Serine palmitoyltransferase inhibitor myriocin induces growth inhibition of B16F10 melanoma cells through G₂/M phase arrest

Lee, Y.‐,S.,Choi, K.‐,M.,Choi, M.‐,H.,Ji, S.‐,Y.,Lee, S.,Sin, D.‐,M.,Oh, K.‐,W.,Lee, Y.‐,M.,Hong, J.‐,T.,Yun, Y.‐,P.,Yoo, H.‐,S. Blackwell Publishing Ltd 2011 Cell proliferation Vol.44 No.4

<P><B>Abstract</B></P><P><B>Objectives: </B> Melanoma is the most aggressive form of skin cancer, and it resists chemotherapy. Candidate drugs for effective anti‐cancer treatment have been sought from natural resources. Here, we have investigated anti‐proliferative activity of myriocin, serine palmitoyltransferase inhibitor, in the <I>de novo</I> sphingolipid pathway, and its mechanism in B16F10 melanoma cells.</P><P><B>Material and methods: </B> We assessed cell population growth by measuring cell numbers, DNA synthesis, cell cycle progression, and expression of cell cycle regulatory proteins. Ceramide, sphingomyelin, sphingosine and sphingosine‐1‐phosphate levels were analysed by HPLC.</P><P><B>Results: </B> Myriocin inhibited proliferation of melanoma cells and induced cell cycle arrest in the G<SUB>2</SUB>/M phase. Expressions of cdc25C, cyclin B1 and cdc2 were decreased in the cells after exposure to myriocin, while expression of p53 and p21<SUP>waf1/cip1</SUP> was increased. Levels of ceramide, sphingomyelin, sphingosine and sphingosine‐1‐phosphate in myriocin‐treated cells after 24 h were reduced by approximately 86%, 57%, 75% and 38%, respectively, compared to levels in control cells.</P><P><B>Conclusions: </B> Our results suggest that inhibition of sphingolipid synthesis by myriocin in melanoma cells may inhibit expression of cdc25C or activate expression of p53 and p21<SUP>waf1/cip1</SUP>, followed by inhibition of cyclin B1 and cdc2, resulting in G<SUB>2</SUB>/M arrest of the cell cycle and cell population growth inhibition. Thus, modulation of sphingolipid metabolism by myriocin may be a potential target of mechanism‐based therapy for this type of skin cancer.</P>

Reproductive Performance, Milk Composition, Blood Metabolites and Hormone Profiles of Lactating Sows Fed Diets with Different Cereal and Fat Sources

Park, M.S.,Shinde, P.L.,Yang, Y.X.,Kim, J.S.,Choi, J.Y.,Yun, K.,Kim, Y.W.,Lohakare, J.D.,Yang, B.K.,Lee, J.K.,Chae, Byung-Jo Asian Australasian Association of Animal Productio 2010 Animal Bioscience Vol.23 No.2

Different dietary cereal sources and fat types in the lactation diet were evaluated to investigate their effects on reproductive performance, milk composition, blood metabolites and hormones in multiparous sows. Twenty-four sows were randomly assigned to one of four treatments according to a 2${\times}$2 factorial arrangement of treatments. Each treatment had 6 replicates comprising 1 sow. Two cereal (corn or wheat) and two fat (tallow or soybean oil) sources were used to prepare iso-caloric and iso-nitrogenous diets. Sows fed corn-based diets lost less body weight (p = 0.003) and backfat thickness (p = 0.034), consumed more feed (p = 0.032) and had shorter wean-to-estrus interval (p = 0.016) than sows fed wheat-based diets. Fewer piglets and lower body weight of piglets (p<0.05) at weaning were noted in sows fed wheat-based diets than in sows fed corn-based diets. However, no significant effects (p>0.05) of dietary fat source and its interaction with dietary cereal source on sow body condition and reproductive performance were observed during lactation. Feeding of a corn-based diet improved (p<0.05) sow milk total solid, protein and fat, increased blood urea nitrogen (p = 0.032) and triglyceride (p = 0.018), and decreased blood creatinine (p = 0.011) concentration at weaning when compared with sows fed wheatbased diets. Sows fed corn-based diets had higher concentration of insulin (p = 0.048) and LH (p<0.05) at weaning than sows fed wheatbased diets. The results indicate that feeding corn-based diets to lactating sows improved sow body condition and reproductive performance compared with wheat-based diets regardless of fat sources.

