were higher in KM12L4a and KM12SM compared with that in KM12C cells. Consistently, an increased clonogenicity of KM12L4a and KM12SM compared with KM12C cells in soft agar was observed. The expression levels of NKG2D ligands, including major histocompatibility complex class I polypeptide-related sequence A/B and UL16 binding protein 2, and of death receptor 5 were significantly higher in KM12L4a and KM12SM than in KM12C cells. Furthermore, the results indicated an increased susceptibility of KM12L4a and KM12SM to NK cell-mediated cytotoxicity in comparison with KM12C cells. These results indicated that metastatic colon cancer cell populations may consist of more cancer stem-like cells, and have greater susceptibility to NK cell-mediated lysis compared with that of primary colon cancers.
PMCID: PMC4356422  PMID: 25789015
metastatic colon cancer cells; clonogenicity; DR5; NKG2D ligands; natural killer cell-mediated lysis
13.  Fermented soybeans by Rhizopus oligosporus reduce femoral bone loss in ovariectomized rats 
Nutrition Research and Practice  2014;8(5):539-543.
Soy isoflavones are structurally similar to estrogen and bind to estrogen receptors, suggesting that they exhibit estrogenic activities; therefore, they are referred to as phytoestrogens. Fermentation may affect the bioavailability of isoflavones altering soy isoflavone glycosides in the form of aglycones. Thus, this study investigated the effects of fermented soybeans by Rhizopus oligosporus on bone metabolism in both young rats as a pilot test and in ovariectomized (ovx) old rats as a model of menopause.
In the pilot test, a total of 24 seven-week-old female Sprague-Dawley (SD) rats were fed one of three diets for a period of four weeks: casein, unfermented soybean product, or fermented soybean product by R. oligosporus. In the ovx rat model, 20-week-old SD rats weighing 260-290 g underwent either sham-operation (n = 10) or bilateral ovariectomy (n = 30) and were then fed the AIN-93M diet for one week. Thereafter, rats were fed sham-casein, ovx-casein, ovx-soybean, or ovx-fermented soybean diet for five weeks. After decapitation, femoral bones were isolated and preserved in 9% formalin for assessment of bone mineral density (BMD), bone mineral content (BMC), and bone-breaking strength (BBS).
Ovx rats showed significantly increased weight gain and decreased uterine wet weight. Of particular interest, ovx rats fed fermented soybeans showed increased uterine wet weights compared to control rats. Fermented soybean diet caused a significant increase in plasma 17-β estradiol concentrations in young rats, and 17-β estradiol levels were enhanced in ovx rats to match those of sham-operated ones. Significantly lower femoral BMD and BMC were observed in ovx rats compared to sham-operated controls, whereas bone areas did not differ statistically among the groups. In addition, BBS tended to be increased in ovx rats fed soybeans and fermented soybeans.
Supplementation of fermented soybeans could have preventive and therapeutic effects against osteoporosis in postmenopausal women.
PMCID: PMC4198967  PMID: 25324934
Fermented soybean; 17-β estradiol; bone mineral density (BMD); bone-breaking strength
16.  Coercively Adjusted Auto Regression Model for Forecasting in Epilepsy EEG 
Recently, data with complex characteristics such as epilepsy electroencephalography (EEG) time series has emerged. Epilepsy EEG data has special characteristics including nonlinearity, nonnormality, and nonperiodicity. Therefore, it is important to find a suitable forecasting method that covers these special characteristics. In this paper, we propose a coercively adjusted autoregression (CA-AR) method that forecasts future values from a multivariable epilepsy EEG time series. We use the technique of random coefficients, which forcefully adjusts the coefficients with −1 and 1. The fractal dimension is used to determine the order of the CA-AR model. We applied the CA-AR method reflecting special characteristics of data to forecast the future value of epilepsy EEG data. Experimental results show that when compared to previous methods, the proposed method can forecast faster and accurately.
PMCID: PMC3655454  PMID: 23710252
17.  Icariside II Induces Apoptosis in U937 Acute Myeloid Leukemia Cells: Role of Inactivation of STAT3-Related Signaling 
PLoS ONE  2012;7(4):e28706.
The aim of this study is to determine anti-cancer effect of Icariside II purified from the root of Epimedium koreanum Nakai on human acute myeloid leukemia (AML) cell line U937.
