Hydroxyurea and Zileuton Differentially Modulate Cell Proliferation and Interleukin-2 Secretion by Murine Spleen Cells: Possible Implication on the Immune Function and Risk of Pain Crisis in Patients with Sickle Cell Disease.

Background: Hydroxyurea (HU) reduces major complications associated with sickle cell disease in part because of the induction of fetal hemoglobin. However, because of its antiproliferative property, its long-term use may impair immunity. Zileuton, a derivative of HU, also induces fetal hemoglobin and has antiinflammatory properties, a feature that can reduce the risk of sickling.

Aneuploidy assessed by DNA index influences the effect of iron status on plasma and/or supernatant cytokine levels and progression of cells through the cell cycle in a mouse model.

Aneuploidy, a condition associated with altered chromosome number, hence DNA index, is frequently seen in many diseases including cancers and affects immunity. Iron, an essential nutrient for humans, modulates the immune function and the proliferation of normal and cancer cells. To determine whether impaired immunity seen in iron-deficient subjects may be related to aneuploidy, we measured spleen cell DNA index, percent of cells in different phases of the cell cycle, plasma and/or supernatant IL-2, IL-10, IL-12, and interferon-gamma in control, pair-fed, iron-deficient, and iron-replete mice (N=20-22/group).

Differential effects of leptin on the invasive potential of androgen-dependent and -independent prostate carcinoma cells.

Obesity has been linked with an increased risk of prostate cancer. The formation of toxic free oxygen radicals has been implicated in obesity mediated disease processes. Leptin is one of the major cytokines produced by adipocytes and controls body weight homeostasis through food intake and energy expenditure.

Hydroxyurea attenuates activated neutrophil-mediated sickle erythrocyte membrane phosphatidylserine exposure and adhesion to pulmonary vascular endothelium.

Activated neutrophils increase erythrocyte phosphatidylserine (PS) exposure. PS-exposed sickle red blood cells (SSRBCs) are more adhesive to vascular endothelium than non-PS-exposed cells. An increase in SSRBC fetal hemoglobin (HbF) concentration has been associated with improved rheology and decreased numbers of vasoocclusive episodes.

Elevation of serum riboflavin carrier protein in hepatocellular carcinoma.

Early detection of hepatocellular cancer (HCC), makes it surgically resectable with a potential for cure. The test most commonly used to detect HCC is the measurement of serum alpha-fetoprotein (AFP) levels. However, the AFP test is negative in HCC detection in more than 30% of the cases.

Fetal hemoglobin induction by histone deacetylase inhibitors involves generation of reactive oxygen species.

Objective: Several compounds, including butyrate and trichostatin A, have been shown to activate gamma-gene expression via p38 mitogen-activated protein kinase (MAPK) signaling. In eukaryotic cells, reactive oxygen species (ROS) act as signaling molecules to mediate phosphorylation of tyrosine kinases such as p38 MAPK to regulate gene expression. Therefore, we determined the role of the reactive oxygen species hydrogen peroxide (H(2)O(2)) in drug-mediated fetal hemoglobin (HbF) induction.

Differential effects of hydroxyurea and zileuton on interleukin-13 secretion by activated murine spleen cells: implication on the expression of vascular cell adhesion molecule-1 and vasoocclusion in sickle cell anemia.

Background: Interleukin-13 (IL-13), a TH2 cytokine, upregulates the expression of vascular cell adhesion molecule-1 on endothelial cells, a factor involved in vasoocclusion in sickle cell disease (SCD). Hydroxyurea improves clinical status of SCD patients in part by induction of fetal hemoglobin. Its effect on IL-13 secretion has not been investigated.

Zileuton induces hemoglobin F synthesis in erythroid progenitors: role of the L-arginine-nitric oxide signaling pathway.

Induction of fetal hemoglobin (Hb F) is an important therapeutic tool in ameliorating complications of sickle cell disease. Nitric oxide has been implicated in the mechanism of Hb F synthesis induced by hydroxyurea (HU). This study examined whether zileuton (ZL), a structural analog of hydroxyurea, possessed Hb F-inducing properties and the potential role nitric oxide plays.

p38 MAP kinase activation mediates gamma-globin gene induction in erythroid progenitors.

Objective: Our goal was to determine the role of p38 mitogen-activated protein kinase (MAPK) signaling in fetal hemoglobin (HbF) induction. Two histone deacetylase inhibitors (HDAIs), sodium butyrate (NB), and trichostatin (TSA) and hemin were analyzed. In addition, the effect of direct activation of p38 MAPK on gamma-globin gene activity was studied.

Combined use of nonmyelosuppressive nitrosourea analogues with hydroxyurea in the induction of F-cell production in a human erythroleukemic cell line.

Objective: Although hydroxyurea (HU) has been used clinically to treat patients with sickle cell disease (SCD), not all patients benefit from HU treatment due to its toxicity. The objective of this study was to investigate the effectiveness of the use of two new Hb F-inducing nitrosourea analogues, 2-[3-(2-methyl, 2-nitroso) ureido]-2-deoxy-D-glucopyranose (MNGU) and 2-[3-(2-chloroethyl) ureido]-2-deoxy-D-glucopyranose (CGU), in combination with HU in K562 cells or erythroid progenitors.

Materials And Methods: After K562 cells were cultured with different concentrations of HU with CGU or MNGU, aliquots of the cells were obtained to determine the total (benzidine-positive) hemoglobin level, number of F cells, and Hb F level.

Differences in iron requirements by concanavalin A-treated and anti-CD3-treated murine splenic lymphocytes.

Fe availability is critical for optimal lymphocyte proliferation; however, the minimum required levels are unknown. Such information is valuable when assessing in vitro immune responses in Fe-deficient subjects, because serum (Fe) added to the culture medium may replete lymphocytes. To address this issue, splenic lymphocytes obtained from seventeen 3-month-old C57BL/6 mice were incubated without and with 1 mg/l concanavalin A or 50 microg/l anti-CD3 antibody in media that contained between 0.

Stat3 beta inhibits gamma-globin gene expression in erythroid cells.

We demonstrated previously gamma-globin gene inhibition in K562 cells and primary erythroid progenitors treated with interleukin-6. Although several cis-acting elements have been identified in the globin promoters, the precise mechanism for cytokine-mediated globin gene regulation remains to be elucidated. In this report we demonstrate inhibitors of Stat3 phosphorylation abrogate interleukin-6-mediated gamma gene silencing in erythroid cells.

Reduced thymocyte proliferation but not increased apoptosis as a possible cause of thymus atrophy in iron-deficient mice.

Iron deficiency induces thymus atrophy in laboratory animals and very likely in humans by unknown mechanisms. The atrophy is associated with impaired cell-mediated immunity. In this study, we tested the hypothesis that thymus atrophy is a result of increased apoptosis and reduced thymocyte proliferation.