P-version Crack Model for Computation of Stress Intensity Factor of Cracked Panels Subjected to Membrane Forces

Yun Y.P.,Soo.K.S.,Park, B.K.Shin Y.S. 한국전산구조공학회 1993 한국전산구조공학회논문집 Vol.6 No.4

Variable number of tandem repeats of 9 Plasmodium vivax genes among Southeast Asian isolates

Wang, B.,Nyunt, M.H.,Yun, S.G.,Lu, F.,Cheng, Y.,Han, J.H.,Ha, K.S.,Park, W.S.,Hong, S.H.,Lim, C.S.,Cao, J.,Sattabongkot, J.,Kyaw, M.P.,Cui, L.,Han, E.T. Verlag fur Recht und Gesellschaft 2017 Acta tropica Vol.170 No.-

<P>The variable number of tandem repeats (VNTRs) provides valuable information about both the functional and evolutionary aspects of genetic diversity. Comparative analysis of 3 Plasmodium falciparum genomes has shown that more than 9% of its open reading frames (ORFs) harbor VNTRs. Although microsatellites and VNTR genes of P. vivax were reported, the VNTR polymorphism of genes has not been examined widely. In this study, 230 P. vivax genes were analyzed for VNTRs by SERV, and 33 kinds of TR deletions or insertions from 29P. vivax genes (12.6%) were found. Of these, 9 VNTR fragments from 8 P. vivax genes were used for PCR amplification and sequence analysis to examine the genetic diversity among 134 isolates from four Southeast Asian countries (China, Republic of Korea, Thailand, and Myanmar) with different malaria endemicity. We confirmed the existence of extensive polymorphism of VNTR fragments in field isolates. This detection provides several suitable markers for analysis of the molecular epidemiology of P. vivax field isolates. (C) 2017 Elsevier B.V. All rights reserved.</P>

Double E1B 19 kDa- and E1B 55 kDa-deleted oncolytic adenovirus in combination with radiotherapy elicits an enhanced anti-tumor effect

Kim, J,Kim, P-H,Yoo, J Y,Yoon, A-R,Choi, H J,Seong, J,Kim, I-W,Kim, J-H,Yun, C-O Macmillan Publishers Limited 2009 Gene Therapy Vol.16 No.9

Radiation therapy, a mainstay for anti-tumor therapeutic regimens for a variety of tumor types, triggers tumor cell apoptotic pathways by either directly eliciting DNA damage or indirectly inducing the formation of oxygen radicals. In an effort to augment radiation therapy, we generated a double E1B 19 kDa- and E1B 55 kDa-deleted oncolytic adenovirus (Ad−ΔE1B19/55). In combination with radiotherapy, greater cytotoxicity was observed for Ad−ΔE1B19/55 than for the single E1B 55 kDa-deleted oncolytic Ad (Ad−ΔE1B55). Consistent with this observation, higher levels of p53, phospho-p53, phospho-Chk1, phospho-Chk2, PI3K (phosphatidylinositol-3-kinase), phospho-AKT, cytochrome c, and cleavage of PARP (poly (ADP-ribose) polymerase) and caspase-3 were observed in cells treated with Ad−ΔE1B19/55 compared with those treated with Ad−ΔE1B55, indicating that the E1B 19 kDa present in Ad−ΔE1B55 may partially block radiation-induced apoptosis. A significant therapeutic benefit was also observed in vivo when oncolytic Ads and radiation were combined. Tumors treated with Ad−ΔE1B19/55 and radiation showed large areas of necrosis and apoptosis with the corresponding induction of p53. Finally, consistent with in vitro observations, the combination of Ad−ΔE1B19/55 and radiation was more efficacious than the combination of Ad−ΔE1B55 and radiation. Taken together, these results present a strong therapeutic rationale for combining radiation therapy with E1B 19 kDa-deleted oncolytic Ad.

