Nelumbo nucifera Leaves Prevent NMU-Induced Mammary Tumor through Downregulation of Fatty Acid Synthase, Estrogen Receptor-α and Her2 Expression.

Diet polyphenol can reportedly prevent the formation of breast-cancer cells. Nelumbo nucifera leaf extract (NLE) is enriched with polyphenols and has several cellular functions, such as anti-atherosclerosis, anti-inflammation, and antitumor. In this study, we investigated the role of NLE in the prevention of N-methyl-N-nitrosourea (NMU)-induced mammary tumor formation. Cotreatment with NLE significantly reduced the NMU-induced tumor incidence, number, and volume. NLE administration significantly repressed the tumor growth and weight of nude mice upon inoculation with BT-474 cancer cells. Immunohistochemical staining indicated that fatty acid synthetase, estrogen receptor (ER)-α, and phosphorylated ER-α were obviously reduced in the cancer part of BT-474 inoculated nude mice upon administration of 2% NLE. Western blot analysis revealed that NLE and NLPE (polyphenol-rich NLE) repressed ER-α expression and phosphorylation and decreased the phosphorylation of Her-2 without affecting their expression. Overall, NLE and NLPE exhibited more effective antitumor abilities in NMU-induced mammary cancer formation than with tamoxifen and Herceptin.

Preventive effect of intravesical ozone supplementation on n-methyl-n-nitrosourea-induced non-muscle invasive bladder cancer in male rats.

Although non-muscle invasive bladder cancer (NMIBC) is widely seen in men, most laboratory studies of new intravesical therapies to prevent NMIBC have been conducted on female animals. In addition, ozone (O3) has been shown to be a beneficial agent as an intravesical application in the treatment of various disorders. In the current study, we evaluated the immunohistopathological and oxidative-antioxidative effects of intravesical O3 treatment on n-methyl-n-nitrosourea (MNU)-induced NMIBC. Male Wistar-Albino rats (n=51) were divided into four groups: sham (n=6), O3 only (n=15), MNU only (n=15), and MNU+O3 (n=15). The MNU-only and MNU+O3 groups received MNU, and the O3-only group received saline every other week for 10 weeks. The MNU-only group received 1 ml saline in place of O3 treatment, whereas the O3-only and MNU+O3 groups were treated with 1 ml 25 µg/ml O3 between the 7th and 12th weeks. Rat bladders were collected in the 15th week for immunohistopathology and oxidant-antioxidant quantitation. Oxidant-antioxidant parameters were determined by ELISA. Although all surviving rats in the MNU-only group had preneoplastic (4/11, 36.4%) or neoplastic changes (7/11, 63.6%), a completely normal urothelium was observed in 2 rats (2/12, 16.7%) in the MNU+O3-group (P=0.478). More high-grade lesions were observed in the MNU-only group (4/11, 36.4%) than in the MNU+O3 group (1/12, 8.3%) (P=0.120). All oxidant-antioxidant parameters significantly increased (P<0.05) in the O3-only group compared with the sham group. However, only antioxidant superoxide dismutase was remarkably higher (178.9%, P=0.060) in the MNU+O3 group compared with the MNU-only group. This is the first methodologically and pathologically well-described male rat orthotopic bladder carcinogenesis model with intravesical MNU and administration of O3 in NMIBC.

In vitro assessment of anticytotoxic and antigenotoxic effects of CANOVA(®).

BACKGROUND: CANOVA(®) (CA) is a homeopathic immunomodulator. It contains several homeopathic medicines prepares according to the Brazilian Pharmacopoeia. CA is indicated in clinical conditions in which the immune system is impaired and against tumors. N-methyl-N-nitrosourea (NMU) is an N-nitroso compound, with genotoxic/mutagenic properties. Although several studies have shown promising results in the use of CA, there are no studies reporting possible antigenotoxic effects. METHOD: This study evaluated the in vitro antigenotoxic and anticytotoxic effects of CA in human lymphocytes exposed to NMU. Samples of human lymphocytes that were subjected to different concentrations of a mixture containing CA and NMU were used. The genotoxicity/antigenotoxicity of CA was evaluated by the comet assay, anticytotoxicity was assessed by quantification of apoptosis and necrosis using acridine orange/ethidium bromide. RESULTS: CA significantly reduced DNA damage induced by NMU and reduced significantly the frequency of NMU-induced apoptosis after 24 h of treatment. CONCLUSION: CA has an important cytoprotective effect significantly reducing the DNA damage and apoptosis induced by the carcinogen NMU.

