cyclic-gmp and Leukemia--Lymphocytic--Chronic--B-Cell

The study objective was to investigate the production of NO, cGMP and superoxide anion radical by neutrophils, and to examine alterations in serum or plasma total nitric oxide, MDA and cGMP levels in B-CLL patients.. PMNs were isolated from 20 patients with B-CLL. Total nitrite was measured in cell supernatants and serum by Griess method. The generation of superoxide anion radical by cells was estimated using cytochrom-c reduction test. The cGMP level in cell supernatants and plasma was assessed by ELISA kit whereas serum MDA level using a spectrophotometric assay by Guege and Aus.. The PMNs in B-CLL patients were characterised by impaired NO generation and enhanced cGMP production. Contrary to the control group, no significant effect was found of rhlL-15 and rhIL-18 on the release of these mediators by PMNs. Superoxide anion radical release by PMNs was decrease. Serum MDA and plasma cGMP levels were elevated in B-CLL patients as compared to the controls.. The reduced production of nitric oxide and superoxide anion radicals by PMNs in B-CLL may impair the cytotoxic effect of neutrophils on leukaemic B cells. Low secretion of nitric oxide by PMNs and high levels of cGMP in PMN supernatants suggest that activation of guanyl cyclase (sGC) in these patients may occur in the presence of agents other than nitric oxide. Moreover, the findings indicate the enhancement of lipid peroxidation with the progression of the neoplastic process in B-CLL patients.

Topics: Aged; Cyclic GMP; Cytochromes c; Disease Progression; Female; Humans; Leukemia, Lymphocytic, Chronic, B-Cell; Lipid Peroxidation; Male; Malondialdehyde; Middle Aged; Nitric Oxide; Reactive Nitrogen Species; Reactive Oxygen Species; Superoxides

The expression of different isoforms of nitric oxide synthase (NOS) was investigated in B-cell chronic lymphocytic leukemia (B-CLL) to delineate a possible role for nitric oxide (NO) in the control of apoptosis of the tumoral cells. By reverse transcription-polymerase chain reaction (RT-PCR), all B-CLL cells were found to express spontaneously inducible NOS (iNOS) mRNA, whereas endothelial constitutive NOS (ecNOS) mRNA was undetectable. The iNOS protein was detected by immunofluorescence in the cytoplasm of permeabilized leukemic cells and identified by Western blotting, using different anti-iNOS antibodies, as a protein of 135 kD in B-CLL cytoplasmic extracts. B-CLL cell lysates also displayed basal NOS enzymatic activity, as measured by the conversion of 14C-labeled L-arginine into 14C-L-citrulline. Ligation of CD23, expressed on the vast majority of B-CLL cells, resulted in increased iNOS expression and activity. The NO released exerted an anti-apoptotic effect on B-CLL cells that was counteracted by NOS inhibitors and engagement of the APO-1/Fas pathway. Therefore, the existence of a functional iNOS in B-CLL cells will provide further insights into the mechanisms that control proliferation and apoptosis in these tumor cells.

Topics: Antigens, Neoplasm; Apoptosis; Cell Fractionation; Cyclic GMP; Enzyme Induction; Female; Gene Expression Regulation, Leukemic; Humans; Leukemia, Lymphocytic, Chronic, B-Cell; Male; Neoplasm Proteins; Nitric Oxide; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Polymerase Chain Reaction; Receptors, IgE; RNA, Messenger; RNA, Neoplasm; Signal Transduction

After the leukemic cell lines were treated with monoclonal antibodies (McAbs) and interferon (IFN-alpha), the changes of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) levels in the corresponding leukemic cell lines were measured by radioimmunoassay. The results showed that when the ratio of antigen to antibody was 80 to 1, the cAMP levels in the leukemic cell lines were obviously higher than those in the controls while the cGMP levels were obviously lower after being treated with the corresponding McAbs for 16-24 h (P < 0.001). The average level of intracellular cAMP was remarkably increased and that of cGMP underwent no significant changes in the leukemic cell lines after treatment with IFN-alpha.

Topics: Antibodies, Anti-Idiotypic; Antibodies, Monoclonal; Cyclic AMP; Cyclic GMP; Humans; Immunoglobulin Isotypes; Interferon-alpha; Leukemia; Leukemia, Lymphocytic, Chronic, B-Cell; Leukemia, Promyelocytic, Acute; Plasmacytoma; Tumor Cells, Cultured

Thioproline (thiazolidino-4-carboxylic acid) is one of promising antineoplastic preparations arousing interest since several years. In view of controversies with respect to the mechanism of thioproline action it was tried to study the effects of the preparation on certain functions of lymphocytes. The experimental model included cultures of T and B lymphocytes obtained from 20 healthy blood donors. The cultures were exposed to various concentrations of thioproline for determining the incorporation of 3H-thymidine into the DNA of these cells, their viability and intracellular concentrations of cAMP and cGMP. The lymphocytes from these healthy donors served also as a control for B-cells isolated from 24 patients with lymphoproliferative syndromes. It was found that at low concentrations thioproline added to the culture of T-cells from healthy donors caused a slight increase of 3H-thymidine incorporation, but at high concentrations a strong cytotoxic effect on T-cells was noted. B-cells isolated from the peripheral blood of healthy subjects and from the patients were highly sensitive to thioproline. These observations demonstrated a cytotoxic effect of thioproline on T and B lymphocytes.

Topics: Adolescent; Adult; Aged; Antineoplastic Agents; B-Lymphocytes; Blood Donors; Cyclic AMP; Cyclic GMP; Cytotoxicity, Immunologic; DNA; Dose-Response Relationship, Drug; Female; Humans; In Vitro Techniques; Leukemia, Lymphocytic, Chronic, B-Cell; Lymphoma, Non-Hodgkin; Male; Middle Aged; Models, Biological; T-Lymphocytes; Thiazoles; Thiazolidines