Increased tumorigenicity of fibronectin receptor deficient Chinese hamster ovary cell variants.

We have developed a series of variant clonal Chinese hamster ovary cell sublines which are deficient in the expression of the alpha 5/beta 1 integrin fibronectin receptor. When these clonal sublines were injected s.c. into nude mice, there were marked differences in the rate of tumor growth. Tumors from clones expressing very low levels of fibronectin receptor grew most rapidly, clones expressing levels of fibronectin receptor comparable to wild type cells grew at an intermediate rate, while a clone expressing elevated levels of fibronectin receptor grew slowly. Cells recovered from the tumors maintained their original phenotypes in terms of levels of fibronectin receptor expression. These results suggest that there is an inverse correlation between the level of expression of the alpha 5/beta 1 fibronectin receptor and the rate of tumor growth.