ABSTRACT
The different tumor cell phenotypes probably represent a continuum with respect to their aggressive behavior. All of the cell populations exhibited anchorage-independent growth (AIG) by their capacity to form colonies in soft agar. The plasticity of the AIGNT phenotype cells provided the means to examine the molecular changes that occurred during the transition between different tumor cell phenotypes. AIGNT cells treated with either MMS or MNNG became converted to an AIGT phenotype. However, the phenotypic transition of these cells was not permanent; rather these cells reverted to the AIGNT phenotype after several population doublings (PDs) in monolayer culture. The onset of the tumorigenic phenotype in the chemically exposed AIGNT cells was thus not associated with a permanently heritable change. The AIGNT phenotype provides a model system to examine changes in cellular phenotype. The results in the chapter examine the cellular changes which accompany the progression of cells through different phenotypic stages and the plasticity of these stages.
