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>

Feasibility of proposed single-nucleotide polymorphisms as predictive markers for targeted regimens in metastatic colorectal cancer

Kim, J C,Ha, Y J,Roh, S A,Choi, E Y,Yoon, Y S,Kim, K P,Hong, Y S,Kim, T W,Cho, D H,Kim, S Y,Kim, Y S Nature Publishing Group 2013 The British journal of cancer Vol.108 No.9

<P><B>Background:</B></P><P>Surrogate biomarkers for metastatic colorectal cancer (mCRC) are urgently needed to achieve the best outcomes for targeted therapy.</P><P><B>Methods:</B></P><P>A clinical association analysis was performed to examine the three single-nucleotide polymorphisms (SNPs) that were previously proposed as markers of chemosensitivity to the cetuximab (124 patients) and bevacizumab regimens (100 patients) in mCRC patients. In addition, biological correlations were examined for the candidate SNPs in terms of their regulatory pathway.</P><P><B>Results:</B></P><P>For cetuximab regimens, patients homozygous for the wild-type alleles (<I>GG</I>) of <I>LIFR rs3729740</I> exhibited a 1.9 times greater overall response rate (ORR) and 1.4 months longer progression-free survival (PFS) than those homozygous or heterozygous for the mutant allele (<I>GA</I> and <I>AA</I>; <I>P</I>=0.022 and 0.027, respectively). For bevacizumab regimens, patients homozygous for the minor alleles (<I>TT</I>) of <I>ANXA11 rs1049550</I> exhibited an ORR twice as high as those homozygous or heterozygous for the ancestral allele (<I>CC</I> and <I>CT</I>; <I>P</I>=0.031). Overall response rate gain was achieved up to 10% in patients with wild-type <I>LIFR rs3729740</I> patients either with wild-type <I>KRAS</I> or skin toxicity (<I>P</I>=0.001) respectively. Specifically in clones treated with cetuximab and bevacizumab regimens, active p-ERK and MMP-9 expressions were significantly reduced in clones expressing wild-type <I>LIFR rs3729740</I> (<I>P</I>=0.044) and in those expressing minor-type <I>ANXA11 rs1049550</I> (<I>P</I>=0.007), respectively.</P><P><B>Conclusion:</B></P><P><I>LIFR rs3729740</I> and possibly <I>ANXA11 rs1049550</I> may be useful as biomarkers for predicting whether mCRC patients are sensitive to relevant target regimens, although further validation in large cohorts is needed.</P>

Confocal microscopic findings of cysteine protease calpain in Plasmodium falciparum

Choi, Y.Y.,Jung, S.Y.,Cho, P.Y.,Soh, B.Y.,Zheng, B.,Kim, S.Y.,Park, K.I.,Park, H. Academic Press 2010 Experimental parasitology Vol.124 No.3

Pf-calpain, a cysteine protease of Plasmodium falciparum, is believed to be one of the central mediators for essential parasitic activity. However, the roles of calpain on parasitic activity have not been determined in P. falciparum. In the present study, the localization of Pf-calpain was investigated using polyclonal antibodies (anti-Pf-calpain antibody A and B) against peptides that distinguished it from human calpain-7 and rat calpain-10 protein. Recombinant Pf-calpain (rPf-calpain) was identified as a 46kDa protein using an anti-Pf-calpain antibody A, which can recognize the Pf-calpain binding site. Confocal microscopy revealed calpain within cytoplasmic localized parasites in the erythrocytic cycle. The findings suggested that the expression of Pf-calpain would be proportional to all different parasites in the erythrocytic cycle. On the other hand, anti-human calpain-7 antibody detected Pf-calpain in schizonts, and the immunofluorescence was stronger than with anti-rat calpain-10 antibody. However, the antibodies reacted with calpains in human red blood cells. These results show that anti-Pf-calpain antibody A and B specifically recognize only Pf-calpain. Taken together, the results suggest that Pf-calpain is expressed in all erythrocytic stages. In particular, the expression of Pf-calpain is increased much more when the late ring matures into the early trophozoite. Moreover, anti-Pf-calpain antibody A and B against synthetic peptides of the catalytic domain of Pf-calpain are useful to specifically detect Pf-calpain in all erythrocytic stages, while human and rat calpain antibody are not useful.

