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Show THE UNIVERSITY OF UTAH UNDERGRADUATE RESEARCH ABSTRACTS A Cell Based Screening Assay for Identifying Inhibitors of Eosinophil Proliferation Jessica J. K. Dustin (Lori A. Wagner) Department of Dermatology University of Utah Eosinophils are white blood cells which contribute to the pathology of asthma. Lidocaine inhibits inter-leukin-5 (IL-5) mediated survival and activation of human eosinophils and is a useful therapy for chronic asthma; however, lidocaine has many undesired side effects. One of the main goals of this research was to enhance the specificity and overcome the undesired effects of lidocaine. Consequently, a diversity of compounds included commercially available lidocaine analogs and some synthesized compounds designed by modification of lidocaine structure was investigated for inhibitory activity on the proliferation of TF-1 cells, an erythroleukemic cell line model for eosinophil development. TF-1 cell proliferation assays were performed at various concentrations of lidocaine and the investigated compounds to determine their values at which fifty percent growth inhibition was observed (IC-50). Among 75 investigated compounds 25 revealed more potent cell growth inhibitory activity with IC-50 ranging from 1-136 uM compared to lidocaine (IC-50 144 uM).The lowest IL-5 IC-50 values were: 4-Amino-N-pyridin-3-yl-methyl-benzamide (1 uM), N-(2,4-difluorophenyl)-2-(4-pyrimidin-2-ylpiperazinyl) ethanamide (5uM), Boc-4-aminohippuric Acid (19uM), 9,10-difluoro-2,3-dihydro-3-methyl-7-OXO-7H-pyrido[1,2,3-DE]-1,4-benzoxazine-6-carboxylic acid (20uM), 7-Bromo-4-methyl-3,4-dihydro-2H-1,4-benzoxazine (24uM), and N-(2,6-dimethylphenyl)quinoline-4-carbox-amide (24uM). Therefore, several investigated compounds were more potent than lidocaine at inhibiting cell growth. The investigated compounds were also tested on cells grown in epoietin- (EPO). IC-50 values that are higher on cells grown in IL-5 compared to EPO suggests drug specificity for inhibiting IL-5 mediated proliferation. N-(2,6-dimethylphenyl)hexanamide, 3,4-ethyledioxyaniline, 2-methyl-N-(3-pyridinyl-methyl)benzamide, and 4-Amino-N-pyridin-3-yl-methyl-benzamide revealed the highest specificity for IL-5 mediated cultures. Consequently, our cell based assay is an effective method for screening chemical compounds and has revealed potential chemicals for the treatment of asthma. Jessica J. K. Dust Lori A. Wagner |