Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:4.6.1.1 (adenylate cyclase)
 19,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Retinoic acid (RA) induces HL-60 and THP-1 leukemic cell lines to differentiate into granulocyte-like and monocyte-like cells. Limited data are available concerning the effects of RA on components of the cyclic AMP pathway in human myeloid leukemic cells. We showed previously a decrease in adenylate cyclase activity in the presence of histamine, prostaglandin E1 and forskolin in RA-treated HL-60 cells as compared to untreated cells. We examined the elements of the signal transduction pathway utilized by RA in the human myeloid cell line HL-60 and the human monocytic cell line THP-1. We therefore studied the effect of RA on the activity of the stimulatory G-protein (Gs). We demonstrate that addition of RA to two human myeloid leukemia cell lines, HL-60 and THP-1, does not induce a reduction of the 2 subunit of Gs (Gs alpha) RNA or Gs alpha protein in the plasma membrane but leads to a rapid decrease in the cholera toxin (CTX)-catalysed ADP-ribosylation of Gs alpha. In addition, this effect seems to be specific to RA, since there was no modification in Gs alpha ADP-ribosylation in the membranes of cells treated with dimethyl sulfoxide (DMSO), another inducer of differentiation in HL-60 cells.
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PMID:Gs alpha availability to cholera toxin-catalysed ADP-ribosylation is decreased in membranes of retinoic acid-treated leukemic cell lines HL-60 and THP-1. A posttranslational effect. 165 20

Leukemic cell growth in the marrow microenvironment may be modulated by stromal cell products, including stimulatory growth factors and the inhibitory regulator prostaglandin E. The production of both of these stromal cell products induced by cytokine mediators appears to be closely linked. Cyclic AMP (cAMP) is an intracellular second messenger that inhibits myeloid cell proliferation and is produced in myeloid leukemia cells on stimulation of adenylate cyclase enzyme by prostaglandin E1 (PGE1). Cells expressing the product of an RAS oncogene have been observed to display diminished hormone-stimulated adenylate cyclase of membranes. If this observation were applicable to myeloid cells, a potentially important mode for leukemia cells expressing p21 RAS to escape inhibitory regulation within the hematopoietic microenvironment would be identified. We studied an interleukin-3 (IL-3)-dependent myeloid cell line, NFS/N1.H7, and a derivative line transfected with H-RAS codon 12 (T24) oncogene, H7 Neo Ras.F3, for inhibition of proliferation by PGE1, 1 microM, alone or in combination with pertussis toxin, which inactivates Gi, an inhibitory regulatory guanosine triphosphate (GTP)-binding protein of adenylate cyclase. NFS/N1.H7 cells were inhibited in interleukin-3-dependent proliferation (dose range, IL-3 10 to 100 U/mL) by PGE1 79 +/- 11%, by pertussis toxin 51 +/- 9%, and by the combination 92 +/- 2%, whereas H7 Neo RAS.F3 was inhibited 51 +/- 7%, 6 +/- 2%, or 58 +/- 9% by PGE1, pertussis toxin, and the combination, respectively. These differences in capacity for inhibition by adenylate cyclase agonists between RAS-transfectant cells (lower inhibition) versus parent cells (greater inhibition) were all highly significant (P less than .0005). Intracellular cAMP formed on PGE1 stimulation of pertussis-intoxicated cells was 150% lower in RAS-transfectant cells than in parent cells. The adenylate cyclase activity of membranes from pertussis-intoxicated RAS-transfected cells was 1.5 to two times lower than that of pertussis-intoxicated parent-cell membranes on Mg2+-dependent activation by hormone and/or guanine nucleotide. However, very similar adenylate cyclase activity was observed in oncogenic p21 RAS-containing membranes compared with parental membranes under conditions of direct activation by 4 mM Mn2+ and forskolin, where inhibitory or stimulatory G-protein influences are minimal. These studies showed diminished adenylate cyclase activity in mutant RAS-bearing myeloid-cell membranes compared with parent-cell membranes independent of the pertussis toxin-sensitive G protein, Gi.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Effector function for RAS oncogene in interleukin-3-dependent myeloid cells involves diminished efficacy of prostaglandin E1-mediated inhibition of proliferation. 267 12

