Glutathione content of human skin carcinomas

Differences in Blood Glutathione Levels of Patients with Advanced or Localized Carcinoma

Aims and background

The increased level of blood glutathione (GSH) is an important biochemical feature in animal epithelial tumor. The aim of this study was to investigate the blood GSH concentrations in well characterized cancer patients and healthy volunteers.

Methods

Two different groups of carcinoma cases were used. The first group consisted of 15 blood samples drawn from disseminated gastric adenocarcinoma patients, and the second group comprised 15 samples obtained from localized or locally advanced skin carcinoma cases without lymph node metastasis. GSH and hemoglobin concentrations were measured by using the method of Beutler et al.

Results

The mean blood GSH in patients who had advanced malignant disease was 129.13 ± 7.49 mg/dl and in patients who had localized cancer was 96.24 ± 3.90 mg/dl. These results indicate that the blood GSH level is 31% higher in localized carcinoma cases and 78% higher in metastatic disease than those of controls. Blood GSH concentrations were expressed on the basis of blood volume and also on hemoglobin content. Similar results were calculated with either mode of expression.

Conclusion

By comparing the two groups of patients, we found that higher blood GSH concentration was correlated with metastatic growth.

Decrease in glutathione may be involved in pathogenesis of acne vulgaris

BACKGROUND

Some past studies reported that oxidative stress components such as reactive oxygen species (ROS) or lipid peroxide (LPO) are involved in the pathogenesis and progression of acne vulgaris. In this study, we hypothesized that the pathogenesis of acne vulgaris may depend on the differences in antioxidative activity among antioxidants in our body. We collected samples of stratum corneum from acne patients and healthy subjects and compared the quantity of gluthathione (GSH), one of many antioxidative components in our body, for comparison.

METHODS

Samples of stratum corneum were collected from facial acne-involved lesion, facial uninvolved area, and the medial side of the upper arm in acne vulgaris patients. Similarly, samples were collected from a facial uninvolved area and the medial side of the upper arm in healthy subjects. The quantity of GSH was measured in each area. In vitro effects of alpha-melanocyte stimulating hormone (α-MSH) on GSH synthesis-related gene were also examined.

RESULTS

The quantity of GSH in stratum corneum from each area was significantly lower in acne vulgaris patients than that of healthy subjects. There was no significant difference in quantity of GSH between the acne-involved lesion and uninvolved area in acne patients. In vitro studies showed that the expression level of Glutamate-cysteine ligase catalytic subunit (GCLC), one of the GSH synthesis-related genes, was significantly decreased by the additional use of α-MSH.

CONCLUSIONS

We conclude that a decline in antioxidative activity led by a decrease in GSH quantity may play an important role in pathogenesis of acne vulgaris. The use of α-MSH may further decrease the GSH level.

Oxidative stress in the pathogenesis of skin disease

Skin is the largest body organ that serves as an important environmental interface providing a protective envelope that is crucial for homeostasis. On the other hand, the skin is a major target for toxic insult by a broad spectrum of physical (i.e. UV radiation) and chemical (xenobiotic) agents that are capable of altering its structure and function. Many environmental pollutants are either themselves oxidants or catalyze the production of reactive oxygen species (ROS) directly or indirectly. ROS are believed to activate proliferative and cell survival signaling that can alter apoptotic pathways that may be involved in the pathogenesis of a number of skin disorders including photosensitivity diseases and some types of cutaneous malignancy. ROS act largely by driving several important molecular pathways that play important roles in diverse pathologic processes including ischemia-reperfusion injury, atherosclerosis, and inflammatory responses. The skin possesses an array of defense mechanisms that interact with toxicants to obviate their deleterious effect. These include non-enzymatic and enzymatic molecules that function as potent antioxidants or oxidant-degrading systems. Unfortunately, these homeostatic defenses, although highly effective, have limited capacity and can be overwhelmed thereby leading to increased ROS in the skin that can foster the development of dermatological diseases. One approach to preventing or treating these ROS-mediated disorders is based on the administration of various antioxidants in an effort to restore homeostasis. Although many antioxidants have shown substantive efficacy in cell culture systems and in animal models of oxidant injury, unequivocal confirmation of their beneficial effects in human populations has proven elusive.

