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Search Results: 1 - 10 of 20843 matches for " Hak-Bong Kim "
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High susceptibility of metastatic cells derived from human prostate and colon cancer cells to TRAIL and sensitization of TRAIL-insensitive primary cells to TRAIL by 4,5-dimethoxy-2-nitrobenzaldehyde
Hak-Bong Kim, Mi-Ju Kim, Dae-Young Kim, Jae-Won Lee, Jae-Ho Bae, Dong-Wan Kim, Chi-Dug Kang, Sun-Hee Kim
Molecular Cancer , 2011, DOI: 10.1186/1476-4598-10-46
Abstract: PC3-MM2 and KM12L4A cells with high level of c-Myc and DNA-PKcs were more susceptible to TRAIL than their poorly metastatic primary PC3 and KM12 cells, which was associated with down-regulation of c-FLIPL/S and Mcl-1 and up-regulation of the TRAIL receptor DR5 but not DR4 in both metastatic cells. Moreover, high susceptibility of these metastatic cells to TRAIL was resulted from TRAIL-induced potent activation of caspase-8, -9, and -3 in comparison with their primary cells, which led to cleavage and down-regulation of DNA-PKcs. Knockdown of c-Myc gene in TRAIL-treated PC3-MM2 cells prevented the increase of DR5 cell surface expression, caspase activation and DNA-PKcs cleavage and attenuated the apoptotic effects of TRAIL. Moreover, the suppression of DNA-PKcs level with siRNA in the cells induced the up-regulation of DR5 and active caspase-8, -9, and -3. We also found that 4,5-dimethoxy-2-nitrobenzaldehyde (DMNB), a specific inhibitor of DNA-PK, potentiated TRAIL-induced cytotoxicity and apoptosis in relatively TRAIL-insensitive PC3 and KM12 cells and therefore functioned as a TRAIL sensitizer.This study showed the positive relationship between c-Myc expression in highly metastatic human prostate and colon cancer cells and susceptibility to TRAIL-induced apoptosis and therefore indicated that TRAIL might be used as an effective therapeutic modality for advanced metastatic cancers overexpressing c-Myc and combination of TRAIL therapy with agent that inhibits the DNA-PKcs/Akt signaling pathway might be clinically useful for the treatment of relatively TRAIL-insensitive human cancers.Despite the improvement of therapeutic strategies against cancer, the acquisition of invasive/metastatic capabilities and the development of resistance to therapy in cancer cells are still critical problems for successful cancer therapy because recurrent or metastatic cancers that appear after the initial radiotherapy or chemotherapy are generally refractory to secondary therapies [1]. Som
TRAIL sensitize MDR cells to MDR-related drugs by down-regulation of P-glycoprotein through inhibition of DNA-PKcs/Akt/GSK-3β pathway and activation of caspases
Suk-Bin Seo, Jung-Gu Hur, Mi-Ju Kim, Jae-Won Lee, Hak-Bong Kim, Jae-Ho Bae, Dong-Wan Kim, Chi-Dug Kang, Sun-Hee Kim
Molecular Cancer , 2010, DOI: 10.1186/1476-4598-9-199
Abstract: MDR variants, CEM/VLB10-2, CEM/VLB55-8 and CEM/VLB100 cells, with gradually increased levels of P-gp derived from human lymphoblastic leukemia CEM cells, were gradually more susceptible to TRAIL-induced apoptosis and cytotoxicity than parental CEM cells. The P-gp level of MDR variants was positively correlated with the levels of DNA-PKcs, pAkt, pGSK-3β and c-Myc as well as DR5 and negatively correlated with the level of c-FLIPs. Hypersensitivity of CEM/VLB100 cells to TRAIL was accompanied by the activation of mitochondrial apoptotic pathway as well as the activation of initiator caspases. In addition, TRAIL-induced down-regulation of DNA-PKcs/Akt/GSK-3β pathway and c-FLIP and up-regulation of cell surface expression of death receptors were associated with the increased susceptibility to TRAIL of MDR cells. Moreover, TRAIL inhibited P-gp efflux function via caspase-3-dependent degradation of P-gp as well as DNA-PKcs and subsequently sensitized MDR cells to MDR-related drugs such as vinblastine and doxorubicin. We also found that suppression of DNA-PKcs by siRNA enhanced the susceptibility of MDR cells to vincristine as well as TRAIL via down-regulation of c-FLIP and P-gp expression and up-regulation of DR5.This study showed for the first time that the MDR variant of CEM cells was hypersensitive to TRAIL due to up-regulation of DR5 and concomitant down-regulation of c-FLIP, and degradation of P-gp and DNA-PKcs by activation of caspase-3 might be important determinants of TRAIL-induced sensitization of MDR cells to MDR-related drugs. Therefore, combination of TRAIL and chemotherapeutic drugs may be a good strategy for treatment of cancer with multidrug resistance.Acquired resistance to chemotherapeutic agents remains a major obstacle for the effective treatment of many advanced and metastatic cancers. Several mechanisms are thought to be involved in the development of multidrug resistance (MDR), defined by simultaneous cross-resistance to a variety of anticancer drugs
