Bifunctional activity of transforming growth factor type beta on the growth of NRK-49F cells, normal and transformed by Kirsten murine sarcoma virus.
Transformation of rat NRK-49F cells (49F) by Kirsten murine sarcoma virus (Ki-MSV) renders these cells (Ki-49F cells) capable of autonomous anchorage independent (AI) growth. As compared to nontransformed 49F cells, the transformation by Ki-MSV does not modify the cell response to transforming growth factor-beta (TGF-beta) in monolayer conditions, but alters it in A I growth conditions. The growth of nontransformed or Ki-MSV-transformed adherent 49F cells is slowed down by porcine TGF-beta, and this effect is reversed by epidermal growth factor (EGF). This decrease in the cell growth rate, induced by TGF-beta, does not affect the cloning efficiency of untransformed and transformed adherent 49F cells. Contrarily, porcine TGF-beta decreases the A I cloning efficiency of Ki-49F cells in agar-gelled medium; this effect is only partly reversed by EGF, which does not synergise with TGF-beta to enhance the A I growth as in the case of untransformed 49F cells. Media conditioned by 49F cells, Ki-49F cells, and chicken embryo fibroblasts contain a latent TGF-beta whose capacity to promote the A I growth of 49F cells and to inhibit that of Ki-49F cells is unmasked by acidification. The same situation exists concerning TGF-beta from human platelets. Neutral extracts are inefficient in both tests of promotion and inhibition of A I growth and contain an acid-activable component with an apparent molecular weight of 600 kd. In acid extracts, a 5-9 kd apparent molecular weight component is responsible for the A I growth enhancement of 49F cells and the A I growth inhibition of Ki-49F cells. Further purification by reverse phase chromatography shows that both activities strictly coelute at the same point (32%) of an acetonitrile gradient. These results indicate that TGF-beta is present in physiological conditions as a latent form which requires activation for inhibiting the A I growth of transformed cells as well as for enhancing that of 49F cells.
Jullien
P
P
Institut Curie, Centre Universitaire, Orsay, France.
Berg
T M
TM
de Lannoy
C
C
Lawrence
D A
DA
D000818:Animals; D001792:Blood Platelets; D002448:Cell Adhesion; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line / Q000187:drug effects; D002472:Cell Transformation, Viral / Q000187:drug effects*; D007668:Kidney; D007708:Kirsten murine sarcoma virus; D010455:Peptides / Q000494:pharmacology*; D051381:Rats; D009053:Sarcoma Viruses, Murine; D015291:Transforming Growth Factors
D010455:Peptides; D015291:Transforming Growth Factors