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Hepatocellular carcinoma (HCC) is one of the most lethal cancers worldwide; however, the genetic mechanisms underlying its pathogenesis are incompletely understood. Genetically engineered mouse (GEM) models of HCC have been developed to elucidate the role of individual cancer-related genes in hepatocarcinogenesis. However, the expensive and time-consuming processes related to generating a GEM model discourage the development of diverse genotype models. Recently, a simple and inexpensive liver-specific transgenic approach was developed, in which a hydrodynamics-based transfection (HT) method was coupled with the Sleeping Beauty transposase system. Various HT models in which different oncogenic pathways are activated and/or tumor-suppressing pathways inactivated have been developed in recent years. The applicability of HT models in liver cancer research is expected to broaden and ultimately elucidate the cooperation between oncogenic signaling pathways and aid in designing molecular therapy to target altered pathways.

Asparaginyl endopeptidases (AEP: EC 3.4.22.34) are a family of cysteine proteases classified into the MEROPS clan CD, family C13. In this study, we characterized the biochemical and antigenic properties of an AEP of Clonorchis sinensis (CsAEP). The recombinant CsAEP showed hydrolytic activity at pH values ranging from acidic to neutral with optimum activity at pH 6.0. While the recombinant CsAEP was stable at neutral pHs, it was unstable at acidic pHs and resulted in loss of enzymatic activity. The recombinant enzyme was effectively inhibited by iodoacetic acid and N-ethylmaleimide, but not by E-64. The partially purified native CsAEP showed biochemical properties similar to the recombinant enzyme. Native CsAEP is likely to be cleaved into an N-terminal mature enzyme and a C-terminal fragment via autocatalytic activation at acidic pHs. Polyclonal antibody raised against the recombinant CsAEP recognized three forms of CsAEP, proenzyme, the N-terminal mature enzyme and the C-terminal fragment, in the worm extract (WE) of C. sinensis. However, only the C-terminal fragment was mainly found in the excretory and secretory (ES) products of the parasite. Strong CsAEP activity was found in the WE, but only a trace level of CsAEP activity was detected in the ES products of the parasite. CsAEP was expressed in various developmental stages of C. sinensis, from metacercariae to adults, and was found to be localized in the intestine of the parasite as well as in intestinal contents. Sera from rats experimentally infected with C. sinensis reacted with CsAEP beginning 4 weeks after infection. These results suggest that CsAEP is a gut-associated enzyme synthesized in the intestine of C. sinensis and subsequently secreted into the intestinal lumen of the parasite.

Paramyosin of Clonorchis sinensis (CsPmy) is a myofibrillar protein localized in subtegumental muscle, tegument, and the muscle layer surrounding the intestine of the parasite. Previously, we have identified that CsPmy reacted with sera of human clonorchiasis and this protein had a potential as a candidate antigen for serodiagnosis of clonorchiasis. However, we also found that CsPmy is able to bind to human immunoglobulin G (IgG) in non-specific manners, which can affect the diagnostic value of the protein. Here, we mapped CsPmy-specific IgG binding site on CsPmy to analyze the putative epitopes recognized by CsPmy-specific IgG in sera of human clonorchiasis. The fragmental expression of CsPmy followed by immunoblot analyses with sera from patients with clonorchiasis and non-specific human IgG revealed that the middle portion of CsPmy (CsPmyC: 301-600 amino acid residues) had epitopes responsible for CsPmy-specific IgG recognition. The precise CsPmy-specific IgG binding site was further narrowed down to a fragment (CsPmyC-2), which harbors 151 amino acid residues (375-525) of CsPmy. Specific antibodies for CsPmyC-2 were produced in rats after two-weeks of post-experimental infection. The CsPmyC-2 showed low levels of cross reactivity against the sera from patients with other helminth parasites. Our results suggested that CsPmyC-2 has real epitopes recognized by CsPmy-specific IgG in sera of human clonorchiasis and the fragment can be useful as a reliable serodiagnostic antigen to develop a serodiagnostic method for clonorchiasis.

Aim Hepatocellular carcinoma (HCC), one of the most common malignancies in adults displays aberrant miRNA expression during its pathogenesis. We assessed expression of miRNA in surgically resected human HCC of an early stage and murine HCC with a high malignancy in order to find miRNA overexpressed in HCC regardless of tumor stage and underlying etiology. Further, the role of the deregulated miRNA in HCC pathogenesis was investigated. Methods miRNA were isolated from HCC tissues and surrounding non-tumorous tissues from HCC patients and a murine transgenic model of HCC. A quantitative reverse transcription polymerase chain reaction was performed to determine expression levels of miRNA. Human HCC cell lines stably expressing individual miRNA were generated to investigate the biological function of overexpressed miRNA. Results We found that levels of miR-221, -181b-1, -155-5p, -25 and -17-5p were significantly upregulated in both human and murine HCC regardless of tumor stage, underlying etiology or the presence of fibrosis. Using HCC cell lines stably expressing respective miRNA, we found that miR-221 increased the proliferation of hepatoma cells, while miR-17-5p induced cell migration. Conclusion We identified miRNA that are consistently upregulated in HCC. The overexpressed miRNA could potentially be used as a bona fide biomarker for HCC.

