GROWTH MODULATION OF MOUSE KERATINOCYTES BY TRANSFORMING GROWTH-FACTORS

  • 15 March 1988
    • journal article
    • research article
    • Vol. 48  (6) , 1596-1602
Abstract
The effects of exogenously added transforming growth factor (TGF.alpha. and TGF.beta. on the growth of BALB/MK cells were examined. TGF.alpha. supplanted the epidermal growth factor (EGF) requirement in these cells. In contrast, TGF.beta. reversibly inhibited the growth of BALB/MK cells by abrogating the stimulatory actions of EGF or TGF.alpha.. The inhibitory effects of TBF.beta. appeared to be mediated by events distal to EGF ligand-receptor interactions. Growth inhibition of BALB/MK cells by TGF.beta. did not result in the induction of differentiation. This fnding is different from the growth inhibition of these cells induced by elevated calcium levels (1.5 mM) which was tightly coupled to terminal differentiation. The BALB/MK cells were found to express TGF.alpha. mRNA, as well as TGF.beta. mRNA and protein. In addition, TGF.alpha., as well as EGF, enhanced TGF.alpha. gene expression. These studies suggest a role for endogenous TGFs in regulating BALB/MK proliferation. TGF.alpha. provides a positive growth signal, while TGF.beta. is a potent inhibitor of growth even in the presence of such positive modulators as TGF.alpha. and EGF.