Methodology/Principal Findings
Icariside II blocked the growth U937 cells in a dose- and time-dependent manner. In this anti-proliferation process, this herb compound rendered the cells susceptible to apoptosis, manifested by enhanced accumulation of sub-G1 cell population and increased the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive cells. Icariside II was able to activate caspase-3 and cleaved poly (ADP-ribose) polymerase (PARP) in a time-dependent manner. Concurrently, the anti-apoptotic proteins, such as bcl-xL and survivin in U937 cells, were downregulated by Icariside II. In addition, Icariside II could inhibit STAT3 phosphorylation and function and subsequently suppress the activation of Janus activated kinase 2 (JAK2), the upstream activators of STAT3, in a dose- and time-dependent manner. Icariside II also enhanced the expression of protein tyrosine phosphatase (PTP) SH2 domain-containing phosphatase (SHP)-1, and the addition of sodium pervanadate (a PTP inhibitor) prevented Icariside II-induced apoptosis as well as STAT3 inactivation in STAT3 positive U937 cells. Furthermore, silencing SHP-1 using its specific siRNA significantly blocked STAT3 inactivation and apoptosis induced by Icariside II in U937 cells.
Our results demonstrated that via targeting STAT3-related signaling, Icariside II sensitizes U937 cells to apoptosis and perhaps serves as a potent chemotherapeutic agent for AML.
PMCID: PMC3320887  PMID: 22493659
18.  Effects of Takju intake and moderate exercise training on brain acetylcholinesterase activity and learning ability in rats 
Nutrition Research and Practice  2011;5(4):294-300.
Takju is a Korean alcoholic beverage made from rice, and is brewed with the yeast Saccharomyces cerevisiae. This study was conducted to evaluate the effects of exercise training and moderate Takju consumption on learning ability in 6-week old Sprague-Dawley male rats. The rats were treated with exercise and alcohol for 4 weeks in six separate groups as follows: non-exercised control (CC), exercised control (EC), non-exercised consuming ethanol (CA), exercised consuming ethanol (EA), non-exercised consuming Takju (CT), and exercised consuming Takju (ET). An AIN-93M diet was provided ad libitum. Exercise training was performed at a speed of 10 m/min for 15 minutes per day. Ethanol and Takju were administered daily for 6-7 hours to achieve an intake of about 10 ml after 12 hours of deprivation, and, thereafter, the animals were allowed free access to deionized water. A Y-shaped water maze was used from the third week to understand the effects of exercise and alcohol consumption on learning and memory. After sacrifice, brain acetylcholinesterase (AChE) activity was analyzed. Total caloric intake and body weight changes during the experiment were not significantly different among the groups. AChE activity was not significantly different among the groups. The number of errors for position reversal training in the maze was significantly smaller in the EA group than that in the CA and ET groups, and latency times were shorter in the EA group than those in the CC, EC, CT, and ET groups. The latency difference from the first to the fifth day was shortest in the ET group. The exercised groups showed more errors and latency than those of the non-exercised groups on the first day, but the data became equivalent from the second day. The results indicate that moderate exercise can increase memory and learning and that the combination of exercise and Takju ingestion may enhance learning ability.
PMCID: PMC3180679  PMID: 21994523
Takju intake; exercise training; water maze; AChE; learning ability
19.  Effects of poly-γ-glutamic acid on serum and brain concentrations of glutamate and GABA in diet-induced obese rats 
Poly-gamma-glutamic acid (γ-PGA) is a mucilaginous and biodegradable compound produced by Bacillus subtilis from fermented soybeans, and is found in the traditional Korean soy product, cheongkukjang. This study was carried out to evaluate the effects of γ-PGA from a food source on the concentration of the neurotransmitter GABA and its metabolic precursor glutamate in diet-induced obese rats. Eight-week old male Sprague-Dawley rats (n=60) were used. The rats were divided into two groups and obesity was induced by providing either a 10% control fat or 45% high fat diet for 5 weeks. The rats were then blocked into 6 groups and supplemented with a 0.1% γ-PGA diet for 4 weeks. After sacrifice, brain and serum GABA and glutamate concentrations were analyzed by high performance liquid chromatography with fluorometric detection. The rats fed the high fat diet had significantly increased body weights. γ-PGA supplementation significantly increased serum concentrations of glutamate and GABA in the control fat diet groups while this effect was not found in the high fat groups. In the brain, glutamate concentrations were significantly higher in the γ-PGA supplemented groups both in rats fed the normal and high fat diets than in the no γ-PGA controls. GABA concentrations showed the same tendency. The results indicated that γ-PGA intake increased GABA concentrations in the serum and brain. However, the effects were not shown in obese rats.
PMCID: PMC2830410  PMID: 20198205
Poly-gamma-glutamic acid (γ-PGA); glutamate; γ-aminobutyric acid (GABA)
20.  Screening of Subtelomeric Rearrangements in 100 Korean Pediatric Patients with Unexplained Mental Retardation and Anomalies Using Subtelomeric FISH (Fluorescence In Situ Hybridization) 
Journal of Korean Medical Science  2008;23(4):573-578.
