Control of the growth of leukemic cells (L1210) through manipulation of trace metals.

Trace metals have a role in the activity of the enzyme ribonucleotide reductase (RR) which is essential for the synthesis of DNA and the growth of lymphocytes. Manipulation of the intracellular metals of leukemic cells has been proposed for the therapeutic control of cell growth. We studied the effects of prolonged metal deprivation (Fe, Cu, Zn) on cell growth and RR activity of murine leukemic lymphocytes in culture in metal-depleted media.

Growth, ribonucleotide reductase and metals in murine leukemic lymphocytes.

Trace metals are essential for the growth and several other properties of human lymphocytes. We studied the effects of media with variable concentrations of three metals (Fe2+, Cu2+, Zn2+), a metal chelator (deferoxamine, DFX) and a cell-growth inhibitor (hydroxyurea) on the growth, intracellular metal concentration and activity of the enzyme ribonucleotide reductase in murine leukemic lymphocytes (L1210). Intracellular concentrations of Fe and Cu fluctuated within narrow limits in normal media, but decreased to very low concentrations in metal-poor media.

Effects of iron, copper and zinc on the activity of ribonucleotide reductase in normal and leukemic human lymphocytes.

The activity of ribonucleotide reductase (RR) extracted from normal and leukemic human lymphocytes was assessed. The activity of the enzyme was five times higher in leukemic cells than in normal lymphocytes. Fe and Cu stimulated and Zn inhibited RR activity in both types of cells.

Trace metals, surface receptors and growth of human normal and leukemic lymphocytes.

To evaluate the modulatory effects of trace metals on lymphocyte growth and maturation, thymidine uptake (TU), protein, ATP, Fe, Cu, Zn, ferritin, CD3, CD4, CD8 antigens, surface transferrin receptors (TFR) and interleukin 2 receptors (IL2R) were assessed in normal and T cell leukemia human lymphocytes, cultured in media with varying Fe, Cu and Zn concentrations [Me]. In normal lymphocytes in media with optimal [Me], all values increased significantly after PHA stimulation, except for intracellular metal concentration and CD3+, CD4+, CD8+ cells which were unchanged. In media with low or high [Me], all parameters except for CD8+ cells were decreased.

Effects of iron, copper, zinc, calcium, and magnesium on human lymphocytes in culture.

The effects of simultaneous changes of calcium, magnesium, iron, copper, and zinc concentrations were evaluated in normal human T and B lymphocytes, cultured in cation-depleted media. Optimal concentrations for thymidine incorporation (TI) in both cell populations were Fe and Zn 15 microM and Cu 5 microM; for T cells Ca 2 mM and Mg 4 mM; for B cells Ca 4 mM and Mg 6 mM. TI decreased with increasing molarity of cations and the decrease was particularly apparent with Cu.

Observations on the use of a cation exchange resin for the preparation of metal-depleted media for lymphocyte culture.

A chelating resin specific for divalent cations (Chelex) was used to prepare metal-depleted media for lymphocyte culture. A batch procedure (resin in pH 7.4 phosphate buffer/specimen, 1:1) removed 70-80% of iron, 77-87% of copper and 88-98% of zinc, calcium and magnesium.

In vitro leukemic cell differentiation in metal-depleted media.

Lymphocytes of children with T cell and pre-B cell acute lymphocytic leukemia (ALL) were cultured in media with different concentrations of Fe, Cu and Zn to detect a possible effect of these ions on leukemic cells. Thymidine uptake was elevated in non-mitogen stimulated ALL cells and increased after mitogen stimulation, whereas intracellular ferritin, Fe and Cu, elevated before culture, decreased thereafter; pre-B ALL cells, positive only for cytoplasmic mu chains, became positive for surface immunoglobulins and released a detectable amount of them; low T4/T8 ratio in cells from T cell ALL returned to normal values after culture. These findings were present only in media with minimal concentrations of Fe, Cu and Zn and suggest that regulation of intracellular levels of these metals may induce some differentiation of leukemic cells.

