Transfection of C3H10T1/2 cells with the Harvey-ras oncogene reduces cytosolic phospholipase A(2) function

Several lines of evidence suggest that phospholipase A(2) may play a role in the activated ras-mediated transformation process. In the present study, phospholipase A(2) activity and expression were assessed in a murine fibroblast cell line (C3H10T1/2 cells) that was stably transfected with the Harvey ras oncogene, a cellular model used for studying multistage carcinogenesis. Reduced levels of fatty acids were released from the ras-transfected cells compared to untransfected controls. The in vitro phospholipase A(2) activity apparent in the C3H10T1/2 showed preference for sn-2 arachidonyl phosphatidylcholine compared to dipalmitoyl phosphatidylcholine. The activity, as well as the cytosolic phospholipase A(2) immunoreactive protein, was reduced by 50% in the ras-transfected cells compared to control cells. These results suggest that the cytosolic phospholipase A(2) is the predominant form of this enzyme family expressed in C3H10T1/2 cells and that the activity and protein amount is reduced by 50% in these cells when stably transfected with the Harvey ras oncogene.