Genistein Supplementation and Bone Health in Breast Cancer in Rats.

The aim of our study was to analyse the effect of supplementation with various forms of genistein (nano-, micro-, and macro-) on the mineral status of rat femurs in conditions of DMBA-induced mammary gland neoplasia. Thirty-two 30-day-old Sprague Dawley rats were used in the study. The rats were divided into four experimental groups: a control group (without supplementation) and groups supplemented with nanosized (92 ± 41 nm), microsized (587 ± 83 nm), and macrosized genistein. Micromorphometric and histological examination of the rat femurs were performed, as well as analysis of the weight and mineral composition (17 elements). Quadrupole ICP-MS was used for analysis of all trace elements. Supplementation with genistein (nano-, micro-, and macro-) was shown to cause changes in the mineral composition of the bones. In the rats receiving nanogenistein, disintegration of the bone tissue was observed. The femurs of these animals had higher content of calcium (by nearly 300%) and potassium (by 25%) than the other groups, while the level of magnesium was about 22% lower. In the case of microelements, there were increases in copper (by 67%), boron (48%), manganese (13%), and nickel (100%), and a 16% decrease in strontium compared to the bones of rats without genistein supplementation. Changes in micromorphometric parameters, resulting in increased bone fragility, were observed. Administration of genistein was found to have an effect on the amount of trace elements in the bone tissue of rats with breast cancer.

Effect of Nano- and Microzinc Supplementation on the Mineral Composition of Bones of Rats with Induced Mammary Gland Cancer.

BACKGROUND: The aim of this study was to determine changes in the mineral composition of the bones of rats with chemically induced mammary gland cancer and to attempt to establish whether a specific diet modification involving the inclusion of zinc ions in two forms-nano and micro-will affect the mineral composition of the bones. METHODS: Female Sprague-Dawley rats were used for the research. The animals were randomly assigned to three experimental groups. All animals were fed a standard diet (Labofeed H), and selected groups additionally received zinc nanoparticles or microparticles in the amount of 4.6 mg/mL. To induce mammary cancer, the animals were given 7,12-dimethyl-1,2-benz[a]anthracene. The content of Ag, As, B, Ba, Cd, Cr, Cu, Mn, Ni, Pb, Rb, Se, Sr, Tl, U, and V was determined using ICP-MS, while that of Ca, Fe, K, Mg, Na, and Zn was determined using FAAS. RESULTS: The use of a diet enriched with zinc nano- or microparticles significantly influenced the content of the elements tested. In the bones of rats fed a diet with zinc nanoparticles, changes were found in the content of Ca, Mg, Zn, Cd, U, V, and Tl, while in the case of the diet supplemented with zinc microparticles, there were differences in six elements-Ca, Mg, B, Cd, Ag, and Pb-compared to animals receiving an unsupplemented diet. CONCLUSIONS: The content of elements in the bone tissue of rats in the experimental model indicates disturbances of mineral metabolism in the tissue at an early stage of mammary cancer.

Effect of Polyphenols and Zinc Co-Supplementation on the Development of Neoplasms in Rats with Breast Cancer.

The aim of the study was to evaluate the effect of selected polyphenolic compounds: epicatechin, apigenin, and naringenin, administered separately or in combination with zinc (Zn), on the growth and development of the neoplastic process induced by 7,12-dimethylbenz[a]anthracene (DMBA) in rats. The impact of supplementation with the above-mentioned compounds on the content of modified derivatives: 1-methyladenosine, N6-methyl-2'-deoxyadenosine, O-methylguanosine, 7-methylguanine, 3-methyladenine, 1-methylguanine, 2-amino-6,8-dihydroxypurine, and 8-hydroxy-2'-deoxyguanosine in the urine of rats with mammary cancer was also assessed. Female Sprague-Dawley rats divided into 7 groups were used in the study: animals without supplementation and animals supplemented with apigenin, epicatechin, and naringenin separately or in combination with zinc. To induce mammary cancer, rats were treated with DMBA. Modified derivatives were determined by a validated high-performance liquid chromatography coupled to mass spectrometry method. Based on the obtained results, it can be said that supplementation of the animals with naringenin inhibits the development and progression of the neoplastic process in rats treated with 7,12-dimethylbenzanthracene. Neoplastic tumors were found in only 2 of 8 rats (incidence: 25%) and were considered to be at most grade 1 malignancy. The first palpable tumors in the group of animals receiving naringenin appeared two-three weeks later when compared to other groups. The combination of zinc with flavonoids (apigenin, epicatechin, and naringenin) seems to stimulate the process of carcinogenesis. The level of N6-methyl-2'-deoxyadenosine and 3-methyladenine in the urine of rats was statistically significantly higher in the groups supplemented with apigenin, epicatechin, and naringenin administered in combination with Zn than in the groups receiving only polyphenolic compounds. In conclusion, supplementation of rats with selected flavonoids administered separately or in combination with Zn has an impact on the development of neoplasms and the level of modified nucleosides in the urine of rats with breast cancer. Our results raise the question of whether simultaneous diet supplementation with more than one anti-cancer agent may reduce/stimulate the risk of carcinogenesis.

