The specific binding of transferrin to the murine fibroblast cell lines AKR-2B and its malignant counterpart AKR-MCA may be related to the transformed state

The specific binding of radiolabelled transferrin to AKR-2B and AKR-MCA murine fibroblasts was studied. The binding of radioligand to both cell lines was specific, being displaced by excess of unlabelled transferrin but not myoglobin, or lactoperoxidase. Under equilibrium conditions the transformed line AKR-MCA bound significantly more radioactive transferrin (22.5 +/- 3.5 fmol/micrograms DNA) than the parental line AKR-2B (14.5 +/- 1.5 fmol/micrograms DNA). The differences in the amount of ligand bound was due to altered receptor numbers. Treatment of AKR-MCA and AKR-2B cells with DMF eliminated the difference in transferrin binding capacities. The maximum decrease in specific ligand binding to AKR-MCA cells brought about by the polar solvent was observed after 48 h. These data suggest an association between transferrin binding and the transformed state of AKR-2B fibroblasts.