11:10-12:00, Rm 103

Cell: signal transductionL-18-14Calcium-sensing receptor regulates cell surface expression of Kir4.1channel via Gaq- and caveolin-1-dependent mechanismSeung-Kuy Cha¹ , ², Chunfa Huang³, Yaxian Ding³, Xiaoping Qi³, Ji-hee Kim¹,Chou-Long Huang²and R. Tyler Miller³ , ⁴ ,¹Department of Physiology, Yonsei University Wonju College of Medicine, Wonju, Gangwon-do220-701, Korea, ²Department of Medicine, University of Texas Southwestern Medical Center,Dallas, Texas 75390, ³Departments of Medicine and ⁴Physiology and Biophysics, Case WesternReserve University, Cleveland, Ohio 44160, USA, the Louis Stokes Veteran Affairs MedicalCenter, Cleveland, Ohio 44106The calcium-sensing receptor (CaR) regulates ion transport in the kidney. Gain-offunctionmutation of CaR shows a salt-wasting phenotype, but the precise mechanism isnot fully understood. The CaR interacts with and inhibits an inwardly rectifying K+channel, Kir4.1, which contributes to the basolateral K+ conductance. Loss-of-functionmutations are associated with a complex phenotype that includes renal salt wasting.Mutant CaRs reduced Kir4.1 cell surface expression and current density in HEK-293cells. Mutant, activated Gαq reduced cell surface expression and current density of Kir4.1,and these effects were blocked by RGS4, a protein that blocks signaling via Gαi and Gαq.Other αsubunits had less effect. Knockdown of caveolin-1 blocked the effect of Gαq onKir4.1, whereas knockdown of the clathrin heavy chain had no effect. CaR had nocomparable effect on other renal K+ channel, the ROMK channel that is internalized byclathrin-coated vesicles. The CaR and Kir4.1 physically associate with caveolin-1 inHEK293 cells and in kidney extracts. Thus, the CaR decreases cell surface expression ofKir4.1 channels via a mechanism that involves Gαq and caveolin. These results provide anovel molecular basis for the inhibition of renal NaCl transport by the CaR.L-18-15Roles of AMP-activated protein kinase in activation of BDNF/TrkB axisand migration and invasion of cancer cellsHana Yoon, Keun-Young Hwang and Insug KangDepartment of Biochemistry and Molecular Biology, School of Medicine, Kyung Hee University,Seoul 130-701, KoreaNeurotrophin BDNF is a key signaling molecule in the development of the nervoussystem. BDNF and its receptor TrkB are often overexpressed in a variety of humancancers, in which these are involved in tumor expansion and resistance to anti-tumoragents. AMP-activated protein kinase (AMPK) is a key regulator of energy homeostasis.In the present study, we examined the roles of AMPK in BDNF/TrkB axis in cervicalcancer cells as well as other carcinoma cells, including ovarian and neuroblastoma cells.We found that BDNF/TrkB mRNA and protein was overexpressed in cervical cancertissues as well as cell lines. TrkB expression was also overexpressed in ovarian andneuroblastoma cells. We then found that specific inhibitors of TrkB, AMPK, and CaMKKsignificantly inhibited the expression of BDNF and TrkB In cervical cancer cell lines.These suggest that AMPK regulates BDNF/TrkB axis by transcriptional activation.Moreover, AMPK was activated in cultured cervical carcinoma cells and inhibition of TrkBblocked AMPK activation. Finally, we found that inhibition of AMPK and TrkB bypharmacological inhibitors or siRNA transfection reduced migration and invasion ofcervical carcinma cells. Taken together, these results suggest that AMPK play roles inBDNF/TrkB axis and tumor expansion.L-18-17Human lactoferrin reduces atherosclerosis in apolipoprotein E-deficientmice via inhibition of intercellular adhesion molecules gene expressionTae Hoon Lee¹, Chan Woo Kim¹, Keun Hyung Park¹, Sang-Yun Choi²and JiyoungKim¹ , *¹College of Life Science and Graduate School of Biotechnology, Kyung Hee University, Yongin446-701, Korea and ²Division of Life Sciences, Graduate School of Biotechnology, KoreaUniversity, Seoul 136-701, KoreaLactoferrin (Lf) is a glycoprotein which exerts a number of biological responses such asprimary defense against microbial infection, activation of NK cells, and lymphokineactivatedkiller cell activity. Lf is known to be internalized, translocated into the nucleus,and to modulate expression of certain genes via binding to DNA. Little information isavailable on naturally occurring target genes that directly interact with Lf. We found thathuman Lf inhibited expression of Intercellular Adhesion Molecule-1 (ICAM-1) andVascular cell adhesion molecule 1 (VCAM-1) in TNF-α-stimulated endothelial cells. Wedemonstrated that Lf inhibited monocyte adhesion to TNF-α-stimulated humanendothelial cells, associated with the inhibition of ICAM-1 and VCAM-1 expression. Wedemonstrated that Lf bound to