PARTICIPATION OF RHOP21 IN SERUM-DEPENDENT INVASION BY RAT ASCITES HEPATOMA-CELLS

Rat ascites hepatoma cells (MM1 cells) penetrate through a cultured me sothelial cell monolayer (MCL) in the presence of fetal calf serum (FC S), but scarcely do so in its absence, Inactivation of rhop21 of MM1 c ells by ADP-ribosyltransferase C3 resulted in the suppression of this serum effect on the penetration, suggesting that the serum effect was mediated by rhop21, To ascertain this assumption MM1 cells were transf ected with an activated (Val(14)) human rhoA cDNA (Neo/RhoA 1-7). The transfectants penetrated MCL extensively even in the absence of FCS an d became largely independent of serum for the penetration. These resul ts suggest that serum-induced invasion by MM1 cells is mainly mediated by rhop21.