Development of exchange lists for Mediterranean and Healthy Eating diets: implementation in an intervention trial.

BACKGROUND: There has been little research published on the adaptation of diabetic exchange list diet approaches for the design of intervention diets in health research despite their clinical utility. The exchange list approach can provide clear and precise guidance on multiple dietary changes simultaneously. The present study aimed to develop exchange list diets for Mediterranean and Healthy Eating, and to evaluate adherence, dietary intakes and markers of health risks with each counselling approach in 120 subjects at increased risk for developing colon cancer. METHODS: A randomised clinical trial was implemented in the USA involving telephone counselling. The Mediterranean diet had 10 dietary goals targeting increases in mono-unsaturated fats, n-3 fats, whole grains and the amount and variety of fruits and vegetables. The Healthy Eating diet had five dietary goals that were based on the US Healthy People 2010 recommendations. RESULTS: Dietary compliance was similar in both diet arms, with 82-88% of goals being met at 6 months, although subjects took more time to achieve the Mediterranean goals than the Healthy Eating goals. The relatively modest fruit and vegetable goals in the Healthy Eating arm were exceeded, resulting in fruit and vegetable intakes of approximately eight servings per day in each arm after 6 months. A significant (P < 0.05) weight loss and a decrease in serum C-reactive protein concentrations were observed in the overweight/obese subgroup of subjects in the Mediterranean arm in the absence of weight loss goals. CONCLUSIONS: Counselling for the Mediterranean diet may be useful for both improving diet quality and for achieving a modest weight loss in overweight or obese individuals.

Is diabetes an acquired disorder of reactive glucose metabolites and their intermediates?

AIMS/HYPOTHESIS: We hypothesised that diabetic patients would differ from those without diabetes in regard to the handling of glucose-derived reactive metabolites, evidenced by triosephosphate intermediates (TP(INT)) and methylglyoxal (MG), irrespective of the type of diabetes, plasma glucose level or HbA(1c) value. METHODS: To test this hypothesis, erythrocytes were isolated from patients with type 1 (n = 12) and type 2 (n = 12) diabetes with varying blood glucose and HbA(1c) levels. These were then compared with erythrocytes isolated from individuals without diabetes (n = 10), with respect to MG, as determined by HPLC, and TP(INT), as determined by endpoint enzymatic assays. RESULTS: The concentrations of intracellular TP(INT) and MG were significantly elevated in erythrocytes from diabetic patients. Normalisation of either TP(INT) or MG to intracellular glucose concentration (nmol glucose/mgHb) confirmed that erythrocytes from diabetic patients accumulated more reactive metabolites than did those from healthy controls. CONCLUSIONS/INTERPRETATION: Diabetic patients can be characterised by an increased formation of TP(INT) and MG. The 25-fold increase of MG in type 1 and the 15-fold increase in type 2 diabetes, together with a several-fold increase in TP(INT) and decreased glyceraldehyde-3-phosphate dehydrogenase activity even under normal glucose conditions, imply that normalising glucose level cannot completely prevent late diabetic complications until this acquired error of metabolism has been restored.

Lipid mechanisms in hallmarks of cancer.

Excess adiposity is a risk factor for several cancer types. This is likely due to complex mechanisms including alterations in the lipid milieu that plays a pivotal role in multiple aspects of carcinogenesis. Here we consider the direct role of lipids in regulating well-known hallmarks of cancer. Furthermore, we suggest that obesity-associated remodelling of membranes and organelles drives cancer cell proliferation and invasion. Identification of cancer-related lipid-mediated mechanisms amongst the broad metabolic disturbances due to excess adiposity is central to the identification of novel and more efficacious prevention and intervention strategies.

Effects of a low-fat diet on levels of oxidative damage to DNA to human peripheral nucleated blood cells.

