11:10-12:00, Rm 103

Chemical biology and drug discoveryD-17-49A new synthetic small molecule exhibits anti-angiogenic effects bytargeting ROS-mediated pathwayKi Hyun Kim, Boram Lee, Hye Jin Jung and Ho Jeong KwonChemical Genomics National Research Laboratory, Department of Biotechnology, TranslationalResearch Center for Protein Function Control, College of Life Science & Biotechnology, YonseiUniversity, Seoul 120-749, KoreaMitochondrial reactive oxygen species (ROS) in the hypoxic cells regulate manyangiogenesis-related diseases. We selected 200 compounds from the 1000 wellcharacterizedfocused chemical library in a structure-based screen targeting mitochondriaComplex III which is a major site of ROS generation. The 200 compounds were subjectedto western blot assay that affected the HIF-1αprotein expression. HIF-1αplays a key rolein the adaptation of tumor cells to hypoxia by activating the transcription of genes. As theresult, G0811 was identified as the most potent inhibitor of HIF-1αexpression. G0811 didnot exhibit the anti-proliferation activities and toxicity on HUVECs. However, G0811inhibited in vitro angiogenesis, such as tube formation and chemoinvasion. In addition,G0811 effectively decreased DCF fluorescence intensity, demonstrating that thecompound decreases ROS levels in the cells. Moreover, stabilization of HIF-1αinducedby ROS under hypoxia condition was also blocked by treatment of the compound in adose-dependent manner and it reduced the HIF-1αhalf-life. G0811 also suppressed theexpression of VEGF, the target gene of HIF-1α. These results demonstrated that G0811could be the potent angiogenesis inhibitor by targeting ROS-mediated pathway in thecells.D-17-52Antibiotic and synergistic effect of AMPs against MDRS isolated frompatientsJin-soon Park¹, Byoung Kwan Son², Joon Soo Hahm³, Yoonkyung Park1¹andKyung-Soo Hahm¹ , ⁴¹Research Center for Proteineous Materials (RCPM), Chosun University, Kwangju, Korea,²Department of Internal Medicine, Eulji General Hospital, Hagye 1-dong, Seoul, Korea, ³Departmentof Medicine, Hanyang University Hospital, Seoul, Korea, ⁴Department of Cellular∙MolecularMedicine School of Medicine, Chosun University, Kwangju, KoreaPseudomonas aeruginosa has developed resistance against flomoxef sodium,isepamicinand cefpiramide.In this study,the antibacterial activity and synergistic effects of theamphipathic-derived P5-18mer antimicrobial peptide were tested against pathogensassociated with cholelithiasis that have developed resistance against commonly usedantibiotics.The results were then compared with the activities of the amphipathic-derivedpeptide,P5-18mer,melittin and common antibiotics.Growth inhibition of planktonic bacteriawas tested using the NCCLS.Synergistic effects were evaluated by testing the effects ofP5-18mer alone and in combination with flomoxef sodium,isepamicin or cefpiramide at0.5 x MIC.P5-18mer peptide displayed strong activity against pathogens and flomoxefsodium, isepamicin and cefpiramide-resistant bacteria cell lines obtained from a patientwith gallstones;however,it did not exert cytotoxicity against the human keratinocyte HaCatcell line.Finally,the use of P5-18mer and antibiotics exerted synergistic effects against celllines that were resistant to commonly used antibiotics.These results indicate that thisclass of pepmay be used as a lead drug for the treatment of acquired pathogens frompatients with cholelithiasis who are affected with antibiotic-resistant bacteria.D-17-50Cell specificity and mechanism of action of novel short AMPsKyung Im Park¹, Chul Ho Jang³, Kyung-Soo Hahm¹ , ²and Yoonkyung Park¹¹Research Center for Proteineous Materials, Chosun University, Gwangju 501-759, Korea,²Department of Cellular & Molecular Medicine, School of Medicine, Chosun University, Gwangju501-759, Korea, ³Department of Otolaryngology, Chonnam National University Medical School,Kwangju, KoreaIn previous study, we reported that the N- (residues 2-3) and C-terminal (residues 17-20)truncated fragments [HP (4-16)] induce increased antibiotic activity against severalbacterial strains without hemolysis from HP (2-20) [derived from the N-terminal region ofHelicobacter pylori Ribosomal Protein L1 (RPL1)]. In this study, to develop novel shortantibiotic peptide useful as therapeutic drug the analogue was designed to increasehydrophobicity by Trp-substitution in position 2 region (HP (4-16)-W) from HP (4-16). HP(4-16)-W showed an enhanced antimicrobial and antitumor activity. The antimicrobialactivity of the peptides was measured by their growth inhibitory effect upon S. aureus, B.subtilis, S. epidermidis, E. coli, S. typimurium, P. aeruginosa, C. albicans, T. beigelii andS. cerevisiae. None of the peptides