Behaviour of normal and neoplastic cultured mouse cells on the chorioallantoic membrane of the chicken.

Cultivated normal and transformed fibroblasts of the mouse (short-term cultures of lung fibroblasts and L-cells) have been implanted onto the chorioallantoic membrane of the chick embryo (CAM). Both cell types formed macroscopically visible nodules on the CAM where they induced a weak angiogenic reaction. Labelling of the cells with activated charcoal or 3H-thymidine gave evidence of their invasion into the CAM mesoderm, where they induced the formation of new capillaries. The successive multiplication of the cells led to the formation of tumours, resp. tumour-like cellular accumulations in the hypertrophied mesoderm of the CAM. Treatment of L-cells with the protease-inhibitor Contrykal reduced the invasive properties of the cells. The results presented clearly demonstrate invasive and angiogenic properties of the normal and malignantly transformed cell cultures of the mouse used in our experiments.