Suppression of Prostate Tumor Progression by Bin 1

DTIC Science & Technology

2006-02-01

experiment). The full protocol was approved by IACUC review. Cohort A. Castration + Testostrone propionate s.c. + MNU i.v. Cohort B. Castration... Testostrone propionate s.c. + MNU i.v. + testosterone pellet Strain 1. mosaic Bin1 flox)/KO  Strain 2. Bin1 flox/+ (control for strain 1) Strain

Cyanidin-3-glucoside extracted from mulberry fruit can reduce N-methyl-N-nitrosourea-induced retinal degeneration in rats.

PubMed

Lee, Seung Hee; Jeong, Eojin; Paik, Sun-Sook; Jeon, Ji Hyun; Jung, Sung Won; Kim, Hyun-Bok; Kim, Muyan; Chun, Myung-Hoon; Kim, In-Beom

2014-01-01

To investigate the effect of cyanidin-3-O-glucoside (C3G) on a rat retinal degeneration (RD) model. Experimental RD was induced in rats by the intraperitoneal injection of N-methyl-N-nitrosourea (MNU) at 50 mg/kg. C3G extracted from mulberry (Morus alba L.) fruit (50 mg/kg) was orally administered, daily for 1, 2 and 4 weeks after MNU injection. The effects of C3G administration on MNU-induced RD retinas were histologically and functionally assessed by hematoxylin and eosin staining and electroretinography (ERG), respectively. The degree of retinal injury in C3G-administered RD rats was evaluated by immunohistochemistry with an antibody against glial fibrillary acidic protein (GFAP). The preferential protective effect of C3G on scotopic vision was examined by western blot analysis. Marked loss of photoreceptors in the outer nuclear layer (ONL) was observed in RD rats at 2 and 4 weeks after MNU injection, while the ONL in the MNU-induced RD rats given C3G was relatively well preserved. Immunohistochemistry with anti-GFAP showed that retinal injury was also reduced in the retinas of the rats given C3G. Functional assessment by using ERG recordings showed that scotopic ERG responses were significantly increased in RD rats given C3G for 4 weeks (p < 0.01) compared with that of untreated RD rats. In the RD rats given short-term C3G (for 1 and 2 weeks), the increase in ERG responses was not significant. In addition, western blot analysis showed that rhodopsin level in the C3G-administered RD retinas significantly increased compared to that in the non-administered RD retinas (p < 0.05), whereas red/green opsin level did not show any significant difference. Long-term administration of C3G extracted from mulberry fruit could structurally reduce photoreceptor damage and functionally improve scotopic visual functions in the RD rat model induced by MNU.

Formation of O2-methylthymine in poly(dA-dT) on methylation with N-methyl-N-nitrosourea and dimethyl sulphate. Evidence that O2-methylthymine does not miscode during DNA synthesis.

PubMed Central

Saffhill, R; Abbott, P J

1978-01-01

The alternating co-polymer has been methylated with either N methyl-N-nitrosourea (MNU) or dimethyl sulphate (DMS) and the levels of the various methylated thymidines (O2-methylthymidine, 3-methylthymidine and O4-methylthymidine) measured. MNU produced all three compounds whereas DMS only produced 3-methylthymidine and O2-methylthymidine at detectable levels. These results have been combined with our earlier results concerning the misincorporation of dGMP with E. coli DNA polymerase using MNU-methylated poly(dA-dT). These results indicate that O2-methylthymidine does not miscode during DNA synthesis. PMID:353735

Modifying effects of lemongrass essential oil on specific tissue response to the carcinogen N-methyl-N-nitrosurea in female BALB/c mice.

PubMed

Bidinotto, Lucas T; Costa, Celso A R A; Costa, Mirtes; Rodrigues, Maria A M; Barbisan, Luís F

2012-02-01

Lemongrass (Cymbopogon citratus Stapf) essential oil has been used worldwide because of its ethnobotanical and medicinal usefulness. Regarding its medicinal usefulness, the present study evaluated the beneficial effects of lemongrass essential oil (LGEO) oral treatment on cell proliferation and apoptosis events and on early development of hyperplastic lesions in the mammary gland, colon, and urinary bladder induced by N-methyl-N-nitrosourea (MNU) in female BALB/c mice. The animals were allocated into three groups: G1, treated with LGEO vehicle for 5 weeks (five times per week); G2, treated with LGEO vehicle as for G1 and MNU (two injections each of 30 mg/kg of body weight at weeks 3 and 5); and G3, treated with LGEO (five times each with 500 mg/kg of body weight per week) and MNU as for G2. Twenty-four hours after the last MNU application, all animals were euthanized, and mammary glands, colon, and urinary bladder were collected for histological and immunohistochemical analysis. LGEO oral treatment significantly changed the indexes of apoptosis and/or cellular proliferation for the tissues analyzed. In particular, the treatment reduced the incidence of hyperplastic lesions and increased apoptosis in mammary epithelial cells. This increment in the apoptosis response may be related to a favorable balance in Bcl-2/Bax immunoreactivity in mammary epithelial cells. These findings indicate that LGEO presented a protective role against early MNU-induced mammary gland alterations in BALB/c mice.

