ACETALDEHYDE EXPOSURE CAUSES GROWTH-INHIBITION IN A CHINESE-HAMSTER OVARY CELL-LINE THAT EXPRESSES ALCOHOL-DEHYDROGENASE

Chronic ethanol exposure causes many pathophysiological changes in cel lular function due to ethanol itself and/or the effects of its metabol ism (i.e., generation of acetaldehyde and redox equivalents). However, the role of each of these effects remains controversial. To address t hese questions, we have developed a cell line that expresses alcohol d ehydrogenase. This cell line permits separate examination of the effec ts of ethanol and its metabolite acetaldehyde on cell function. An exp ression vector for the mouse liver alcohol dehydrogenase was construct ed and transfected into Chinese hamster ovary cells. Cells expressing alcohol dehydrogenase were identified by screening with allyl alcohol, which is metabolized by alcohol dehydrogenase to the toxic aldehyde a crolein. A number of cell lines were identified that expressed alcohol dehydrogenase. A-10 cells were selected for further study because of their high sensitivity to allyl alcohol, suggesting a high level of al cohol dehydrogenase expression. These cells expressed a mRNA that hybr idizes with the alcohol dehydrogenase cDNA and had an alcohol dehydrog enase activity comparable to murine liver. When cultures of these cell s were exposed to ethanol, acetaldehyde was detected in both the mediu m and cells. The acetaldehyde concentration in the medium remained con stant for at least 1 week in culture and was a function of the added e thanol concentration. Chronic exposure of A-10 cells to ethanol result ed in a dose-dependent reduction in the number of cells that accumulat ed over 7 days. Ethanol-treated cells remained viable, and growth inhi bition was reversible. Growth inhibition was blocked by the alcohol de hydrogenase inhibitor 4-methylpyrazole, suggesting that acetaldehyde a nd not ethanol was responsible for growth inhibition in these cells.