[Actinomycin D and 6-mercaptopurine-resistant Djungarian hamster cell line: karyotype, morphology, malignancy]

Djungarian hamster cell lines resistant to actinomycin D (AD) were developed from SV40 transformed HGPRT- cell, line DM-15. Increase in resistance to AD up to 4000 fold was obtained. The acquisition of resistance to AD did not influence the expression of the first mutation--HGPRT-. The cells retained resistance to 6-mercaptopurine and could not grow in HAT medium, as well as the parent cell line DM-15. The acquisition of resistance to AD resulted in production of cell cultures with a less malignant phenotype, than that of the parent cell line DM-15. So, the cells resistant to AD had lower tumorigenicity in vivo, the reduced ability to form colonies in soft agar and were less transformed, as shown by morphological criteria. The obtained cell lines with two genetic markers--resistance to 2 microgram/ml of AD and HGPRT- can be used in somatic cell genetics, especially, for somatic hybridisation, and also to study the role of the cell membrane in malignant transformation.