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EXAMINATION OF CULTURE CONDITIONS ON ESTERASE ACTIVITIES IN HUMAN AND MOUSE NEUROBLASTOMA CELLS
Citation:
Ehrich, M., K. Correll, K. Carlson, J. Wilcke, AND B. Veronesi. EXAMINATION OF CULTURE CONDITIONS ON ESTERASE ACTIVITIES IN HUMAN AND MOUSE NEUROBLASTOMA CELLS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-95/543.
Description:
Because neuroblastoma cell lines have potential to be used as in vitro alternatives for screening of antiesterase compounds (e.g., organophosphates (OPs) and carbamates), information is needed on conditions under which the cells are grown as these conditions may contribute to expression and inhibition of esterase enzymes. n addition, the use of cell lines as in vitro alternatives offers the possibility of testing in the major species of interest (the human), but, since most in vivo testing is done in animal models, especially rodents, comparison of cell lines from human and rodent sources is warranted. he present study examines several parameters and their effect on target esterase expression in human (SH-SY5Y) and murine (NB4lA3) neuroblastma cells. hese conditions include nutrient media, forzoen storage, and differentiation. he investigations indicated that both human and rodent cell lines express true acetylcholinesterase (AChE) activities because a specific inhibitor (BW antiChE) caused 90% inhibition of AChE activity while pseudocholinesterase inhibitor tetraisopropyl-pyrophosphoamide (isoOMPA) caused no esterase inhibition. oth human and mouse cells also express neuropathy target esterase activity (neurotoxic esterase, NTE), whose inhibition is associated with organophosphorus-induced delayed neuropathy (OPIDN). he medium in which the cells were grown could affect the activities of ACHE, although effects on NTE or carboxylesterase (CbxE, one enzyme that inactivates antiesterase compounds), were in both human and rodent cell lines. he growth medium in which human and neuroblastoma cells demonstrated the higher basal ACHE activities were different (F12 with 15% fetal bovine serum for human SH-SY5Y cells; minimal essential medium (MEM) with 10% fetal bovine serum for mouse NB41A3 cells). Ps that inhibited ACHE (e.g., DFP, paraoxon, mipafox) did so, however, in cells grown in either medium. CHE activity in human neuroblastoma cells, grown in F12 medium, was more sensitive to loss in frozen storage than were activities of NTE or CbxE. lthough nerve growth factor (NGF) or retinoic acid can be used for morphological differentiation of neuroblastoma cells, this differentiation had little effect on the baseline activities of ACHE, NTE, and CbxE, and the relative inhibition of these esterases in the presence of OPs (DFP, paraoxon, parathion, and mipafox).