Abstract
The growth and differentiation of the mouse embryonal carcinoma cell line F9 in completely defined culture media were studied. The defined growth medium, referred to as EM-3, contains plasma fibronectin, insulin and transferrin in place of serum. F9 cells cultured in EM-3 for over 15 generations retain their ability to form tumors and to differentiate. Fibronectin is essential for the attachment of F9 cells in defined media and its effect can be blocked with affinity-purified anti-fibronectin. When retinoic acid was added to EM-3, the F9 cells differentiated. The majority of the newly formed cells differed from the parent F9 cells in 2 major respects: they were morphologically different; and they secreted plasminogen activator, and the secretion was stimulated by dibutyryl cyclic AMP.