Alteration of adenosine deaminase levels in peripheral blood lymphocytes of patients with gastric cancer

Purine-Metabolising Enzymes and Apoptosis in Cancer

The enzymes of both de novo and salvage pathways for purine nucleotide synthesis are regulated to meet the demand of nucleic acid precursors during proliferation. Among them, the salvage pathway enzymes seem to play the key role in replenishing the purine pool in dividing and tumour cells that require a greater amount of nucleotides. An imbalance in the purine pools is fundamental not only for preventing cell proliferation, but also, in many cases, to promote apoptosis. It is known that tumour cells harbour several mutations that might lead to defective apoptosis-inducing pathways, and this is probably at the basis of the initial expansion of the population of neoplastic cells. Therefore, knowledge of the molecular mechanisms that lead to apoptosis of tumoural cells is key to predicting the possible success of a drug treatment and planning more effective and focused therapies. In this review, we describe how the modulation of enzymes involved in purine metabolism in tumour cells may affect the apoptotic programme. The enzymes discussed are: ectosolic and cytosolic 5'-nucleotidases, purine nucleoside phosphorylase, adenosine deaminase, hypoxanthine-guanine phosphoribosyltransferase, and inosine-5'-monophosphate dehydrogenase, as well as recently described enzymes particularly expressed in tumour cells, such as deoxynucleoside triphosphate triphosphohydrolase and 7,8-dihydro-8-oxoguanine triphosphatase.

Prognostic value of serum liver enzymes in oral and oropharynx squamous cell carcinomas

BACKGROUND

Serum liver enzymes, which catalyze relevant catabolic pathways, have been indicated to be diagnostic and prognostic tools for several malignant tumors. The correlation between serum liver enzymes levels and survival in patients with oral and oropharynx squamous cell carcinomas (OSCC) is still absent. Here, we conducted a study focusing on predictive value of serum liver enzymes in terms of prognosis in the patients.

METHODS

A retrospective study including 134 OSCC patients from years 2009 to 2014 was performed to investigate the association between levels of pre-treatment serum liver enzymes, various clinical parameters and prognostic outcomes, which are overall survival (OS) and disease-free survival (DFS). Log-rank tests with Kaplan-Meier method were used to detect potential prognostic biomarkers. Multivariate analyses by Cox proportional hazards model were used to identify significant predictors of prognosis.

RESULTS

Serum adenosine deaminase (ADA) level was associated with patients' OS and DFS by univariate analyses (P = 0.006 and P = 0.024, respectively). Multivariate analyses showed that higher serum ADA (>17.2 U/L) (P = 0.019) as well as positive lymph node status (P = 0.035) independently predicted worse OS of patients with OSCC. In addition, older age (≥60 years) (P = 0.043) and positive lymph node status (P = 0.027) were independently prognostic parameters for poorer DFS.

CONCLUSIONS

Pre-operative serum ADA levels may serve as a reliable independent prognostic predictor for OS in OSCC patients.

Reconstruction of Tissue-Specific Metabolic Networks Using CORDA

Human metabolism involves thousands of reactions and metabolites. To interpret this complexity, computational modeling becomes an essential experimental tool. One of the most popular techniques to study human metabolism as a whole is genome scale modeling. A key challenge to applying genome scale modeling is identifying critical metabolic reactions across diverse human tissues. Here we introduce a novel algorithm called Cost Optimization Reaction Dependency Assessment (CORDA) to build genome scale models in a tissue-specific manner. CORDA performs more efficiently computationally, shows better agreement to experimental data, and displays better model functionality and capacity when compared to previous algorithms. CORDA also returns reaction associations that can greatly assist in any manual curation to be performed following the automated reconstruction process. Using CORDA, we developed a library of 76 healthy and 20 cancer tissue-specific reconstructions. These reconstructions identified which metabolic pathways are shared across diverse human tissues. Moreover, we identified changes in reactions and pathways that are differentially included and present different capacity profiles in cancer compared to healthy tissues, including up-regulation of folate metabolism, the down-regulation of thiamine metabolism, and tight regulation of oxidative phosphorylation.

Serum adenosine deaminase, catalase and carbonic anhydrase activities in patients with bladder cancer

OBJECTIVES

The relationship between adenosine deaminase and various cancers has been investigated in several studies. However, serum adenosine deaminase activity and carbonic anhydrase and catalase activities in patients with bladder cancer have not previously been reported. Therefore, the aim of this study was to measure serum adenosine deaminase, carbonic anhydrase and catalase activities in patients with bladder cancer.

MATERIALS AND METHODS

Forty patients with bladder cancer and 30 healthy controls were enrolled in the study. Serum adenosine deaminase, carbonic anhydrase and catalase activities were measured spectrophotometrically.

RESULTS

Serum adenosine deaminase, carbonic anhydrase and catalase activities were significantly higher in patients with bladder cancer than controls (all significant, p<0.001).

CONCLUSIONS

These markers might be a potentially important finding as an additional diagnostic biochemical tool for bladder cancer.