Fat in the diet has been associated with increased breast cancer risk. In this study, blood samples were obtained from 21 women at high risk for breast cancer who had been randomly assigned to either a nonintervention diet or a low-fat diet. Oxidative damage was examined in the DNA from nucleated peripheral blood cells. The levels of oxidized thymine, specifically 5-hydroxymethyluracil, were threefold higher in the nonintervention diet group than in the low-fat diet group. Without regard to diet arm, there also was a significant linear relationship between daily total fat intake and 5-hydroxymethyluracil level. These results suggest that oxidative damage to DNA may be a marker of dietary fat intake. In addition, oxidative DNA damage may be a mechanistic link between fat in the diet and cancer risk, since such damage is associated with the process of tumor promotion.

DNA damage and cytotoxicity in L1210 cells by ellipticine and a structural analogue, N-2-(diethylaminoethyl)-9-hydroxyellipticinium chloride.

N-2-(Diethylaminoethyl)-9-hydroxyellipticinium chloride (DHE) is a structural analogue of ellipticine that is currently a leading compound for clinical trials. We have investigated the mechanism of DNA damage by this compound in murine L1210 leukemia cells using the method of alkaline elution. Although DHE was about 100-fold more cytotoxic than ellipticine, this increased cytotoxicity was not accompanied by greater amounts of DNA strand breakage or protein-DNA cross-linking. The single strand breaks caused by both compounds were protein associated and could be accounted for by the presence of double strand breaks. DNA damage by the compounds therefore was consistent with topoisomerase II inhibition. Unlike DHE, 80% of the DNA damage elicited by ellipticine was repaired within 1 h after removal of drug. For DHE, 20-h incubations in drug-free media were required to obtain 70% repair of single strand DNA breaks. These data indicated that although both ellipticine and DHE may inhibit topoisomerase II, the type of DNA damage which resulted in topoisomerase II inhibition by DHE was much more persistent than the DNA damage elicited by ellipticine.

The selective antiproliferative effects of alpha-tocopheryl hemisuccinate and cholesteryl hemisuccinate on murine leukemia cells result from the action of the intact compounds.

In the present study we have established that the antitumor activity of alpha-tocopheryl succinate (TS, vitamin E succinate) and cholesteryl succinate (CS) result from the action of the intact TS and CS compounds and not from the release of alpha-tocopherol, cholesterol, or succinate. We report that treatment of murine leukemia cell lines C1498 (myeloid) and L1210 (lymphocytic), with the tris salts of TS or CS, but not alpha-tocopherol and tris succinate or cholesterol and tris succinate, significantly inhibit the growth of these tumor cells and significantly enhance doxorubicin-induced tumor cell kill in a similar fashion. In contrast, the treatments mentioned above did not adversely affect the growth of murine normal bone marrow cells (colony-forming unit-granulocyte-macrophage). In fact, colony-forming unit granulocyte-macrophage cell growth was stimulated by exposure to CS and TS (as well as their ether analogues) at concentrations above 100 microM. Furthermore, pretreatment of colony-forming unit granulocyte-macrophage cells with TS or CS appears to protect these normal cells from the lethal effect of doxorubicin exposure. Selective inhibition of leukemia cell proliferation (identical to that noted for CS and TS) was also observed following the treatment of cells with the nonhydrolyzable ether forms of CS (cholesteryloxybutyric acid) and TS (alpha-tocopheryloxybutyric acid). These findings suggest that TS, alpha-tocopheryloxybutyric acid, CS, and cholesteryloxybutyric acid may prove clinically useful as selective antitumor agents when administered alone or in combination with doxorubicin by a route that ensures tissue accumulation of the intact compound.

Carotenoids are degraded by free radicals but do not affect lipid peroxidation in unilamellar liposomes under different oxygen tensions.

It has been questioned whether carotenoids can act as antioxidants in biological membranes. Biological membranes can be modeled for studies of lipid peroxidation using unilamellar liposomes. Both carotenoid depletion and lipid peroxidation were increased with increasing oxygen tension in unilamellar liposomes. Carotenoids in such liposomes were found to be very sensitive to degradation by free radicals generated from iron and 2,2'-azobis(2-amidinopropane) dihydrochloride, but they were not protective against lipid peroxidation. Lycopene and beta-carotene were more sensitive to free radical attack than lutein, zeaxanthin, and beta-cryptoxanthin.