Copper, zinc, and iron in normal and leukemic lymphocytes from children.

Copper, zinc, and iron were quantitated in the serum and lymphoid cells of the peripheral blood of healthy children and children with acute lymphocytic leukemia. Copper and iron concentrations in serum and cells were significantly higher and zinc concentration in the cells significantly lower in leukemic patients than in healthy donors, whereas the increase of zinc in the serum was not significant. The concentration of all minerals was higher in T-cell enriched preparations.

Zinc deficiency and blood lymphocyte function with sickle cell disease.

A relationship between zinc deficiency and lymphocyte function in children with sickle cell disease (SCD) has been suggested. Number and function of B and T lymphocytes were assessed in 3 matched groups of children: normal subjects with Hb A and normal zinc; patients with SCD; and normal zinc (SCD-N); and patients with SCD and decreased zinc (SCD-D). Percentages of B and T cells, response to cutaneous antigens and increases in tetanus antibody titres were similar among all groups.

Leukemia with a novel 4q11q rearrangement.

Translocation (4;11)(q21;q23) is characteristic of a distinct acute leukemic syndrome. We report an 8-wk-old male patient with the clinical features ascribed to t(4;11), but with an unusual chromosome rearrangement consisting of an insertion of the 11q23 band into the q21 region of chromosome #4.

Neutrophils and zinc in infection-prone children with sickle cell disease.

Neutrophils can be distinguished as EA negative (EA-N) or EA positive (EA+N), according to rosette formation with sheep erythrocytes. EA- neutrophils show a bactericidal activity 50% to 70% lower than EA+ neutrophils. Thirty children with sickle cell disease were studied during steady state and crises/infections, together with matched control children.

Adenylate cyclase and guanylate cyclase activity in normal and leukemic human lymphocytes.

Adenylate cyclase (AC) and guanylate cyclase (GC) activities were studied in normal B-enriched and T-enriched lymphocytes, in lymphocytes of children with acute lymphocytic leukemia (ALL), and in lymphocytes of adults with chronic lymphocytic leukemia (CLL). AC activity was greater in normal B than T lymphocytes (215 pmole/min/mg protein versus 80 pmole in the membrane-enriched fraction) and i both increased greatly after stimulation with isoproterenol and more so with prostaglandins E and F2 alpha. In leukemic lymphocytes, AC showed depressed activity (20 pmole in ALL cells and 55 pmole in CLL cells) and was less sensitive to hormonal stimulation: this loss of sensitivity occurred to a greater extent in ALL than in CLL lymphocytes.

Observations on prostaglandins in normal and leukemic human lymphocytes.

Prostaglandins E (PGE) and F2 alpha (PGF2 alpha) were measured in lymphocytes of normal subjects, children with acute lymphocytic leukemia (ALL), and adults with chronic lymphocytic leukemia (CLL). In ALL lymphocytes PGE increased from a normal value of 25 pgrams to 270 pgrams/10(6) cells, and PGF 2 alpha increased from a normal value of 31 pgrams to 482 pgrams/10(6) cells. In CLL lymphocytes, levels of PGE and PGF2 alpha were normal or low.

Variation of activity of protein kinases in unstimulated and phytohemagglutinin-stimulated normal and leukemic human lymphocytes.

Cyclic adenosine 3':5'-monophosphate-dependent protein kinase (kinase A) and cyclic guanosine 3':5'-monophosphate-dependent protein kinase (kinase G) were assayed in lymphocytes of normal subjects, adults with chronic lymphocytic leukemia (CLL), and children with acute lymphocytic leukemia (ALL). There was a good correlation between the activity of the two kinases and the level of the corresponding cyclic nucleotides. This was true for cultured phytohemagglutinin-stimulated normal lymphocytes and CLL lymphocytes as well.