Effect of Copper and Selenium Supplementation on the Level of Elements in Rats' Femurs under Neoplastic Conditions.

A study was conducted to determine the effect of long-term supplementation with selenium and copper, administered at twice the level used in the standard diet of rats, on the content of selected elements in the femoral bones of healthy rats and rats with implanted LNCaP cancer cells. After an adaptation period, the animals were randomly divided into two experimental groups. The rats in the experimental group were implanted with prostate cancer cells. The rats in the control group were kept in the same conditions as those in the experimental group and fed the same diet, but without implanted cancer cells. The cancer cells (LNCaP) were intraperitoneally implanted in the amount of 1 × 106 (in PBS 0.4 mL) at the age of 90 days. The content of elements in the samples was determined by a quadrupole mass spectrometer with inductively coupled plasma ionization (ICP-MS). In the femoral bones of rats with implanted LNCaP cells, in the case of the standard diet and the copper-enriched diet, there was a marked decreasing trend in the content of the analysed elements relative to the control rats. This may indicate slow osteolysis taking place in the bone tissue. Contrasting results were obtained for the diet enriched with selenium; there was no significant reduction in the level of these elements, and there was even an increase in the concentrations of Fe and K in the bones of rats with implanted LNCaP cells. Particularly, numerous changes in the mineral composition of the bones were generated by enriching the diet with copper. The elements that most often underwent changes (losses) in the bones were cobalt, iron, manganese and molybdenum. The changes observed, most likely induced by the implantation of LNCaP cells, may indicate a disturbance of mineral homeostasis.

The Influence of Supplementation with Zinc in Micro and Nano Forms on the Metabolism of Fatty Acids in Livers of Rats with Breast Cancer.

The aim of this study was to investigate the effect of zinc supplementation (in the form of nano or microparticles) on the profile and metabolism of fatty acids in the liver microsomes of rats with induced breast cancer. The activity of desaturases (Δ5, Δ6, Δ9) and the level of cholesterol and its oxidized derivatives were measured. The aim of this study was also to determine the effect of various forms of zinc supplements on rats that were on 5-, 12- and 15-hydroxyeicosatetraenoic (5-, 12- and 15-HETE) and hydroxyoctadecadienoic (HODE) acids, and the level of prostaglandin E2 (PGE2). Female Spraque-Dawley rats (n = 24) were divided into 2 groups that were supplemented with zinc in the micro form (342 nm) or nano form (99 nm) particles, respectively, and a group with a standard diet (control group). All animals received 7,12-dimethylbenz[a]anthracene twice for the induction of breast cancer. Dietary nano-Zn supplementation increased vaccenic acid content (p = 0.032) and decreased Δ6-desaturase activity (p = 0.006), whereas micro-Zn increased cholesterol (p = 0.006), ∑COPs (total cholesterol-oxidation products) (p = 0.019) and PGE2 (p = 0.028) content. Dietary enrichment with Zn microparticles resulted in lower concentrations of the metabolites 15-, 12- and 5-HETE and HODE. Our study indicates that the effect of zinc supplementation on the metabolism of fatty acids in the liver microsomes under neoplastic conditions depends on the form in which it is administered.

Effect of Genistein Supplementation on the Progression of Neoplasms and the Level of the Modified Nucleosides in Rats With Mammary Cancer.

