Ehrlich ascites tumour cell spreading is induced upon contact with immobilized isolated fibroblast plasma membranes and fibronectin.

Ehrlich ascites tumour (EAT) cells normally growing in suspension, adhere and spread upon contact with fibroblasts. Changes in EAT cell morphology and adhesiveness induced in contact with purified fibroblast plasma membranes, fibroblast extracellular matrix and fibronectin were investigated. EAT cells adhered readily to glass covered with fibroblast extracellular matrix or fibronectin, but they did not spread. Immobilization of fibroblast plasma membranes or fibronectin on nitrocellulose restored EAT cell ability to spread. Tumour cells spread on immobilized plasma membranes or fibronectin maintained a "fried egg" morphology, while these spread on living fibroblasts were rather elongated. EAT cells preincubated with anti-fibronectin serum lost their ability to adhere to any of the tested substrata: living and fixed fibroblasts, fibroblast extracellular matrix, nitrocellulose with immobilized fibroblast plasma membranes or fibronectin. When anti-fibronectin serum was applied only to these substrata and it was washed out before EAT cell plating, EAT cell adhesion and spreading were not significantly changed. Extraction of extracellular matrix components from immobilized fibroblast plasma membranes did not influence EAT adhesion and spreading. The results are discussed with reference to the specific role of fibronectin in the growth of EAT cells as a solid tumour or suspension.