Toxicity, single-strand breaks, and 5-hydroxymethyl-2'-deoxyuridine formation in human breast epithelial cells treated with hydrogen peroxide.

DNA damage induced by oxidants includes formation of DNA strand breaks as well as oxidative damage to DNA bases. We quantified both forms of DNA damage concurrently in two model human breast epithelial cell lines treated with hydrogen peroxide to compare the dose-dependent induction of each form of DNA damage with growth inhibition. Antioxidant defenses also were quantified. MCF-7 breast cancer cells had relatively higher levels of non-protein thiols, oxidized glutathione (GSSG) reductase, catalase, and superoxide dismutase than did the MCF-10A line of immortalized, but not transformed, human breast epithelial cells. The levels of antioxidant defenses were not predictive of endogenous oxidative DNA damage levels nor of toxicity and DNA damage induced by hydrogen peroxide. The endogenous levels of 5-hydroxymethyl-2'-deoxyuridine were higher in MCF-7 than MCF-10A cells. The cells were treated with 10-200 microM hydrogen peroxide for 15 min at 37 degrees C in complete media. Low concentrations of hydrogen peroxide were growth stimulatory to both cell lines. At higher concentrations, growth inhibition by hydrogen peroxide was greater in MCF-7 than in MCF-10A cells. Accordingly, induction of both single-strand DNA breaks and 5-hydroxymethyl-2'-deoxyuridine in DNA was greater in MCF-7 than MCF-10A cells. In both cell lines, the dose-dependent induction of single-strand breaks paralleled growth inhibition more closely than did formation of 5-hydroxymethyl-2'-deoxyuridine.

Soy isoflavone supplementation in healthy men prevents NF-kappa B activation by TNF-alpha in blood lymphocytes.

Dietary intake of soy has been associated with a decreased risk of cancer. Soy isoflavones have been postulated to be the protective compounds in soybeans; however, the precise mechanism by which soy isoflavones prevent human cancer is not known. The major soy isoflavones, genistein and daidzein, are antioxidant compounds, therefore one possible mechanism of action is through their antioxidant effect. We have previously demonstrated that the soy isoflavone, genistein, inhibits the activation of the redox-sensitive transcription factor, NF-kappa B, in prostate cancer cells in vitro. In this study, we have demonstrated that genistein, but not daidzein, inhibits TNF-alpha-induced NF-kappa B activation in cultured human lymphocytes. Additionally, we investigated the in vivo effect of soy isoflavone supplementation on NF-kappa B activation induced by TNF-alpha in vitro in peripheral blood lymphocytes of six healthy men. We show that healthy male subjects receiving 50 mg isoflavone mixture (Novasoy) twice daily for 3 weeks are protected from TNF-alpha induced NF-kappa B activation. Additionally, we observed a reduction of 5-hydroxymethyl-2'-deoxyuridine (5-OHmdU), a marker for oxidative DNA damage, following isoflavone supplementation. The inhibitory effect of soy isoflavones was no longer present 3 months after the supplementation. This preliminary study demonstrates that soy isoflavone supplementation may protect cells from oxidative stress-inducing agents by inhibiting NF-kappa B activation and decreasing DNA adduct levels.

Flow cytometric analysis of DNA damage in nucleoids from cultured human breast epithelial cells treated with hydrogen peroxide.