Path Tracking Controller of Quadruped Robot for Obstacle Avoidance Using Potential Functions Method
Giang Hoang,Hak Kyeong Kim,Sang Bong Kim
International Journal of Science and Engineering , 2013,
Abstract: This paper proposes a tracking controller for obstacle avoidance of a quadruped robot using potential functions method. The followings are done for this task. At first, a ceiling-mounted camera system is installed for image processing. The goal point and obstacles are separated and recognized by a color recognition method. Second, a path planning algorithm using potential functions method is proposed to generate the path to avoid obstacles and to plan a path for the quadruped robot to reach from start point to goal point. Third, a quadruped robot is chosen as the mobile platform for this study and the kinematic model for the robot is presented. Fourth, a tracking controller is designed for the quadruped robot to track the trajectory based on the backstepping method using Lyapunov function. Finally, the simulation results are presented to show the effectiveness of the proposed trajectory planning algorithm and the tracking controller.
Protein Disulfide Isomerase-Like Protein 1-1 Controls Endosperm Development through Regulation of the Amount and Composition of Seed Proteins in Rice
Yeon Jeong Kim, Song Yion Yeu, Bong Soo Park, Hee-Jong Koh, Jong Tae Song, Hak Soo Seo
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0044493
Abstract: Protein disulfide isomerase (PDI) is a chaperone protein involved in oxidative protein folding by acting as a catalyst and assisting folding in the endoplasmic reticulum (ER). A genome database search showed that rice contains 19 PDI-like genes. However, their functions are not clearly identified. This paper shows possible functions of rice PDI-like protein 1-1 (PDIL1-1) during seed development. Seeds of the T-DNA insertion PDIL1-1 mutant, PDIL1-1Δ, identified by genomic DNA PCR and western blot analysis, display a chalky phenotype and a thick aleurone layer. Protein content per seed was significantly lower and free sugar content higher in PDIL1-1Δ mutant seeds than in the wild type. Proteomic analysis of PDIL1-1Δ mutant seeds showed that PDIL1-1 is post-translationally regulated, and its loss causes accumulation of many types of seed proteins including glucose/starch metabolism- and ROS (reactive oxygen species) scavenging-related proteins. In addition, PDIL1-1 strongly interacts with the cysteine protease OsCP1. Our data indicate that the opaque phenotype of PDIL1-1Δ mutant seeds results from production of irregular starch granules and protein body through loss of regulatory activity for various proteins involved in the synthesis of seed components.
Arabidopsis SIZ1 positively regulates alternative respiratory bypass pathways
Bong Soo Park1, Sung-Il Kim1, Jong Tae Song2 & Hak Soo Seo1,3,*
BMB Reports , 2012,
Abstract: Plant mitochondria possess alternative respiratory pathwaysmediated by the type II NAD(P)H dehydrogenases and alternativeoxidases. Here, E3 SUMO ligase was shown to regulatealternative respiratory pathways and to participate in the maintenanceof carbon and nitrogen balance in Arabidopsis. Thetranscript abundance of the type II NAD(P)H dehydrogenasesNDA2 and NDB2 and alternative oxidases AOX1a and AOX1dgenes was low in siz1-2 mutants compared to that in wild-type.The addition of nitrate or ammonium resulted in a decrease oran increase in the expression of the same gene families, respectively,in both wild-type and siz1-2 mutants. The amountof free sugar (glucose, fructose and sucrose) was lower in siz1-2mutants than that in wild-type. These results indicate that lownitrate reductase activity due to the AtSIZ1 mutation is correlatedwith an overall decrease in alternative respiration andwith a low carbohydrate content to maintain the carbon to nitrogenratio in siz1-2 mutants.
