We previously reported that exposure of HeLa cells to selenite for 2 hours results in a decrease in their ability to attach to fibronectin [Yan & Frenkel, Cancer Res. 52:5803-5807(1992)]. We have now found that after exposure to selenite there was a decrease in the cellular content of the fibronectin receptor protein (α5β1 integrin), as well as in the level of the mRNAs for both of the subunits. Exposure of cells to Actinomycin D (an inhibitor of RNA synthesis) also resulted in a decrease in the level of these mRNAs, as well as in the ability of cells to attach to fibronectin. These effects of both selenite and Actinomycin 1) occurred only when high density cells were exposed to the agents. These results have suggested the following scheme for the mechanism of the inhibition of cell attachment by selenite: After exposure to selenite for 2 hours there is a significant inhibition of cellular RNA synthesis which results in a general decrease in the cellular level of those mRNAs with relatively short half-lives, including in particular, those of the fibronectin receptor. This leads to a decrease in the intracellular level of the receptor protein, and consequently in its level at the cell surface, which in turn causes a decrease in the rate of cell attachment to fibronectin.
|Original language||English (US)|
|State||Published - 1997|
All Science Journal Classification (ASJC) codes
- Molecular Biology