Glutathione S-transferase alpha as marker for hepatocellular damage in pre-eclampsia and HELLP syndrome.
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Abdominal Pain↗
Biomedical subjects
W H Peters
Publications and source records attributed to W H Peters.
Glutathione S-transferase pi in colorectal tumors is predictive for overall survival.
Glutathione S-transferases (GSTs) are enzymes involved in the detoxification of xenobiotics and are divided into four subclasses, alpha, mu, pi, and theta, with different although overlapping substrate specificities. Most human gastrointestinal tumors contain increased amounts of GST-pi and GST enzyme activity. The relationship between GST parameters and tumor and patient characteristics, including overall survival, were studied retrospectively in 100 primary colorectal adenocarcinomas. Levels of GST-alpha, GST-mu, GST-pi, and GST enzyme activity were not related to the Dukes stage, differentiation grade, localization, histological type and diameter of the tumor, or gender and age of the patient. Fifty-seven patients died (median survival, 21 months; range, 1-65 months) during follow-up, and 43 patients were still alive at the closing date of the study (median follow-up, 68 months; range, 60-87 months). Optimal dichotomization and uni- and multivariate analyses were done with the Cox proportional hazard model. Multivariate analysis with all clinicopathological parameters revealed higher Dukes stage (hazard ratio, 2.7; P < 0.001) and older age (hazard ratio, 2.8; P = 0.001) to be the only independent prognostic variables for overall survival. In contrast to GST-alpha and GST-mu, high levels of GST-pi (hazard ratio, 3.1; P = 0.002) and GST enzyme activity (hazard ratio, 2.0; P = 0.020) in the tumors were found to have a significant prognostic value independent from the clinicopathological parameters when added separately to this Cox model. Thus, this study indicates that GST subclass levels in colorectal adenocarcinomas are not related to clinicopathological parameters and that the GST-pi level and GST enzyme activity have a prognostic value for the overall survival of the patients.
Adenocarcinoma↗
Cellular basis for differential sensitivity to cisplatin in human germ cell tumour and colon carcinoma cell lines.
Cisplatin (CDDP) resistance mechanisms were studied in a model of three germ cell tumour and three colon carcinoma cell lines representing intrinsically CDDP-sensitive and -resistant tumours respectively. The CDDP sensitivity of the cell lines mimicked the clinical situation. The glutathione levels of the cell lines correlated with CDDP concentrations inhibiting cell survival by 50% (IC50); total cellular sulphydryl content (TSH) was unexpectedly inversely correlated with IC50. IC50 correlated neither with glutathione S-transferase (GST) nor with GST pi expression, topoisomerase I or II activity. Immediately after 4 h incubation with CDDP, platinum (Pt) accumulation and Pt bound to DNA were not correlated, but after another 24 h drug-free culture, Pt binding to DNA in germ cell tumour but not in colon carcinoma cell lines correlated with IC50. With the exception of in vitro sensitivity and TSH, none of the parameters studied discriminated between the two groups of cell lines. Correction of CDDP sensitivity parameters for phenotypical differences did not influence statistical correlations. Analysis of variance revealed a correlation between IC50 and the combination of glutathione, GST activity and Pt bound to DNA. But at other CDDP cytotoxicity levels sensitivity was also correlated with Pt accumulation, topoisomerase II activity and TSH in various combinations. This model of intrinsic CDDP resistance showed that multiple parameters ought to be studied to explain CDDP resistance, but did not elucidate the cause of the unique sensitivity of germ cell carcinoma, although the unexpected values of TSH deserve further attention.
Adenocarcinoma↗
Enhancement of rat hepatic and gastrointestinal glutathione and glutathione S-transferases by alpha-angelicalactone and flavone.