Effect of ß-sitosterol against methyl nitrosourea-induced mammary gland carcinoma in albino rats.

BACKGROUND: The present study was in quested to study the effects of ß-sitosterol on methyl nitrosourea (MNU) induced mammary gland carcinoma in albino wistar rats. METHODS: Animals were randomized and divided into four groups of eight animals each. Group I (sham control 1 % CMC in normal saline p.o.); Group II (toxic control, MNU 47 mg/kg, i.v); Group III (MNU 47 mg/kg, i.v + ß-sitosterol, 10 mg/kg, p.o); Group IV (MNU 47 mg/kg, i.v + ß-sitosterol, 20 mg/kg, p.o). Toxicity was induced by single i.v. injection of MNU followed by ß-sitosterol supplementation therapy for 115 days at the dose mentioned above. RESULTS: Treatment with ß-sitosterol evidenced decrease in the alveolar bud and lobule score in the whole mount of the mammary gland. ß-sitosterol exhibited diminishing effect on oxidative stress through synchronizing lipid and enzymatic antioxidant defense. A significant decrease in the saturated and unsaturated fatty acid was evident with the MNU treatment and ß-sitosterol demonstrated a marked effect on it. Pgp 9.5 expression was dose dependently upregulated by ß-sitosterol treatment in comparison to MNU treatment. On the contrary, downregulated NF-kB expression was perceived, when ß-sitosterol was concomitantly administered with MNU. CONCLUSION: ß-sitosterol afforded significant protection against the deleterious effects of MNU.

Leaves of Persimmon (Diospyros kaki Thunb.) Ameliorate N-Methyl-N-nitrosourea (MNU)-Induced Retinal Degeneration in Mice.

The purpose of the study was to investigate the protective effects of the ethanol extract of Diospyros kaki (EEDK) persimmon leaves to study N-methyl-N-nitrosourea (MNU)-induced retinal degeneration in mice. EEDK was orally administered after MNU injection. Retinal layer thicknesses were significantly increased in the EEDK-treated group compared with the MNU-treated group. The outer nuclear layer was preserved in the retinas of EEDK-treated mice. Moreover, EEDK treatment reduced the MNU-dependent up-regulation of glial fibrillary acidic protein (GFAP) and nestin expression in Müller and astrocyte cells. EEDK treatment also inhibited MNU-dependent down-regulation of rhodopsin expression. Quercetin exposure significantly attenuated the negative effects of H2O2 in R28 cells, suggesting that quercetin can act in an antioxidative capacity. Thus, EEDK may be considered as an agent for treating or preventing degenerative retinal diseases, such as retinitis pigmentosa and age-related macular degeneration.

An anthocyanin-rich extract from Hibiscus sabdariffa linnaeus inhibits N-nitrosomethylurea-induced leukemia in rats.

A previous study reported that anthocyanins from roselle (Hibiscus sabdariffa L.) showed significant anticancer activity in human promyelocytic leukemia cells. To explore the antitumor effect of anthocyanin, a roselle bioactive polyphenol in a rat model of chemical-induced leukemia was assayed. Anthocyanin extract of roselle (Hibiscus anthocyanins, HAs) was supplemented in the diet (0.1 and 0.2%). This study was carried out to evaluate the protective effect of HAs on N-nitrosomethylurea (NMU)-induced leukemia of rats. The study employed male Sprague-Dawley rats (n = 48), and leukemia was induced by intravenous injection of 35 mg kg(-1) body weight of NMU dissolved in physiologic saline solution. The rats were divided into four groups (n = 12): control, NMU only, and HAs groups that received different doses of HAs (0.1 and 0.2%) daily, orally, after NMU injection. After 220 days, the animals were killed, and the following parameters were assessed: morphological observation, hematology examination, histopathological assessment, and biochemical assay. When compared with the NMU-only group, HAs significantly prevented loss of organ weight and ameliorated the impairment of morphology, hematology, and histopathology. Treatment with HAs caused reduction in the levels of AST, ALT, uric acid, and MPO. Also, the results showed that oral administration of HAs (0.2%) remarkably inhibited progression of NMU-induced leukemia by approximately 33.3% in rats. This is the first report to demonstrate that the sequential administration of HAs followed by NMU resulted in an antileukemic activity in vivo.