BACKGROUND/AIM: The aim of the study was to assess the impact of nano-, micro-, and macro-sized-genistein on the growth and development of neoplasms in rats with mammary cancer. Additionally, the effect on the kinetics of changes (9-11-17-20 week of a rat's life) in the levels of methyl derivatives: 1-methyladenine, 3-methyladenine, 7-methylguanine, 1-methylguanine, 1-methyladenosine, 7-methylguanosine, O-methyl-guanosine and N6-methyl-2'-deoxyguanosine in the urine of rats was analyzed. MATERIALS AND METHODS: Female Sprague-Dawley rats divided into 4 groups were used in the study. Animals were fed only a control diet or diets supplemented with the nano-, micro- and macro-sized genistein. To induce the mammary adenocarcinoma, rats were treated with 7,12-dimethylbenz[a]anthracene (DMBA). Modified nucleosides were determined by a high-performance liquid chromatography coupled to mass spectrometry method (LC-MS/MS). RESULTS: The supplementation of the diet of animals with genistein resulted in an increase in the excretion of methylated derivatives in the urine of rats. In the animals receiving standard diet, the levels of methyl derivatives increased during the study or remained relatively low. In the case of animals whose diet was supplemented with the various forms of genistein, the levels of methylated derivatives were very high from the beginning. CONCLUSION: High levels of methyl derivatives can influence carcinogenesis.

Zinc Affects Cholesterol Oxidation Products and Fatty Acids Composition in Rats' Serum.

The purpose of this work was to evaluate the effect of the nanosized or microsized zinc (Zn) particles on fatty acid profile, enzyme activity and the level of cholesterol, squalene and oxysterols in rats with breast cancer. Rats (female, n = 24) were divided into the following groups: control, and two test groups, whose diets were enriched with either Zn microparticles (342 nm) or Zn nanoparticles (99 nm). All rats were treated twice with the carcinogenic agent; 7,12-dimethylbenz[a]anthracene. In rats whose diet was enriched with zinc (especially in the form of nanoparticles), the number and sizes of tumors were lower. Diet supplementation also significantly reduced the cholesterol (p = 0.027) and COPs (cholesterol oxidation products) levels (p = 0.011) in rats serum. Enriching the diet with Zn microparticles decreased the Δ6-desaturase activity (p < 0.001). Zn influences fatty acids' profile in rats' serum as well as inhibiting desaturating enzymes. A reduced amount of pro-inflammatory arachidonic acid derivatives may be the expected effect.

Changes in the Mineral Composition of Rat Tissues Induced by Breast Cancer and Dietary Supplementation.

BACKGROUND/AIM: The aim of the study was to determine the effect of various diets with zinc or zinc in combination with resveratrol or genistein on mineral contents of the serum, urine, liver, kidney and heart in rats with chemically-induced mammary carcinoma. MATERIALS AND METHODS: The manuscript presents the tissues and body fluids content of iron, calcium, zinc, magnesium and copper in control rats or rats treated with 7,12-dimethyl-1,2-benz[a]anthracene to induce mammary carcinogenesis, under four dietary conditions: standard feed, Zn supplemented feed (6.9 mg Zn/ml), Zn and resveratrol (0.2 mg/kg body) supplemented feed, or Zn and genistein (0.2 mg/kg body) supplemented feed. RESULTS: The content of calcium and copper highly varied depending on the tissue and the type of dietary supplement (no change for zinc and magnesium). Irrespective of the diet used, the chemical induction of mammary cancer caused a decrease in iron concentration in most samples analysed. Only supplementation of the rats' diet with zinc and genistein induced no changes in iron distribution in the serum, urine, liver, kidney and heart. CONCLUSION: Further research using various levels of zinc and genistein in the diet should be conducted to determine how the development and progression of cancer is linked to iron content in cells and its ability to accumulate in tumour tissue.

Effect of Zinc Supplementation on the Serum Metabolites Profile at the Early Stage of Breast Cancer in Rats.

The cytotoxic properties of zinc nanoparticles have been evaluated in vitro against several types of cancer. However, there is a lack of significant evidence of their activity in vivo, and a potential therapeutic application remains limited. Herein we report the effective inhibition of tumor growth by zinc nanoparticles in vivo, as the effect of the dietary intervention, after the chemical induction in a rodent model of breast cancer. Biopsy images indicated grade 1 tumors with multiple inflammatory infiltrates in the group treated with zinc nanoparticles, whereas, in the other groups, a moderately differentiated grade 2 adenocarcinoma was identified. Moreover, after the supplementation with zinc nanoparticles, the levels of several metabolites associated with cancer metabolism, important to its survival, were found to have been altered. We also revealed that the biological activity of zinc in vivo depends on the size of applied particles, as the treatment with zinc microparticles has not had much effect on cancer progression.