The naturally occurring anticarcinogens flavone and alpha-angelicalactone incorporated separately and simultaneously in the diet at 0.5, 0.1, 0.05 and 0.01% w/w, were studied with respect to their effects on oesophageal, gastric, intestinal, colonic and hepatic (i) glutathione S-transferase (GST) enzyme activity, (ii) GST isozyme levels and (iii) glutathione (GSH) content in male Wistar rats. GST enzyme activity was significantly increased in the three treatment groups at one or more sites. The most substantial inductions were seen in oesophagus and stomach by 0.5% alpha-angelicalactone (1.9- and 2.3-fold respectively); and in small intestine, colon and liver by 0.5% combination diet (2.5-, 1.4- and 4.0-fold respectively). The inducing capacities declined with decreasing anticarcinogen concentrations. GST enzyme activity was induced in liver and to a lesser extent in small intestine and stomach. In general, in combination groups similar effects were seen as after treatment with alpha-angelicalactone or flavone separately. However, colonic GST enzyme activity was increased in the 0.5% combination group (1.4-fold), whereas in the corresponding flavone or alpha-angelicalactone groups no induction was observed. Concomitant changes in GST isozyme levels occurred. The involvement was the highest for GST-alpha (75%), followed by GST-mu (58%) and GST-pi (33%). Increased GSH levels were obtained in stomach and liver in all three treatment groups at various concentrations. These data demonstrate that dietary administration of flavone or alpha-angelicalactone, even at relatively low concentrations, may exert chemopreventive effects in stomach, small intestine, liver and to a lesser extent in oesophagus by enhancing the GST detoxification system, mainly by induction of GST-alpha and GST-mu isozymes. In addition, simultaneous administration of flavone and alpha-angelicalactone may result in anticarcinogenic effects in the colon by the same principle.
4-Butyrolactone↗
Glutathione S-transferases and glutathione in human head and neck cancer.
Glutathione S-transferase (GST) enzyme activity, GST isoenzyme composition and glutathione (GSH) concentration were assessed in normal and squamous cell carcinoma specimens of 14 patients with oral or oropharyngeal cancer and 11 patients with laryngeal cancer. Comparing malignant with normal oral/oropharyngeal tissues, no significant differences in GSH content, GST enzyme activity or isoenzyme composition were found. However, some tumours had up to 3-fold increased GST enzyme activities and 11 malignant samples over-expressed GST-pi. GST-pi was present in all normal and malignant oral/oropharyngeal specimens investigated, whereas class alpha and class mu were detected in only a few samples. GST-mu was present in 28% of the patients with oral/oropharyngeal tumors as compared with approximately 60% in the normal population. GST-alpha, -mu and -pi were detected in 91, 64 and 100% of the normal laryngeal tissues respectively. In laryngeal tumours significantly higher levels of GST-pi and GSH but significantly lower amounts of GST-alpha were detected. Levels of class mu GST were generally lower in cancerous tissues, but differences were not significant. In comparison with normal oral/oropharyngeal tissues, normal laryngeal tissues contained almost twice the amount of GST enzyme activity due to higher class alpha enzyme levels. It is concluded that GST-pi is elevated in 11 out of 14 tumours of the oral cavity and values are significantly increased in tumours of the larynx, which may contribute to the inherent anti-cancer drug resistance of these malignancies. In laryngeal tumours the increased GSH levels may confer additional resistance to radiation therapy.
Aged↗
Effects of consumption of brussels sprouts on plasma and urinary glutathione S-transferase class-alpha and -pi in humans.
The effects of consumption of glucosinolate-containing Brussels sprouts on plasma and urinary glutathione S-transferase (GST) class-alpha and -pi were investigated. Five male and five female non-smoking volunteers were randomly assigned to two groups in a crossover design. Five persons started on a glucosinolate-free diet (control period), while the other five consumed 300 g of cooked Brussels sprouts per day, at the expense of 300 g of glucosinolate-free vegetables (sprouts period). Dietary regimes were reversed after 1 week. GST levels were measured by enzyme-linked immunoabsorbent assay. At the end of the sprouts period, a significant increase (1.5-fold) in plasma class-alpha GST levels was observed in males but not in females (control versus sprouts, paired t-test; P-values 0.031 and 0.317 respectively), while plasma GST class-pi levels as well as secretion of urinary GST class-alpha and -pi levels remained unchanged. We conclude that (i) increased plasma GST class-alpha levels in males originate probably solely from the liver and not from stomach, intestine or kidney; (ii) males are more susceptible for induction of hepatic GSTs than females; and (iii) urinary GST concentration seems less useful as a biomarker for hepatic GST induction.
