11:10-12:00, Rm 103

Cancer biologyB-17-135Syndecan-2 regulates melanin synthesis via protein kinase CβIImediatedtyrosinase activationHyejung Jung¹, Heesung Chung¹, Jung Ran Choi¹, Sungeun Chang²and Eok-SooOh¹¹Department of Life Sciences, Division of Life and Pharmaceutical Sciences, Ewha WomansUniversity, Seoul 120-750, Korea ²Department of Dermatology, University of Ulsan College ofMedicine, Asan Medical Center, 388-1 Pungnap-2 dong, Songpa-gu, Seoul 138-736, KoreaSyndecan-2, a transmembrane heparan sulfate proteoglycan, highly expressed inmelanoma cells is known to regulate melanoma functions such as migration. Sincemelanoma is a malignant tumor of melanocytes of which major function is melaninsynthesis, we investigated further involvement of syndecan-2 in the process ofmelanogenesis. In two different mouse melanoma cell lines, syndecan-2 expressionlevels correlated with melanin contents. Silencing of syndecan-2 gene caused reductionof melanin synthesis, whereas the opposite effects were observed when syndecan-2 wasoverexpressed. In addition, melanin-inducing medications such as FK506 enhancedsyndecan-2 expression and immunohistochemical study showed that syndecan-2expression correlated with the melanin content of a hyperpigmented disease tissue.Interestingly, however, syndecan-2 expression did not affect on the expression oftyrosinase, a key enzyme of melanin synthesis. Instead, syndecan-2 expressionenhanced the enzymatic activity of tyrosinase. Furthermore, our results revealed thatsyndecan-2 interacted and increased membrane localization of PKCβII to regulatetyrosinase activity. Taken together, these data suggest that syndecan-2 regulate melaninsynthesis through tyrosinase activity regulated by protein kinase CβII.B-17-138Syndecan-2 cytoplasmic domain regulates migration through aninteraction with syntenin-1 in colon cancer cellsYeonhee Kim*, Hawon Lee*, Youngsil Choi, Sojoong Choi, Eunkyoung Hong andEok-Soo Oh Department of Life Sciences, Division of Life and Pharmaceutical Sciences and the Center for CellSignaling & Drug Discovery Research, Ewha Womans University, Seoul 120-750, KoreaThe cell surface heparan sulfate proteoglycan syndecan-2 is crucial for the tumorigenicactivity of colon caner cells. However, regulatory role of the cytoplasmic domain remainsunclear. In colon cancer cells transfected with various syndecan-2 cytoplasmic domaindeletion mutant showed that syndecan-2-induced migration activity resides in thesequence of EFYA at the C-terminal, and deletion of this sequence abolished bothincreased cell migration, and interaction with and membrane localization of syntenin-1,suggesting syntenin-1 as a cytosolic downstream signal-effector. Colon cancer cellstransfected with syntenin-1 showed increased migration, whereas cell migration wasdecreased in the syntenin-1 knock-down cells with small inhibitory RNA. In addition,syntenin-1 expression potentiated colon cancer cell migration induced by syndecan-2.However, syntenin-1-mediated potentiating of migration was not seen in colon cancercells transfected with syndecan-2 mutant lacking the cytoplasmic domain. Furthermore,correlated with increased cell migration, syntenin-1 mediated syndecan-2-mediated Racactivation. Taken together, these data suggest that syndecan-2 cytoplasmic domainregulates colon cancer cell migration through an interaction with syntenin-1.B-17-136Enhanced adenosine-mediated cytotoxicity in cancer cells withmethylated promoter CpG islands of ADASeong-Yeol Park¹, Hai-li Hwang¹, Hyun-Kyoung Kim¹, Yong-Bock Choi¹, Sei-HoonYang², Won-Cheol Park³, Yeong-Wook Song⁴, Kyeong-Man Hong¹¹Research Institute, National Cancer Center, Ilsandong-gu, Goyang-si 410-769, Korea,²Department of Internal Medicine and ³Department of General Surgery, Wonkwang University,College of Medicine, Iksan 570-749, Korea, ⁴Department of Internal Medicine, Seoul NationalUniversity College of Medicine, Yungon-dong, Chongro-gu, Seoul 110-744, KoreaAdenosine induces cytotoxic effect on cancer cells in the presence of adenosinedeaminase (ADA) inhibitors. The cytotoxic mechanism is mediated by intracellularmechanism not by extracellular adenosine receptor. Promoter CpG island (CGI)methylation of ADA was found in a lot of lung cancer cells/tissues that showed decreasedexpression of ADA protein. Our assumption is that the CGI methylation of ADA in cancercells might be a marker for adenosine sensitivity. In consistent with this, cancer cells withmethylated ADA promoter CGIs showed higher sensitivity to adenosine ordeoxyadenosine. When ADA was transfected to cell line with methylated ADA promoterCGIs, the sensitivity to adenosine decreased, suggesting the presence of ADA is theresistant mechanism. These findings indicates that a lot of cancer cells with methylatedADA promoter CGIs show higher sensitivity to adenosine and that