This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Recent studies indicate that various selenium compounds show considerable chemopreventative anticarcinogenic effects in both humans and laboratory animals. However, the efficacy of different species varies significantly, with inorganic selenium being less effective than organoselenium compounds, whose properties in turn are affected by whether or not they become involved in the selenoprotein assimilatory pathway. Monomethylated species are proposed as the active agents, with the unstable methylselenol the most likely suspect. Methylselenol is suggested to be produced endogenously from either Se-methylselenocysteine or methylseleninic acid via different mechanisms. Elucidation of the chemopreventative mechanism of Se compounds is exceedingly valuable and is a problem eminently suited to study with XAS. In an attempt at proving what has been proposed by Ip et. al, we propose the treatment of several different cell lines (including Chinese hamster V79 lung cancer and human A549 lung cells) with a range of concentrations of selenate, selenite, selenomethionine, Se-methylselenocysteine and methylseleninic acid (all readily available except the last which is easily synthesised) to determine a) the uptake properties of the different species into the cells, and b) biotransformations and metabolic products of the compounds.
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