Effect of Wood Vinegar on the Performance, Nutrient Digestibility and Intestinal Microflora in Weanling Pigs

Choi, J.Y.,Shinde, P.L.,Kwon, I.K.,Song, Y.H.,Chae, Byung-Jo Asian Australasian Association of Animal Productio 2009 Animal Bioscience Vol.22 No.2

Two experiments were conducted to investigate the feeding value of wood vinegar in weanling pigs. In Experiment 1, weanling pigs (n = 224; Landrace ${\times}$Yorkshire ${\times}$Duroc, 21${\pm}$3 d-old, initial BW 6.12${\pm}$0.10 kg) were assigned to four dietary treatments. Different levels of wood vinegar were added to the diets as dietary treatments (0, 0.1, 0.2 and 0.3%). Each treatment comprised 4 replicates with 14 piglets in each. Experimental feeding was conducted for 28 d in two phases (phase I, d 0 to 14 and phase II, d 15 to 28). Feeding of wood vinegar linearly (p<0.05) improved the phase I, phase II and overall ADG and increased (linear, p<0.05) the overall and phase II ADFI. Linear improvements in the apparent fecal digestibility of dry matter (p = 0.013), gross energy (p = 0.019) and crude protein (p = 0.033) were observed as the level of wood vinegar was increased in the diet of pigs. Experiment 2 was conducted to compare dietary wood vinegar with commonly used growth promoters, organic acid (mixture of 21% phosphoric acid, 3.25% propionic acid, 2.8% formic acid, 10% calcium formate and 5% calcium propionate) and antibiotic (aparamycin). A total of 288 weanling piglets (Landrace ${\times}$Yorkshire ${\times}$Duroc, 22${\pm}$2 d-old, initial BW 6.62${\pm}$0.31 kg) were assigned to four treatments with four replicates (18 piglets/pen) for 28 days and fed in 2 phases: phase I, d 0 to 14 and phase II, d 15 to 28. The dietary treatments were control (corn-soybean meal basal diet without antibiotics) and diets containing 0.2% antibiotic, 0.2% organic acid and 0.2% wood vinegar. Pigs fed antibiotic showed higher (p<0.001) ADG and better feed efficiency followed by pigs fed wood vinegar and organic acid diets while those fed the control diet had lowest ADG and poorest feed efficiency. The overall and phase I ADFI was highest (p<0.001) in pigs fed wood vinegar and lowest in pigs fed the control diet. Apparent fecal digestibility of dry matter, gross energy and crude protein was significantly higher (p<0.05) in pigs fed the antibiotic diet when compared with pigs fed the control but comparable among pigs fed antibiotic, organic acid and wood vinegar diets. Higher populations of Lactobacillus (p = 0.004) were noted in the ileum of pigs fed the wood vinegar diet, while the population of coliforms in the ileum and cecum was higher (p<0.001) in pigs fed the control diet when compared with pigs fed antibiotic, organic acid or wood vinegar diets. These results indicated that wood vinegar could improve the performance of weanling pigs by improving the nutrient digestibility and reducing harmful intestinal coliforms; moreover performance of pigs fed wood vinegar was superior to those fed organic acid.

p34 is a novel regulator of the oncogenic behavior of NEDD4-1 and PTEN

Hong, S-W,Moon, J-H,Kim, J-S,Shin, J-S,Jung, K-A,Lee, W-K,Jeong, S-Y,Hwang, J J,Lee, S-J,Suh, Y-A,Kim, I,Nam, K-Y,Han, S,Kim, J E,Kim, K-p,Hong, Y S,Lee, J-L,Lee, W-J,Choi, E K,Lee, J S,Jin, D-H,Kim, Macmillan Publishers Limited 2014 CELL DEATH AND DIFFERENTIATION Vol.21 No.1

PTEN is one of the most frequently mutated or deleted tumor suppressors in human cancers. NEDD4-1 was recently identified as the E3 ubiquitin ligase for PTEN; however, a number of important questions remain regarding the role of ubiquitination in regulating PTEN function and the mechanisms by which PTEN ubiquitination is regulated. In the present study, we demonstrated that p34, which was identified as a binding partner of NEDD4-1, controls PTEN ubiquitination by regulating NEDD4-1 protein stability. p34 interacts with the WW1 domain of NEDD4-1, an interaction that enhances NEDD4-1 stability. Expression of p34 promotes PTEN poly-ubiquitination, leading to PTEN protein degradation, whereas p34 knockdown results in PTEN mono-ubiquitination. Notably, an inverse correlation between PTEN and p34/NEDD4-1 levels was confirmed in tumor samples from colon cancer patients. Thus, p34 acts as a key regulator of the oncogenic behavior of NEDD4-1 and PTEN.

