Selection for experimental metastatic ability of heterologous tumor cells in the chick embryo after DNA-mediated transfer.

The chick embryo is an immune-deficient host able to support growth of a wide variety of transformed cells. Since growth of normal cells is not observed, this system appears to be generally useful for investigating malignant properties of different cells. Recently, we developed a sensitive assay to quantitate and select for rodent cells able to survive and grow in embryonic chick organs following i.v. injection (Cancer Res., 42: 4018-4025, 1982). We envisage this assay as a model system for studying aspects of the metastatic process. We have used DNAs from murine and human melanoma cell lines (which grow well in chick embryos after i.v. injection) to transfect murine LTA cells (which do not grow in chicks after i.v. injection). From the transfected LTA cells, we were able to isolate clones which grow well in the chick after i.v. injection. Such clones were not observed in untransfected LTA cells or with LTA cells transfected with LTA DNA. These experiments clearly demonstrate the feasibility of using the chick embryo as a host system to study genes involved in growth control alteration of the sort seen in malignant transformation.