Pomegranate Seed Oil and Bitter Melon Extract Affect Fatty Acids Composition and Metabolism in Hepatic Tissue in Rats.

Pomegranate seed oil (PSO) and bitter melon dried fruits (BME) are used as natural remedies in folk medicine and as dietary supplements. However, the exact mechanism of their beneficial action is not known. The aim of study was to assess how the diet supplementation with PSO and/or with an aqueous solution of Momordica charantia affects the metabolism of fatty acids, fatty acids composition and the level of prostaglandin E2 (PGE2) in rat liver. Animals (Sprague-Dawley female rats, n = 48) were divide into four equinumerous groups and fed as a control diet or experimental diets supplemented with PSO, BME or both PSO and BME for 21 weeks. Fatty acids were determined using gas chromatography with flame ionization detection. PSO added to the diet increased the rumenic acid content (p < 0.0001) and increased accumulation of n-6 fatty acids (p = 0.0001) in hepatic tissue. Enrichment of the diet either with PSO or with BME reduced the activity of Δ6-desaturase (D6D) (p = 0.0019), whereas the combination of those dietary factors only slightly increased the effect. Applied dietary supplements significantly reduced the PGE2 level (p = 0.0021). No significant intensification of the influence on the investigated parameters resulted from combined application of PSO and BME. PSO and BME have potential health-promoting properties because they influence fatty acids composition and exhibit an inhibiting effect on the activity of desaturases and thus they contribute to the reduction in the metabolites of arachidonic acid (especially PGE2).

Oils' Impact on Comprehensive Fatty Acid Analysis and Their Metabolites in Rats.

Fatty acids, especially polyunsaturated, and their metabolites (eicosanoids) play many pivotal roles in human body, influencing various physiological and pathological processes. The aim of the study was to evaluate the effect of supplementation with edible oils diverse in terms of fatty acid composition on fatty acid contents, activities of converting their enzymes, and on lipoxygenase metabolites of arachidonic and linoleic acids (eicosanoids) in rat serum. Female Sprague-Dawley rats divided into seven groups were used in the study. Animals from six groups were fed one of oils daily (carotino oil, made up by combining of red palm oil and canola oil, linseed oil, olive oil, rice oil, sesame oil, or sunflower oil). One group received a standard diet only. Fatty acids were determined using gas chromatography with flame ionization detection. Eicosanoids-hydroxyeicosatetraenoic (HETE) and hydroxyoctadecadienoic acids (HODE) were extracted using a solid-phase extraction method and analyzed with HPLC. Vegetable oils given daily to rats caused significant changes in serum fatty acid profile and eicosanoid concentrations. Significant differences were also found in desaturases' activity, with the linseed and olive oil supplemented groups characterized by the highest D6D and D5D activity. These findings may play a significant role in various pathological states.

Inflammation factors and element supplementation in cancer.

The aim of the study was to evaluate the effect of dietary supplementation with chosen minerals (Zn, Se, Fe) on expression of selected cytokines (IL-1, IL-6, TNFα) in spleen of rats and on their concentrations in rat serum under inflammatory and pathological conditions obtained by implantation of prostate cancer cells (LnCaP). Serum levels of metabolites of arachidonic, eicosapentaenoic and linoleic acids (hydroxyeicosatetraenoic, hydroxyeicosapentaenoic and hydroxyoctadecadienoic acids, respectively), as compounds involved in inflammation and cancer development, were also investigated. Male rats were randomised into dietary groups supplemented with Zn, Se or Fe. Prostate cancer cells were implanted to some rats in each group. The study demonstrated that minerals supplemented with the diet may exert various effects on an organism. Selenium, zinc and iron influence pro-inflammatory cytokine expression, what leads to stimulation of inflammation. They also affect synthesis of arachidonic and linoleic acid metabolites that exert pro-inflammatory action and enable cancer development and metastasis.

Title Changes in the Mineral Composition of Rat Femoral Bones Induced by Implantation of LNCaP Prostate Cancer Cells and Dietary Supplementation.