Garlic and associated allyl sulfur components inhibit N-methyl-N-nitrosourea induced rat mammary carcinogenesis.

PubMed

Schaffer, E M; Liu, J Z; Green, J; Dangler, C A; Milner, J A

1996-04-19

Our previous studies demonstrated that dietary garlic powder supplementation inhibits N-nitrosamine induced DNA alkylation in liver and mammary tissue. The present studies compared the impact of dietary supplementation with garlic powder or two garlic constituents, water-soluble S-allyl cysteine (SAC) and oil-soluble diallyl disulfide (DADS), on the incidence of mammary tumorigenesis induced by N-methyl-N-nitrosourea (MNU). Female Sprague-Dawley rats were fed semi-purified casein based diets with or without supplements of garlic powder(20g/kg), SAC (57 micromol/kg) or DADS (57 micromol/kg) for 2 weeks prior to treatment with MNU (15 mg/kg body wt). Garlic powder, SAC and DADS supplementation significantly delayed the onset of mammary tumors compared to rats receiving the unsupplemented diet. Tumor incidence 23 weeks after MNU treatment was reduced by 76, 41 and 53% in rats fed garlic, SAC and DADS, respectively, compared to controls (P<0.05). Total tumor number was reduced 81, 35 and 65% by these supplements, respectively (P<0.05). In a separate study the quantity of mammary DNA alkylation occurring 3 h after MNU treatment was reduced in rats fed garlic, SAC or DADS (P<0.05). Specifically, O(6)-methylguanine adducts were reduced by 27, 18 and 23% in rats fed supplemental garlic, SAC and DADS, respectively, compared to controls. N(7)-Methylguanine adducts decreased by 48, 22 and 21% respectively, compared to rats fed the control diet. These studies demonstrate that garlic and associated allyl sulfur components, SAC and DADS, are effective inhibitors of MNU-induced mammary carcinogenesis.

DNA Alkylating Agent Protects Against Spontaneous Hepatocellular Carcinoma Regardless of O6-Methylguanine-DNA Methyltransferase Status.

PubMed

Herzig, Maryanne C S; Zavadil, Jessica A; Street, Karah; Hildreth, Kim; Drinkwater, Norman R; Reddick, Traci; Herbert, Damon C; Hanes, Martha A; McMahan, C Alex; Reddick, Robert L; Walter, Christi A

2016-03-01

Hepatocellular carcinoma is increasingly important in the United States as the incidence rate rose over the last 30 years. C3HeB/FeJ mice serve as a unique model to study hepatocellular carcinoma tumorigenesis because they mimic human hepatocellular carcinoma with delayed onset, male gender bias, approximately 50% incidence, and susceptibility to tumorigenesis is mediated through multiple genetic loci. Because a human O(6)-methylguanine-DNA methyltransferase (hMGMT) transgene reduces spontaneous tumorigenesis in this model, we hypothesized that hMGMT would also protect from methylation-induced hepatocarcinogenesis. To test this hypothesis, wild-type and hMGMT transgenic C3HeB/FeJ male mice were treated with two monofunctional alkylating agents: diethylnitrosamine (DEN; 0.025 μmol/g body weight) on day 12 of life with evaluation for glucose-6-phosphatase-deficient (G6PD) foci at 16, 24, and 32 weeks or N-methyl-N-nitrosurea (MNU; 25 mg MNU/kg body weight) once monthly for 7 months starting at 3 months of age with evaluation for liver tumors at 12 to 15 months of age. No difference in abundance or size of G6PD foci was measured with DEN treatment. In contrast, it was unexpectedly found that MNU reduces liver tumor prevalence in wild-type and hMGMT transgenic mice despite increased tumor prevalence in other tissues. hMGMT and MNU protections were additive, suggesting that MNU protects through a different mechanism, perhaps through the cytotoxic N7-alkylguanine and N3-alkyladenine lesions which have low mutagenic potential compared with O(6)-alkylguanine lesions. Together, these results suggest that targeting the repair of cytotoxic lesions may be a good preventative for patients at high risk of developing hepatocellular carcinoma. ©2015 American Association for Cancer Research.