EPIGALLOCATECHIN-3 GALLATE, SELECTIVELY INHIBITS THE PLATELET-DERIVED GROWTH FACTOR-BB-INDUCED SIGNALING TRANSDUCTION PATHWAYS IN VASCULAR SMOOTH MUSCLE CELLS

Ahn, Hee-Yul,K.R. Hadizadeh Kharrazi,Yun, Y-P,Park, J-B,Choi, W,H. Vetter,A. Sachinidis 이화여자대학교 세포신호전달연구센터 2000 고사리 세포신호전달 심포지움 Vol. No.2

Vascular smooth muscle cells(VSMCs) proliferation may participate in the pathophysiology of cardiovascular diseases. Platelet-derived growth factor-BB(PDGF-BB) is a potent mitogenic factor for VSMCs. Epigallocatechin gallate(EGCG) is the main compound of green tea and is believed to be the active component in tea for the prevention against several diseases. We investigated the effect of EGCG on the PDGF-BB-induced proliferation of VSMCs. VSMCs were preincubated in serum-free medium for 24 h(quiescent VSMCs) before EGCG was added to the medium. Following 24 h incubation with EGCG per se, VSMCs were trypsinized and cell counts were determined using CASY-1 system based on the coulter counter principle(Scharfe). Treatment of the cells with 0μM, 20μM, 50μM and 100μM EGCG resulted in a decrease of cell counts from 1.49×10^(6) ± 1.2×10^(5)(0μM) to 9.7×10^(5) ± 1.1×10⁴, 5.3×10^(5) ± 6.3×10⁴, 3.8×10^(5) ± 2.5×10⁴ counts/ml(mean±SD, n=3), respectively. Stimulation of quiescent cells with 50 ng/ml PDGF-BB for 24 h resulted in a 35% increase in cell counts. In the presence of 50μM EGCG, the effect of PDGF-BB on cell counts was abrogated. Activation of the 42 and 44 kDa mitogen-activated protein kinase(MAP) kinases(p44^(mapk)/p42^(mapk)) was deteced by chemiluminescence western blotting method using primary antibodies which recognizes the Tyr204-phosphorylated active isoforms. Stimulation of quiescent VSMCs with 50 ng/ml PDGF-BB caused at 5 min an 8-fold increase of the the p44^(mapk)/p42^(mapk) phosphorylation above control levels. Pretreatment of cells for 24 h with 50㎍/ml EGCG resulted in 70% inhibition of the p44^(mapk)/p42^(mapk) phosphorylation. Stimulation of the cells with PDGF-BB caused a maximal increase in [Ca^(2+)]_(i) from 40±10(basal value) to 145±15nM(mean±SD, n=4) at 25 sec(determined by the fura-2 method). Preincubation of VSMCs for 24 h with EGCG resulted in a complete inhibition of the PDGF-BB-induced increase in [Ca^(2+)]_(i). These results demonstrate that EGCG may exert its anti-proliferative effects via inhibition of the PDGF-BB-induced intracellular signaling events like stimulation of the p44^(mapk)/p42^(mapk) and elevation of [Ca^(2+)]_(i).

Inhibitory effect of fenofibrate on neointima hyperplasia via G₀/G₁ arrest of cell proliferation

Lee, J.J.,Yu, J.Y.,Zhang, W.Y.,Kim, T.J.,Lim, Y.,Kwon, J.S.,Kim, D.W.,Myung, C.S.,Yun, Y.P. North-Holland ; Elsevier Science Ltd 2011 european journal of pharmacology Vol.650 No.1

We have previously reported that fenofibrate displayed a potent antithrombotic effect by the inhibition of platelet aggregation. The present study was designed to investigate the effects of fenofibrate on the neointimal hyperplasia and its possible molecular mechanism. Neointimal hyperplasia was measured in balloon-inflated-induced vascular injury model of male Sprague-Dawley rats and cell proliferation was measured in primary cultured rat aortic vascular smooth muscle cells (VSMCs). Fenofibrate-treated group showed a significant reduction in neointimal formation (0.07+/-0.04mm<SUP>2</SUP>) from the control (0.13+/-0.04mm<SUP>2</SUP>). Fenofibrate significantly inhibited platelet-derived growth factor (PDGF)-BB-induced cell counting and [<SUP>3</SUP>H]-thymidine incorporation into DNA. Fenofibrate suppressed the PDGF-BB-inducible progression through G<SUB>0</SUB>/G<SUB>1</SUB> to S phase of cell cycle. Moreover, fenofibrate inhibited not only phosphorylation of retinoblastoma (Rb) protein and expression of cyclin D/E, CDK 2/4 and proliferating cell nuclear antigen (PCNA) proteins but also mitogen-activated protein kinase (MAPK) signaling pathways such as ERK ½, p38 and JNK phosphorylation. In conclusion, the present study demonstrates that fenofibrate significantly inhibits neointimal formation via G<SUB>0</SUB>/G<SUB>1</SUB> arrest of PDGF-BB-induced cell proliferation in association with the inhibition of MAPK, which resulted in the downregulation of expressions of cyclin D/E, CDK 2/4 and PCNA proteins, suggesting that fenofibrate may be useful for individuals with a high risk of thrombotic or cardiovascular diseases.

