Glia maturation factor promotes contact inhibition in cancer cells.

The effect of bovine glia maturation factor on the growth pattern of cancer cells was investigated in the rat glioma cell line 354A. When the cells were grown in the serum-free defined medium N2 in the absence of the factor, the cells proliferated with a doubling time of 24 hr without showing contact inhibition. After reaching confluency, the cell layer formed numerous foci from which heaps of cell colonies arose. The addition of glia maturation factor to the culture stimulated cell division in the logarithmic phase but prevented overgrowth once the cells arrived at confluency. The ability of glia maturation factor to restore contact inhibition suggests a regulatory role in normal and neoplastic cells.