Tpl-2 kinase downregulates the activity of p53 and enhances signaling pathways leading to activation of activator protein 1 induced by EGF

Khanal, P.,Lee, K.-Y.,Kang, K.-W.,Kang, B. S.,Choi, H. S. Oxford University Press 2009 Carcinogenesis Vol.30 No.4

<P>Tumor progression locus-2 (Tpl-2) kinase is a member of the mitogen-activated protein kinase kinase kinase family that has been implicated in cellular transformation. The enhanced expression of this protein has been shown to activate both the mitogen-activated protein kinase and c-Jun N-terminal kinase pathways. However, the molecular mechanisms responsible for the oncogenic potential of Tpl-2 are still largely unknown. Here, we showed that Tpl-2 interacted with p53 both in vitro and ex vivo. The overexpression of Tpl-2 inhibited the epidermal growth factor (EGF)-induced p53 phosphorylation (Ser15) through upregulating the activity of protein phosphatase 2A, which interacted with p53 stimulated by EGF. Also, the EGF-induced p53 activity was suppressed in the Tpl-2 wild-type (WT)-transfected HEK 293 cells, but had no effect in the Tpl-2-mutant (S413A)-transfected cells. Furthermore, introduction of small interfering RNA-Tpl-2 into HEK 293 cells resulted in decreased cell viability compared with only adenovirus-p53-infected cells. In addition, the Tpl-2 WT, but not Tpl-2 mutant (S413A), showed increased EGF-induced c-fos promoter activity, followed by activator protein 1 (AP-1) transactivation activity, which was associated with the cell transformation prompted by the H-Ras-Tpl-2-AP-1 signaling axis. These results indicated that the Ser413 of Tpl-2 plays an important role in EGF-induced carcinogenesis as well as inactivation of the p53.</P>

Extensions of smooth mappings into biduals and weak continuity

Choi, Y.S.,Hajek, P.,Lee, H.J. Academic Press ; Elsevier Science B.V. Amsterdam 2013 Advances in mathematics Vol.234 No.-

We study properties of uniformly differentiable mappings between real Banach spaces. Among our main results are generalizations of a number of classical results for linear operators on L<SUB>~</SUB>-spaces into the setting of uniformly differentiable mappings. Denote by B<SUB>X</SUB> the closed unit ball of a Banach space X. Let X be a L<SUB>~,λ</SUB>-space, λ≥1, and let Y be a Banach space. Let T:B<SUB>X</SUB>→Y be a continuous mapping which is uniformly differentiable in the open unit ball of X. Assuming that T is weakly compact, then T can be extended, preserving its best smoothness properties, into the mapping from the 1λ-multiple of the unit ball of any superspace of the domain space X into the same range space Y. We also show that T maps weakly Cauchy sequences from λB<SUB>X</SUB> into norm convergent sequences in Y. This is a uniformly smooth version of the Dunford-Pettis property for the L<SUB>~,λ</SUB>-spaces. We also show that a uniformly differentiable mapping T, which is not necessarily weakly compact, still maps weakly Cauchy sequences from λB<SUB>X</SUB> into norm convergent sequences in Y, provided Y<SUP>**</SUP> does not contain an isomorphic copy of c<SUB>0</SUB>. We prove that for certain pairs of Banach spaces the completion of the space of polynomials equipped with the topology of uniform convergence on the bounded sets (of the functions and their derivatives up to order k) coincides with the space of uniformly differentiable (up to order k) mappings. Our work is based on a number of tools that are of independent interest. We prove, for every pair of Banach spaces X,Y, that any continuous mapping T:B<SUB>X</SUB>→Y, which is uniformly differentiable of order up to k in the interior of B<SUB>X</SUB>, can be extended, preserving its best smoothness, into a bidual mapping T@?:B<SUB>X^*^*</SUB>→Y<SUP>**</SUP>. Another main tool is a result of Zippin's type. We show that weakly Cauchy sequences in X=C(K) can be uniformly well approximated by weakly Cauchy sequences from a certain C[0,α], α is a countable ordinal, subspace of X<SUP>**</SUP>.