Optimal dose selection of N-methyl-N-nitrosourea for the rat comet assay to evaluate DNA damage in organs with different susceptibility to cytotoxicity.

PubMed

Kitamoto, Sachiko; Matsuyama, Ryoko; Uematsu, Yasuaki; Ogata, Keiko; Ota, Mika; Yamada, Toru; Miyata, Kaori; Funabashi, Hitoshi; Saito, Koichi

2015-07-01

The in vivo rodent alkaline comet assay (comet assay) is a promising technique to evaluate DNA damage in vivo. However, there is no agreement on a method to evaluate DNA damage in organs where cytotoxicity is observed. As a part of the Japanese Center for the Validation of Alternative Methods (JaCVAM)-initiative international validation study of the comet assay, we examined DNA damage in the liver, stomach, and bone marrow of rats given three oral doses of N-methyl-N-nitrosourea (MNU) up to the maximum tolerated dose based on systemic toxicity. MNU significantly increased the % tail DNA in all the organs. Histopathological analysis showed no cytotoxic effect on the liver, indicating clearly that MNU has a genotoxic potential in the liver. In the stomach, however, the cytotoxic effects were very severe at systemically non-toxic doses. Low-dose MNU significantly increased the % tail DNA even at a non-cytotoxic dose, indicating that MNU has a genotoxic potential also in the stomach. Part of the DNA damage at cytotoxic doses was considered to be a secondary effect of severe cell damage. In the bone marrow, both the % tail DNA and incidence of micronucleated polychromatic erythrocytes significantly increased at non-hematotoxic doses, which were different from the non-cytotoxic doses for liver and stomach. These findings indicate that an optimal dose for detecting DNA damage may vary among organs and that careful attention is required to select an optimum dose for the comet assay based on systemic toxicity such as mortality and clinical observations. The present study shows that when serious cytotoxicity is suggested by increased % hedgehogs in the comet assay, histopathological examination should be included for the evaluation of a positive response. Copyright © 2015 Elsevier B.V. All rights reserved.

Congenic rats with higher arylamine N-acetyltransferase 2 activity exhibit greater carcinogen-induced mammary tumor susceptibility independent of carcinogen metabolism.

PubMed

Stepp, Marcus W; Doll, Mark A; Samuelson, David J; Sanders, Mary Ann G; States, J Christopher; Hein, David W

2017-03-31

Recent investigations suggest role(s) of human arylamine N-acetyltransferase 1 (NAT1) in breast cancer. Rat NAT2 is orthologous to human NAT1 and the gene products are functional homologs. We conducted in vivo studies using F344.WKY-Nat2 rapid/slow rats, congenic at rat Nat2 for high (rapid) and low (slow) arylamine N-acetyltransferase activity, to assess a possible role for rat NAT2 in mammary tumor susceptibility. Mammary carcinogens, methylnitrosourea (MNU) and 7,12-dimethylbenzanthracene (DMBA) neither of which is metabolized by N-acetyltransferase, were administered to assess mammary tumors. MNU was administered at 3 or 8 weeks of age. DMBA was administered at 8 weeks of age. NAT2 enzymatic activity and endogenous acetyl-coenzyme A (AcCoA) levels were measured in tissue samples and embryonic fibroblasts isolated from the congenic rats. Tumor latency was shorter in rapid NAT2 rats compared to slow NAT2 rats, with statistical significance for MNU administered at 3 and 8 weeks of age (p = 0.009 and 0.050, respectively). Tumor multiplicity and incidence were higher in rapid NAT2 rats compared to slow NAT2 rats administered MNU or DMBA at 8 weeks of age (MNU, p = 0.050 and 0.035; DMBA, p = 0.004 and 0.027, respectively). Recombinant rat rapid-NAT2, as well as tissue samples and embryonic fibroblasts derived from rapid NAT2 rats, catalyzed p-aminobenzoic acid N-acetyl transfer and folate-dependent acetyl-coenzyme A (AcCoA) hydrolysis at higher rates than those derived from rat slow-NAT2. Embryonic fibroblasts isolated from rapid NAT2 rats displayed lower levels of cellular AcCoA than slow NAT2 rats (p < 0.01). A novel role for rat NAT2 in mammary cancer was discovered unrelated to carcinogen metabolism, suggesting a role for human NAT1 in breast cancer.