exhibited hemolytic activity against human erythrocytecells except melittin as a positive control. Its antibiotic activity suggests that HP (4-16)-Wis an excellent candidate as a lead compound for the development of novel antibioticagents.D-17-53Bacterial cell selectivity and biofilm reduction of AMP on clinicalisolates of P. aeruginosaJong-Kook Lee¹, Chul Ho Jang³, Yoonkyung Park¹, Kyung-Soo Hahm¹ , ²¹Research Center for Proteineous Materials (RCPM) and ²Department of Cellular∙MolecularMedicine School of Medicine, Chosun University, ³Department of Otolaryngology, ChonnamNational University Medical School, Kwangju, KoreaBiofilms are microbial communities attached to solid surfaces and enclosed in a selfproducedpolymeric matrix.Resistance to conventional antibacterial agents is a keyfeature of biofilm infections, which highlights the necessity for the development of novelcompounds able to effectively control them. Accordingly,antimicrobial peptides representa promising class of molecules with which to combat these pathogens,and among thoseis the analogue peptide P5, which was designed and synthesized from a hybridpeptide,CA-MA [derived from cecropin A (1-8) and magainin 2 (1-12)].All of the strainswere found to be resistant to the tested compounds.Nonetheless,P5 inhibited theformation of biofilms at very low concentrations and also showed positive synergy whenapplied at its MBIC50 concentration in combination with vancomycin.P5 also inhibitedproduction of such extracellular matrix components as exopolysaccharides, proteins andnucleic acids,as evidenced by epifluorescence microscopic and spectrofluorometricanalyses.The results obtained using this multiparametric approach suggest that P5 couldpotentially be useused as an agent for the prevention of biofilm formation by drugresistantstrains.D-17-51Antibiotic activity of synthetic D-form AMPs against MDRS clinicalisolatesYoonjin Kim¹, Yoonkyung Park¹, Kyung-Soo Hahm¹ , ²¹Research Center for Proteineous Materials (RCPM), Chosun University, Korea ²Department ofCellular Molecular Medicine, School of Medicine, Chosun University, KoreaIncreasing resistance of pathogenic bacteria to antibiotics is a serious problem in healthcare system and has intensified the search for potent novel drugs. Cationic antibacterialpeptides are the most abundant antibiotics in nature and have been frequently proposedas new anti-infective agents. In this study, a set of diastereomeric peptides is researchedabout their antibiotic activity against multiple drug resistant clinical isolates and theirmodes of action against Gram-positive cocci. MIC was suggested by the NCCLS againstten clinically isolated antibiotic-resistant strains. Mode of action studies included killingkinetics and a series of experiments designed to characterize the impact of thediastereomeric peptides on bacterial membranes. The antimicrobial activity ofdiastereomeric P5-18mer was two times stronger against Gram-negative bacteria thaneither CA-MA-20mer or P5-18mer. When tested against ten clinically isolated antibioticresistantstrains in the presence of 0, 150 or 300 mM NaCl, diastereomeric-P5-18merretained strong activity against all bacteria, yet showed little or no cytotoxicity against theHaCaT human keratinocyte cell line. Finally, D-P5-18mer showed resistance againsttrypsin digestion unlike other analogues.D-17-54Antimicrobial activity and mechanism of a substituted AMPsRamamourthy Gopal¹, Kyung-Soo Hahm¹ , ², Yoonkyung Park¹¹Research Center for Proteineous Materials (RCPM) and ²Department of Cellular∙MolecularMedicine School of Medicine, Chosun University, Kwangju, KoreaAlthough we reported that HPA3NT3, an analogue peptide derived from HP(2-20)(peptide with residues 2-20 of Helicobacter pylori Ribosomal protein L1),was a potentantimicrobial peptide (Biochim. Biophys. Acta, 2008, 1778(1), 229-41), its cytotoxicacitivity at high concentration was considered when it was applied in vivo as anantimicrobial drug. Hence, phenylalanine( 1 and 8 position ) and asparagines (13position) residues of HPA3NT3 peptide were substituted to reduce cytotoxicity by alanineand to enhance antimicrobial actitvity by lysine, respectively, and named to HPA3NT3-A2. Interestingly, HPA3NT3 peptide exerted a potent antimicrobial activity as it forms porein cytoplasmic membrane, while HPA3NT3-A2 peptide bound to nucleic acids andinhibited protein synthesis through penetration into cytoplasm. In addition, HPA3NT3-A2D, which all lysine residues by D-enantiomer, was resistant to proteolytic cleavage inhuman serum and its antibacterial activity was enhanced in physiological conditions, suchas saline, magnesium and calcium, etc.226 Korean Society for Biochemistry and Molecular Biology