ABSTRACT
This chapter focuses on mechanisms of carcinogenesis from which arises in vitro mammalian assays to detect carcinogens, especially the nongenotoxic ones. A few models based on the use of mammalian cells have been developed to screen nongenotoxic carcinogens. The Syrian hamster embryo (SHE) cell morphological transformation assay may detect nongenotoxic as well as genotoxic carcinogens. Morphological transformation is a recognized step in the multistage process of the conversion of a nontumorigenic to a neoplastic state. Most transformed and tumorigenic cells show aberrant Gap junctional intercellular communication (GJIC), but the transfection of connexin genes into these tumorigenic cells may restore the normal phenotype. GJIC is one of the major means by which multicellular organisms mediate the direct intercellular exchange of cellular signal factors from the interior of one cell to neighboring cells. The SHE cell transformation system and measurements of intercellular communication through gap junctions will be described.