Rearrangements of the subtelomeric regions of chromosomes account for a significant proportion of the underlying genetic defects in both idiopathic mental retardation (MR) and multiple congenital anomalies. To detect the rearrangements, a set of subtelomeric fluorescence in situ hybridization (FISH) probes has been developed. The aim of this study was to reveal the frequency of subtelomeric rearrangements in Korean patients with MR or multiple anomalies. We performed a FISH study using a commercially available subtelomeric FISH probes on a series of unrelated Korean pediatric patients with MR or multiple anomalies without identifiable causes. We used a checklist to evaluate the developmental delay and/or MR. Patients who were shown to have chromosome abnormalities, metabolic disorders, or recognizable dysmorphic syndromes by clinical and laboratory findings were excluded. As a result, 100 patients were eligible for the Subtelomeric FISH study, and a total of 29 patients (29%) were suspected to have subtelomeric rearrangements on initial screening by the multiprobe FISH kit. Among theses, confirmatory FISH studies by using single locus-specific FISH probes were performed in 24 patients. One patient (a 10-yr-old girl) was confirmed to have rearrangement, deletion of the telomeric portion of the short arm of chromosome 4 (4p). Her clinical manifestation was compatible with Wolf-Hirschhorn syndrome, which is known to be caused by 4p deletion. The frequency of subtelomeric rearrangements in this study was 1.1% (1/95), lower than those previously reported (0.5-16.3%). We suggest that subtelomeric FISH test is a useful screening tool for patients with idiopathic MR and/or dysmorphism regardless of its false positive value.
PMCID: PMC2526410  PMID: 18756040
Chromosomal Rearrangement; Idiopathic Mental Retardation; Subtelomeric FISH
21.  Molecular Cytogenetic Analysis of Gene Rearrangements in Childhood Acute Lymphoblastic Leukemia 
The aims of this study were to estimate the incidences of BCR/ABL, MLL, TEL/AML1 rearrangements, and p16 deletions in childhood acute lymphoblastic leukemia (ALL), to identify new abnormalities, and to demonstrate the usefulness of interphase fluorescence in situ hybridization (FISH). We performed G-banding analysis and FISH using probes for BCR/ABL, MLL, TEL/AML1 rearrangements, and p16 deletions on 65 childhood ALL patients diagnosed and uniformly treated at a single hospital. Gene rearrangements were identified in 73.8% of the patients using the combination of G-banding and FISH, while the chromosomal abnormalities were identified in 49.2% using G-banding alone. Gene rearrangements were disclosed by FISH in 24 (72.7%) of 33 patients with normal karyotype or no mitotic cell in G-banding. Among the gene rearrangements detected by FISH, the most common gene rearrangement was p16 deletion (20.3%) and the incidences of others were 14.1% for TEL/AML1, 11.3% for MLL, and 1.8% for BCR/ABL translocations. Infrequent or new aberrations such as AML1 amplification, MLL deletion, ABL deletion, and TEL/AML1 fusion with AML1 deletion were also observed. We established the rough incidences of gene rearrangements in childhood ALL, found new abnormalities and demonstrated the diagnostic capability of interphase FISH to identify cryptic chromosome aberrations.
PMCID: PMC2808572  PMID: 15716599
In Situ Hybridization, Fluorescence; Leukemia, Lymphocytic, Acute; Childhood; Gene Rearrangements
22.  De novo CD5 Positive Diffuse Large B-cell Lymphomas with Bone Marrow Involvement in Korean 
Journal of Korean Medical Science  2004;19(6):815-819.
In CD5 positive (CD5+) mature B-cell lymphomas, newly recognized CD5+ diffuse large B-cell lymphoma (DLBCL) has been characterized by aggressive features. We studied twenty-five cases with CD5+ lymphomas involving bone marrow. Eleven cases were diagnosed as chronic lymphocytic leukemia, six cases were diagnosed as mantle cell lymphoma (MCL), and three cases with morphologic characteristics of MCL and without both the cyclin D1 expression and IGH/CCND1 rearrangement were unclassifiable. The remaining five cases, showing large to medium-sized lym-phoid cells with prominent nucleoli and a moderate amount of cytoplasm, were diagnosed as DLBCL. Five DLBCL cases were positive for CD5, CD20, surface immuno-globulin, but negative for CD23. Patients with CD5+ DLBCL showed a high age of onset (median, 68 yr) and two patients expired one month after the diagnosis. Since CD5+ DLBCL forms a distinct subgroup of DLBCL, a study of CD5 expression in DLBCL would be helpful to predict prognosis and to determine future therapeutic strategy. To the best of our knowledge, this is the first report on de novo CD5+ DLBCL in Koreans.
PMCID: PMC2816303  PMID: 15608391
Antigens, CD5; Leukemia, Lymphocytic, Chronic; Lymphoma, Mantle-Cell; Lymphoma, Large-Cell, Diffuse
23.  Coordination tuning of cobalt phosphates towards efficient water oxidation catalyst 
Nature Communications  2015;6:8253.