Adult↗
Effects of consumption of Brussels sprouts on intestinal and lymphocytic glutathione S-transferases in humans.
A high intake of glucosinolate-containing cruciferous vegetables, such as Brussels sprouts (Brassica oleraceae), has been linked to a decreased cancer risk, but the underlying mechanism is still unclear. The aim of this study was to reveal possible modulating effects of consumption of Brussels sprouts on duodenal, rectal and lymphocytic (i) glutathione S-transferase (GST) enzyme activity, (ii) GST isozyme levels and (iii) glutathione (GSH) content. Ten healthy non-smoking volunteers were randomly assigned to two groups in a cross-over design. Five persons started on a glucosinolate-free diet (control period), while the other five consumed 300 g/day cooked Brussels sprouts, at the expense of 300 g glucosinolate-free vegetables (sprouts period). After 7 days the regimen was changed for a further week. At the end of both periods blood samples and duodenal and rectal biopsies were taken. Mean GST activity showed marked differences between duodenal, rectal and lymphocytic cytosols (737 +/- 54, 321 +/- 29 and 154 +/- 14 nmol/min/mg protein respectively), but was uninfluenced by the dietary regimen. Isozyme distribution varied greatly between the tissues. In duodenum GST-alpha, -pi, and -mu isozymes were expressed in considerable amounts (8441 +/- 1365, 3002 +/- 223 and 536 +/- 248 ng/mg protein respectively). Rectal biopsies also contained above three GST classes, but here GST-pi was the most pronounced expressed isozyme (2849 +/- 246) followed by GST-mu (495 +/- 242), while GST-alpha was only present in minor quantities (149 +/- 31). In lymphocytes only GST-pi (755 +/- 96) and GST-mu (83 +/- 54) could be detected. As a result of the dietary regimen rectal GST-alpha and -pi levels were slightly increased at the end of the sprouts period, by 30 and 15% respectively. GSH contents were uninfluenced by the dietary regimen. In conclusion, consumption of glucosinolate-containing Brussels sprouts for 1 week results in increased rectal GST-alpha and -pi isozyme levels. We hypothesize that these enhanced detoxification enzyme levels may partly explain the epidemiological association between a high intake of glucosinolates (cruciferous vegetables) and a decreased risk of colorectal cancer.
Adult↗
Glutathione peroxidases in human head and neck cancer.
Glutathione peroxidases (GPX), enzymes that catalyze the reduction of reactive intermediates have been implicated in the action of several cytostatic drugs. Two major types of GPX have been found: a selenium-dependent form (SeGPX) which is active with both hydrogen peroxide and organic hydroperoxides, and a selenium-independent GPX which is only active with organic hydroperoxides. SeGPX and total GPX (tGPX) activity were assayed in cytosolic fractions from malignant and adjacent normal tissue in 13 patients with oral/oropharyngeal, and 10 patients with laryngeal squamous cell carcinoma. Neck lymph node metastases were available from 2 and 5 of these patient respectively. Tumors from the oral/oropharyngeal region contained significantly less SeGPX and tGPX activity than laryngeal tumors. Primary oral/oropharyngeal and laryngeal tumors had lower SeGPX activities than the matched normal mucosa. tGPX activities were similar in normal and tumor tissue. Metastases contained slightly more SeGPX and tGPX activity than the matched tumor tissue. We conclude that the inherent anti-tumor drug resistance of human neck squamous cell carcinoma is not mediated by increased glutathione peroxidase enzyme activity in the tumor tissue.
Adult↗
Monochlorobimane does not selectively label glutathione in peripheral blood mononuclear cells.
