LOSS OF NEOPLASTIC PROPERTIES IN VITRO. I. OBSERVATIONS WITH S-180 CELL LINES.

Abstract

Summary Cell lines isolated from a subline of Sarcoma 180 maintained in CFW mice lost their original capacity to produce tumors in the mouse strain of origin and the cheek pouch of the Syrian hamster sometime between the 26th and 85th in vitro passage, or between 230 and 824 days following isolation. These cell lines were characterized by their capacity to grow in Eagle9s basal medium in the absence of l-tryptophan, their requirement being satisfied by the l-tryptophan provided by the dialyzed serum supplement. More recently isolated cell lines derived from the same mouse-maintained subline of Sarcoma 180 which were capable of producing tumors in the mouse strain of origin and in the cheek pouch of the Syrian hamster also were capable of growth in the absence of l-tryptophan other than that provided by the dialyzed serum supplement. Unlike those derived from Sarcoma 180, cell lines similarly derived from normal tissues of CFW mice required the usual concentration of added l-tryptophan in addition to that provided by the dialyzed serum supplement for maximum growth. The unusual l-tryptophan requirement of these cell lines does not appear to be related to their ability or inability to produce tumors upon transplantation in mice or Syrian hamsters but serves as a “marker” indicating the probable identity of the original cell line which is no longer capable of producing tumors, and the more recently isolated, tumor-producing cell lines of Sarcoma 180. Concurrent with the loss of capacity to produce tumors when transplanted to animals, the original cell line also exhibited alterations in certain cytochemical parameters. The events underlying these changes in biological and cytochemical characteristics are not evident from the present experiments.