Dose-Response for Multiple Biomarkers of Exposure and Genotoxic Effect Following Repeated Treatment of Rats with the Alkylating Agents, MMS and MNU.

PubMed

Ji, Zhiying; LeBaron, Matthew J; Schisler, Melissa R; Zhang, Fagen; Bartels, Michael J; Gollapudi, B Bhaskar; Pottenger, Lynn H

2016-05-01

The nature of the dose-response relationship for various in vivo endpoints of exposure and effect were investigated using the alkylating agents, methyl methanesulfonate (MMS) and methylnitrosourea (MNU). Six male F344 rats/group were dosed orally with 0, 0.5, 1, 5, 25 or 50mg/kg bw/day (mkd) of MMS, or 0, 0.01, 0.1, 1, 5, 10, 25 or 50 mkd of MNU, for 4 consecutive days and sacrificed 24h after the last dose. The dose-responses for multiple biomarkers of exposure and genotoxic effect were investigated. In MMS-treated rats, the hemoglobin adduct level, a systemic exposure biomarker, increased linearly with dose (r (2) = 0.9990, P < 0.05), indicating the systemic availability of MMS; however, the N7MeG DNA adduct, a target exposure biomarker, exhibited a non-linear dose-response in blood and liver tissues. Blood reticulocyte micronuclei (MN), a genotoxic effect biomarker, exhibited a clear no-observed-genotoxic-effect-level (NOGEL) of 5 mkd as a point of departure (PoD) for MMS. Two separate dose-response models, the Lutz and Lutz model and the stepwise approach using PROC REG both supported a bilinear/threshold dose-response for MN induction. Liver gene expression, a mechanistic endpoint, also exhibited a bilinear dose-response. Similarly, in MNU-treated rats, hepatic DNA adducts, gene expression changes and MN all exhibited clear PoDs, with a NOGEL of 1 mkd for MN induction, although dose-response modeling of the MNU-induced MN data showed a better statistical fit for a linear dose-response. In summary, these results provide in vivo data that support the existence of clear non-linear dose-responses for a number of biologically significant events along the pathway for genotoxicity induced by DNA-reactive agents. © The Author 2015. Published by Oxford University Press on behalf of the UK Environmental Mutagen Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Multiple programmed cell death pathways are involved in N-methyl-N-nitrosourea-induced photoreceptor degeneration.

PubMed

Reisenhofer, Miriam; Balmer, Jasmin; Zulliger, Rahel; Enzmann, Volker

2015-05-01

To identify programmed cell death (PCD) pathways involved in N-methyl-N-nitrosourea (MNU)-induced photoreceptor (PR) degeneration. Adult C57BL/6 mice received a single MNU i.p. injection (60 mg/kg bodyweight), and were observed over a period of 7 days. Degeneration was visualized by H&E overview staining and electron microscopy. PR cell death was measured by quantifying TUNEL-positive cells in the outer nuclear layer (ONL). Activity measurements of key PCD enzymes (calpain, caspases) were used to identify the involved cell death pathways. Furthermore, the expression level of C/EBP homologous protein (CHOP) and glucose-regulated protein 78 (GRP78), key players in endoplasmic reticulum (ER) stress-induced apoptosis, was analyzed using quantitative real-time PCR. A decrease in ONL thickness and the appearance of apoptotic PR nuclei could be detected beginning 3 days post-injection (PI). This was accompanied by an increase of TUNEL-positive cells. Significant upregulation of activated caspases (3, 9, 12) was found at different time periods after MNU injection. Additionally, several other players of nonconventional PCD pathways were also upregulated. Consequently, calpain activity increased in the ONL, with a maximum on day 7 PI and an upregulation of CHOP and GRP78 expression beginning on day 1 PI was found. The data indicate that regular apoptosis is the major cause of MNU-induced PR cell death. However, alternative PCD pathways, including ER stress and calpain activation, are also involved. Knowledge about the mechanisms involved in this mouse model of PR degeneration could facilitate the design of putative combinatory therapeutic approaches.

Organ differences in the impact of p27(kip1) deficiency on carcinogenesis induced by N-methyl-N-nitrosourea.