the ADA promotermethylation might be a molecular marker for the treatment of cancer patients withadenosine or adenosine analogues.B-17-137Krüppel-like factor 4 activates the transcription of the gene for theplatelet isoform of phosphofructokinase in breast cancerJong-Seok Moon¹, Hee Eun Kim¹, Eun Jin Kho¹, Se Ho Park², Won-Ji Jin¹,Byeong-Woo Park², Sahng Wook Park¹and Kyung-Sup Kim¹¹Department of Biochemistry and Molecular Biology, Institute of Genetic Science, Center forChronic Metabolic Disease Research, Brain Korea 21 Project for Medical Science, YonseiUniversity, College of Medicine, Seodaemungu, Seoul, Korea, ²Department of Surgery, BrainKorea 21 Project for Medical Science, Yonsei University, College of Medicine, Seodaemungu, Seoul,KoreaKrüppel-like factor 4 (KLF4) is a transcription factor that plays an important role in celldifferentiation, proliferation, and survival, especially in the context of cancers. This studyrevealed that KLF4 plays an important role in activation of glycolytic metabolism by upregulatingthe platelet isoform of phosphofructokinase (PFKP) in breast cancer cells.KLF4 activated the transcription of the PFKP gene by directly binding to the PFKPpromoter. While glucose uptake and lactate production were inhibited by the knockdownof KLF4, they were activated by the overexpression of KLF4. Unlike PFKP, theexpressions of the other isoforms of phosphofructokinase and glycolytic genes wereunaffected by KLF4. The human breast cancer tissues showed a close correlationbetween KLF4 and PFKP expression. This study also showed that PFKP plays a criticalrole in cell proliferation in breast cancer cells. In conclusion, it is suggested that KLF4plays a role in maintenance of high glycolytic metabolism by transcriptional activation ofthe PFKP gene in breast cancer cells and contributes to cancer progression as a result.B-17-139Induction of MMP-9 in gastric epithelial cells by CagA protein of H.pylori.Hyun Jae Shim*, Young-Hee Nam*, Eunju Ryu , Doyeon Lee Yong Chan Lee andSeung-Taek Lee**Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University,Department of Internal Medicine, Brain Korea 21 Project for Medical Science, College ofMedicine, Yonsei University, and Division of Cell and Immunobiology, National Cancer Center,KoreaCagA injected into gastric epithelial cells by Helicobacter pylori contributes to pepticulcers and gastric adenocarcinoma. We have analyzed a role of the EPIYA motif withinCagA and CagA-dependent signaling pathways in the H. pylori-mediated MMP-9induction using a pair of isogenic cagA strains, 147C and 147A. We found that 147Cstrain expressing tyrosine-phosphorylated CagA (EPIYA present) induced larger amountof MMP-9 secretion in AGS cells than 147A strain expressing non-tyrosinephosphorylatedCagA (EPIYA absent). In addition, in CagA-inducible AGS cells,expression of wild type CagA containing EPIYA motifs induced greater MMP-9 secretionthan the phosphorylation-resistant CagA. Inhibition of CagA phosphorylation by a Srcfamily kinase inhibitor downregulated the CagA-mediated MMP-9 secretion. Knockdownof SHP-2 phosphatase severely hampered the MMP-9 secretion. ERK inhibitors and NFκBpathway inhibitors also inhibit the MMP-9 expression. These results suggest thatCagA containing EPIYA motif play a role in induction of MMP-9 secretion in gastricepithelial cells via its tyrosine phosphorylation by Src family kinases and then activation ofsignaling pathways mediated by SHP-2, ERKs, and NF-κB. [Supported from SUF, MCR,BK21 programs from NRF and a BR grant from YUCM]B-17-140Potassium channel as a molecular target for malignant cancerSookja Lee, Inkyoung Lee, Ji-Young Gu, Won Ki Kang and Chaehwa ParkBiomedical Research Institute, Samsung Medical Center, Sungkyunkwan University School ofMedicine, Seoul 135-710, KoreaNFkB regulates cell proliferation, apoptosis, inflammation and migration. NFkB has beenshown to be constitutively activated in many types of cancer cells includinghaematological malignancies and epithelial tumors. We present data demonstrating thatover-expression of a potassium channel NBSP leads to proliferation of cancer cells thatcorrelates with cell cycle modulation. NFkB was identified as a binding partner of NBSP ina yeast-two-hybrid screening system. NBSP modulates the intracellular location andtranscription factor function of NFkB, thereby increasing cyclin D1 expression. NBSP isover- expressed in malignant tissues when compared to normal counterparts and NBSPexpression increases with malignant progression. Knockdown of NBSP leads to cell cyclearrest and reduced tumorigenesis. Therefore, our data identify a previously unrecognizedinteraction between NBSP and NFkB, which is likely to contribute to the carcinogenesis.(Supported by grant from NRF 2008-313-E00058)190 Korean Society for Biochemistry and Molecular Biology