GROWTH-FACTORS AND APOPTOSIS IN DEVELOPMENT - THE ROLE OF INSULIN-LIKE GROWTH-FACTOR-I AND TGF-BETA-1 IN REGULATING CELL-GROWTH AND CELL-DEATH IN A HUMAN TERATOCARCINOMA DERIVED CELL-LINE

The balance between different cell populations in the developing organ ism is controlled by regulating the rates of multiplication, different iation or death of its constituent cells. The human teratocarcinoma de rived cell line Tera 2, which in several aspects mirrors early embryon ic cells, can be induced to undergo programmed cell death (apoptosis) by depriving cell cultures of serum, This study demonstrates that this process can be reversed by replacing serum with physiological concent rations of insulin like growth factor I (IGF I), As a result, IGF I en hances the rate of Tera 2 cell proliferation in serum free medium, In contrast, Transforming Growth Factor beta 1 did not exert any effect o n growth or apoptosis in Tera 2 cells. The results indicate that one e ffect of growth factors on pluripotential cells is to regulate the bal ance between cell proliferation and cell death.