Pubertal supplementation of lipotropes in female rats reduces mammary cancer risk by suppressing histone deacetylase 1.

PURPOSE: The time from puberty to the first pregnancy is known to be important for a woman's life-time breast cancer risk. Recent studies suggest that epigenetic mechanisms may involve pubertal maturation processes, which can affect the risk of breast cancer in later life. Epigenetic alterations are related to lipotropes (methionine, choline, folate, and vitamin B12), which are methyl donors and cofactors. However, the effects of pubertal supplementation of lipotropes in breast cancer remain largely unknown. METHODS: Twenty female Sprague-Dawley rats, aged 6 weeks, were divided into two groups and fed a normal control diet or a lipotrope-fortified diet formulated to provide five times basal levels of lipotropes during puberty. All rats were injected intraperitoneally with N-nitroso-N-methylurea at 50 days of age to induce mammary tumors. RESULTS: Tumor multiplicity and tumor volume decreased significantly as a result of lipotrope supplementation. Interestingly, quantitative RT-PCR revealed significantly decreased expression of histone deacetylase 1 (Hdac1) and DNA methyltransferase 1 (Dnmt1) genes in tumor tissues of the rats supplemented with lipotrope-fortified diet, suggesting that reduced risk of breast cancer can be attributed, at least in part, to decreased expression of these two genes. CONCLUSIONS: This study demonstrates that supplementation of lipotrope-fortified diet during puberty suppresses tumor growth, potentially through down-regulating Hdac1 and Dnmt1 gene expression. Our findings suggest that pubertal methyl diet plays an important role in the etiology of breast cancer, and further studies are warranted to develop preventative strategies against breast cancer.

Diosgenin, a steroidal saponin, exhibits anticancer activity by attenuating lipid peroxidation via enhancing antioxidant defense system during NMU-induced breast carcinoma.

Diosgenin, a natural steroidal saponin, has been reported to be found predominantly in fenugreek and has diverse biological properties. N-Methyl-N-nitrosourea (NMU) is a mammary gland-specific carcinogen that closely mimics human breast cancer in many aspects. The aim of this study was to investigate the anticarcinogenic property of diosgenin with reference to lipid peroxidation, status of antioxidants, and activities of marker enzymes against NMU-induced experimental mammary carcinogenesis. Breast cancer was induced in female Sprague Dawley rats by an intraperitoneal administration of a single dose of NMU (a concentration of 50 mg/kg body weight) diluted in 0.9% saline, and the rats were treated with oral diosgenin, 20 mg/kg body weight, for 45 days. The results were interesting, and the diosgenin treatment remarkably downregulated the peroxidation reaction and marker enzymes and extraordinarily enhanced the indigenous antioxidant defense system. The factor for this remarkable restoration might be due to the effect of the intervention strategy on the downregulation of the peroxidation reaction through the strong antioxidant nature, which ultimately reflected in the downregulation of marker enzyme activities. The histopathological study of breast and liver tissues inevitably confirms the biochemical changes. Thus, it can be concluded that diosgenin exhibits anticarcinogenic activity via reducing peroxidation reaction and marker enzymes through enhancing the intrinsic antioxidant defense system.

[Genoprotective activities of the oils from leaves and fruits of Fagus orientalis Lipsky].

The antimutagenic activities of the oils obtained from leaves and fruits of Fagus orientalis have been shown in experiments with spontaneous and mutagen- and ageing-induced variability. The aberrations of chromosomes in the meristematic cells of the Allium cepa L., Vicia faba L., Triticum aestivum L., and marrow cells of Vistar rats as well as Arabidopsis thaliana gene mutations have been mobilized as experimental tests.

[Retinal gene expression profiles of MNU-induced rat retinal degeneration treated with qijudihuangtang].

