Interactions of embryonic with neoplastic cells

Adhesive interactions of embryonic with neoplastic cells have been studied in cultures of 7 day old chick embryo neural retina cells and embryo hamster, baby hamster cell lines and some of their neoplastic derivative cell lines. Two futures of adhesion were studied, the alteration of neural retina cell adhesiveness by the conditioned media of the hamster cell lines and the mutual adhesiveness of the neural retina cells and the hamster cell linos. Experiments to test for conditioned media were done using either the Couette Viscometers or the collecting cell lawn assay. The results of these experiments indicate the presence of factors which affect the adhesiveness of 7 day old chick embryo neural retina cells. The results varied depending upon which technique was used. The mutual adhesiveness of the neural retina cells and the hamster cell lines was studied with the collecting cell lawn system and in two and three dimensional mixed cultures. The collecting ceil lawn assay indicates that the neural retina cells do not associate with the neoplastic cells as well as the normal cells and that the embryonic hamster cells associate better than the baby hamster cells. The results are discussed on the bases of a classification of the different cell types according to their origin as baby, embryonic or neoplastic cells. The two dimensional mixed cultures show that the neural retina cells and the hamster cells do not make any important contacts and that the increase by growth of the number of the hamster cells force the neural retina cells to come off the culture dishes. The three dimensional mixed cultures indicate that the neural retina cells associate to some extent with the normal baby and embryonic hamster cells but not with the neoplastic ones. In these mixed cultures two and three dimensional ones, the sorting out pattern observed was discussed in relation to the secretion effects. The results give support to the "morphogen theory" for the control of sorting out in mixed aggregates