Flow cytometric analysis of nucleoids is useful to investigate nuclear matrix-DNA associations in cells. We have now applied this technique to examine whether differences in nucleoid structure can be detected between tumor and normal-like human breast epithelial cells. We have previously shown that MCF-7 tumor and MCF-10A normal-like human breast cells exhibit different levels of endogenous oxidative DNA damage as well as differences in response to hydrogen peroxide. We therefore examined whether flow cytometric analysis of nucleoids can be used to detect both endogenous DNA damage and DNA damage induced by hydrogen peroxide in these cells. Nucleoids were prepared by lysis of MCF-7 and MCF-10A cells with a high-salt buffer. The size of the DNA loops around the nuclear matrix core was detected by measuring the forward light-scatter signal in the presence of ethidium bromide. The relaxation and supercoiling of DNA in the presence of low and high concentrations of ethidium bromide, respectively, was similar in MCF-7 tumor and MCF-10A normal-like cells. After treatment of cells with 100 microM and higher of hydrogen peroxide, there was a statistically significant increase in the forward light scatter from nucleoids prepared in the presence of high concentrations of ethidium bromide, and this increase was similar in both cell lines. The changes in the forward light scatter signal with increasing hydrogen peroxide concentration did not mimic the patterns of increases in single strand breaks or formation of 5-hydroxymethyl-2 '-deoxyuridine that we reported previously. This indicates that the flow cytometric technique probably detects other types of changes induced by hydrogen peroxide.

Levels of 5-hydroxymethyl-2'-deoxyuridine in DNA from blood of women scheduled for breast biopsy.

Systemic oxidative stress is thought to contribute to risk of various cancers, including breast cancer. DNA repair ability also has been associated with breast cancer risk. In this work, we examined levels of oxidative DNA damage as an indication of breast cancer risk in women because oxidative DNA damage levels should reflect the net balance of oxidative stress and DNA repair ability. Levels of 5-hydroxymethyl-2'-deoxyuridine, one form of oxidative DNA damage, were measured in DNA from blood of women scheduled for breast biopsy. The blood samples analyzed included women whose biopsy results indicated invasive breast cancer, high-risk lesions (atypical hyperplasia or carcinoma in situ), or benign lesions. Mean levels of 5-hydroxymethyl-2'-deoxyuridine were significantly higher in blood of women who had high risk or invasive breast lesions versus women with benign lesions. If atypical hyperplasia or carcinoma in situ are precursor lesions for breast cancer, then these results suggest that oxidative DNA damage may be involved in the cancer process before invasive cancer develops.

Phase II randomized clinical trial of lycopene supplementation before radical prostatectomy.

An inverse association has been observed between dietary intake of lycopene and the risk of prostate cancer. We investigated the effects of lycopene supplementation in patients with prostate cancer. Twenty-six men with newly diagnosed, clinically localized (14 T(1) and 12 T(2)) prostate cancer were randomly assigned to receive 15 mg of lycopene (n = 15) twice daily or no supplementation (n = 11) for 3 weeks before radical prostatectomy. Biomarkers of differentiation and apoptosis were assessed by Western blot analysis on benign and malignant parts of the prostate gland. Prostatectomy specimens were entirely embedded, step-sectioned, and evaluated for pathological stage, Gleason score, volume of cancer, and extent of high-grade prostatic intraepithelial neoplasia. Plasma levels of lycopene, insulin-like growth factor-1 (IGF-1), IGF binding protein-3, and prostate-specific antigen were measured at baseline and after 3 weeks of supplementation or observation. Eleven (73%) subjects in the intervention group and two (18%) subjects in the control group had no involvement of surgical margins and/or extra-prostatic tissues with cancer (P = 0.02). Twelve (84%) subjects in the lycopene group and five (45%) subjects in the control group had tumors <4 ml in size (P = 0.22). Diffuse involvement of the prostate by high-grade prostatic intraepithelial neoplasia was present in 10 (67%) subjects in the intervention group and in 11 (100%) subjects in the control group (P = 0.05). Plasma prostate-specific antigen levels decreased by 18% in the intervention group, whereas they increased by 14% in the control group (P = 0.25). Expression of connexin 43 in cancerous prostate tissue was 0.63 +/- 0.19 absorbance in the lycopene group compared with 0.25 +/- 0.08 in the control group (P = 0.13). Expression of bcl-2 and bax did not differ significantly between the two study groups. IGF-1 levels decreased in both groups (P = 0.0002 and P = 0.0003, respectively). The results suggest that lycopene supplementation may decrease the growth of prostate cancer. However, no firm conclusions can be drawn at this time because of the small sample size.

