Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.5.4.17 (adenosine deaminase)
 5,206 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The induction of apoptosis by adenosine was studied in the mouse neuroblastoma cell line N1E-115. Apoptosis was characterized by fluorescence and electron microscopy, fluorescence-activated cell sorter (FACS) analysis, and caspase activity assays. A sixteen-hour exposure to 100 microM of adenosine led to chromatin condensation and caspase activation. However, selective agonists for all four adenosine receptors were ineffective. Caspase activation could be blocked partially by an inhibitor of the nucleoside transporter, dipyridamole, and completely by uridine, a competing substrate for adenosine transport. 2'-Deoxycoformycin, an inhibitor of adenosine deaminase, enhanced caspase activation by adenosine but had no effect by itself. Caspase activation could be blocked by 5'-amino-5'-deoxyadenosine, which inhibits the phosphorylation of adenosine by adenosine kinase. These results indicate that adenosine receptors are not involved in adenosine-induced apoptosis in N1E-115 cells, but that uptake of adenosine and its subsequent phosphorylation is required.
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PMID:Extracellular adenosine-induced apoptosis in mouse neuroblastoma cells: studies on involvement of adenosine receptors and adenosine uptake. 1122 75

Pentostatin (2prime prime or minute-deoxycoformycin, dCF) is a product of the fermentation of Streptomyces antibioticus. It is a tight-binding inhibitor of adenosine deaminase (ADA), an enzyme essential in cellular metabolism of purines. Children with congenital absence of ADA suffer from atrophy of lymphoid tissues and severe combined immune deficiency (SCID) syndrome. It was speculated that pentostatin would be lymphocytotoxic, and this proved to be the case, promoting its investigation in lymphoid neoplasms. It was anticipated that pentostatin would be most active in neoplasms with high intracellular concentrations of ADA---e.g., acute lymphocytic leukemia (ALL), particularly its T cell variety. Although pentostatin proved to be active in ALL, large doses were required and toxic effects outweighted therapeutic benefits. By contrast, pentostatin proved to be exceptionally active in hairy cell leukemia (HCL), a B cell neoplasm with low intracellular concentrations of ADA. Pentostatin has since been shown to possess activity in chronic lymphocytic leukemia, prolymphocytic leukemia, cutaneous T cell lymphomas, adult T cell lymphoma-leukemia, and low-grade non-Hodgkin's lymphomas. It potentiates the activity of vidarabine against viruses and against the cells of acute myeloid leukemia. Pentostatin is inactive in melanoma and renal carcinoma, but has not been adequately evaluated in other solid tumors. The toxic effects of pentostatin include renal failure, central nervous system (CNS) depression, immunosuppression, keratoconjunctivitis, and opportunistic infections. In the absence of pre-existing bone marrow compromise, pentostatin produces only mild myelosuppression. Aside from its use as an antineoplastic agent, pentostatin has potential applications as an immunosuppresive drug, as an antiviral agent, as an antimalarial compound, and in the protection of cells of the CNS from damage induced by ischemia and anoxia.
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PMID:Pentostatin (2prime prime or minute-Deoxycoformycin): Clinical Pharmacology, Role In Cancer Chemotherapy, and Future Prospects. 1184 52

The ability of increased endogenous adenosine to mitigate microvascular derangements in sepsis was studied. Pentostatin (2'-deoxycoformycin), an inhibitor of adenosine deaminase, was administered to mice immediately after induction of sepsis by cecal ligation and puncture. Intravital video microscopy of cremasteric postcapillary venules was performed. Leukocyte rolling and adhesion were significantly increased in septic mice compared with control mice. Treatment of septic mice with pentostatin significantly decreased leukocyte rolling and adhesion (6.02 +/- 0.09 versus 1.72 +/- 0.12 rolling cells/min, 2.07 +/- 0.04 versus 0.62 +/- 0.05 adherent cells/100 microm per minute; p < 0.001). Albumin leakage (ratio) was significantly attenuated in septic animals treated with pentostatin (0.42 +/- 0.05 versus 0.21 +/- 0.04; p < 0.01). Circulating levels of interleukin-6, tumor necrosis factor-alpha, and soluble tumor necrosis factor type II receptor were decreased in septic mice treated with pentostatin. Survival was significantly improved at 48 hours in mice treated with pentostatin. These results suggest an important role for adenosine in modulating both leukocyte-dependent and -independent mechanisms of endothelial injury in sepsis. Exploiting the advantageous action of endogenous adenosine represents a potentially useful and novel therapeutic approach for the treatment of sepsis.
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PMID:Adenosine deaminase inhibition attenuates microvascular dysfunction and improves survival in sepsis. 1209 Nov 65