Effects of oxygen on the antioxidant responses of normal and transformed cells

Basal antioxidant defense levels are often aberrant in tumor cells; however, less attention has been given to differences in the way that normal and transformed cells respond to changes in oxidative stress. This study evaluated differences in the responses of various normal and transformed cell lines to different oxygen tensions. Exposure to hyperoxia generally failed to induce either the activity of GSH peroxidase (GPx) or the manganese-containing form of superoxide dismutase (MnSOD) after 48 h, although at 605 mm Hg oxygen, small inductions of MnSOD activity were observed in adult lung fibroblasts and amelanotic melanoma. Exposure to 605 mm Hg O2 for 48 h was inhibitory to GPx activity. MnSOD activity was strongly induced in virally transformed WI-38 cells by treatment with the herbicide paraquat or inhibition of GSH synthesis with BSO. In normal cells GSH concentration was proportional to ambient oxygen tension. Tumor cells exhibited greater GSH concentrations at low oxygen tensions than normal cells but were unable to increase GSH in response to elevation of oxygen tension. These results reveal differences in tumor and normal cell responses to changes in ambient oxygen tension and show that MnSOD activity is inducible when an appropriate stimulus is applied.

Oxidative stress and gene regulation

Reactive oxygen species are produced by all aerobic cells and are widely believed to play a pivotal role in aging as well as a number of degenerative diseases. The consequences of the generation of oxidants in cells does not appear to be limited to promotion of deleterious effects. Alterations in oxidative metabolism have long been known to occur during differentiation and development. Experimental perturbations in cellular redox state have been shown to exert a strong impact on these processes. The discovery of specific genes and pathways affected by oxidants led to the hypothesis that reactive oxygen species serve as subcellular messengers in gene regulatory and signal transduction pathways. Additionally, antioxidants can activate numerous genes and pathways. The burgeoning growth in the number of pathways shown to be dependent on oxidation or antioxidation has accelerated during the last decade. In the discussion presented here, we provide a tabular summary of many of the redox effects on gene expression and signaling pathways that are currently known to exist.

S-allylmercaptocysteine, a stable thioallyl compound, induces apoptosis in erythroleukemia cell lines

The antiproliferative potential of S-allylmercaptocysteine (SAMC), a stable organosulfur compound of aged garlic extract, has been investigated using two erythroleukemia cell lines, HEL and OCIM-1. It induces a dose-dependent inhibition of cell growth with a 50% lethal dose of 0.046 mM for OCIM-1 cells and 0.093 mM for HEL cells. [3H]thymidine incorporation was reduced in cells treated with this thioallyl compound, and analysis of high-molecular-weight DNA showed fragmentation compatible with apoptosis. Flow cytometric analyses of DNA revealed an abnormal cell cycle progression in both types of erythroleukemia cells, with the major portion of the unsynchronized cells in the G2/M phase. Measurement of acid-soluble free sulfhydryl groups showed an initial increase in response to SAMC followed by a progressive dose-dependent decrease with extended incubation of cells. We conclude from these studies that SAMC is an effective antiproliferative agent against erythroleukemia cells that induces cell death by apoptosis.