Prostate cancer (PCa) is the second most frequent cancer in men and the fifth most common cause of death worldwide, with an estimated 378,553 deaths in 2020. Prostate cancer shows a strong tendency to form metastatic foci in the bones. A number of interactions between cancer cells attacking bones and cells of the bone matrix lead to destruction of the bone and growth of the tumour. The last few decades have seen increased interest in the precise role of minerals in human health and disease. Tumour cells accumulate various minerals that promote their intensive growth. Bone, as a storehouse of elements, can be a valuable source of them for the growing tumour. There are also reports suggesting that the presence of some tumours, e.g., of the breast, can adversely affect bone structure even in the absence of metastasis to this organ. This paper presents the effect of chronic dietary intake of calcium, iron and zinc, administered in doses corresponding maximally to twice their level in a standard diet, on homeostasis of selected elements (Ca, K, Zn, Fe, Cu, Sr, Ni, Co, Mn and Mo) in the femoral bones of healthy rats and rats with implanted cancer cells of the LNCaP line. The experiment was conducted over 90 days. After the adaptation period, the animals were randomly divided into four dietary groups: standard diet and supplementation with Zn, Fe and Ca. Every dietary group was divided into experimental group (with implanted cancer cells) and control group (without implanted cancer cells). The cancer cells (LnCaP) were implanted intraperitoneally in the amount 1 × 106 to the rats at day 90 of their lifetime. Bone tissue was dried and treated with microwave-assisted mineral digestation. Total elemental content was quantified by ICP-MS. Student's t-test and Anova or Kruskal-Wallis tests were applied in order to compare treatment and dietary groups. In the case of most of the diets, especially the standard diet, the femoral bones of rats with implanted LNCaP cells showed a clear downward trend in the content of the elements tested, which may be indicative of slow osteolysis taking place in the bone tissue. In the group of rats receiving the standard diet, there were significant reductions in the content of Mo (by 83%), Ca (25%), Co (22%), Mn (13%), K (13%) and Sr (9%) in the bone tissue of rats with implanted LNCaP cells in comparison with the control group receiving the same diet but without LNCaP implantation. Supplementation of the rat diet with calcium, zinc and iron decreased the frequency of these changes relative to the standard diet, which may indicate that the diet had an inhibitory effect on bone resorption in conditions of LNCaP implantation. The principal component analysis (PCA) score plot confirms the pronounced effect of implanted LNCaP cells and the standard diet on bone composition. At the same time, supplementation with calcium, zinc and iron seems to improve bone composition. The microelements that most often underwent quantitative changes in the experimental conditions were cobalt, manganese and molybdenum.

Mammary cancer risk and serum lipid profile of rats supplemented with pomegranate seed oil and bitter melon extract.

The objective of the present study was to determine the influence of dietary supplementation with pomegranate seed oil (PSO) and/or an aqueous extract of dried bitter melon fruits (BME) on breast cancer risk and fatty acid profile in serum of female rats with chemical carcinogen-inflicted mammary tumours. Sprague-Dawley rats (n = 96) were fed control diet or experimental diets supplemented with 0.15 ml PSO/day, BME or jointly PSO and BME. After 21 weeks mammary tumours were subjected to histopathological examination and in serum fatty acids, 8-isoprostaglandin F2α content and indices of desaturases activity were analysed. Supplementation of the diet with PSO and BME did not inhibit the breast cancer formation. Conjugated linolenic acids (CLnA), present in PSO, were converted into cis-9, trans-11 conjugated linoleic acid (CLA), however, its content was lower in groups treated with a carcinogen. A similar tendency was observed for the content of SFA, MUFA, PUFA, 8-iso PGF2α and the activity of Δ6-desaturase. Enhanced pro-carcinogenic effect of 7,12-dimethylbenz[a]anthracene (DMBA), caused by applied supplements, may be a result of their influence on DMBA metabolism.

Evaluation of the Effect of Epilobium angustifolium Aqueous Extract on LNCaP Cell Proliferation in In Vitro and In Vivo Models.