Monochlorobimane (MCB) has been used by several investigators as a fluorescent label for quantifying glutathione (GSH) levels in human peripheral blood mononuclear cells (PBMC). This paper describes a biochemical evaluation of this approach. PBMC were incubated with MCB (10-100 microM) and the fluorescence in extracellular medium and cell lysates was measured. Nonlinear curves were obtained in both cases and no "plateau" was reached. The majority of the fluorescence was in the medium. Gel permeation (Sephadex G-25) of the lysate indicated a linear increase in protein-bimane adduct formation, reaching about 50% of the intracellular fluorescence after 1 h. Fractionation of the deproteinized samples with Sephadex G-10 showed that only about one-third of the "low-molecular-weight" fluorescence could be ascribed to GSH-bimane, in either the lysate or the medium. Furthermore, about 40% of the free GSH in lysates appeared unbound even after 1 h of incubation. These data are in line with our observation of an extremely low activity in PBMCs of glutathione S-transferase under the conditions employed. Our findings indicate that many variables influence the cellular fluorescence, including the presence of alternative metabolic pathways for MCB and the rapid excretion of GSH-bimane out of the cell. This lack of specificity limits the value of MCB as a GSH probe for PBMC and confirms earlier suggestions that a careful biochemical evaluation is a prerequisite for its application to any particular cell type.
Adult↗
Glutathione S-transferases in liver metastases of colorectal cancer. A comparison with normal liver and primary carcinomas.
Glutathione S-transferase activity and levels of glutathione S-transferases-alpha, -mu and -pi were determined in 10 matched pairs of normal liver and liver metastasis from patients with colorectal cancer. For comparison, six matched pairs of colorectal cancer and normal mucosa were analysed. All metastases had a lower glutathione S-transferase activity when compared to the matched normal liver tissue (224 +/- 21 versus 900 +/- 95 nmol/min.mg protein respectively, P < 0.001). Mean activities in primary tumours and normal colorectal tissue were 176 +/- 22 and 150 +/- 13 nmol/min.mg protein respectively. When analysed by immunoblot techniques, each metastasis contained less glutathione S-transferase-alpha than the surrounding normal liver (mean values 3.3 +/- 0.8 versus 21.8 +/- 1.8 micrograms/mg protein respectively, P < 0.001). Glutathione S-transferase-alpha was undetectable in all primary tumours and normal colonic mucosa. Glutathione S-transferase-mu was detected in only two patients with liver metastases and in two patients with primary colorectal cancer. All metastases contained more glutathione S-transferase-pi than the surrounding normal liver tissue (3.7 +/- 0.5 versus 0.4 +/- 0.1 micrograms/mg protein respectively, P < 0.001). The values in the metastases were very similar to those in the primary colonic tumours (normal mucosa 2.3 +/- 0.3 and tumours 3.3 +/- 0.7 micrograms/mg protein). Immunohistochemical investigation of the metastases revealed that glutathione S-transferase-alpha is not located in the malignant cells, but only in hepatocytes in what macroscopically seemed to be pure metastatic tissue. Staining for glutathione S-transferase-pi reveals generally positive tumour cells and, except for the biliary epithelium, only faint staining of the hepatocytes. It is concluded that liver metastases of colorectal carcinomas have very similar glutathione S-transferase enzyme activities and composition as compared with primary tumours.
Adenocarcinoma↗
Quantification of induction of rat oesophageal, gastric and pancreatic glutathione and glutathione S-transferases by dietary anticarcinogens.
Four dietary, naturally occurring anticarcinogens (flavone, coumarin, alpha-angelicalactone and ellagic acid) were studied with respect to their effects on oesophageal, gastric and pancreatic (i) glutathione S-transferase (GST) enzyme activity, (ii) GST isozyme levels and (iii) glutathione (GSH) content in male Wistar rats. GST enzyme activity was significantly increased in the oesophagus by flavone, coumarin and alpha-angelicalactone (125, 240 and 155% respectively) and in the stomach by coumarin and alpha-angelicalactone (140 and 230%). No change in pancreatic GST activity was observed. In addition, class- and tissue-specific changes in GST isozyme levels occurred. Class alpha GSTs were induced in the oesophagus by flavone, coumarin and alpha-angelicalactone (570, 1580 and 570%), but did not change in the stomach. GST-alpha was undetectable in the pancreas. GST-mu was expressed at high levels in all three tissues investigated, but only pancreatic GST-mu levels of ellagic acid-fed rats were increased (160%). GST-pi was induced in the stomach by coumarin and alpha-angelicalactone (470 and 1120%) and in the pancreas by flavone (200%). GST-pi was detectable at low levels in rat oesophageal epithelium of coumarin-fed animals only. GSH concentrations were uninfluenced by the dietary anticarcinogens in all tissues. These results suggest that dietary ellagic acid and, more especially, flavone, coumarin and alpha-angelicalactone may exert strong chemoprotective effects by selective enhancement of members of the GST detoxification system in the oesophagus or stomach and, to a lesser extent, in the pancreas.
