Increase of epidermal growth factor receptor expression associated with a lack of antiproliferative effect of IFN-beta in human lung cancer nodules in organotypic culture.

The possible relationship between the effects of alpha 2-, beta- and gamma-interferons (IFNs) on the growth of alveolar II pulmonary tumor cells (A549) maintained in tridimensional organotypic culture (nodules) and the modulation of epidermal growth factor receptor (EGF-R) expression was investigated. Treatment with rHu IFN-alpha 2 or IFN-gamma which results in the inhibition of the growth of A549 nodules had no effect on the binding of 125I-EGF to these cells. In contrast, treatment with rHu IFN-beta which exhibits no antiproliferative activity on A549 nodules resulted in a reproducible increase of the binding of 125I-EGF. Scatchard analysis of the EGF binding data indicated that a 48-hour exposure period resulted in an increase in the apparent number of cell surface EGF-R but did not significantly alter receptor affinity. Results from Northern blot analysis showed that the enhanced expression of EGF-R on the A549 nodule cells treated with IFN-beta correlates with an increase in mRNA for EGF-R. No modification of the EGF-R mRNA expression was observed in nodules treated with IFN-alpha 2 or IFN-gamma. In this model, our results suggest a relationship between resistance to antiproliferative effect of IFN-beta and modulation of EGF-R.