PubMed

Ogawa, Kumiko; Murasaki, Toshiya; Sugiura, Satoshi; Nakanishi, Makoto; Shirai, Tomoyuki

2013-06-01

To evaluate the impact of p27 on carcinogenesis in various organs, N-methyl-N-nitrosourea (MNU), a direct-acting alkylating agent, was given to p27 knock-out mice. Groups of 20-40 male and female mice with null, hetero- or wild-type p27 alleles were given drinking water containing 240 ppm MNU or distilled water every other week for five cycles. The incidence and multiplicity of the induced proliferative lesions were then histologically evaluated at weeks 14 and 20. MNU treatment induced various lesions including squamous hyperplasia and squamous cell carcinoma in the forestomach, atypical hyperplasia and adenocarcinomas in the fundic and pyloric glands, adenomas and adenocarcinomas in the duodenum, malignant lymphomas in the thymus, liver, kidney and spleen and alveolar hyperplasia, adenomas, adenocarcinomas and malignant lymphomas in the lung. Although the incidences of the lesions in the forestomach, fundic and pyloric glands did not differ among the p27 genotypes, those of alveolar hyperplasia of the lung and malignant lymphoma of the thymus were significantly increased in p27-null males as compared with both wild- and hetero-type animals. Moreover, in both p27(+/+) and p27(+/-) cases, the rates for p27-positive cells were obviously increased in proliferative lesions of the pyloric gland and the lung. However, an increased rate of p27-positive cells was not observed in malignant lymphoma of the thymus. These findings suggest that p27 does not control the cell cycle equally in all organs affected by MNU-induced carcinogenesis. Copyright © 2011 John Wiley & Sons, Ltd.

Increased phospho-AKT is associated with loss of the androgen receptor during the progression of N-methyl-N-nitrosourea-induced prostate carcinogenesis in rats.

PubMed

Liao, Zhiming; Wang, Shihua; Boileau, Thomas W-M; Erdman, John W; Clinton, Steven K

2005-07-01

Characterization of molecular events during N-methyl-N-nitrosourea (MNU)-induced rat prostate carcinogenesis enhances the utility of this model for the preclinical assessment of preventive strategies. Androgen independence is typical of advanced human prostate cancer and may occur through multiple mechanisms including the loss of androgen receptor (AR) expression and the activation of alternative signaling pathways. We examined the interrelationships between AR and p-AKT expression by immunohistochemical staining during MNU-androgen-induced prostate carcinogenesis in male Wistar-Unilever rats. Histone nuclear staining and image analysis was employed to assess parallel changes in chromatin and nuclear structure. The percentage of AR positive nuclei decreased (P < 0.01) as carcinogenesis progressed: hyperplasia (92%), atypical hyperplasia (92%), well-differentiated adenocarcinoma (57%), moderately-differentiated adenocarcinoma (19%), and poorly-differentiated adenocarcinoma (10%). Conversely, p-AKT staining increased significantly during carcinogenesis. Sparse staining was observed in normal tissues (0.2% of epithelial area) and hyperplastic lesions (0.1%), while expression increased significantly (P < 0.001) in atypical hyperplasia (7.6%), well-differentiated adenocarcinoma (16.7%), moderately-differentiated adenocarcinoma (19.6%), and poorly-differentiated adenocarcinoma (17.4%). In parallel, nuclear morphometry revealed increased nuclear size, greater irregularity, and lower DNA compactness as cancers became more poorly differentiated. In the MNU model, the progressive evolution of dominant tumor cell populations showing an increase in p-AKT in parallel with a decline in AR staining suggests that activation of AKT signaling may be one of several mechanisms contributing to androgen insensitivity during prostate cancer progression. Our observations mimic findings suggested by human studies and support the relevance of the MNU model in preclinical studies of preventive strategies. (c) 2005 Wiley-Liss, Inc.

Anti-angiogenic effects of the superantigen staphylococcal enterotoxin B and bacillus Calmette-Guérin immunotherapy for nonmuscle invasive bladder cancer.

PubMed

Reis, Leonardo O; Ferreira, Ubirajara; Billis, Athanase; Cagnon, Valéria H A; Fávaro, Wagner J