Animals↗
Response to adjuvant chemotherapy in primary breast cancer: no correlation with expression of glutathione S-transferases.
Of 139 node-positive breast cancer patients treated with adjuvant chemotherapy, the pre-treatment levels of glutathione S-transferase (GST) classes alpha, mu and pi, were determined by immuno-quantification on Western blots in cytosols of the primary tumours. Their expression was studied with respect to cytosolic oestrogen-receptor, progesterone-receptor and cathepsin D levels, and to the length of disease-free survival. GST class pi was negatively correlated with oestrogen receptor and progesterone receptor, and positively correlated with cathepsin D. There was no correlation between GST isoenzymes and the length of disease-free survival. These data suggest that glutathione S-transferases are not useful as markers to predict the response to adjuvant chemotherapy in human breast cancer.
Adult↗
Glutathione S-transferases in esophageal cancer.
Glutathione content and glutathione S-transferase enzyme activity as well as isoenzyme composition were studied in normal gastric cardia, normal squamous esophageal epithelium and corresponding malignant tumor of 10 patients with esophageal cancer. Mean values of glutathione (38 +/- 6 versus 36 +/- 12 nmol/mg protein) and glutathione S-transferase activity (532 +/- 44 versus 532 +/- 108 nmol/min mg protein) did not differ significantly between normal esophageal and tumor tissue. However, great individual differences exist. In two patients, glutathione S-transferase activity was much higher in the tumor (1081 and 1381 nmol/min mg protein) due to overexpression of class alpha, mu and pig glutathione S-transferases in one case, and of class mu and pi in the other case. In the other patients, glutathione S-transferase activity was equal (one case) or lower (seven cases) in the tumor. In normal gastric cardia glutathione content as well as glutathione S-transferase activity was significantly lower as compared to normal esophageal epithelium. In conclusion, in contrast to other gastrointestinal tumors, glutathione S-transferases are overexpressed in esophageal tumors in only a limited number of patients.
Adult↗
Induction of rat hepatic and intestinal glutathione S-transferases by dietary butylated hydroxyanisole.
To obtain insight into the protection mechanism of butylated hydroxyanisole (BHA), a widely used food preservative with anticarcinogenic properties, we investigated the effects of dietary BHA on rat hepatic and intestinal glutathione S-transferase (GST) enzyme activity, and GST isozyme levels. In the proximal small intestine and liver, BHA supplementation significantly increased GST enzyme activity as compared with controls (2.3- and 1.7-fold, respectively, P less than 0.05). GST class alpha and mu contents were significantly higher only in the small intestine (1.6-2.1-fold and 1.3-1.5-fold, respectively, P less than 0.05), whereas GST class pi was significantly induced in liver (4.6-fold, P less than 0.05).
Animals↗
Biochemical characterization of resistance to mitoxantrone and adriamycin in Caco-2 human colon adenocarcinoma cells: a possible role for glutathione S-transferases.