S-allylmercaptocysteine inhibits cell proliferation and reduces the viability of erythroleukemia, breast, and prostate cancer cell lines

Organosulfur compounds are the biologically active components of allium vegetables. Many health benefits have been ascribed to them, including inhibition of carcinogenesis. Inasmuch as several of these thioallyl compounds are quite unstable and others are rapidly inactivated in the body, we have investigated one of the stable components present in aged garlic extract, S-allylmercaptocysteine (SAMC), in an effort to determine whether it can inhibit proliferation of cancer cells. Proliferation and viability of two erythroleukemia cell lines, HEL and OCIM-1, two hormone-responsive breast and prostate cancer cell lines, MCF-7 and CRL-1740, respectively, and normal human umbilical vein endothelial cells in response to different concentrations of SAMC were studied for up to two weeks. There were variations in sensitivity to this organosulfur compound in the different cell lines examined, but the two hormone-responsive cancer cell lines of breast and prostate clearly were far more susceptible to the growth-inhibitory influence of the thioallyl compound. The antiproliferative effect of SAMC was limited to actively growing cells. Human umbilical vein endothelial cells that had reached confluence escaped the reduction in viability so noticeable in the cancer cell lines tested. Our studies thus give evidence of a direct effect of SAMC on established cancer cells.

Relationship of glutathione and glutathione-S-transferase to cisplatin sensitivity in human head and neck squamous carcinoma cell lines

Factors controlling glutathione metabolism may govern sensitivity to chemotherapeutic agents such as cisplatin. Using a battery of cell lines derived from previously untreated head and neck squamous cell carcinomas, we examined cisplatin resistance relative to (a) glutathione-S-transferase (GST)-pi gene amplification and expression, (b) basal and inducible GST-total and GST-pi enzymatic activity, and (c) cellular levels of reduced glutathione (GSH). Using Southern blot analysis and northern blot hybridization, no relationship between GST-pi gene amplification, mRNA expression and drug resistance could be identified. Despite the capacity of cisplatin to induce GST enzyme activity, the response was variable and unrelated to cisplatin responsiveness. However, an inverse relationship between GSH levels and cisplatin sensitivity was identified. To further clarify these effects, cells were treated with S-allyl cysteine (SAC), a thioallyl derivative isolated from garlic (Allium sativum), which altered cellular GSH in a biphasic manner. Pretreatment with SAC to lower cellular GSH levels followed by exposure to cisplatin significantly enhanced the cytotoxic effects of cisplatin, while SAC alone had no effect on cell growth.

Alterations in erythrocyte glutathione metabolism associated with cervical dysplasias and carcinoma in situ

The study was designed to test the hypothesis whether cervical dysplasias of the more severe grades are associated with elevated erythrocyte glutathione levels. Subjects were women who obtained Pap tests and were subsequently found (1) not to have any cervical lesions or (2) to have colposcopically visualized, biopsy-confirmed cervical abnormalities histopathologically diagnosed as mild, moderate, severe dysplasias, or carcinoma in situ (CIS). The erythrocyte levels of reduced glutathione (GSH), oxidized glutathione (GSSG), glutathione reductase (GR), glucose-6-phosphate dehydrogenase (G6PD), and 6-phosphogluconate dehydrogenase (6PGD) were analyzed from coded peripheral venous blood samples. GSH and GR concentrations increased with increasing severity of dysplasia. Exploratory data analysis and multiple pairwise comparisons suggested comparable levels of the glutathione-related variables between these histopathological pairs: (1) mild and moderate dysplasias or (2) severe dysplasia and CIS. We suggest that the changes in erythrocyte glutathione-related indices in conjunction with histopathological diagnosis may have the potential to distinguish between low- and high-grade cervical dysplastic lesions.

Alteration in glutathione level during carcinogenesis of hamster buccal pouch mucosa

This study examined the level of glutathione (GSH)--a tripeptide that may have an important role in detoxification of carcinogens--in the hamster buccal pouch mucosa (HBPM) by a 12-week regimen of tri-weekly topical application of 7,12-dimethylbenz[a]anthracene (DMBA) in mineral oil. GSH was quantified periodically and shown to be doubled in carcinogen-treated vs. control pouch mucosa. In the tumors that developed, the level of GSH was three times that of the controls. Previous studies showed that gamma-glutamyl transpeptidase (GGT), one of the enzymes that may be responsible for the detoxification of carcinogens, was increased in the hamster mucosa pre-neoplastic foci, but decreased with the formation of overt neoplasia. GGT and GSH are intimately related, since GGT is the only enzyme that can cleave the intact GSH molecule. The increase in both GSH and GGT levels may be responsible for the increased resistance of the pre-neoplastic pouch epithelium to the toxic effects of the carcinogen.