2012-02-01

We compared and characterized the effects of intravesical bacillus Calmette-Guérin and/or staphylococcal enterotoxin B for nonmuscle invasive bladder cancer. A total of 75 female Fisher 344 rats were anesthetized. Of the rats 15 received 0.3 ml saline (control) and 60 received 1.5 mg/kg MNU (N-methyl-n-nitrosourea) intravesically every other week for 6 weeks. The rats were divided into 5 groups. The MNU and control groups received 0.3 ml saline. The bacillus Calmette-Guérin group received 10(6) cfu bacillus Calmette-Guérin. The staphylococcal enterotoxin B group received 10 μg/ml staphylococcal enterotoxin B. The bacillus Calmette-Guérin plus staphylococcal enterotoxin B group received the 2 treatments simultaneously. Each group was treated intravesically for 6 weeks. At 15 weeks all bladders were collected for histopathological and immunological evaluation, and Western blot. Papillary carcinoma (pTa) and high grade intraepithelial neoplasia (carcinoma in situ) were more common in the MNU group. Papillary hyperplasia was more common in the bacillus Calmette-Guérin and enterotoxin groups. Flat hyperplasia was more common in the bacillus Calmette-Guérin plus enterotoxin group. No significant toxicity was observed. The apoptosis and cellular proliferation indexes decreased in the bacillus Calmette-Guérin, enterotoxin and bacillus Calmette-Guérin plus enterotoxin groups compared to the MNU group. Intensified vascular endothelial growth factor, matrix metalloproteinase-9, Ki-67 and insulin-like growth factor receptor-1 immunoreactivity was verified in the MNU group, moderate in the bacillus Calmette-Guérin and enterotoxin groups, and weak in the bacillus Calmette-Guérin plus enterotoxin and control groups. In contrast, intense endostatin immunoreactivity was verified in the control and bacillus Calmette-Guérin plus enterotoxin groups. Bacillus Calmette-Guérin and staphylococcal enterotoxin B showed similar anti-angiogenic effects. Bacillus Calmette-Guérin plus enterotoxin treatment had additional activity compared to that of monotherapy. It was more effective in restoring apoptosis and balancing cellular proliferation, and it correlated with increased endostatin, and decreased vascular endothelial growth factor, matrix metalloproteinase-9, Ki-67 and insulin-like growth factor receptor-1 reactivity. Copyright © 2012 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Effects of Dietary Xanthophylls, Canthaxanthin and Astaxanthin on N-Methyl-N-nitrosourea-induced Rat Mammary Carcinogenesis.

PubMed

Yuri, Takashi; Yoshizawa, Katsuhiko; Emoto, Yuko; Kinoshita, Yuichi; Yuki, Michiko; Tsubura, Airo

Natural xanthophylls, canthaxanthin and astaxanthin are known to exhibit anticancer activity. However, the dietary effects of canthaxanthin and astaxanthin on N-methyl-N-nitrosourea (MNU)-induced mammary cancer remain controversial, and their mechanisms of action have not been clearly identified. Three-week-old female Sprague-Dawley rats were fed a xanthophyll-free (basal diet) diet or experimental diets containing canthaxanthin or astaxanthin (0.04% and 0.4%) for 5 weeks (until 8 weeks of age), after which all rats were provided the basal diet (n=15 each). Rats were administered MNU at 6 weeks of age, and the incidence of mammary tumors at 20 weeks of age was compared. The expression of adiponectin in mammary adipose tissues taken at 7 weeks of age was also compared. Compared to the basal diet group, the 0.4% (but not the 0.04%) astaxanthin diet significantly reduced the incidence of palpable mammary carcinoma (92% vs. 42%; p<0.05), while the low and high canthaxanthin diets produced no significant inhibition. Adiponectin immunoblotting showed significantly higher expression in the 0.4% astaxanthin diet group, while the other groups were similar to the basal diet group. High concentrations of astaxanthin suppress MNU-induced mammary carcinoma. Changes in adiponectin may be involved in the mechanism of action. Copyright © 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

Effect of pharmacologically induced retinal degeneration on retinal autofluorescence lifetimes in mice.

PubMed

Dysli, Chantal; Dysli, Muriel; Zinkernagel, Martin S; Enzmann, Volker

2016-12-01

Fluorescence lifetime imaging ophthalmoscopy (FLIO) was used to investigate retinal autofluorescence lifetimes in mouse models of pharmacologically induced retinal degeneration over time. Sodium iodate (NaIO 3 , 35 mg/kg intravenously) was used to induce retinal pigment epithelium (RPE) degeneration with subsequent loss of photoreceptors (PR) whereas N-methyl-N-nitrosourea (MNU, 45 mg/kg intraperitoneally) was employed for degeneration of the photoreceptor cell layer alone. All mice were measured at day 3, 7, 14, and 28 after the respective injection of NaIO 3 , MNU or NaCl (control). Fluorescence lifetime imaging was performed using a fluorescence lifetime imaging ophthalmoscope (Heidelberg Engineering, Heidelberg, Germany). Fluorescence was excited at 473 nm and fluorescence lifetimes were measured in a short and a long spectral channel (498-560 nm and 560-720 nm). Corresponding optical coherence tomography (OCT) images were consecutively acquired and histology was performed at the end of the experiments. Segmentation of OCT images and histology verified the cell type-specific degeneration process over time. Retinal autofluorescence lifetimes increased from day 3 to day 28 in mice after NaIO 3 treatment. Finally, at day 28, fluorescence lifetimes were prolonged by 8% in the short and 61% in the long spectral channel compared to control animals (p = 0.21 and p = 0.004, respectively). In mice after MNU treatment, the mean retinal autofluorescence lifetimes were already decreased at day 3 and retinal lifetimes were finally shortened by 27% in the short and 51% in the long spectral channel at day 28 (p = 0.0028). In conclusion, degeneration of the RPE with subsequent photoreceptor degeneration by NaIO 3 lead to longer mean fluorescence lifetimes of the retina compared to control mice, whereas during specific degeneration of the photoreceptor layer induced by MNU shorter lifetimes were measured. Therefore, short retinal fluorescence lifetimes may originate from the RPE and may be modified by the overlaying retinal layers. Copyright © 2016 Elsevier Ltd. All rights reserved.