Methionine aminopeptidases (MetAPs), ubiquitous enzymes that play an important role in nascent protein maturation, have been recognized as attractive targets for the development of drugs against pathogenic protozoa including Plasmodium spp. Here, we characterized partial biochemical properties of a type I MetAP of Plasmodium vivax (PvMetAP1). PvMetAP1 had the typical amino acid residues essential for metal binding and substrate binding sites, which are well conserved in the type I MetAP family enzymes. Recombinant PvMetAP1 showed activity in a broad range of neutral pHs, with optimum activity at pH 7.5. PvMetAP1 was stable under neutral and alkaline pHs, but was relatively unstable under acidic conditions. PvMetAP1 activity was highly increased in the presence of Mn(2+), and was effectively inhibited by a metal chelator, EDTA. Fumagillin and aminopeptidase inhibitors, amastatin and bestatin, also showed an inhibitory effect on PvMetAP1. The enzyme had a highly specific hydrolytic activity for N-terminal methionine. These results collectively suggest that PvMetAP1 belongs to the family of type I MetAPs and may play a pivotal role for the maintenance of P. vivax physiology by mediating protein maturation and processing of the parasite.

Background & Aims Transforming growth factor beta (TGF-β) suppresses early stages of tumorigenesis, but also contributes to migration and metastasis of cancer cells. A large number of human tumors contain mutations that inactivate its receptors, or downstream proteins such as Smad transcription factors, indicating that the TGF-β signaling pathway prevents tumor growth. We investigated the effects of TGF-β inhibition on liver tumorigenesis in mice. Methods C57BL/6 mice received hydrodynamic tail-vein injections of transposons encoding HRAS G12V and a short hairpin RNA (shRNA) to down-regulate p53, or those encoding HRAS G12V and MYC, or those encoding HRAS G12V and TAZ S89A , to induce liver tumor formation; mice were also given injections of transposons encoding SMAD7 or shRNA against SMAD2, SMAD3, SMAD4, or SNAI1 (Snail), with or without ectopic expression of Snail. Survival times were compared, and livers were weighted and examined for tumors. Liver tumor tissues were analyzed by quantitative reverse-transcription PCR, RNA sequencing, immunoblots, and immunohistochemistry. We analyzed gene expression levels in human hepatocellular carcinoma samples deposited in The Cancer Genome Atlas. A cell proliferation assay was performed using human liver cancer cell lines (HepG2 and Huh7) stably expressing Snail or shRNA against Snail. Results TGF-β inhibition via overexpression of SMAD7 (or knockdown of SMAD2, SMAD3, or SMAD4) consistently reduced formation and growth of liver tumors in mice that expressed activated RAS plus shRNA against p53, or in mice that expressed activated RAS and TAZ. TGF-β signaling activated transcription of the Snail gene in liver tumors induced by HRAS G12V and shRNA against p53, and by activated RAS and TAZ. Knockdown of Snail reduced liver tumor formation in both tumor models. Ectopic expression of Snail restored liver tumorigenesis suppressed by disruption of TGF-β signaling. In human hepatocellular carcinoma, Snail expression correlated with TGF-β activation. Ectopic expression of Snail increased cellular proliferation, whereas Snail knockdown led to reduced proliferation in human hepatocellular carcinoma cells. Conclusions In analyses of transgenic mice, we found TGF-β signaling to be required for formation of liver tumors upon expression of activated RAS and shRNA down-regulating p53, and upon expression of activated RAS and TAZ. Snail is the TGF-β target that is required for hepatic tumorigenesis in these models.

Massive multiple-input multiple-output (MIMO) systems are a core technology designed to achieve the performance objectives defined for 5G wireless communications. They achieve high spectral efficiency, reliability, and diversity gain. However, the many radio frequency chains required in base stations equipped with a high number of transmit antennas imply high hardware costs and computational complexity. Therefore, in this paper, we investigate the use of a transmit-antenna selection scheme, with which the number of required radio frequency chains in the base station can be reduced. This paper proposes two efficient transmit-antenna selection (TAS) schemes designed to consider a trade-off between performance and computational complexity in massive MIMO systems. The spectral efficiency and computational complexity of the proposed schemes are analyzed and compared with existing TAS schemes, showing that the proposed algorithms increase the TAS performance and can be used in practical systems. Additionally, the obtained results enable a better understanding of how TAS affects massive MIMO systems.

