Interactions between cell populations influence expression of the transformed phenotype in irradiated rat tracheal...

A combined in vivo-in vitro model has been utilized to evaluate the influence of cell-cell interactions on expression of radiation-induced transformation in irradiated rat tracheal epithelial cells. Two types of cell interactions are evaluated. One type of interaction appears to involve direct cell-cell contact as occurs within the intact tissue. The other type of communication appears to be mediated via a diffusible factor, most likely transforming growth factor type-beta. The data suggest the need to be cautious when extrapolating from transformation data obtained following irradiation of low-density rapidly proliferating cell cultures to the in vivo model.