Disruption of the Membrane Nuclease Gene (MBOVPG45_0215) of Mycoplasma bovis Greatly Reduces Cellular Nuclease Activity

PubMed Central

Sharma, Shukriti; Tivendale, Kelly A.; Markham, Philip F.

2015-01-01

ABSTRACT Although the complete genome sequences of three strains of Mycoplasma bovis are available, few studies have examined gene function in this important pathogen. Mycoplasmas lack the biosynthetic machinery for the de novo synthesis of nucleic acid precursors, so nucleases are likely to be essential for them to acquire nucleotide precursors. Three putative membrane nucleases have been annotated in the genome of M. bovis strain PG45, MBOVPG45_0089 and MBOVPG45_0310, both of which have the thermonuclease (TNASE_3) functional domain, and MBOVPG45_0215 (mnuA), which has an exonuclease/endonuclease/phosphatase domain. While previous studies have demonstrated the function of TNASE_3 domain nucleases in several mycoplasmas, quantitative comparisons of the contributions of different nucleases to cellular nuclease activity have been lacking. Mapping of a library of 319 transposon mutants of M. bovis PG45 by direct genome sequencing identified mutants with insertions in MBOVPG45_0310 (the Δ0310 mutant) and MBOVPG45_0215 (the Δ0215 mutant). In this study, the detection of the product of MBOVPG45_0215 in the Triton X-114 fraction of M. bovis cell lysates, its cell surface exposure, and its predicted signal peptide suggested that it is a surface-exposed lipoprotein nuclease. Comparison of a ΔmnuA mutant with wild-type M. bovis on native and denatured DNA gels and in digestion assays using double-stranded phage λ DNA and closed circular plasmid DNA demonstrated that inactivation of this gene abolishes most of the cellular exonuclease and endonuclease activity of M. bovis. This activity could be fully restored by complementation with the wild-type mnuA gene, demonstrating that MnuA is the major cellular nuclease of M. bovis. IMPORTANCE Nucleases are thought to be important contributors to virulence and crucial for the maintenance of a nutritional supply of nucleotides in mycoplasmas that are pathogenic in animals. This study demonstrates for the first time that of the three annotated cell surface nuclease genes in an important pathogenic mycoplasma, the homologue of the thermostable nuclease identified in Gram-positive bacteria is responsible for the majority of the nuclease activity detectable in vitro. PMID:25691526

Alkylating agent (MNU)-induced mutation in space environment

NASA Astrophysics Data System (ADS)

Ohnishi, T.; Takahashi, A.; Ohnishi, K.; Takahashi, S.; Masukawa, M.; Sekikawa, K.; Amano, T.; Nakano, T.; Nagaoka, S.

2001-01-01

In recent years, some contradictory data about the effects of microgravity on radiation-induced biological responses in space experiments have been reported. We prepared a damaged template DNA produced with an alkylating agent (N-methyl-N-nitroso urea; MNU) to measure incorrect base-incorporation during DNA replication in microgravity. We examined whether mutation frequency is affected by microgravity during DNA replication for a DNA template damaged by an alkylating agent. Using an in vitro enzymatic reaction system, DNA synthesis by Taq polymerase or polymerase III was done during a US space shuttle mission (Discovery, STS-91). After the flight, DNA replication and mutation frequencies were measured. We found that there was almost no effect of microgravity on DNA replication and mutation frequency. It is suggested that microgravity might not affect at the stage of substrate incorporation in induced-mutation frequency.

Null Activity of Selenium and Vitamin E as Cancer Chemopreventive Agents in the Rat Prostate1

PubMed Central

McCormick, David L.; Rao, K.V.N.; Johnson, William D.; Bosland, Maarten C.; Lubet, Ronald A.; Steele, Vernon E.