The broadcasting of the analog TV was terminated in 2012 and was converted into the broadcasting of the digital TV, so methods for arrival of DAB(Digital Audio Broadcasting) are planned recently. Thus, with digitization of analog broadcasting and appearance of new service, it takes effort to improve efficiency of broadcasting frequency. T-DMB which came in 2005 uses existing analog TV band and its channel is allocated inefficiently in order to avoid interference between mutual services. However, the foundation which can afresh reorganize T-DMB channel is building up because the broadcasting of the analog TV was terminated. So, this paper proposes the method for national SFN composition of T-DMB considering existing local broadcasting in order to provide better service to users as well as improve efficiency of broadcasting frequency. Key Words : DAB, T-DMB, National SFN, Broadcasting frequency Ⅰ. 서 론 우리나라는 2001년 수도권에서 지상파 디지털 TV 방송을 시작하여 2012년 12월 31일 지상파 아날로그 방송이 완전히 종료되었고, 현재는 완전한 디지털 TV방송으로 전환이 되었다. 또한 2006년부터 논의돼 오던 디지털 라디오의 도입을 위해 최근 미래창조과학부와 방송통신위원회가 공동 연구반을 발족하여 2014년 기본 계획을 수립하기로 하는 등 방송통신 환경이 재편성되고 있다. 이렇게 다양한 매체를 통한 디지털 방송 서비스가 점차 증가되고 있어, 이에 따른 방송 주파수의 효율적 사용에 대한 필요성이 크게 증가하고 있다.이에 따라 아날로그 TV 채널 7～13번(174～215MHz)에 배정되어 2005년 본방송을 시작한 T-DMB의 채널 을

CsCF-6 is a member of the multigene family of cathepsin F cysteine proteases of Clonorchis sinensis . Similar to other papain family proteases, CsCF-6 is synthesized as a proenzyme and is converted to the mature form by autocatalytic removal of the prodomain. Here, we analyzed the regulatory and inhibitory elements within the CsCF-6 prodomain to understand the regulatory mechanism of CsCF-6 by its prodomain. The CsCF-6 prodomain played an essential role in the folding of CsCF-6. Particularly, the ERFNAQ motif within the prodomain was essential, and the minimum segment required for this event was the C-terminal part of the prodomain, including Asn 58 and downstream residues. The CsCF-6 prodomain effectively inhibited CsCF-6, in which the ERFNAQ motif played a critical role in the inhibition, but the GTFD motif was also required for complete inhibition of CsCF-6. The CsCF-6 prodomain showed broad inhibitory activity against several cysteine proteases. These results suggest that the CsCF-6 prodomain plays bi-functional roles in correct folding and inhibition of its cognate enzyme.

Short life span of MPC mice. Description of Data: Survival graphs. (PDF 209 kb)

Histological analysis of livers harvested at 15 days post hydrodynamic transfection with transposons encoding cMyc and shp53. Description of Data: H&E and IHC images. (PDF 220 kb)

Leucine aminopeptidases (LAP; EC 3.4.11.1) are a group of metalloexopeptidases, which catalyze the sequential removal of leucine amino acids from the N-termini of the polypeptides or proteins. In this study, we identified two novel genes that encode LAPs of Clonorchis sinensis (CsLAP1 and CsLAP2) and characterized their biochemical and functional properties. Multiple sequence alignment of the deduced amino acid sequences of CsLAP1 and CsLAP2 with those of other organisms revealed that typical metal-binding coordinating and active site residues for LAPs were well conserved in CsLAP1 and CsLAP2. Recombinant CsLAP1 and CsLAP2 showed similar biochemical properties such as pH optima at pH 8.0 and stability at neutral pHs. Both enzymes were specifically inhibited by bestatin and showed preferential substrate specificity for Leu-MCA. However, the enzymes differed in that they required different metal ions for maximum activity. Expressions of CsLAP1 and CsLAP2 were detected throughout the various developmental stages of C. sinensis, and their transcription levels increased gradually in accordance with the maturation of the parasite. Both enzymes were identified in soluble worm extract of C. sinensis, but not in excretory and secretory products. Immunolocalization studies showed that both enzymes were co-localized to the intestinal epithelial cells and gastrodermis of the parasite. These results collectively suggest that CsLAP1 and CsLAP2 are synthesized in the intestinal epithelial and gastrodermal cells of C. sinensis and may be involved in the final digestion of peptides that hydrolyzed within intestinal lumen followed by absorbed into gastrodermal cells of the parasite.

SUMMARYLeucine aminopeptidases (LAPs) are a group of metalloexopeptidases that catalyse the sequential removal of amino acids from the N-termini of polypeptides or proteins. They play an important role in regulating the balance between catabolism and anabolism in living cells. LAPs of apicomplexa parasitic protozoa have been intensively investigated due to their crucial roles in parasite biology as well as their potentials as drug targets. In this study, we identified an M17 leucine aminopeptidase of Cryptosporidium parvum (CpLAP) and characterized the biochemical properties of the recombinant protein. Multiple sequence alignment of the deduced amino acid sequence of CpLAP with those of other organisms revealed that typical amino acid residues essential for metal binding and active-site formation in M17 LAPs were well conserved in CpLAP. Recombinant CpLAP shared similar biochemical properties such as optimal pH, stability at neutral pHs, and metal-binding characteristics with other characterized LAPs. The enzyme showed a marked preference for Leu and its activity was effectively inhibited by bestatin. These results collectively suggest that CpLAP is a typical member of the M17 LAP family and may play an important role in free amino acid regulation in the parasite.