The effect of dietary fat on malondialdehyde concentrations in Fischer 344 rats.

The effects of dietary fat and age on the level of malondialdehyde (MDA), a product of lipid peroxidation, were investigated in cerebellum, kidney, and liver tissues of female Fischer 344 rats. Groups of rats were fed diets containing various levels of corn oil (3, 5, 10, 15, or 20%), starting at 57 days of age, for a duration of 2, 10, or 20 weeks. High fat diets are thought to promote tumor formation, diabetes, and cardiovascular diseases via induction of oxidation stress, and this can begin early in the lifespan. However, it was observed that rats chronically consuming 3 and 5% corn oil diets yielded significantly higher levels of MDA, as analyzed by high-performance liquid chromatography, compared with those fed higher fat diets. After 20 weeks of feeding, the concentration of MDA in each of the three organs studied showed no significant differences among rats consuming diets containing 10, 15, or 20% corn oil. The levels of MDA were highest in the cerebellum, followed by kidney, and lowest in liver. Over the 20-week feeding period, a decrease in MDA level in both cerebellum and liver was observed.

Comparative reduction of 1-nitro-3-nitrosopyrene and 1-nitro-6-nitrosopyrene: implications for the tumorigenicity of dinitropyrenes.

Dinitropyrenes are mutagenic environmental pollutants. Of these compounds, 1,6-dinitropyrene is a potent tumorigen while 1,3-dinitropyrene appears to be weakly or non-tumorigenic. Two-electron reduction of dinitropyrenes yields nitro-nitrosopyrenes, which have been shown previously to be the major aerobic metabolites of these compounds in vitro. Further reduction of nitrosopyrenes is required for their activation to a DNA-reactive N-hydroxylamines. In this work, 1-nitro-3-nitrosopyrene was synthesized and the electrochemical and enzyme-catalyzed reduction of 1-nitro-3-nitrosopyrene has been compared with that of 1-nitro-6-nitrosopyrene. As determined by cyclic voltammetry, the reduction potentials of 1-nitro-3-nitrosopyrene, 1-nitro-6-nitrosopyrene and their parent dinitropyrenes were similar, although 1-nitro-3-nitrosopyrene did have a slightly more negative cathodic peak potential than the other three compounds. The NADPH-mediated reduction of 1-nitro-6-nitrosopyrene to intermediates which reduce succinoylated cytochrome c was faster than that of 1-nitro-3-nitrosopyrene. In the presence of rat liver microsomes or cytosol, the reduction of 1-nitro-6-nitrosopyrene was faster than that of 1-nitro-3-nitrosopyrene. These differences in the rates of nitro-nitrosopyrene reduction may be one factor contributing to the lower tumorigenic potential of 1,3-dinitropyrene relative to 1,6-dinitropyrene.

Differences in reduction of 1,6-dinitropyrene and 1-nitro-6-nitrosopyrene by rat liver cytosolic enzymes and formation of oxygen-reactive metabolites by nitrosoreduction.

1,6-Dinitropyrene is a carcinogenic environmental pollutant that is activated to a DNA binding species via nitroreduction. The major reduced metabolite of 1,6-dinitropyrene in aerobic incubations with rat liver cytosol is 1-nitro-6-nitrosopyrene, and further reduction of this metabolite results in formation of DNA-reactive species. We were able to separate the nitroreductase activity in rat liver cytosol from the nitrosoreductase activity by gel filtration. The ability of the nitroreductase to reduce 1,6-dinitropyrene was not affected by the presence of oxygen. Reduction of 1-nitro-6-nitrosopyrene is catalyzed by different enzymes and results in formation of metabolites which can react with oxygen. In aerobic incubations with cytosol, this reaction of reduced intermediates with oxygen does not decrease the binding of 1,6-dinitropyrene to DNA. The ability of rat liver enzymes to reduce 1,6-dinitropyrene to reactive intermediates in the presence of oxygen may be an important factor contributing to the potent tumorigenicity of this compound.