The development of efficient and stable water oxidation catalysts is necessary for the realization of practically viable water-splitting systems. Although extensive studies have focused on the metal-oxide catalysts, the effect of metal coordination on the catalytic ability remains still elusive. Here we select four cobalt-based phosphate catalysts with various cobalt- and phosphate-group coordination as a platform to better understand the catalytic activity of cobalt-based materials. Although they exhibit various catalytic activities and stabilities during water oxidation, Na2CoP2O7 with distorted cobalt tetrahedral geometry shows high activity comparable to that of amorphous cobalt phosphate under neutral conditions, along with high structural stability. First-principles calculations suggest that the surface reorganization by the pyrophosphate ligand induces a highly distorted tetrahedral geometry, where water molecules can favourably bind, resulting in a low overpotential (∼0.42 eV). Our findings emphasize the importance of local cobalt coordination in the catalysis and suggest the possible effect of polyanions on the water oxidation chemistry.
The role of metal-coordination environment on the effectiveness of water oxidation catalysts is relatively unexplored. Here, the authors study a range of cobalt phosphate catalysts with varying coordination environments and observe high activity and stability for a distorted tetrahedral cobalt system.
PMCID: PMC4579784  PMID: 26365091
24.  The Relationship between Anemia and the Initiation of Dialysis in Patients with Type 2 Diabetic Nephropathy 
Diabetes & Metabolism Journal  2015;39(3):240-246.
Anemia is associated with various poor clinical outcomes in chronic kidney disease patients. The aim of this study was to investigate the relationship between anemia and the initiation degree and time of dialysis in type 2 diabetic nephropathy patients.
This observational retrospective study included 130 type 2 diabetic nephropathy patients in Korea. The existence of anemia, the degree and time of dialysis initiation were reviewed. Clinical characteristics and variables were also compared.
The levels of hemoglobin and serum creatinine were significantly correlated with the dialysis initiation (P<0.05) during the 10-year follow-up period. Patients with anemia showed rapid decline of renal function, causing significantly more dialysis initiation (54.1% vs. 5.4%, P<0.05) compare to the patients without anemia. Average time to initiate dialysis in patients with anemia was 45.1 months (range, 8.0 to 115.8 months), which was significantly faster than that (68.3 months [range, 23.3 to 108.8 months]) in patients without anemia (P<0.01). The risk to dialysis initiation was significantly increased in patients with anemia compared to the patients without anemia (adjusted hazard ratio, 8.1; 95% confidence interval, 2.4 to 27.0; P<0.05).
Anemia is associated with rapid decline of renal dysfunction and faster initiation of dialysis in diabetic nephropathy patients. Therefore, clinicians should pay an earlier attention to anemia during the management of diabetes.
PMCID: PMC4483609  PMID: 26124994
Anemia; Diabetes; Dialysis; Nephropathy
25.  Results of an Inpatient Smoking Cessation Program: 3-Month Cessation Rate and Predictors of Success 
Hospitalization presents smokers with an opportunity to initiate smoking cessation. We studied the effect of inpatient counseling and follow-up after discharge on smoking cessation and assessed predictors of successful cessation.
This study included a total of 125 patients (118 male and 7 female) who were admitted to departments of neurology, cardiology, and pulmonology. They were referred to the smoking cessation clinic, and participated between September 2011 and February 2013. A counseling service lasting about thirty minutes was provided by the third-year family medicine residents during hospitalization. The follow-up counseling services, which were either by telephone or in-person physician counseling were provided at 1 week, 4 weeks, and 3 months. Smoking habits and nicotine dependency data were gathered using questionnaires, and patient information was collected from electronic medical records.
The average age in the study was 57.9 ± 10.2 years and duration of smoking was 35.9 ± 11.7 years. Daily tobacco consumption was 23.5 ± 13.2 cigarettes. The smoking cessation rate after 3 months was 42.4%. The only differences between patients in the successful cessation and failed groups were cause of admission (P = 0.039) and total number of counseling sessions after discharge (P < 0.001). In a multivariate analysis, smoking cessation was more likely when patients experienced more instances of follow-up after discharge (1-2 visits: odds ratio [OR], 8.186; 95% confidence interval [CI], 1.060 to 63.239; ≥3 visits: OR, 121.873; 95% CI, 14.462 to 1,027.055).
Smoking cessation counseling during hospitalization and further follow-up by telephone or outpatient counseling after discharge contributed to an increased smoking cessation rate. The smoking cessation rate also tended to increase with total counseling numbers.
PMCID: PMC4369661  PMID: 25802686
Inpatients; Smoking Cessation; Counseling

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