ICAM-1 promoter region and inhibited binding of NF-κB toits proximal site in ICAM-1 promoter. Furthermore, administration of Lf in theapolipoprotein E (ApoE)-decicient mouse model inhibited plasma levels of inflammatorycytokines, and reduced sizes of atherosclerotic lesions and expression levels of aorticVCAM-1 and ICAM-1, with inhibiting atherosclersosis development. We suggest that Lfpossesses the anti-atherogenic effect at least partially via inhibition of ICAM-1 andVCAM-1 expression.L-18-18Curcumin suppresses TPA-induced MMP-9 expression by blocking theNF-κB and AP-1 activation via MAPK signaling pathways in MCF-7human breast carcinoma cellsEun-Mi Noh¹, Jeong-Mi Kim¹, Young-Rae Lee¹, Jin-Ki Hwang¹, Bo-mi Hwang¹,Hyun Zo Youn², Sung Ho Jung², Jong-Suk Kim¹¹Department of Biochemistry and Institute for Medical Sciences, ²Department of Dermatology,Chonbuk National University Medical School, Jeonju, Jeonbuk 560-182, KoreaCell migration and invasion are crucial in neoplastic metastasis. Matrix metalloproteinase-9 (MMP-9), which degrades the extracellular matrix, is a major component in cancer cellinvasion. Nuclear factor-kappaB (NF-κB) and activator protein-1 (AP-1) are majortranscription factors that have been associated with breast cancer metastasis by inducingMMP-9 expressions. In the present study, we investigated effects of curcumin on 12-Otetradecanoylpho-bol-13-acetate(TPA)-induced MMP-9 expression. We found thatcurcumin, a natural biologically active compound extracted from rhizomes of Curcumalonga, significantly inhibited the TPA-induced increase in MMP-9 expression and cellinvasion in MCF-7 cells. Curcumin suppressed activation of mitogen-activated proteinkinase (MAPK), NF-κB and AP-1. These results suggest that curcumin down-regulatesMMP-9 expression and tumor cell invasion through the suppression of MAPK/NF-κB/AP-1 pathway in MCF-7 cells.L-18-16The increase of intracellular Ca 2+ induces IRE1-α-dependent CREBphosphorylation through ERK activation in human glioma cellsHee Doo Lee, Bikash Thapa, Harim Jeon, Bon-Hun Koo, Yeon Hyang Kim, Doo-SikKimDepartment of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul120-749, KoreaIn this study, the function of Ca 2+ in endoplasmic reticulum (ER)-related cell death inhuman glioma cells was investigated. Treatment of human CRT-MG cells with S-nitroso-N-acetyl-D,L-penicillamine (SNAP), DETA and thapsigargin increased cytosolic Ca 2+ andcaused apoptosis in a dose-dependent manner, respectively. Expression of the ERassociatedmolecules inositol-requiring enzyme 1 (IRE1)-α, p-eIF, and Ero1-αwere alsoelevated in thapsigargin- or SNAP- treated cells. Furthermore, thapsigargin and SNAPtreatment increased IRE1-αnuclease activity, induced IRE1- α/TRAF2 complexformation, and increased p-JNK1/2 levels. The elevation of IRE1-αexpression and theformation of IRE1- α/TRAF2 complex in SNAP- or thapsigargin-treated cells wereinhibited by BAPTA, the Ca 2+ signal antagonist, suggesting that the elevation of Ca 2+ isnecessary for activation of IRE1-a. Thapsigargin and SNAP treatment increased p-ERK1/2 levels and the increase of p-ERK1/2 level was inhibited by U0126, MAPKinhibitor. siRNA knock down of IRE1-αreduced phospho-CREB levels and abolished itsnuclear translocation. Therefore, an IRE1-α-dependent phospho-CREB signalingpathway responsive to increase of intracellular Ca 2+ may play an important role inregulating ERK-mediated ER signals in glioma.L-18-19TM4SF5 is induced by a cross-talk between TGFβ1-activated Smads andEGFR signaling pathways during liver fibrosisMinkyung Kang¹and Jung Weon Lee²¹Departments of Biomedical Scienecs or ²Pharmacy, Seoul National University, Seoul 151-742,KoreaChronic inflammation causes an epithelial-mesenchymal transition (EMT) during liverfibrosis and cirrhosis consequently leading to development of hepatocellular carcinoma(HCC). Transmembrane 4 L6 family member 5 (TM4SF5) is highly expressed in HCCand induces the EMT, thus it may contribute to development of hepatic malignance. Herewe show that TGFβ1-mediated Smads activate the EGFR pathway, resulting in TM4SF5induction and EMT. Inhibition of Smad, EGFR, or TM4SF5 using Smad7 or smallcompounds blocked TM4SF5 expression, EMT, and liver fibrosis in vivo. TM4SF5transgenic mice showed this signaling correlation. These results suggest that duringchronic liver injuries TGFβ1- and growth factor-mediated TM4SF5 expression andthereby EMT of hepatocytes induces collagen I expression leading to liver malignancy.Thus TM4SF5 is a candidate target to prevent liver malignancies. (Supported by 2010-0001622, 2010-00150029, NRF-M1AXA002-2010-0029778, and A100727 to JW Lee)278 Korean Society for Biochemistry and Molecular Biology