Growth inhibition of MCF-7 and MCF-10A human breast cells by alpha-tocopheryl hemisuccinate, cholesteryl hemisuccinate and their ether analogs.

The growth inhibitory properties of alpha-tocopheryl hemisuccinate (vitamin E succinate) and related compounds were examined in MCF-7 human breast tumor cells and MCF-10A normal-like human breast cells since they have been suggested to be an effective antitumor compound. The data showed that both alpha-tocopherol hemisuccinate and a structurally-similar compound, cholesteryl hemisuccinate, inhibited the growth of MCF-7 and MCF-10A cells, while alpha-tocopherol, cholesterol, cholesteryl sulfate and Tris succinate had little effect on cell growth. The ether analogs of the succinate esters, alpha-tocopheryloxybutyric acid and cholesteryloxybutyric acid, also inhibited growth of MCF-7 and MCF-10A cells, indicating that hydrolysis of the succinate esters by esterases is not required for the antiproliferative effects. The antiproliferative effects of these succinate esters and ethers may be related to their physiochemical properties that allow incorporation into cell membranes.

Effect of soy isoflavone supplementation on markers of oxidative stress in men and women.

Dietary intake of soy has been linked with decreased cancer risk, and the active compounds in soy that have been identified include the isoflavones genistein and daidzein. Since these compounds have antioxidant properties, we examined levels of oxidative damage in blood of six women and six men before and during soy supplementation using Novasoy tablets. Blood samples were obtained at weekly intervals for 3 weeks from the women taking 50-mg isoflavones once daily and the men taking 50-mg isoflavones twice daily. Plasma levels of genistein and daidzein increased after supplementation with maximal levels occurring at 2 weeks for the women while levels in men kept increasing over the 3 weeks of study. There was wide variation between individuals in the levels of isoflavones achieved. Mean levels of 5-hydroxymethyl-2'-deoxyuridine (5-OHmdU) in DNA from nucleated blood cells decreased after 1 week of supplementation in the women, with a decrease of 47% in mean 5-OHmdU levels after 3 weeks. In men, mean 5-OHmdU levels did not decrease until after 3 weeks of supplementation, at which there was 61% decrease. Mean plasma levels of 8-isoprostanes were not changed appreciably in either men or women. These pilot results suggest that soy isoflavone supplementation decreases levels of oxidative DNA damage in humans, and this may be a mechanism behind the cancer-preventive effects of soy isoflavones.

Formation of DNA adducts and oxidative DNA damage in rats treated with 1,6-dinitropyrene.

In vitro metabolism studies have indicated that the tumorigenic environmental pollutant 1,6-dinitropyrene has the potential to bind covalently to DNA and to induce oxidative DNA damage. We have determined if 1,6-dinitropyrene treatment will cause both types of DNA damage in vivo. Female Sprague-Dawley rats were given a single intraperitoneal injection of 1,6-dinitropyrene, and covalent DNA adduct formation, as indicated by the presence of N-(deoxyguanosin-8-yl)-1-amino-6-nitropyrene, and oxidative DNA damage, as indicated by increases in 5-hydroxymethyl-2'-deoxyuridine and 8-hydroxy-2'-deoxyguanosine, were assessed at 3, 12, 24 and 48 h after dosing. 32P-postlabeling analyses of DNA isolated from liver, mammary gland, bladder and nucleated blood cells indicated the formation of N-(deoxy-guanosin-8-yl)-1-amino-6-nitropyrene, with the levels being highest in the bladder. 5-hydroxymethyl-2'-deoxyuridine was detected in DNA from each of these tissues, and the levels of this oxidized nucleoside were higher in the mammary glands and livers of 1,6-dinitropyrene-treated rats. 1,6-Dinitropyrene dosing did not affect the levels of 8-hydroxy-2'-deoxyguanosine in these two tissues. These results indicate that exposure to 1,6-dinitropyrene can result in increased levels of 5-hydroxymethyl-2'-deoxyuridine in addition to covalent DNA adduct formation.