Cytotoxicity of Adriamycin on human colon adenocarcinoma cell lines was investigated. Concentrations of Adriamycin producing 50% inhibition were very similar in HT29, Sw480, Sw620, and Sw1116 cells, whereas Caco-2 cells were relatively insensitive. As compared to the Sw1116 cell line, Caco-2 cells were also insensitive to mitoxantrone. Sensitivity to cisplatin, 5-fluorouracil, or ethacrynic acid was comparable in both cell lines. To find the mechanism for this mitoxantrone and Adriamycin resistance, several potential Adriamycin-detoxifying systems were characterized and quantified in both Sw1116 and Caco-2 cells. No dramatic differences in glutathione content and expression of both selenium dependent- and independent glutathione peroxidase, UDP-glucuronyltransferase, and cytochrome P-450 were found. However, highly significant differences in glutathione S-transferase activity were present, the expression of both class pi and class alpha glutathione S-transferases being much higher in the Caco-2 cell line. In addition, a slightly higher content of P-170 glycoprotein was present in the Caco-2 cells. These findings suggest that glutathione S-transferases, and to a lesser extent the P-170 glycoprotein, may be involved in mitoxantrone and Adriamycin resistance of Caco-2 colon carcinoma cells.
ATP Binding Cassette Transporter, Subfamily B, Mem↗
Expression of drug-metabolizing enzymes and P-170 glycoprotein in colorectal carcinoma and normal mucosa.
Resistance to chemotherapy is a significant problem in the treatment of colorectal carcinomas. To obtain insight into the mechanism of drug resistance, the expression of P-170 glycoprotein and biotransformation enzymes that are potentially able to contribute to drug resistance were investigated in paired samples of normal mucosa and tumors from 24 patients with colorectal cancer. In the tumors, glutathione S-transferase (GST) enzyme activity and content of GST-pi and P-170 glycoprotein were increased significantly compared with normal mucosa (P less than 0.03, P less than 0.003, and P less than 0.02, respectively). In contrast, GST-alpha and -mu, present in minor amounts compared with GST-pi, were downregulated in the tumor. Cytochrome P-450(4,5,6) and UDP-glucuronyltransferase (towards 4-nitrophenol and bilirubin) levels were significantly lower in the tumors (P less than 0.0001 and P less than 0.0002, respectively). Because decreased expression of cytochrome P-450 and increased levels of GST-pi and the P-170 glycoprotein have been implicated in (multi)drug resistance, these findings strongly suggest that in colorectal tumors the inherent resistance is multifactorial. Research to overcome this resistance should therefore be directed toward a combined treatment that eliminates all of these different mechanisms.
ATP Binding Cassette Transporter, Subfamily B, Mem↗
Epidermal growth factor receptor levels are lower in carcinomatous than in normal colorectal tissue.
A series of 24 paired samples of colorectal carcinoma and the respective normal colorectal mucosa were analysed for Epidermal Growth Factor Receptor (EGFR) content by means of a standardised ligand binding assay. We, for the first time, found that EGFR levels are statistically significantly higher in normal colorectal mucosa biopsy samples than they are in colorectal carcinoma biopsy samples, the median EGFR levels being 77.5 fmol mg-1 of membrane protein (range 35-239), against 46 fmol mg-1 of membrane protein (range 22-81), respectively, P less than 0.001. In addition, we found that there are significant regional differences in EGFR expression in the normal human colon mucosa. The EGFR levels were significantly higher in samples from the proximal part of the colon than they were in samples from the distal part, the median EGFR levels being 124 fmol mg-1 of membrane protein (range 70-239) vs 55 fmol mg-1 membrane protein (range 35-156), P less than 0.05. The EGFR levels of the colorectal carcinoma samples did not show any regional variation.
Aged↗
Cyclosporin metabolism by human gastrointestinal mucosal microsomes.
The in vitro metabolism of the immunosuppressant cyclosporin (CsA) by human gastrointestinal mucosal microsomes has been studied. Macroscopically normal intestinal (n = 4) and liver (n = 2) tissue was obtained from kidney transplant donors, and microsomes prepared. Intestinal metabolism was most extensive with duodenal protein (15% conversion to metabolites M1/M17 after 2 h incubation at 37 degrees C; metabolite measurement by h.p.l.c). Western blotting confirmed the presence of P-4503A (enzyme subfamily responsible for CsA metabolism) in duodenum and ileum tissue, but not in colon tissue. The results of this study indicate that the gut wall may play a role in the first-pass metabolism of CsA, and could therefore be a contributory factor to the highly variable oral bioavailability of CsA.
Biological Availability↗