Inhibition of growth of the lymphocyte lines by iron-binding agent deferoxamine under various iron-supply conditions was studied. Three different defined culture media, representing three different iron-supply conditions, were used: (1) ferric citrate (500 microM) medium, (2) transferrin (5 micrograms/ml) medium, and (3) low-iron medium (this medium without any iron compound added contains 0.6 microM contaminative non-transferrin iron). Mouse B cell line PLV-01, human T cell line Jurkat, and human B cell lines Raji and HSCE- were employed. Raji and HSCE- cells are able to grow in low-iron medium but PLV-01 and Jurkat cells do not grow in the medium. For all cell lines tested in ferric citrate medium, a 50% growth inhibition was achieved with 440-500 microM deferoxamine. In transferrin medium, deferoxamine concentrations of 4.4-5.5 microM were required for a 50% inhibition of PLV-01, Jurkat and HSCE- cells. For the same degree of inhibition of Raji cells, 39 microM deferoxamine was required. In the case of low-iron medium, a 50% inhibition of Raji and HSCE- cells was achieved with about 1.4-2.1 microM deferoxamine. The data demonstrate that the sensitivity of the lymphocyte lines to deferoxamine depends on iron-supply conditions. Under the same iron-supply conditions, individual cell lines can exhibit different sensitivity. However, the sensitivity does not correlate with the ability of the cell lines to grow in low-iron medium.

Department of Pediatrics National Jewish Center for Immunology and Respiratory Medicine Denver Colorado

Growth of human tumor cell lines in transferrin-free, low-iron medium