alpha-Interferon potentiates the growth inhibitory effects of anti-transferrin receptor monoclonal antibodies

We have demonstrated that interferon-alpha 2 recombinant (IFN alpha) inhibits the growth and modulates the expression of the receptor for transferrin (TRF-R) in human epidermoid carcinoma KB cells. Receptor upregulation results in the reconstitution of intracellular iron levels in the IFN alpha-treated cells. Several anti-TRF-R murine monoclonal antibodies (MAbs) have been generated which induce tumor cell growth inhibition through blockade of receptor function. We have evaluated by MTT assay the effect of anti-TRF-R 42/6, E2.3, A27.15 and D65.30 MAbs given in combination with IFN alpha on the growth of human epidermoid carcinoma KB cells. We found that IFN alpha and A27.15 MAb induced a synergistic antiproliferative effect on these cells. These results suggest that IFN alpha may potentiate the antitumor efficacy of TRF-R-targeted therapy.