EGb761, a Ginkgo Biloba Extract, Is Effective Against Atherosclerosis In Vitro, and in a Rat Model of Type 2 Diabetes
Soo Lim, Ji Won Yoon, Seon Mee Kang, Sung Hee Choi, Bong Jun Cho, Min Kim, Ho Seon Park, Hyun Ju Cho, Hayley Shin, Young-Bum Kim, Hyo Soo Kim, Hak Chul Jang, Kyong Soo Park
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0020301
Abstract: Background EGb761, a standardized Ginkgo biloba extract, has antioxidant and antiplatelet aggregation and thus might protect against atherosclerosis. However, molecular and functional properties of EGb761 and its major subcomponents have not been well characterized. We investigated the effect of EGb761 and its major subcomponents (bilobalide, kaemferol, and quercetin) on preventing atherosclerosis in vitro, and in a rat model of type 2 diabetes. Methods and Results EGb761 (100 and 200 mg/kg) or normal saline (control) were administered to Otsuka Long-Evans Tokushima Fatty rats, an obese insulin-resistant rat model, for 6 weeks (from 3 weeks before to 3 weeks after carotid artery injury). Immunohistochemical staining was performed to investigate cell proliferation and apoptosis in the injured arteries. Cell migration, caspase-3 activity and DNA fragmentation, monocyte adhesion, and ICAM-1/VCAM-1 levels were explored in vitro. Treatment with EGb761 dose-dependently reduced intima-media ratio, proliferation of vascular smooth muscle cells (VSMCs) and induced greater apoptosis than the controls. Proliferation and migration of VSMCs in vitro were also decreased by the treatment of EGb761. Glucose homeostasis and circulating adiponectin levels were improved, and plasma hsCRP concentrations were decreased in the treatment groups. Caspase-3 activity and DNA fragmentation increased while monocyte adhesion and ICAM-1/VCAM-1 levels decreased significantly. Among subcomponents of EGb761, kaemferol and quercetin reduced VSMC migration and increased caspase activity. Conclusions EGb761 has a protective role in the development of atherosclerosis and is a potential therapeutic agent for preventing atherosclerosis.
Performance Measurement for Construction CALS Application of Ubiquitous Technology Using the Process Chart Method  [PDF]
Tae Hak Kim, Seong Yun Jeong
Open Journal of Social Sciences (JSS) , 2013, DOI: 10.4236/jss.2013.15002
Abstract: From the industrial field that spearheaded IT created new added values and markets, and with the fusion of the traditional industry composition, researches are actively being conducted to steer advancement. The application possibility of the high-tech IT technique in the construction industry is increasing. Therefore, when a technique similar to this ubiquitous technique is applied to the Construction CALS system, the effectiveness of the business transaction is augmented, and a business that could reduce the various needed expenses is predicted. In this research, the exhibition features developed and detailed the features of the Construction CALS system to measure the effectiveness of the development so as to prove the validity of the Process Chart using techniques with detailed exhibition features, and will want to conduct quantitative performance measurement.