The role of adenosine deaminase in the interactions between adenosine A(1) and dopamine D(1) receptors was studied in a mouse fibroblast cell line stably cotransfected with human D(1) receptor and A(1) receptor cDNAs (A(1)D(1) cells). Confocal laser microscopy analysis showed a high degree of adenosine deaminase immunoreactivity on the membrane of the A(1)D(1) cells but not of the D(1) cells (only cotransfected with human D(1) receptor cDNAs). In double immunolabelling experiments in A(1)D(1) cells and cortical neurons a marked overlap in the distribution of the A(1) receptor and adenosine deaminase immunoreactivities and of the D(1) receptor and adenosine deaminase immunoreactivities was found. Quantitative analysis of A(1)D(1) cells showed that adenosine deaminase immunoreactivity to a large extent colocalizes with A(1) and D(1) receptor immunoreactivity, respectively. The A(1) receptor agonist caused in A(1)D(1) cells and in cortical neurons coaggregation of A(1) receptors and adenosine deaminase, and of D(1) receptors and adenosine deaminase. The A(1) receptor agonist-induced aggregation was blocked by R-deoxycoformycin, an irreversible adenosine deaminase inhibitor. The competitive binding experiments with the D(1) receptor antagonist [(3)H]SCH-23390 showed that the D(1) receptors had a better fit for two binding sites for dopamine, and treatment with the A(1) receptor agonist produced a disappearance of the high-affinity site for dopamine at the D(1) receptor. R-Deoxycoformycin treatment, which has previously been shown to block the interaction between adenosine deaminase and A(1) receptors, and which is crucial for the high-affinity state of the A(1) receptor, also blocked the A(1) receptor agonist-induced loss of high-affinity D(1) receptor binding. The conclusion of the present studies is that the high-affinity state of the A(1) receptor is essential for the A(1) receptor-mediated antagonistic modulation of D(1) receptors and for the A(1) receptor-induced coaggregates of A(1) and adenosine deaminase, and of D(1) and adenosine deaminase. Thus, the confocal experiments indicate that both A(1) and D(1) receptors form agonist-regulated clusters with adenosine deaminase, where the presence of a structurally intact adenosine deaminase bound to A(1) receptors is important for the A(1)-D(1) receptor-receptor interaction at the level of the D(1) receptor recognition.
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PMID:Interactions among adenosine deaminase, adenosine A(1) receptors and dopamine D(1) receptors in stably cotransfected fibroblast cells and neurons. 1215 Jul 91