PURPOSE: Our previous studies demonstrated that qijudihuangtang, a compound of traditional Chinese medicine, protects from MNU (N-methy-N-nitrosourea)-induced rat retina photoreceptor injury. The current study was aimed to investigate protective effect of qijudihuangtang on the gene expression of retina in the same model. METHODS: Thirty 46-day-old female Sprague-Dawley rats were randomly divided into three groups (each group, n=10). The rats received a daily intragastric administration of qijudihuangtang in drug group, and 0.9% NaCl in model and normal groups for 4 days. On the fifth day, the rats in model and drug groups received a single intraperitoneal injection of 40 mg/kg body weight of N-methy-N-nitrosourea (MNU). Equivalent volume of 0.9% NaCl was injected to the rats of normal group. After 12 h of injection, all animals were sacrificed. Fresh retinas were used to extract total RNA, which was assayed by microarray and real time RT-PCR. The differentially expressed genes were also analyzed for the functional annotation and signal network mapping. RESULTS: There were 75 and 118 genes differently expressed (ratio > or = 2.0) in model group versus normal group and model group versus drug group, respectively. The former mainly included genes upregulated and the latter included most genes downregulated. These genes were mainly assigned to the categories binding transcription factor, signaling molecular, receptor, nucleic binding and extracellular matrix, and involved biological processes including signal transduction, development, immune and defense, apoptosis. The differential expressed genes contributed to MAPK signaling pathways, Toll-like receptor signaling pathway and apoptosis pathway. CONCLUSION: The gene expression in the early stage of MNU-induced rat retinal degeneration can be regulated significantly by the administration of qijudihuangtang. These changed genes were associated with specific functional groups.

Role of maternal dietary antioxidant supplementation in murine placental and fetal limb development.

Methylnitrosourea (MNU) is a multisystem teratogen that damages proliferating cells through macromolecule alkylation and generation of reactive oxygen species (ROS). Murine dams exposed to MNU midgestation produce offspring with distal limb malformations, an outcome reduced by maternal immune stimulation. Immunostimulatory effects of antioxidant therapy may in part explain this improved birth outcome. The present study hypothesizes that placental, rather than fetal, damage from excessive ROS may contribute to MNU-induced embryopathy. Fetal limbs and placentas were examined in immunotolerant CD-1 and immunosensitive C57BL/6N mice exposed to MNU, dietary antioxidant butylated hydroxytoluene (BHT), or both. MNU increased fetal resorptions and incidence of syndactyly, oligodactyly, polydactyly, and interdigital webbing, and decreased fetal size in both mouse strains. BHT reduced syndactyly and oligodactyly in both strains, and reduced polydactyly in C57BL/6N mice. Increased webbing in MNU and MNU+BHT groups likely represented maturational delay. Placentas from CD-1 and C57BL/6N MNU-exposed dams demonstrated decreased trophoblasts and increased necrosis of endothelium. Similar to distal limb defects, placental damage was reduced in mice receiving MNU+BHT. These results suggest that placental damage and fetal defects caused by MNU are in part ROS-mediated, and reduced distal limb defects following MNU+BHT may be related to improved placental integrity and function.

Effects of Seocalcitol (EB1089) on nitrosomethyl urea-induced rat mammary tumors.

Although 1,25-dihydroxyvitamin D3 is a potent cell-differentiating agent, its use in cancer prevention or therapy is precluded because it induces hypercalcemia. Synthetic analogs have been developed which inhibit tumor progression in animal models of breast cancer. One analog, Seocalcitol (EB1089) has been shown to be effective in causing regression of N-methyl-nitrosourea-induced rat mammary tumors. However, at the most effective oral dose, a significant increase in serum and urinary calcium levels were observed. In order to compare the efficacy of different dosing schedules of Seocalcitol, rats were treated either 6 times weekly (1 microg/kg) or by intermittent dosing to achieve the same total weekly dose. All dosing schedules of Seocalcitol were effective in inhibiting tumor progression. Once daily dosing was significantly more effective than intermittent dosing but was associated with a greater rise in serum calcium concentration. In order to evaluate alternative treatment strategies to limit calcemic effects, we assessed the efficacy of limiting vitamin D-induced hypercalcemia using bisphosphonates. Seocalcitol (2.5 microg/kg daily p.o. for 4 weeks) alone and in combination with pamidronate (APD 0.4 mg/kg per day s.c.) or the same dose of the bisphosphonate EB 1053 caused substantial tumor regression. No statistically significant difference was seen between combination treatment and Seocalcitol treatment alone. Co-treatment with APD or EB 1053 did not limit the rise in serum calcium induced by Seocalcitol alone. Cessation of treatment or administration of a lower dose (1microg/kg twice weekly) reversed hypercalcemia, hypercalciuria and weight loss induced by high dose Seocalcitol. However, reduction in tumor volume was maintained in the majority of animals.

