One of the early observations that stimulated a great deal of research on FN was its loss from the surfaces of cells transformed by tumor viruses (Hynes, 1973; Gahmberg and Hakomori, 1973). This observation was followed quickly by the discoveries that plasma FN promotes cell adhesion (Section 8.2) and that plasma FN is related to the cell surface protein lost on transformation (Ruoslahti and Vaheri, 1975). It was then shown that addition of FN to transformed cells that lack it can restore some aspects of the normal cellular phenotype (Yamada et al, 1976a,b; Ali et al, 1977). These results and offshoots from them led to many different lines of research including studies of cell adhesion (Chapter 8), the relationship of FN with the cytoskeleton (Chapter 9), and its role in cell migration (Chapter 10). The work on transformation has proceeded in parallel with the development of our understanding of the various roles of FN in the behavior of normal cells, which we have discussed in earlier chapters. With each advance in knowledge about the structure, function, and expression of FN, the issue of the loss on transformation had to be reexamined in light of the new data. The initially simple picture that loss of FN leads to the reduced adhesion and altered morphology of transformed cells proved, on examination, to be true in outline but more complex than anticipated. In this chapter, I will review the work on the expression of FN in transformed and tumor cells, the phenotypic consequences of the loss of FN and data concerning the mechanisms of the change.
KeywordsPhorbol Ester Phorbol Myristate Acetate Oncogenic Transformation Focal Contact Rous Sarcoma Virus
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