열처리 단백질-광물질 복합제제 첨가가 In Vitro 발효성상과 착유우의 유량 및 유성분에 미치는 영향

최낙진,배귀석,남경표,장문백,엄재상,고종렬,하종규 한국동물자원과학회 2002 한국축산학회지 Vol.44 No.5

본 연구의 in vitro 실험결과를 살펴보면, 배양액의 pH와 암모니아 생성량은 전 배양시간 동안 처리구간 통계적 유의차가 없었다. Total VFA, acetate, propionate, butyrate 생성량은 12 h에서 HPM을 0.2%, 1% 첨가한 시험구에서 대조구와 비교하여 증가하는 경향이 있었으나, 2% 첨가구에서는 오히려 감소되었고, 48 h 에서는 HPM 첨가한 세 처리구에서 대조구와 비교하여 모두 증가하는 경향을 보였다. 반면에, 다른 배양시간대에서는 처리구간 통계적 유의차는 발견되지 않았다. A/P ratio 경우에도 처리구간 유의차는 없었다. 총 gas 생성량은 배양시간 24 h과 48 h에 HPM 처리구에서 대조구와 비교하여 증가하였다 (P<0.05). 한편 사양실험은 열처리된 단백질 (대두박)과 광물질의 복합 제제 (HPM)가 젖소의 유생산량과 유성분에 끼치는 영향을 조사하기 위하여 수행되었는데 그 결과를 요약하면, 유생산량은 대조구와 비교하여 HPM 시험구에서 하루에 약 1㎏ 정도 더 높았고 (27. 7 vs 28.8 ㎏/d, P<0.001), 4% FCM 생성량 또한 대조구와 비교하여 볼 때 HPM 시험구에서 1.3㎏/d 이 더 높았다 (P<0.001). 유단백 (P<0.05)과 SNF (P<0.05)도 대조구와 비교하여 HPM 시험구에서 그 생산량이 증가되었다. 반면에, 유지방, MUN과 체세포수는 처리구간 통계적 유의차가 발견되지 않았다. 이상의 결과로 보아, HPM 첨가에 의한 반추위 발효 저해현상은 없었으며, HPM 내 함유되어 있는 열처리된 단백질과 광물질의 결합체와 잔여 광물질이 반추위 내 단백질과 결합하여 단백질 분해 속도를 지연시킴으로써, 단백질의 by-pass율을 증가시켜, 유생산량 증가와 유질을 개선 (유단백질, SNF 함량 증가 등) 하는 등 젖소의 생산성을 향상시킨 것으로 요약할 수 있다. This study, consisting of two experiments, was conducted to determine the effects of feeding heat treated protein and mineral complex (HPM) on milk production and composition, and ruminal fermentation of Holstein dairy cows. In in vitro experiment, HPM levels were 0, 0.2, 1 and 2%, and Timothy hay, which was substrate, was milled as 1 ㎜ size, and the effect of HPM on pH and ammonia and VFA were analyzed after incubation times of 0, 6, 12, 24 and 48 h, respectively. The pH and ammonia production were not significantly different between treatments during the incubation. In addition, generally, total VFA and individual VFA were not affected by HPM on 0, 6 and 24 h. While, total VFA and individual VFA were increased in 0.2% and 1% of HPM supplemented treatments, but decreased in 2% of HPM treatment compared with control on 12 h. On 48 h, total VFA and individual VFA were increased in HMP treatment compared to control(P<0.05). However, A/P ratio was not affected by HPM supplementation. Gas production was higher in HPM treatment compared to control on 24 h (P<0.05) and 48 h (P<0.05). In lactating experiment, fourteen lactating Holstein cows were used for 4 months in a cross over experimental design. There were two treatment; no added HPM as a control and 0.2% of HPM added as a test treatment. Daily milk yield (P<0.001), 4% FCM (P<0.001), milk protein (P<0.05) and SNF (solid not fat; P<0.05) were increased in HPM treatment compared to control. While, milk fat, MUN (milk urea nitrogen) and SCC (somatic cell count) were not significantly different between treatments.

