Functional interleukin 4 receptor and interleukin 2 receptor common gamma-chain on human non-small cell lung cancers: novel targets for immune therapy.

Abstract

The interleukin 4 receptor has been demonstrated on the surface of human non-small cell lung carcinoma cell lines and tumor specimens. Interleukin 4 causes G1-phase cell-cycle arrest of non-small cell lung cancer cell lines expressing the interleukin 4 receptor; the effect directly correlates with the expression of the interleukin 4 receptor and is seen within 48 hours after treatment. We examined signal transduction pathways used by the interleukin 4 receptor that may account for growth arrest of the cell line LUst but had no effect on another non-small cell lung cancer cell line, SK-MES-1. Western blot analysis was performed on both LUst and SK-MES-1 cell lines cultured in the presence of interleukin 4 (500 U/mL). Cells were lysed, protein extracted, and electroblotted; blots were then probed with murine monoclonal antibodies to specific intracellular proteins. Western blotting of the cell lines with antiphosphotyrosine antibody (4G10) demonstrated multiple (140 kd, 100-130 kd, and 65 kd) phosphoproteins seen only in the interleukin 4-treated LUst cell line and not observed in the SK-MES-1 cell lines. Immunoprecipitation and blotting of the LUst cell line with specific secondary antibodies demonstrated that the 140-kd phosphoprotein was the interleukin 4 receptor, the 130-kd phosphoprotein was Janus kinase 1, the 116-kd phosphoprotein was Janus kinase 3, and the 65-kd phosphoprotein was the interleukin 2 receptor gamma-chain. Specific binding was not observed in the non-small cell lung cancer cell line SK-MES-1, suggesting that a functional interleukin receptor gamma-chain was not present. Southern blotting with complementary DNA probes to interleukin 2 receptor gamma-chain confirmed the absence of this receptor on cell line SK-MES-1. These results suggest that non-small cell lung cancer cells may express functional cytokine receptors, including the interleukin 2 receptor gamma-chain commonly found in association with the lymphocyte interleukin 2 receptor. These receptors may be novel targets for directing cytokine-based immune therapy.