Inhibitory effect of obovatol on nitric oxide production and activation of NF-κB/MAP kinases in lipopolysaccharide-treated RAW 264.7cells

Choi, M.S.,Lee, S.H.,Cho, H.S.,Kim, Y.,Yun, Y.P.,Jung, H.Y.,Jung, J.K.,Lee, B.C.,Pyo, H.B.,Hong, J.T. North-Holland ; Elsevier Science Ltd 2007 european journal of pharmacology Vol.556 No.1

The components of Magnolia obovata are known to have many pharmacological activities. In this study, we investigated the effects of obovatol, a neolignan compound isolated from the leaves of M. obovata, on nitric oxide (NO) production and NF-κB activity in lipopolysaccharide (LPS)-activated RAW 264.7 cells. The results show that obovatol (1-5 μM) significantly inhibited LPS-induced NO production in a concentration-dependent manner (IC<SUB>50</SUB>: 0.91 μM). Consistent with the inhibitory effect on NO production, obovatol inhibits the expression of inducible nitric oxide synthase and cyclooxygenase-2 expression. Furthermore, obovatol suppressed NF-κB (p50 and p65) translocation to the nucleus as well as IκB release resulting in the inhibition of the DNA binding activity of the NF-κB. Obovatol also inhibited c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK) signal, which are the most significantly involved signal in NO production and NF-κB activation. When the cells were treated with the combination of obovatol with U0126 (an ERK inhibitor) or SP600125 (a JNK inhibitor) as well as with SC-514 (an IKK2 inhibitor), much more inhibition of NO production was observed than that by obovatol alone. The present results suggest that obovatol has an inhibitory effect on NO production through the inhibition of NF-κB/MAPK activity, and thus can be used as an anti-inflammatory agent.

산물퇴적 청과물의 송풍저항 특성

윤홍선,조영길,박판규,박경규 한국농업기계학회 1995 바이오시스템공학 Vol.20 No.4

Inactivation of 3-strain cocktail pathogens inoculated into Bajirak jeotkal, salted, seasoned, and fermented short-necked clam (Tapes pilippinarum), by gamma and electron beam irradiation

Song, H.P.,Kim, B.,Yun, H.,Kim, D.H.,Kim, Y.J.,Jo, C. Butterworths ; Taylor Francis ; Elsevier Science 2009 FOOD CONTROL Vol.20 No.6

The objective of this study was to determine the efficacy of gamma and electron beam irradiation of the food-borne pathogens including 3-strain cocktail of Listeria monocytogenes (ATCC 19114, 19115, and 19111), Staphylococcus aureus (ATCC 6538, 25923, and 29213), and Vibrio parahaemolyticus (ATCC 17802, 33844, and 27969) in Bajirak jeotkal (8% salt), salted, seasoned and fermented short-necked clam, commercially available in the market. Irradiation (0.5, 1, 2, and 5kGy) significantly reduced the initial microbial level not only immediately after irradiation but also during storage at 10<SUP>o</SUP>C for 4 weeks (P<0.05). No viable cells were detected at 5kGy of irradiation at a detection limit of 10<SUP>1</SUP>CFU/g. Gamma irradiation was more effective than electron beam irradiation, and yielded D<SUB>10</SUB> values of 0.64, 0.63, and 0.29kGy for L. monocytogenes, S. aureus, and V. parahaemolyticus, and those of electron beam irradiation were 0.79, 0.81, and 0.36kGy, respectively. Results suggest that a low dose irradiation can improve the microbial quality and reduce the risk by the food-borne pathogens of Bajirak jeotkal, which has limited alternative sterilization methods due to the temperature characteristics of the products. Furthermore, in practical application, the irradiation source should be considered to obtain an effective dose for decontamination.