The combination of adenosine deaminase inhibition and deoxyadenosine induces apoptosis in a human astrocytoma cell line.

Alterations in the functions of astrocytes contribute to the appearance of a variety of neurological pathologies. Gliomas, especially those of astrocytic origin, are particularly resistant to chemotherapy and are often characterized by a poor prognosis. Neuroblastoma is the tumour with the higher incidence in infants. Anticancer drugs can induce apoptosis and their cytotoxic effect is often mediated by this process. We have previously demonstrated that the combination of deoxycoformycin, a strong adenosine deaminase inhibitor, and deoxyadenosine is toxic for a human astrocytoma cell line. In fact, after 15 h of treatment, this combination increases both mitochondrial reactive oxygen species and mitochondrial mass, induces apoptosis as indicated by cytochrome c release from mitochondria and activation of caspase-3. These events are preceded by reduction in lactate release in the medium. In this work we demonstrate that after 8 h of incubation with deoxyadenosine and deoxycoformycin, caspase-8 is activated, mitochondrial mass increases and mitochondrial reactive oxygen species decrease. The addition of baicalein to the incubation medium reduces cell death and caspase-3 activity induced by deoxycoformycin and deoxyadenosine in combination. This protective effect is correlated to an increase of lactate released in the medium, a decrease in the intracellular levels of dATP, and an increase in ATP levels, as compared with the cells subjected to the treatment with deoxycoformycin and deoxyadenosine without any further addition. The effect of baicalein appears to be related to an inhibition of deoxyadenosine phosphorylation, rather than or in addition to the well known antioxidant activity of the compound. This work indicates that an astrocytoma cell line, reported to be resistant to mitochondria-dependent pathways of apoptosis, is indeed very sensitive to a manipulation affecting the balance of cellular purine metabolite concentrations. The same treatment is also cytotoxic on a neuroblastoma cell line, thus suggesting long term implications for cancer therapy.

Standard pentostatin dose reductions in renal insufficiency are not adequate: selected patients with steroid-refractory acute graft-versus-host disease.

BACKGROUND AND OBJECTIVE: Pentostatin is an irreversible inhibitor of adenosine deaminase and has been used to prevent graft-versus-host disease (GVHD) and to treat both acute and chronic GVHD. Dose reduction equations for patients with renal insufficiency are based on few patients with limited pharmacokinetic and clinical results. This phase II study (NCT00201786) was conducted to assess pentostatin efficacy and infectious complications seen from our previous phase I study in steroid-refractory acute GVHD (aGVHD). PATIENTS AND METHODS: Hospitalized patients with steroid-refractory aGVHD were given pentostatin 1.5 mg/m(2)/day intravenously on days 1-3 of each 14-day cycle. Prior to each dose, dose modifications were based on Cockcroft-Gault estimated creatinine clearance (eCrCL) with 30-50 mL/min/1.73 m(2) leading to a 50 % dose reduction and eCrCL less than 30 mL/min/1.73 m(2) leading to study removal. Plasma pentostatin area under the concentration-time curve (AUC) and incidence of infectious complications were evaluated. RESULTS: Two of the eight patients treated demonstrated excessive pentostatin exposure as determined by measurement of AUC. One of these patients had renal impairment, whereas the other patient demonstrated borderline renal function. Despite dose reduction to 0.75 mg/m(2), AUCs were significantly increased compared to the other patients in this study. Seven of eight patients treated with pentostatin had cytomegalovirus (CMV) viremia after pentostatin treatment; however none developed proven CMV disease. CONCLUSION: A 50 % dose reduction in patients with eCrCL 30-50 mL/min/1.73 m(2) seems reasonable. However, the eCrCL should be interpreted with extreme caution in patients who are critically ill and/or with poor performance status. Renal function assessment based on the Cockcroft-Gault method could be significantly overestimated thus risking pentostatin overdosing. These results imply a need to closely monitor pentostatin exposure in patients with renal insufficiency.

Acute effect of ß-sitosterol on calcium uptake mediates anti-inflammatory effect in murine activated neutrophils.

OBJECTIVES: To evaluate the effect of ß-sitosterol on 45Ca²âº uptake in activated murine neutrophils, and upon myeloperoxidase and adenosine deaminase activity, and interleukin-1ß (IL-1ß) and tumour necrosis factor-α (TNF-α) levels, in carrageenan-induced inflammation in the mouse air pouch model. METHODS: Dried Esenbeckia leiocarpa bark was macerated and extracted resulting in a crude hydroalcoholic extract (CHE) that was partitioned to obtain an alkaloid fraction. The alkaloid was then partitioned in polar and nonpolar subfractions. ß-Sitosterol was isolated from the nonpolar subfraction and identified by comparison with the literature. The effect of ß-sitosterol on 45Ca²âº uptake in activated murine neutrophils, and upon myeloperoxidase and adenosine deaminase activity, IL-1ß and TNF-α levels in carrageenan-induced inflammation in mice were evaluated. KEY FINDINGS: ß-Sitosterol promoted a time- and dose-dependent increase of the calcium uptake in activated neutrophils that was promptly reversed by nifedipine, BAPTA-AM, LY294002, and colchicine. ß-Sitosterol inhibited myeloperoxidase and adenosine deaminase activity, and IL-1ß and TNF-α levels. CONCLUSIONS: ß-Sitosterol inhibited either myeloperoxidase and adenosine deaminase activity or IL-1ß and TNF-α levels. This effect seemed to be mediated by the calcium uptake in activated neutrophils in a time- and concentration-dependent manner through L-type voltage dependent calcium channels, intracellular calcium, phosphoinositide kinase-3, and microtubule modulation.