DNA adduct formation and mutation induction by nitropyrenes in Salmonella and Chinese hamster ovary cells: relationships with nitroreduction and acetylation.

Nitrated pyrenes are environmental pollutants and potent mutagens in the Salmonella reversion assay. In this study reversion induction by 1-nitropyrene and 1,8-dinitropyrene in Salmonella typhimurium TA1538 and mutation induction by 1-nitropyrene in Chinese hamster ovary (CHO) cells were related to the extent of metabolism and DNA adduct formation. In suspension cultures of Salmonella typhimurium TA1538, 1,8-dinitropyrene was up to 40-fold more mutagenic than 1-nitropyrene, although both compounds were metabolized at similar rates with nitroreduction being the major pathway. The major metabolite formed from 1-nitropyrene after 2 hr of incubation was 1-nitrosopyrene, while 1-amino-8-nitropyrene was the major metabolite formed from 1,8-dinitropyrene. 1-Nitrosopyrene and 1-nitro-8-nitrosopyrene elicited mutation values consistent with their being intermediates in the activation pathways. However, subsequent to nitroreduction, 1,8-dinitropyrene appeared to be further activated by acetylation, while 1-nitropyrene was not. Each nitrated pyrene produced a major DNA adduct substituted at the C8-position of deoxyguanosine. Although 1,8-dinitropyrene was more mutagenic than 1-nitropyrene, both compounds induced a similar number of revertants per adduct. Incubation of 1-nitrosopyrene with CHO cells produced a rapid concentration- and time-dependent induction of mutations and the conversion of 1-nitrosopyrene to 1-aminopyrene. In contrast, 1-nitropyrene did not induce mutations and was not converted to 1-aminopyrene. Both compounds produced the same major adduct, but adduct formation by 1-nitropyrene was much lower than by 1-nitrosopyrene.(ABSTRACT TRUNCATED AT 250 WORDS)

Detoxifying enzymes in human ovarian tissues: comparison of normal and tumor tissues and effects of chemotherapy.

Many anticancer drugs exert their cytotoxic effects via formation of oxygen free radicals. Cellular thiols, glutathione (GSH)-dependent enzymes and other redox enzymes are involved in the metabolism of these anticancer drugs and of the oxygen free radicals that may be generated during their metabolism. We quantified these biochemical parameters in cytosol from human ovarian tissues. We compared non-protein thiol levels, GSH transferase, GSH peroxidase, superoxide dismutase, catalase, DT diaphorase and aldehyde dehydrogenase activity in serous ovarian tumors (n = 15), other malignant ovarian tumors (n = 12), benign ovarian tissue (n = 10) and histologically normal ovarian tissue (n = 12). Mean GSH transferase and DT diaphorase activities were similar in serous and other malignant ovarian tumors. GSH transferase activity was decreased in malignant tissues relative to normal and benign tissues. Mean DT diaphorase and superoxide dismutase activities were increased in the malignant tissues, although this was not statistically significant. The mean levels of all enzymes except superoxide dismutase and aldehyde dehydrogenase in benign tissues were fairly similar to the mean levels found in normal tissue samples. Tissues from patients with serous ovarian tumors, who had received cyclophosphamide and cisplatin prior to surgery, also were analyzed (n = 7). Except for aldehyde dehydrogenase, all the parameters measured were decreased in these samples relative to serous tissue from untreated patients. These biochemical analyses may be useful in understanding the mechanisms involved in the response to chemotherapy.