Association of adenosine deaminase, superoxide dismutase, and catalase activities with Helicobacter pylori

Our purpose was to investigate associations between adenosine deaminase (ADA), superoxide dismutase (SOD), and catalase (CAT) activities and H. pylori.Ninety-nine patients were studied. Eight antral mucosal biopsies were taken for biochemical assessment of ADA, CAT, AND SOD activity and histological assessment. H. pylori density wAS evaluated according to the updated Sydney system. Patients were divided into three groups according to Sydney classification. ADA activity was found to be higher in patients having H. pylori in the present study. Also, ADA activity was higher in patients with a severe density of H. pylori. SOD level was found to be significantly higher with increased H. pylori density in our study (P < 0.05). In addition, SOD activity was higher in it H. Pylori-positive than H. pylori-negative patients. We did not find CAT activity in some antral tissue specimens. The significantly high levels of ADA activity in patients with H. pylori infection may reflect the regulator role of ADA in acid secretion. The higher ADA level with increased H. pylori density and H. pylori positivity indicate the probable malign lymphoid process of the stomach. But these findings must be confirmed with larger studies that include different gastric lesions.

Adenosine deaminase and xanthine oxidase activities in bladder washing fluid from patients with bladder cancer: a preliminary study

Activities of adenosine deaminase (AD), and xanthine oxidase (XO) enzymes were measured in bladder washing fluid (BWF) from 37 patients with bladder cancer. The patients were divided into several groups according to their sex; pattern, number, and depth of the tumors; and tumor grade. There was a statistically significant difference in XO activities between the patients having no tumor and papillary tumor (p < 0.002). The differences in XO values between the patients having no tumor and single tumor; and with no tumor and multiple tumors were statistically significant (p < 0.012, p < 0.016 respectively). XO activities were increased in patients with both papillary and multiple tumors compared to tumor-free group. Regarding to the depth of tumors, only the differences in XO values between the patients having no tumor and superficial tumor was statistically significant (p < 0.037). XO values of patients in grade1 were higher than the patients having no tumor (p < 0.010). AD activities in patients with multiple and invasive tumor were increased compared to patients with single and superficial tumor. AD values in grade 3 were lower than grade 2. However, we did not find any statistically significant differences in AD activities in all groups. As a conclusion, increased XO activity in BWF might be a potentially important finding as an additional diagnostic biochemical tool for bladder cancer. But we could not say this for AD activity. Further investigations in a larger cohort of patients with bladder cancer are needed to enlighten the possible diagnostic role of XO and AD in BWF.

Activities of adenosine deaminase and 5'-nucleotidase in cancerous and noncancerous human colorectal tissues

In order to characterize human colorectal cancer, much attention has been paid to enzyme studies. However, little is known about the correlation between the levels of key enzymes of purine nucleotide pathway and some clinical and biological indicators of tumor invasiveness and aggressiveness. Adenosine deaminase (ADA) and 5'-nucleotidase (5'-NT) were measured in cancerous and cancer-free adjacent large bowel tissues from 38 patients with colorectal carcinoma. We have analyzed the relationship between the enzyme levels and some clinical and pathological parameters. The enzymes' activities were markedly higher in primary tumors than in corresponding normal mucosae. The ADA level in tumor tissue was significantly correlated with lymph node metastasis, histologic type, tumor location, and patient's age, whereas the 5'-NT level showed a significant correlation with tumor grade and tumor location. ADA activity in tumor tissues was significantly higher in patients whose clinical course remained stable than in those with recurrent diseases. The purine metabolism and salvage pathway activity of purine nucleotides are accelerated in the cancerous human colorectal tissue. Although our findings suggest that these enzymes' activities are most likely related to the same histomorphological architecture of the tumor, the authors believe that long-term follow-up studies are needed to evaluate the prognostic value of purine enzymes for colorectal cancer.

Tumor-promoting functions of adenosine

Tumor growth is a multifactorial process that, in addition to mutations leading to dysregulated expression of oncogenes and tumor suppressive genes, requires specific conditions that provide a supportive physiological environment at the primary and metastatic sites of the disease. Adenosine is one of the factors potentially contributing to tumor growth that thus far has not received adequate attention, despite evidence for a broad range of cytoprotective, growth-promoting, and immunosuppressive activities. Adenosine accumulates in solid tumors at high concentrations, and has been shown to stimulate tumor growth and angiogenesis and to inhibit cytokine synthesis, adhesion of immune cells to the endothelial wall, and the function of T-cells, macrophages, and natural killer cells. However, the mechanisms whereby adenosine accumulates in cancer and the specific effects that result from this accumulation are not well understood. This article surveys the available evidence that supports an important role of adenosine in cancer.