Regulation of cerebrospinal fluid production by caffeine consumption
Myoung-Eun Han, Hak-Jin Kim, Young-Suk Lee, Dong-Hyun Kim, Joo-Taek Choi, Chul-Sik Pan, Sik Yoon, Sun-Yong Baek, Bong-Seon Kim, Jae-Bong Kim, Sae-Ock Oh
BMC Neuroscience , 2009, DOI: 10.1186/1471-2202-10-110
Abstract: In the present study we found that the long-term consumption of caffeine can induce ventriculomegaly; this was observed in 40% of the study rats. In the caffeine-treated rats with ventriculomegaly, there was increased production of CSF, associated with the increased expression of Na+, K+-ATPase and increased cerebral blood flow (CBF). In contrast to the chronic effects, acute treatment with caffeine decreased the production of CSF, suggesting 'effect inversion' associated with caffeine, which was mediated by increased expression of the A1 adenosine receptor, in the choroid plexus of rats chronically treated with caffeine. The involvement of the A1 adenosine receptor in the effect inversion of caffeine was further supported by the induction of ventriculomegaly and Na+, K+-ATPase, in A1 agonist-treated rats.The results of this study show that long-term consumption of caffeine can induce ventriculomegaly, which is mediated in part by increased production of CSF. Moreover, we also showed that adenosine receptor signaling can regulate the production of CSF by controlling the expression of Na+, K+-ATPase and CBF.Methylxanthine caffeine is present in many common beverages, and is widely consumed worldwide [1,4]. Caffeine consumption has been estimated to be 76 mg per person per day worldwide, as high as 238 mg per person per day in the United States and Canada, and more than 400 mg per person per day in Sweden and Finland [5,6]. Caffeine is absorbed rapidly after oral administration and distributed to various organs and tissues. In the liver, caffeine is metabolized to dimethyl- and monomethylxanthines, dimethyl and monomethyl uric acids, trimethyl- and dimethylallantoin, and uracil derivatives. Some metabolites of caffeine including 1,3-dimethylxanthine (theophylline) and 1,7-dimethylxanthine (paraxanthine) have pharmacological activity similar to caffeine [4]. The half-life of caffeine is ~5 hours in humans and ~1 hour in rats [4,7].The main mechanism of action of caffei
Retiform Sertoli-Leydig Cell Tumor of the Ovary  [PDF]
Gyu-Bong Yu, Seung-Kyu Choi, Yun-Dan Kang, Choong-Hak Park
International Journal of Clinical Medicine (IJCM) , 2016, DOI: 10.4236/ijcm.2016.79065
Abstract: Sertoli-Leydig cell tumor of the ovary is a kind of sex cord-stromal tumor, which occurs between teens and twenties with symptoms including abdominal pain and swelling. The incidence rate is infinitely rare comprising less than 0.5% of all ovarian tumor. The average age of “retiform Sertoli-Leydig cell tumor” is 17 years as compared to 25 years for Sertoli-Leydig cell tumors as a group. We have experienced this rare case of retiform Sertoli-Leydig cell tumor in a 25-year-old foreign patient with the complaint of palpable mass on the right lower quadrant and an irregular menstrual period. The patient underwent right salpingo-oophorectomy and tumor stage was FIGO stage 1A. We report with a brief review of literature.
Effect of a Dipeptidyl Peptidase-IV Inhibitor, Des-Fluoro-Sitagliptin, on Neointimal Formation after Balloon Injury in Rats
Soo Lim, Sung Hee Choi, Hayley Shin, Bong Jun Cho, Ho Seon Park, Byung Yong Ahn, Seon Mee Kang, Ji Won Yoon, Hak Chul Jang, Young-Bum Kim, Kyong Soo Park
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0035007
Abstract: Background Recently, it has been suggested that enhancement of incretin effect improves cardiac function. We investigated the effect of a DPP-IV inhibitor, des-fluoro-sitagliptin, in reducing occurrence of restenosis in carotid artery in response to balloon injury and the related mechanisms. Methods and Findings Otsuka Long-Evans Tokushima Fatty rats were grouped into four: control (normal saline) and sitagliptin 100, 250 and 500 mg/kg per day (n = 10 per group). Sitagliptin or normal saline were given orally from 1 week before to 2 weeks after carotid injury. After 3 weeks of treatment, sitagliptin treatment caused a significant and dose-dependent reduction in intima-media ratio (IMR) in obese diabetic rats. This effect was accompanied by improved glucose homeostasis, decreased circulating levels of high-sensitivity C-reactive protein (hsCRP) and increased adiponectin level. Moreover, decreased IMR was correlated significantly with reduced hsCRP, tumor necrosis factor-α and monocyte chemoattractant protein-1 levels and plasminogen activator inhibitor-1 activity. In vitro evidence with vascular smooth muscle cells (VSMCs) demonstrated that proliferation and migration were decreased significantly after sitagliptin treatment. In addition, sitagliptin increased caspase-3 activity and decreased monocyte adhesion and NFκB activation in VSMCs. Conclusions Sitagliptin has protective properties against restenosis after carotid injury and therapeutic implications for treating macrovascular complications of diabetes.
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