The expression of the interleukin-2 receptor (IL-2-R) is regulated by transcriptional and post-transcriptional mechanisms. IL-2-R gene expression is induced by pharmacological agents including calcium ions, phorbol esters such as phorbol myristate acetate (PMA) and forskolin (FK), a direct activator of adenylate cyclase. HTLV-I(+) leukemic T cells and T cell lines from patients with adult T cell leukemia (ATL) continuously expressed IL-2-R without production of IL-2. However, there was no abnormality of the structural gene for IL-2-R in these cell lines as well as in fresh leukemic cells of ATL. We have detected that many HTLV-I(+) T4(+) T cell lines constitutively produce a non-IL-2 lymphokine named ATL-derived factor (ADF), which induced the expression of the high-affinity IL-2-R on a variety of cells including HTLV-I(+) T cells, myeloid leukemia cells and YT cells. IL-2-R-inducing agents such as ADF and FK were shown to induce elevation of the mRNA levels for IL-2-R through transcriptional enhancement of the IL-2-R gene. The possible involvement of IL-2-R-inducing cytokines in the physiological lymphocyte activation and the leukemogenesis in ATL and other T cell leukemias is discussed.
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PMID:Interleukin-2 receptor-inducing factor(s) in adult T cell leukemia. 289 6

In normal human megakaryocytes, we identified a delayed rectifier type of voltage-gated outward K+ current (DRK). In two human megakaryoblastic tumor cell lines (DAMI, CHRF-288-11) and the human erythroleukemia cell line (HEL) the DRK current was not detected. To determine if the absence of the DRK current in the tumor cells is the result of the underlying malignant state, we examined megakaryocytes from myelogenous leukemia patients. In 24 of 29 megakaryocytes from the myelogenous leukemia patients, the DRK current was greatly suppressed, whereas in the remaining 5 megakaryocytes a normal large amplitude DRK current was present. We had the opportunity to reexamine megakaryocytes from a patient with acute promyelocytic leukemia (M3), after chemotherapy. Whereas the DRK current was suppressed before treatment, the current reappeared after chemotherapy. Exposure to the adenylate cyclase activator, forskolin, caused the appearance of a voltage-gated outward current in the megakaryocytes of patients with acute myelogenous leukemia. This finding suggests either that the channels underlying the DRK current are present but somehow suppressed in megakaryocytes from these patients or that forskolin induces a different voltage-gated outward current. We suggest that the megakaryocytes from the myelogenous leukemia patients with suppressed DRK current are abnormal, whereas the others may be normal megakaryocytes. The suppression of the DRK current may be a contributory factor to the dysregulation of thrombopoiesis (Zittoun et al: Semin Hop Paris 44:183, 1968 and Rabellino et al: Blood 63:615, 1984) in myelogenous leukemias.
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PMID:Suppression of the delayed rectifier type of voltage gated K+ outward current in megakaryocytes from patients with myelogenous leukemias. 762 Jan 58

The effects of several compounds acting through adenylate cyclase system and/or influencing prostaglandin biosynthesis on spermine-FBS cytotoxicity to human myelogenous leukemia K562 cells were studied. Salbutamol, a beta 2-adrenoceptor agonist inhibited to a certain extent spermine-FBS cytotoxic action to K562 cells, and propranolol, a beta 2-adrenoceptor antagonist, did not affect this inhibition. Aminophylline, an inhibitor of cyclic nucleotide phosphodiesterase, acted suppressing spermine-FBS cytotoxicity to K562 cells. Pretreatment of the cells with dexamethasone did not significantly alter salbutamol-related inhibition of spermine-FBS cytotoxicity. Indomethacin, an inhibitor of cyclooxygenases directly involved in prostaglandin biosynthesis, did not interfere with protective terbutaline effects against spermine-FBS cytotoxicity to K562 cells during the 24-hour period.
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PMID:To the mechanism of spermine-FBS cytotoxicity toward K562 human myelogenous leukemia cells. 820 12