Cellular and adenovirus dl312 DNA metabolism in cycling or mitotic human cultures exposed to supralethal gamma radiation

Cellular repair of DNA damage due to lethal gamma irradiation was studied to reveal differences between strains and cell cycle stages that are otherwise difficult to detect. Cycling and metaphase-blocked cultures of normal fibroblasts and carcinoma cells were compared for repair of gamma sites (gamma radiation-induced nicks, breaks, and alkalilabile sites in DNA) at supralethal exposures ranging from 7 to 150 krad 137Cs radiation and at postirradiation incubations of 20-180 min. Fibroblasts from normal human skin or lung repaired gamma sites efficiently when cycling but did not repair them when blocked at mitosis. Bladder (253J) or lung (A549) carcinoma cells, unlike normal fibroblasts, repaired gamma sites efficiently even when blocked at mitosis. HeLa cells degraded their DNA soon after exposure at all doses tested, regardless of mitotic arrest. Whether the above differences in DNA repair between cell cycle stages and between strains result from differences in chromatin structure (cis effects) or from differences in the nuclear enzymatic environment (trans effects) could be resolved by placing an inert, extrachromosomal DNA molecule in the cell nucleus. Specifically, cis effects should be confined to the host chromosomes and would not be detected in the inert probe whereas trans effects should be detected in host chromosomes and inert probe DNA alike. Indeed, we found a suitable DNA molecule in the adenovirus deletion mutant dl312, which does not proliferate in the absence of E1A complementation. Gamma sites in 32P-labeled adenovirus dl312 DNA were repaired efficiently in all hosts, regardless of mitotic arrest. Failure of mitosis-arrested fibroblasts to repair gamma sites was therefore due to a cis effect of chromatin organization rather than to a trans effect such as repair enzyme insufficiency. In sharp contrast, chromosomes of mitotic carcinoma cells remained accessible to repair enzymes and nucleases alike. By means of these new tools, we should get a better understanding of higher-order chromatin management in normal and cancer cells.

Actinic DNA damage and the pathogenesis of cutaneous malignant melanoma

The near epidemic of melanoma and non-melanoma skin cancer in the United States and certain other industrialized nations is attributable to cutaneous exposure to sunlight more than to any other factor. Chronic exposure to UV irradiation and a high total cumulative dose may be less deleterious than are periodic bursts of large amounts of sun exposure leading to severe sunburn. Such an exposure pattern is characteristic of individuals such as office workers whose outdoor activities are irregular rather than daily, as with farmers or fisherman. Although UV irradiation is injurious to many cellular elements, the mechanisms underlying UV-mediated skin cancer are thought to be most likely related to DNA damage to cutaneous cells. Various types of UV-induced DNA damage have been identified, and they differ in biologic significance. Damage which is apt to be most cytotoxic is probably less effective as an inducer of skin cancer than is more subtle damage, which is tolerated but can initiate malignant transformation. Repair of DNA damage involves specific cellular activities which vary in their effectiveness in restoring cutaneous cell function to normal. Other biologic effects of UV irradiation may contribute to the development of skin cancer through effects on such defenses as pigmentation and the immune response. Sun-induced damage to DNA, however, is apparently necessary. Biologic consequences of dangerous environmental exposure to UV irradiation can be modulated by changes in life-style, the depth of the ozone layer, use of sunscreens, and possibly by hormones or their synthetic analogs.

Oxidative influence on development and differentiation: an overview of a free radical theory of development

Metabolic gradients exist in developing organisms and are believed to influence development. It has been postulated that the effects of these gradients on development result from differential oxygen supplies to tissues. Oxygen has been found to influence the course of development. Cells and tissues in various stages of differentiation exhibit discrete changes in their antioxidant defenses and in parameters of oxidation. Metabolically generated oxidants have been implicated as one factor that directs the initiation of certain developmental events. Also implicated as factors that modulate developmental processes are the cellular distribution of ions and the cytoskeleton both of which can be influenced by oxidants. The interaction of oxidants with ion balance and cytoskeleton is discussed.

