Using NIH3T3 cells of look at MAPK activation by Ras - (Feb/24/2009 )

When looking through the literature I have noticed that lots of people use NIH3T3 cells for foci formation assays etc, but then switch to Cos cells for looking at activation of MAPK and PI3K pathways when studying activated forms of Ras. Does anyone know why this is done? Have people here looked at p-erk/p-akt levels in NIH3T3 cells in response to activated Ras?

Thanks

NIH3T3 cells are non-transformed ie they are not cancerous and they have a finite lifespan. So people use them for focus formation assay to prove that the gene they have put in is capable of making a normal cell line transformed. but, for routing cell culture , in general, transformed cell lines are a lot easier to grow. so i guess people switch.