Epilobium sp. are commonly used in traditional medicine in the treatment of early stages of benign prostatic hyperplasia and inflammation. It is suggested that a dominating constituent, oenothein B, is responsible for the extracts therapeutic effects. Several bioactivities were established for extracts and oenothein B in various in vitro models, but due to the questionable bioavailability of this dimeric macrocyclic ellagitannin, their significance in the in vivo effects remains unresolved. We have thus focused our attention on a complex comparative investigation of the in vitro and in vivo activities of phytochemically characterized Epilobium angustifolium aqueous extract and oenothein B on prostate cancer cells proliferation.Incubation of different cell lines with E. angustifolium aqueous extract resulted in a significant reduction of proliferation of PZ-HPV-7 and LNCaP cells, which was partly associated with antiandrogenic activity. These effects were fully congruent with oenothein B, examined in parallel. Oral supplementation of rats implanted with LNCaP cells with E. angustifolium aqueous extract 50-200 mg/kg b. w. resulted in a reduction of the occurrence of prostatic adenoma up to 13 %. Oenothein B was not detected in the urine and feces of the E. angustifolium aqueous extract-treated group, however, conjugates of nasutins gut microbiota metabolites of ellagitannins were detected in the urine, while in human volunteers supplemented with Epilobium tea, only urolithin conjugates were present.Despite observing significant and consistent effects in vitro and in vivo, we were unable to point out unequivocally the factors contributing to the observed E. angustifolium aqueous extract activity, facing the problems of an unknown metabolic fate of oenothein B and interspecies differences in E. angustifolium aqueous extract gut microbiota metabolism.

Effect of zinc and polyphenols supplementation on antioxidative defense mechanisms and the frequency of microsatellite instability in chemically-induced mammary carcinogenesis in the rat.

The aim of the present study was to assess the effect of dietary supplementation (with zinc or zinc and polyphenolic compounds - resveratrol or genistein) on antioxidant enzymes (glutathione peroxidase - GPx, catalase - CAT and superoxide dismutase - SOD) and the frequency of microsatellite instability (MSI) in a widely used model of mammary carcinogenesis induced in the rat by treatment with 7,12-dimethyl-1,2-benz[a]anthracene (DMBA). The impact of selected compounds on the intensity of DMBA-induced carcinogenesis was also assessed. Sixty four Sprague-Dawley female rats were divided into study groups which, apart from the standard diet and DMBA, were treated with zinc, zinc and resveratrol or zinc and genistein via gavage for a period ranging from 40 days to 20 weeks of age. On the basis of the obtained results it can be said that synergistic reaction between Zn(II) and genistein causes a delay in cancer development as compared with the animals treated with DMBA but with no food supplementation. Supplementation with Zn(II) and polyphenolic compounds resulted in the occurrence of microsatellite instabilities in tumors. LOH (loss of heterozygosity) was found in tumor samples at microsatellite D1Mgh6 and D3Mgh9. DMBA treatment increased significantly the glutathione peroxidase activity whereas it had no effect on the SOD and CAT activities, as compared with control rats. Diet supplementation has an effect on the activity of selected antioxidant enzymes. Diet supplementation has an effect on the occurrence of microsatellite instabilities as well as on the intensity of the neoplastic process. The intensity of occurrence of microsatellite instabilities does not depend on the activity of selected antioxidant enzymes.

Copper and resveratrol attenuates serum catalase, glutathione peroxidase, and element values in rats with DMBA-induced mammary carcinogenesis.

In this paper, a hypothesis was assessed whether or not the intoxication with copper and supplementation with copper plus resveratrol would result in changes in the activities of catalase and glutathione peroxidase and moreover if the characteristic changes would appear in concentrations of copper, iron, calcium, magnesium, and zinc in the serum of rats with chemically induced carcinogenesis. Female Sprague-Dawley rats were divided into study groups which, apart from the standard diet, were treated with copper (42.6 mg Cu/kg food as CuSO4·5H2O) or copper plus resveratrol (0.2 mg/kg body) via gavage for a period from 40 days until 20 weeks of age. In cancer groups, the rats were treated with a dose of 80 mg/body weight of 7,12-dimethyl-1,2-benz[a]anthracene (DMBA) given in rapeseed oil at 50 and 80 days of age to induce mammary carcinogenesis. The control groups included the rats kept in the same conditions and fed with the same diet as the animals from the study groups, but not DMBA-treated. The activity of catalase significantly decreased in groups of rats with mammary carcinogenesis that were supplemented with copper (p < 0.05) or copper plus resveratrol (p < 0.001) in comparison with the control groups that received the same diets. In cancer groups of nonsupplemented rats, the increase of glutathione peroxidase activity was observed. The process of carcinogenesis and the applied supplementation significantly altered the concentrations of trace elements in serum, in particular as concerns iron and copper. The mean serum iron levels in rats with breast cancer were significantly lower than those in the control groups (p < 0.001). The mean serum copper levels significantly decreased in the groups of rats with mammary carcinogenesis that were supplemented with copper or copper plus resveratrol in comparison with the control groups that received the same diets (p < 0.001). The characteristic changes in iron content and the zinc/copper and zinc/iron ratios in blood may be used as one of the prognostic factors in breast cancer research.