Aggressive adult T-cell leukemia-lymphoma (ATL) generally has a very poor prognosis. Deoxycoformycin (DCF, pentostatin), an inhibitor of adenosine deaminase, has shown promising therapeutic efficacy for ATL. To develop a new effective therapy against aggressive ATL, we carried out a multicenter phase II study of DCF-containing combination chemotherapy. Sixty-two previously untreated patients with ATL (34, 21, and 7 patients with diseases of the acute, lymphoma, and unfavorable chronic types, respectively) were enrolled, but 2 were ineligible because they were judged to be favorable chronic types. A regimen of 1 mg/m2 vincristine intravenously on days 1 and 8, 40 mg/m2 doxorubicin intravenously on day 1, 100 mg/m2 etoposide intravenously on days 1 through 3, 40 mg/m2 prednisolone orally on days 1 and 2, and 5 mg/m2 DCF intravenously on days 8, 15, and 22 was administered every 28 days for 10 cycles unless disease progression or toxic complications occurred. Fifty-two percent of 60 eligible patients responded (95% confidence interval [CI], 38%-65%), with 17 patients (28%) achieving a complete response (CR) (95% CI, 17%-41%) and 14 achieving a partial response. The CR rate was inferior to those of both the previous Japan Clinical Oncology Group (JCOG) study (JCOG8701, 43%), a 9-drug combination chemotherapy of the second generation, and the subsequent JCOG9303 study (35%), a granulocyte colony-stimulating factor-supported, dose-intensified, 9-drug regimen. The median survival time of the 60 eligible patients in JCOG9109 was 7.4 months, and the estimated 2-year survival rate was 15.5%; these results were identical with those of JCOG8701 but inferior to those of JCOG9303. Grade 4 neutropenia and infection of grade 3 or greater were frequent (67% and 22%, respectively), and treatment-related death was observed in 4 patients (7%), septicemia in 2, and cytomegalovirus pneumonia in 2. We conclude that DCF-containing combination chemotherapy is not a promising regimen against aggressive ATL.
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PMID:Deoxycoformycin-containing combination chemotherapy for adult T-cell leukemia-lymphoma: Japan Clinical Oncology Group Study (JCOG9109). 1262 52

Pentostatin (2'-deoxycoformycin; Nipent), a potent inhibitor of adenosine deaminase, is a purine nucleoside analogue that is highly effective in the treatment of hairy-cell leukemia. This agent is capable of inducing durable complete remissions in the majority of patients, and is capable of re-inducing a complete remission in many of the patients who have relapsed. Pentostatin appears to have changed the natural history of this disease. Long-term follow-up studies suggest that patients with hairy-cell leukemia who are induced into complete remission have a projected survival comparable to age-matched controls. While purine nucleoside analogues induce profound T-cell dysfunction and longstanding immunosuppression, the incidence of secondary malignancies is apparently not increased. Infections still pose a threat to these patients, and effective strategies for treating this disease that do not further compromise the immune system are needed. Patients with this disease should be encouraged to participate in ongoing clinical trials to better define the optimal treatment regimen. New studies should explore the combination of pentostatin and rituxan in treating the typical form of hairy-cell leukemia, and the incorporation of new agents for those with the rare variant form of this disease.
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PMID:Pentostatin in the treatment of hairy-cell leukemia. 1267 Apr 68

Pentostatin is an adenosine deaminase (ADA) inhibitor with antineoplastic activity. CD26 is a surface glycoprotein with a key role in T cell function as the ADA binding protein. We conducted a phase II study to evaluate pentostatin efficacy in relapsed T-non-Hodgkin's lymphoma (T-NHL) and to correlate response with tumor CD26 expression. We also examined the lymphopenic effect of pentostatin on CD26+ T lymphocytes. Eighteen patients were registered for the study. Pentostatin was administered as intravenous bolus daily over 3 days at an initial dose of 5 mg/m(2)/day, repeated every 4 weeks. CD26 surface expression on tumor cells and T lymphocytes was determined by flow cytometry. Out of 14 patients evaluable for response, there was 1 (7%) complete response (CR) and 6 (43%) partial responses (PR). Median progression-free survival for responders was 6 months (range: 2-15 months); median number of courses was 4 (range: 1-6). Responders included 1 of 2 CD26+ and 5 of 9 CD26- cases. Pentostatin also specifically depleted CD26+ rather than CD26- T lymphocytes, potentially associated with immunosuppression. We therefore conclude that while pentostatin is a safe and active agent for T-NHL regardless of CD26 expression, it may selectively deplete CD26+ T lymphocytes, with potentially significant clinical implications.
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PMID:Pentostatin in T-non-Hodgkin's lymphomas: efficacy and effect on CD26+ T lymphocytes. 1288 33

