Actinomycin-D-resistant in vitro mouse cell line derived from a methylcholanthrene-induced sarcoma: Decrease of malignancy and antigenic characteristics
✍ Scribed by J. Belehradek Jr.; J. L. Biedler; M. Thonier; G. Barski
- Publisher
- John Wiley and Sons
- Year
- 1974
- Tongue
- French
- Weight
- 761 KB
- Volume
- 14
- Category
- Article
- ISSN
- 0020-7136
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✦ Synopsis
Abstract
The tumorigenic EPO clonal cell line, derived from a methylcholanthrene‐induced murine sarcoma, was exposed to increasing concentrations of actinomycin D and gave rise to a subline, resistant to 0.02 μg of actinomycin D per ml of medium, which was designated EPO/ADj. Drug resistance was accompanied by a striking decrease of tumorigenic capacity as determined by the tumor take incidence and tumor growth rate in syngeneic C57BL/6 mice (normal and X‐irradiated), as well as by tumor take incidence in the cheek pouch of cortisone‐treated weanling Syrian hamsters. One of the tumors obtained after inoculation of EPO/ADj cells into syngeneic mice was reexplanted in culture and developed as the EPO/ADj/T subline. It was found to be relatively resistant to actinomycin D as compared to the parental EPO cells. The morphology of cells changed with actinomycin‐D‐resistance: EPO/ADj cells were more spread and flattened and less overlapping than the original fibroblast‐like EPO cells. EPO/ADj/T cells, however, had an aspect similar to that of EPO cells. No major differences were seen between the karyotypes of EPO, EPO/ADj and EPO/ADj/T cells. Tumor‐specific antigen(s), characteristic of the drug‐sensitive, parental EPO line, was expressed in the resistant EPO/ADj and EPO/ADj/T lines, as shown by: (a) transplantation resistance to challenge with EPO cells in syngeneic mice pretreated with EPO/ADj cells; and (b) cross‐reactivity in indirect immunofluorescence tests performed with sera from syngeneic animals hyperimmunized with EPO or EPO/ADj cells. Furthermore, an additional surface antigen (s), absent from EPO cells, was demonstrated in EPO/ADj and EPO/ADj/T cells by means of immunofluorescence tests performed with specific anti‐EPO/ADj syngeneic sera previously absorbed on EPO or EPO/ADj cells.