Isostructural metal-insulator transition in VO₂

Lee, D.,Chung, B.,Shi, Y.,Kim, G.-Y.,Campbell, N.,Xue, F.,Song, K.,Choi, S.-Y.,Podkaminer, J. P.,Kim, T. H.,Ryan, P. J.,Kim, J.-W.,Paudel, T. R.,Kang, J.-H.,Spinuzzi, J. W.,Tenne, D. A.,Tsymbal, E. Y. American Association for the Advancement of Scienc 2018 Science Vol.362 No.6418

<P><B>Separating structure and electrons in VO<SUB>2</SUB></B></P><P>Above 341 kelvin—not far from room temperature—bulk vanadium dioxide (VO<SUB>2</SUB>) is a metal. But as soon as the material is cooled below 341 kelvin, VO<SUB>2</SUB> turns into an insulator and, at the same time, changes its crystal structure from rutile to monoclinic. Lee <I>et al.</I> studied the peculiar behavior of a heterostructure consisting of a layer of VO<SUB>2</SUB> placed underneath a layer of the same material that has a bit less oxygen. In the VO<SUB>2</SUB> layer, the structural transition occurred at a higher temperature than the metal-insulator transition. In between those two temperatures, VO<SUB>2</SUB> was a metal with a monoclinic structure—a combination that does not occur in the absence of the adjoining oxygen-poor layer.</P><P><I>Science</I>, this issue p. 1037</P><P>The metal-insulator transition in correlated materials is usually coupled to a symmetry-lowering structural phase transition. This coupling not only complicates the understanding of the basic mechanism of this phenomenon but also limits the speed and endurance of prospective electronic devices. We demonstrate an isostructural, purely electronically driven metal-insulator transition in epitaxial heterostructures of an archetypal correlated material, vanadium dioxide. A combination of thin-film synthesis, structural and electrical characterizations, and theoretical modeling reveals that an interface interaction suppresses the electronic correlations without changing the crystal structure in this otherwise correlated insulator. This interaction stabilizes a nonequilibrium metallic phase and leads to an isostructural metal-insulator transition. This discovery will provide insights into phase transitions of correlated materials and may aid the design of device functionalities.</P>

Comparison of Bioavailability of Organic Selenium Sources in Finishing Pigs

Jang, Y.D.,Choi, H.B.,Durosoy, S.,Schlegel, P.,Choi, B.R.,Kim, Y.Y. Asian Australasian Association of Animal Productio 2010 Animal Bioscience Vol.23 No.7

This experiment was conducted to evaluate the bioavailability of different organic selenium (Se) products in finishing pigs. A total of 48 growing pigs, average body weight $47.6kg{\pm}0.05$, were allotted to four different treatments in a randomized complete block (RCB) design in three replicates with four pigs per pen. Three different organic Se products, Se-enriched yeast (treatments A and B) and Se-proteinate (treatment C), were used in conjunction with a basal diet with no added Se as a control treatment. In growing period, pigs were fed the same diet but finishing pigs were fed each treatment diet containing organic Se products for 6 weeks. During the experimental period, feed intake and body weight were measured and blood samples were collected to determine the Se concentration. At the end of this experiment, 3 pigs per treatment were killed and various tissues (loin, liver, kidney, pancreas and spleen) were collected to analyze the Se concentration. The body weight, and average daily feed intake (ADFI) were similar among treatments, but the average daily gain (ADG) was increased on Se-proteinate treatment (p<0.01) and gain-to-feed ratio (G/F ratio) was improved on Se yeast B or Se-proteinate treatment (p<0.01). The tissue Se content was also increased when pigs were fed organic Se sources, and Se was retained efficiently in loin (p<0.01) and kidney (p<0.05) when Se yeast B was provided. The serum Se concentration was increased when organic Se was provided and was higher when pigs were fed Se-proteinate (p<0.01); subsequently liver Se was also higher on Se-proteinate treatment than other treatments. The Se yeast A treatment did not show any increment of Se concentration both in serum and tissues. This result demonstrated that Se retention and bioavailability in finishing pigs were varied by Se products although organic sources were provided. Consequently, each organic Se product should be evaluated before it is used as a supplement in animal feed.