Prevention of N-methylnitrosourea-induced colon carcinogenesis in rats by oxygenated carotenoid capsanthin and capsanthin-rich paprika juice.

Epidemiological and animal studies have provided evidence that dietary carotenoids may reduce the risk of certain types of cancer. An inhibitory activity of oxygenated carotenoid capsanthin, a potent antioxidant, and paprika juice rich in capsanthin (3.54 mg/100 ml) against colon carcinogenesis was investigated in F344 rats. In Experiment I (short-term assay), six rats each were given a gavage of 5 mg, 0.2 mg, or 0.008 mg capsanthin six times a week for Weeks 2-6 after receiving three intrarectal doses of 4 mg N-methylnitrosourea in Week 1. The number of colonic aberrant crypt foci, preneoplastic lesions, at Week 6 was significantly fewer (by 42%) in the 0.2 mg capsanthin group, but not in other groups, than the control group. In Experiment II (long-term assay), five groups of 30 or 25 rats each received an intrarectal dose of 2 mg N-methylnitrosourea three times a week for Weeks 1-3, and had either of 10 p.p.m. or 2 p.p.m. capsanthin solutions, 1:2.5 and 1:16.7 diluted solution of paprika juice (containing 10 p.p.m. or 2 p.p.m. capsanthin), and tap water (control fluid) as drinking fluid throughout the experiment. The experimental groups were fed 0.2 mg or 0.04 mg capsanthin/day/rat. The colon cancer incidence at Week 30 was significantly lower in the highly diluted paprika juice group (40%), but not in the moderately diluted paprika juice group (60%) and the capsanthin solution groups (68% and 68%) than the control group (83%). The results suggested that paprika juice may affect colon carcinogenesis. However, capsanthin alone failed to inhibit colon tumorigenesis, in spite of suppression of aberrant crypt foci formation in the short-term assay. Further studies are needed to explain this discrepancy.

Chemoprevention by melatonin and combined melatonin-tamoxifen therapy of second generation nitroso-methylurea-induced mammary tumours in rats.

Melatonin, an indole of pineal origin, is known to have an oncostatic effect on carcinogen-induced rat mammary tumours. We have assessed for the first time, the efficacy of melatonin alone and in combination with a sub-optimal dose of tamoxifen, a partial oestrogen antagonist, on N-nitroso-N-methylurea-induced rat mammary tumours. Both these agents were administered to Sprague-Dawley rats following excision of the primary tumours. Melatonin (200 micrograms/day/rat) at the given dose level could significantly suppress the appearance of second generation mammary tumours and the latency period of tumour appearance was also significantly increased (P < 0.001) as compared to vehicle-treated animals. Tamoxifen (60 micrograms/week/rat) does not suppress the development of second generation mammary tumours. Co-administration of melatonin and low dose of tamoxifen had no additive or synergistic effect on the prevention of second generation of mammary tumours. The results warrant the clinical evaluation of melatonin for chemoprevention and adjuvant therapy.

Screening of potential chemical carcinogens by means of mammalian cells in vitro.

A survey is presented about the current state of the efforts to the development of rapid screening systems for carcinogenic substances by means of mammalian cells in vitro. At present two fundamental ways for the realization of this task seem possible: a) So-called host-mediated assays which are a combination of carcinogen application into intact animals (possibly pregnant animals) and succeeding explantation of organs from these animals or establishment of cell cultures from fetuses following transplacental action of the compound tested. In this type of experiment the metabolization of the compound is accomplished within the organism and the critical problem of metabolic competence of cultured cells is bypassed. b) Direct application of the carcinogen into cell cultures. Beside the hitherto most used fresh embryonic cells there is an increasing tendency to use established cell lines with a rigid post-confluence inhibition of proliferation and an extremely low background of spontaneous alteration in vitro. Possibilities for the metabolic activation in this system are pointed out. The value of "indicators" of carcinogen-induced alterations in relation to neoplastic properties is discussed. Most of the higherto existing test systems are problematic in their relevancy, but the findings published in literature indicate that cell cultures offer a very promissing possibility for the early detection of carcinogenic agents in human environment.