Effect of zinc and copper supplementation on the prognostic value of urinary 5-methyl-2'- deoxycytidine in DMBA-induced carcinogenesis in rats.

BACKGROUND: Epigenetic alterations have been identified as promising new targets for cancer prevention strategies as they occur early during carcinogenesis and represent potentially initiating events for cancer development. OBJECTIVE: The aim of the present study was to assess the effect of zinc and copper on the DNA methylation in rats whose breast adenocarcinoma was simultaneously induced with 7, 12 dimethylbenz[a]anthracene (DMBA). The research focused on the kinetics of alterations in urinary 5-MedC (5-methyl-2'-deoxycytidine) at the early and late stages of carcinogenesis, as well as the influence of dietary factors on the process. METHODS: The content of 5-methyl-2'-deoxycytidine in the rats' urine was determined by the ELISA (enzyme-linked immunosorbent assay) method. The 5-MedC level was standardized by conversion to the creatinine level. RESULTS: It was found that in the rats fed only the standard diet and DMBA-treated the urinary levels of 5-MedC collected after the 10th week were considerably lower in comparison with the content of this biomarker in urine starting from the 19th week (43.56 ± 14.34 vs. 71.84 ± 42.64). The animals treated with DMBA and additionally obtaining copper were characterized by a much higher content of the examined biomarker in urine, both in the early phase of carcinogenesis (10th week) and later (19th week), as compared with the animals fed only the standard diet or the zinc-supplemented diet. In the rats with a fully developed tumor (100% incidence of the disease) the applied dose of resveratrol (0.2 mg/kg bw) was too low to prevent the intensive formation and increase of 5-MedC level in urine, additionally stimulated by the presence of Cu in the diet as well as by the active, ongoing neoplastic process. CONCLUSIONS: Summing up the obtained results of investigations it can be said that the urinary level of 5-MedC depends on the applied supplementation.

The effect of dietary zinc--and polyphenols intake on DMBA-induced mammary tumorigenesis in rats.

BACKGROUND: The aim of the study was to investigate the effect of dietary supplementation with zinc and polyphenol compounds, i.e. resveratrol and genistein, on the effectiveness of chemically induced mammary cancer and the changes in the content of selected elements (Zn, Cu, Mg, Fe, Ca) in tumors as compared with normal tissue of the mammary gland. METHODS: Female Sprague-Dawley rats were divided into study groups which, apart from the standard diet and DMBA (7,12-dimethyl-1,2- benz[a]anthracene), were treated with zinc ions (Zn) or zinc ions + resveratrol (Zn + resveratrol) or zinc ions + genistein (Zn + genistein) via gavage for a period from 40 days until 20 weeks of age. The ICP-OES (inductively coupled plasma optical emission spectrometry) technique was used to analyze the following elements: magnesium, iron, zinc and calcium. Copper content in samples was estimated in an atomic absorption spectrophotometer. RESULTS: Regardless of the diet (standard; Zn; Zn + resveratrol; Zn + genistein), DMBA-induced breast carcinogenesis was not inhibited. On the contrary, in the Zn + resveratrol supplemented group, tumorigenesis developed at a considerably faster rate. On the basis of quantitative analysis of selected elements we found--irrespectively of the diet applied--great accumulation of copper and iron, which are strongly prooxidative, with a simultaneous considerable decrease of the magnesium content in DMBA-induced mammary tumors. The combination of zinc supplementation with resveratrol resulted in particularly large differences in the amount of the investigated elements in tumors as compared with their content in normal tissue. CONCLUSIONS: Diet supplementation with zinc and polyphenol compounds, i.e. resveratrol and genistein had no effect on the decreased copper level in tumor tissue and inhibited mammary carcinogenesis in the rat. Irrespectively of the applied diet, the development of the neoplastic process in rats resulted in changes of the iron and magnesium content in the cancerous tissue in comparison with the healthy mammary tissue. The application of combined diet supplementation with zinc ions and resveratrol considerably promoted the rate of carcinogenesis and increased the number of DMBA-induced mammary tumors.