A cautionary note on the use of stable transformed cells

Gene transfection and ectopic expression is a widely used method in experimental biology. In the present report, we would like to point out that this approach may, in certain circumstances, lead to a modification of the transfected cell phenotype. Indeed, we observed that after transfection of bcl-2 gene in the neuronal PC12 cell line some of the selected clones have lost their neuronal and catecholaminergic characteristics, i.e. TH expression and ability to grow neurites in response to NGF. Thus, the resistance of some PC12-Bcl-2 clones against neurotoxic insults may not necessarily reflect the potential benefit afforded by Bcl-2 expression. We therefore encouraged authors to verify cell phenotype after stable transfection to avoid misinterpretation of their results.