Activities of DNA turnover and free radical metabolizing enzymes in cancerous human prostate tissue

Activities of adenosine deaminase (ADA), 5'nucleotidase (5'NT), xanthine oxidase (XO), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) and levels of thiobarbituric acid reagent substances (TBARS) were measured in 10 cancerous and 10 noncancerous human prostate tissues. Decreased activities of DNA turnover enzymes (ADA and 5'NT), increased activities of GSH-Px and CAT, and unchanged activities of SOD and XO were observed in cancerous prostate tissues compared with those of noncancerous ones. TBARS levels were found to be higher in cancerous tissues than noncancerous ones. In correlation analysis, mostly positive correlations were established between enzyme activities of the cancerous tissues, whereas no meaningful correlations were found between enzyme activities of the noncancerous tissues except for a positive correlation between XO and SOD. The results indicate that the activities of DNA turnover enzymes were reduced, which was possibly an attempt to lower the rate of purine catabolism, and the activities of GSH-Px and CAT enzymes were increased, probably in response to increased free radical stress occurring in cancerous prostate tissues. Increased concentrations of TBARS suggested oxidant stress and thus accelerated peroxidative reactions in the cancerous tissues, even though antioxidant defense mechanisms were activated. These findings suggest that enzymatic antioxidant systems of cancerous prostate tissues cannot sufficiently eliminate oxidant factors and prevent cellular peroxidative reactions occurring during the carcinogenic process.

Adenosine deaminase activity in patients with the intestinal type of gastric carcinoma

Adenosine deaminase activity was studied in tissue slices taken endoscopically from gastric mucosa of patients with the intestinal type of gastric carcinoma. The enzyme activity was measured in mucosal homogenates by determination of ammonia liberated from substrate during 10-min incubation. It was found that: (1) the enzyme activity of de novo gastric cancer was significantly lower than that of recurrent cancer of the gastric remnant; and (2) the enzyme activity of uninvaded gastric mucosa surrounding the neoplastic lesion of non-operated stomach was significantly lower than of the gastric mucosa of partially resected stomach due to malignancy. Since the enzyme activity in gastric cancer and surrounding uninvaded gastric mucosa correlated well with the advance of neoplastic disease estimated by ultrasonography examination, we speculate that some systemic factors associated with tumor progression might be implicated in the regulation of adenosine deaminase activity.

Adenosine deaminase, 5'nucleotidase, xanthine oxidase, superoxide dismutase, and catalase activities in cancerous and noncancerous human bladder tissues

Activities of adenosine deaminase (ADA), 5'nucleotidase (5NT), xanthine oxidase (XO), superoxide dismutase (SOD), and catalase (CAT) enzymes were measured in cancerous and cancer-free adjacent bladder tissues from 36 patients with bladder cancer and in control bladder tissues from 9 noncancer patients. Increased ADA and decreased XO, SOD, and CAT activities were found in cancerous bladder tissues compared with those of cancer-free adjacent tissues and of control bladder tissues. Differences were also found between enzyme activities in the bladder of different disease stages and grades. In the cancerous tissues, only positive intracorrelations were found, but in the cancer-free adjacent tissues and control tissues, both positive and negative correlations were established between enzyme activities. Results suggested that purine metabolism and salvage pathway activity of purine nucleotides were accelerated in the cancerous human bladder tissues via increased ADA and decreased XO activities, probably together with changes in some other related enzyme activities and, free radical metabolising-enzyme activities were depressed in cancerous bladder tissues, which indicated exposure of cancerous tissues to more radicalic stress.

Adenosine deaminase, 5'-nucleotidase, xanthine oxidase, superoxide dismutase, and catalase activities in gastric juices from patients with gastric cancer, ulcer, and atrophic gastritis

Adenosine deaminase (ADA), 5'-Nucleotidase (5NT), Xanthine oxidase (XO), Cu-Zn Superoxide dismutase (SOD) and Catalase (CAT) activities were determined in gastric juices from patients with gastric cancer, ulcer, gastritis and from healthy subjects. Enzyme activities were given as units per ml gastric juice and units per mg protein in gastric juice. ADA, 5NT and XO activities were found lower and protein concentrations were found higher in the cancer group than controls. There was however no significant difference between Cu-Zn SOD activities of the cancer and control groups. In all groups including control one, we could not find catalase activities in most of the samples. On the other hand, ADA, 5NT activities and protein concentrations in the gastric juice were lower in the gastritis group than control group. In the ulcer group, we found higher Cu-Zn SOD and XO activities and lower 5NT activity and protein concentrations compared with control values. In an attempt to establish statistical correlations between mean enzyme activities, pH and protein concentrations in the gastric juices of the groups, we found noticeable intra and inter-correlations, which indicated possible relations between DNA and free radical metabolizing enzymes.

Serum adenosine deaminase activity in brain tumours

Adenosine deaminase (ADA) activity in serum was estimated in 86 patients with intracranial tumours and 40 healthy volunteers. Although high ADA concentrations in biological fluids and tumour tissues were observed in several neoplastic conditions, there was no significant difference in the ADA in sera of brain tumour patients when compared to the control values. Therefore, cell-mediated immunity probably does not play a significant role in brain tumours.