Pentostatin (2'-deoxycoformycin, dCF) is a purine nucleoside analog and a product of the fermentation of Streptomyces antibioticus. It is a tight-binding inhibitor of adenosine deaminase (ADA), an enzyme essential in the cellular metabolism of purines. Children with congenital absence of ADA suffer from atrophy of lymphoid tissues and severe combined immune deficiency (SCID) syndrome. It was hypothesized that pentostatin would be lymphocytotoxic and this proved to be true; this finding prompted its investigation in lymphoid neoplasms. It was anticipated that pentostatin would be most active in neoplasms with high intracellular concentrations of ADA, e.g. acute lymphocytic leukemia (ALL), particularly of the T-cell variety. Although pentostatin proved to be active in ALL, large doses were required and major toxic effects outweighed therapeutic benefits. By contrast, pentostatin proved to be exceptionally active in hairy cell leukemia (HCL), a B-cell neoplasm with low intracellular concentrations of ADA. Pentostatin has since been shown to possess activity in chronic lymphocytic leukemia, prolymphocytic leukemia, cutaneous T-cell lymphomas, adult T-cell lymphoma-leukemia, and low grade non-Hodgkin's lymphomas. It potentiates the activity of vidarabine against viruses and against the cells of acute myeloid leukemia. Pentostatin is inactive in melanoma and renal carcinoma, but has not been adequately evaluated in other solid tumors. The toxic effects of pentostatin include renal failure, central nervous system (CNS) depression, immunosuppresion, keratoconjunctivitis, and opportunistic infections. In the absence of pre-existing bone marrow compromise, pentostatin produces only mild myelosuppression. Aside from its use as an antineoplastic agent, pentostatin has potential applications as an immunosuppressive drug, as an antiviral agent, as an antimalarial compound, and in the protection of cells of the CNS from damage induced by ischemia and anoxia. Clinical studies with pentostatin are ongoing, and its roles in the management of neoplastic and non-neoplastic diseases have yet to be fully defined.
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PMID:Deoxycoformycin (pentostatin): clinical pharmacology, role in the chemotherapy of cancer, and use in other diseases. 1465 Dec 24

Pentostatin (Nipent), formerly known as deoxycoformycin, is a profound inhibitor of the enzyme adenosine deaminase, resulting in the accumulation of metabolites that inhibit ribonucleotide reductase, which in turn inhibits DNA synthesis. Pentostatin was the first of the purine analogs to undergo extensive testing as an anticancer agent and the first to receive US Food and Drug Administration approval for a treatment indication. It is highly effective as first-line monotherapy in hairy cell leukemia, with a complete response rate of 80% and a 10-year survival rate of around 80%. Pentostatin is also active in chronic lymphocyte leukemia as a single agent, but appears even more promising in combination approaches with the alkylating agents chlorambucil or cyclophosphamide. Due to the increasing recognition of delayed severe stem cell and immune suppression following therapy with other purine analogs, there has been renewed interest in pentostatin, especially in combination with chemotherapy and/or the monoclonal antibody rituximab (Rituxan) in chronic lymphocyte leukemia.
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PMID:Pentostatin (Nipent) in the treatment of chronic lymphocyte leukemia and hairy cell leukemia. 1474 54

Peripheral T-cell lymphomas (PTCLs) comprise a heterogeneous group of lymphomas with different clinical presentation and morphologic, immunophenotypic, and cytogenetic markers. Many of these malignancies follow an aggressive course and current therapeutic strategies are limited. The prognosis for these patients is usually very poor. The purine analogues are a class of drugs that have been shown to be active in patients who have T-cell lymphoma. T cells have a very high concentration of adenosine deaminase (ADA), a key enzyme in the purine degradation pathway, which is blocked by this class of agent. Pentostatin has been the most extensively studied of these drugs in PTCL and has shown variable response rates. However, many of the reports are limited to small single-center studies. Larger prospective randomized trials will be necessary to examine this therapy and to further explore combination regimens, which may result in increased responses.
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PMID:Role of single-agent purine analogues in therapy of peripheral T-cell lymphomas. 1654 11


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