IDENTIFICATION OF CONSTITUTIVE AND GAMMA-INTERFERON-REGULATED AND INTERLEUKIN-4-REGULATED PROTEINS IN THE HUMAN RENAL-CARCINOMA CELL-LINE-ACHN

The effects of IFN-gamma and interleukin 4 (IL-4) on cell proliferatio n and two-dimensional gel electrophoretic protein patterns of the huma n renal carcinoma cell line ACHN were studied. Treatment of the cells with IFN-gamma resulted in a 40-50% decrease in their proliferation. I L-4 treatment resulted in a 30-40% decrease. Treating cells with both cytokines had the same effect as with IFN-gamma alone, thus precluding a synergistic antiproliferative interaction of these two cytokines. T o identify IL-4- and IFN-gamma-regulated proteins in ACHN, two-dimensi onal preparative gel electrophoresis was used, combined with either ca pillary electrophoresis or high-performance liquid chromatography and either Edman or mass spectrometric sequencing. The following cytokine- induced proteins were identified: tropomyosin, heat shock protein 27, manganese superoxide dismutase, glutathione S-transferase pi, and prot ein kinase C inhibitor I. Tropomyosin increased 2-fold when cells were treated with IFN-gamma. Levels of heat shock protein 27 increased 2-f old with IL-4, 3-fold with IFN-gamma, and I-fold when the cytokines we re used in combination. Manganese superoxide dismutase increased 3-fol d with IFN-gamma but was unaffected by IL-4. Glutathione S-transferase rr increased 3-fold with IFN-gamma. Levels of protein kinase C inhibi tor I increased greater than 3-fold with IL-4, 4-fold with IFN-gamma, and 7-fold when both cytokines were used. In addition, the following c onstitutive ACHN proteins were identified: copper zinc superoxide dism utase, 60S acidic ribosomal protein P2, and a second heat shock protei n 27 isoform. These findings help define the biochemical modes of acti on of IFN-gamma and IL-4 and their potential in the biological therapy of renal cell carcinoma.