The transformation of c-jun-overexpressing cells is correlated with IGFS-induced c-jun phosphorylation.
We have analyzed, in parental and c-jun-transfected rat liver epithelial (REL) cells, the capacity of the insulin-like growth factors (IGF1 and 2) to stimulate growth under anchorage dependent and independent conditions and the role of the c-jun protein in the response to these factors. Although the increase of the proliferation of cells in monolayer was similar for the two lines, only the c-jun-transfected cells formed colonies in soft agar after IGFs exposure. We showed that IGF1 and 2 did not modify the expression of c-fos or c-jun proteins during short-time exposures but both factors enhanced c-jun phosphorylation which suggests that this phenomenon could be involved in IGFs-regulated gene expression. Moreover, we showed that both the overexpression and the increase of phosphorylation status of c-jun protein were necessary to transform REL cells.
Lagarrigue
S
S
Laboratoire de Nutrition et Sécurité Alimentaire-INRA, Jouy en Josas, France.
Heberden
C
C
Martel
P
P
Gaillard-Sanchez
I
I
D000818:Animals; D002471:Cell Transformation, Neoplastic / Q000378:metabolism*; D002478:Cells, Cultured; D008099:Liver / Q000166:cytology; D010766:Phosphorylation; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction; D013002:Somatomedins / Q000502:physiology*
D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D013002:Somatomedins