Oxygen free radicals play a role in cellular differentiation: an hypothesis

Evidence from a variety of sources supports the view that oxygen free radicals play a role in cellular differentiation. It is postulated that cellular differentiation is accompanied by changes in the redox state of cells. Differentiated cells have a relatively more prooxidizing or less reducing intracellular environment than the undifferentiated or dedifferentiated cells. Changes in the redox balance during differentiation appear to be due to an increase in the rate of O2- generation. Differentiated cells, in general, exhibit higher rates of cyanide-resistant respiration, cyanide-insensitive SOD activity, and peroxide concentration and lower levels of GSH as compared to undifferentiated cells. The effects of free radicals on cellular differentiation may be mediated by the consequent changes in ionic composition.

Alterations in superoxide dismutase, glutathione, and peroxides in the plasmodial slime mold Physarum polycephalum during differentiation

Changes in the level of antioxidant defenses and the concentration of free radical by-products were examined in differentiating (M3cVII and LU897 X LU863), non-differentiating (LU887 X LU897), and heterokaryon microplasmodia of the slime mold Physarum polycephalum during spherulation in salts-only medium. As differentiation proceeded, superoxide dismutase activity increased by as much as 46 fold; glutathione concentration and the rate of oxygen consumption decreased; cyanide-resistant respiration, hydrogen peroxide, and organic peroxide concentrations increased. The non-differentiating culture failed to exhibit any of these changes. A heterokaryon obtained by the fusion of differentiating and non-differentiating strains was observed to differentiate at a very retarded rate and to exhibit the changes observed in the spherulating strains at a correspondingly slower rate. These observations suggest that a free radical mechanism may be involved in the differentiation of Physarum microplasmodia into spherules.

Glutathione and GSH-dependent enzymes in the human gastric mucosa

The gamma-glutamyl-transferase activity, the total glutathione content, the GSH-peroxidase activity, and the GSH S-transferase activity using an aryl substrate were estimated in the S9 fraction of gastric biopsy specimens taken from patients with normal stomach morphology (n = 24), acute gastritis (n = 15), chronic-atrophic gastritis (n = 10), gastric ulcer (n = 9), and carcinoma of the stomach (n = 12). The total glutathione content of normal gastric mucosal specimens was significantly higher than that of human liver biopsy specimens, whereas the GSH-peroxidase and the GSH S-aryltransferase activities were much lower than those found in the liver. Specimens of gastric ulcer had significantly lower enzyme activities of GSH-peroxidase and GSH-aryltransferase, whereas gastric cancer tissue had significantly lower concentrations of total glutathione. The intraindividual comparison of tumorous and non-tumorous tissue showed a consistent decrease of total glutathione as well as of GSH-aryltransferase activity in carcinomatous tissue.

Glutathione in human epidermal tumors. Basal and squamous cell epithelioma, verruca seborrhoeica

Methods for the determination of glutathione in small epidermal and tumor fragments are compared. The best results were obtained by an enzymatic cycling technique. The total glutathione concentrations in basal cell epithelioma, squamous cell epithelioma, and verruca seborrhoeica were 2.08, 1.81, and 1.87 mg/g dry weight, respectively. In normal epidermis adjacent to the basal cell epitheliomas the concentration was 1.27 mg/g dry weight.

Glutathione reductase in human epidermal tumors. Basal and squamous cell epithelioma, verruca seborrhoeica

Glutathione reductase activities, both with NADPH and NADH, were determined in basal and squamous cell epitheliomas, in verrucae seborrhoeicae and in human epidermis. Significantly elevated activites were measured in basal cell epitheliomas and in verrucae seborrhoeicae. Some properties of the enzyme were also investigated.