Induction of selective DNA amplification and morphological cell transformation in Syrian hamster embryo cells.

DNA amplification is a frequently observed event in continuous cell lines and in tumors. It is likely that a common mechanism underlies the amplification of specific DNA sequences which confer drug resistance and genes which give a growth advantage to the tumor. To find a correlation between the induction of DNA amplification by chemicals and morphological cell transformation we treated Syrian hamster embryo (SHE) cells with diverse antineoplastic agents of different classes. Analysis of these agents seems to be important since they are potentially carcinogenic and resistance inducing. For the measurement of DNA amplification we established a new system using adeno-associated virus type 2 (AAV)-infected primary SHE cells as target cells and amplification of viral DNA as marker of DNA amplification. Simultaneously we determined morphological cell transformation in SHE cells. Our findings demonstrate that there is only a limited correlation between the induction of AAV DNA amplification and the morphological cell transformation in SHE cells. The newly established system of AAV DNA amplification appears to be a useful tool for the investigation of drug resistance in target cells of choice.