Prophylaxis of graft-versus-host disease in unrelated donor transplantation with pentostatin, tacrolimus, and mini-methotrexate: a phase I/II controlled, adaptively randomized study.

PURPOSE: Acute graft-versus-host disease (aGVHD) is a major cause of morbidity and mortality after matched unrelated, related, or mismatched related donor hematopoietic stem-cell transplantation (HSCT). Improved GVHD prevention methods are needed. Pentostatin, an adenosine deaminase inhibitor, leads to lymphocyte depletion with low risk of myelosuppression. We hypothesized that addition of pentostatin to GVHD prophylaxis with tacrolimus and mini-methotrexate may improve outcomes, and we conducted a Bayesian adaptively randomized, controlled, dose-finding study, taking into account toxicity and efficacy. PATIENTS AND METHODS: Success was defined as the patient being alive, engrafted, in remission, without GVHD 100 days post-HSCT and no grade ≥ 3 GVHD at any time. Patients were randomly assigned to pentostatin doses of 0, 0.5, 1.0, 1.5, and 2.0 mg/m(2) with drug administered on HSCT days 8, 15, 22, and 30. Eligible patients were recipients of mismatched related (n = 10) or unrelated (n = 137) donor HSCT. RESULTS: Median age was 47 years. Thirty-seven, 10, 29, 61, and 10 patients were assigned to the control and four treatment groups, respectively, with comparable baseline characteristics. Pentostatin doses of 1.0 and 1.5 mg/m(2) had the highest success rates (69.0% and 70.5%) versus control (54.1%). The posterior probabilities that the success rates were greater with 1.5 mg/m(2) or 1.0 mg/m(2) versus control are 0.944 and 0.821, respectively. Hepatic aGVHD rates were 0%, 17.2%, and 11.1%, respectively, for 1.5 mg/m(2), 1.0 mg/m(2), and control groups. No grades 3 to 4 aGVHD occurred in 11 HLA-mismatched recipients in the 1.5 mg/m(2) group. CONCLUSION: Pentostatin increased the likelihood of success as defined here, and should be further investigated in larger randomized, confirmatory studies.

Utilidad de la adenosina deaminasa (ADA): interferón gamma y biopsia pleural para el diagnóstico de tuberculosis pleural / Efficacy of the adenosine deaminase: interferon gamma and pleural biopsy for the diagnosis of pleural tuberculosis

El diagnóstico de la tuberculosis pleural es difícil usando solo los métodos convencionales. El objetivo de este trabajo es demostrar la eficacia de la adenosina deaminasa, interferón gamma y biopsia pleural para el diagnóstico de tuberculosis pleural y si estos biomarcadores podrían obviar la práctica de la biopsia. Se realizó el estudio prospectivo de 52 muestras de líquido pleural y 54 biopsias pleurales de 52 pacientes (M/F: 30/22). La edad promedio fue 38,8 ± 20,6 años. Los derrames fueron: tuberculosis pleural, 33 (63,46%), asociados a infección respiratoria baja. 10 (19,23%) y 9 neoplásicos (17,30%). La sensibilidad de interferon gamma, adenosina deaminasa y biopsia fue de: 88,0%, 76,0% y 65,0%, respectivamente y especificidad de: 78,0%, 63,0% y 100,0% respectivamente. Conclusiones: la adenosina deaminasa no es util aislada como método diagnóstico para la tuberculosis pleural. Se recomienda no obviar el cultivo ni la biopsia plaural y siendo Venezuela un país de alta prevalencia de tuberculosis, hacer de rutina, la medición de interferón gamma y la toracoscopia.

The diagnosis of pleural tuberculous is difficult using only conventional methods. The aim of this paper is to demostrate the efficacy of the adenosine deaminase Interferon gamma and pleural biopsy for the diagnosis of pleural tuberculosis and if these biomarkers could ignore the practice of the biopsy. The prospective study of 52 samples of pleural fluid and 54 pleural biopsies of 52 patients was conducted. The median age was 38.8 (20.6 years.). Tuberculosis etiology spills were 33 (63.46%): associated with low respiratory infection 10 (19.23%) and 9 neoplastic (17,30%). The sensitivity of Interferon gamma, adenosine deaminase and biopsy was 88.0%, 76.0% to 65.0% respectively and the specificity was 78.0% and 63.0% 100.0% respectively. Conclusions: the adenosine deaminase is not useful only as a diagnostic method for the pleural tuberculosis. It is recommended to not override the cultivation or do the pleural biopsy and being Venezuela as a country of high prevalence of tuberculosis. make routine, the measurement of gamma interferon and the thoracoscopy it is recommended.