The present invention relates to a method for the generation of immortalized transduced cell lines susceptible to senescence whereby the senescence is exogenously inducible and said cells can switch severalfold between the senescent stage and the immortalized stage. In particular, the present invention relates to a method for the generation of immortalized transduced cell lines susceptible to senescence wherein two or more different immortalizing gene sequences have been incorporated whereby said immortalizing gene sequences are regulated by regulators controlled via exogenous means. In a further aspect, the present invention relates to immortalized transduced cell lines obtainable with said method. In addition, methods for screening molecules influencing senescence of cells are provided as well as kits for conducting the same.
