Figure 5.

Specific inhibition of the IGF-IR pathway blocks correction of the radiosensitivity in AT cells by the ATM cDNA. GM5849 cells, deficient in ATM, were transfected with an ATM expression plasmid, yielding subclones expressing wild-type ATM (see Fig. 1). (A) The radiation survival of one complemented subclone, 5849cA4, was determined in the presence and absence of a neutralizing anti-IGF-IR antibody added to the growth medium. (B) The ATM cDNA-complemented subclone 5849cA4 was further transfected with a vector expressing a dominant negative variant of IGF-IR (486stop). The clonogenic survival of one transfectant subclone (c1) and of a cell population consisting of a number of pooled transfected clones (pooled) was determined in comparison with 5849cA4 and with the original parent line, 5849.