2009-01-01

To evaluate the potential efficacy of selenium and vitamin E as inhibitors of prostate carcinogenesis, four chemoprevention studies using a common protocol were performed in a rat model of androgen-dependent prostate cancer. After stimulation of prostate epithelial cell proliferation by a sequential regimen of cyproterone acetate followed by testosterone propionate, male Wistar-Unilever rats received a single intravenous injection of N-methyl-N-nitrosourea (MNU) followed by chronic androgen stimulation via subcutaneous implantation of testosterone pellets. At one week post-MNU, groups of carcinogen-treated rats (39–44/group) were fed either basal diet or basal diet supplemented with L-selenomethionine (3 or 1.5 mg/kg diet; Study 1); DL-α-tocopherol (Vitamin E; 4000 or 2000 mg/kg diet; Study 2); L-selenomethionine + Vitamin E (3 + 2000 mg/kg diet or 3 + 500 mg/kg diet; Study 3), or selenized yeast (target selenium levels of 9 or 3 mg/kg diet; Study 4). Each chemoprevention study was terminated at 13 months post-MNU, and prostate cancer incidence was determined by histopathologic evaluation. No statistically significant reductions in prostate cancer incidence were identified in any group receiving dietary supplementation with selenium and/or vitamin E. These data do not support the hypotheses that selenium and vitamin E are potent cancer chemopreventive agents in the prostate, and when considered with the recent clinical data reported in the SELECT trial, demonstrate the predictive nature of this animal model for human prostate cancer chemoprevention. PMID:20145190

Mutagenicity of streptozotocin and several other nitrosourea compounds in Salmonella typhimurium.

PubMed

Zimmer, D M; Bhuyan, B K

1976-11-01

The following nitrosourea compounds were compared for their ability to induce mutation (to histidine independence) in the histidine-requiring auxotroph Salmonella typhimurium his G46: MNU, streptozotocin (SZ, streptozocin) and its analogs SZA1 and SZA2, and the antitumor drugs BCNU, CCNU and DCNU. At equitoxic doses SZ, SZA1, SZA2 and MNU were almost equally mutagenic causing 150, 42, 140 and 170 mutants/106 survivors at 20% lethal dose (ID20) ALTHOUGH, ON A WIEGHT BASIS, SZ was the most mutagenic of all the compounds tested. At ID20 BCNU, CCNU and DCNU gave about 0.5 mutants/106 survivors. Our results show that these nitrosoureas, in common with many other drugs (such as cyclophosphamide, daunomycin, etc.) used in cancer chemotherapy, are highly mutagenic. The implication of our results in the screening of drugs for their mutagenicity to man is discussed.

Vanillin as a modulator agent in SMART test: inhibition in the steps that precede N-methyl-N-nitrosourea-, N-ethyl-N-nitrosourea-, ethylmethanesulphonate- and bleomycin-genotoxicity.

PubMed

Sinigaglia, Marialva; Lehmann, Maurício; Baumgardt, Paula; do Amaral, Viviane Souza; Dihl, Rafael Rodrigues; Reguly, Maria Luíza; de Andrade, Heloísa Helena Rodrigues

2006-09-05

Vanillin (VA), the world's major flavoring compound used in food industry and confectionery products - that has antimutagenic and anticarcinogenic activity against a variety of mutagenic/carcinogenic agents - was tested for the interval between the formation of premutational lesion and it is finalization as a DNA lesion. The overall findings using co-treatment protocols in SMART test suggest that VA can lead to a significant protection against the general genotoxicity of ethylmethanesulphonate (EMS), N-ethyl-N-nitrosourea (ENU), N-methyl-N-nitrosourea (MNU) and bleomycin sulphate (BLEO). Considering MNU, ENU and EMS the desmutagenic activity observed could result from VA-stimulation of detoxification, via induction of glutathione S-transferase. However, the protector effect related to BLEO could be attributed to its powerful scavenger ability, which has the potential to prevent oxidative damage induced by BLEO.

Null activity of selenium and vitamin e as cancer chemopreventive agents in the rat prostate.

PubMed

McCormick, David L; Rao, K V N; Johnson, William D; Bosland, Maarten C; Lubet, Ronald A; Steele, Vernon E

2010-03-01

To evaluate the potential efficacy of selenium and vitamin E as inhibitors of prostate carcinogenesis, four chemoprevention studies using a common protocol were done in a rat model of androgen-dependent prostate cancer. After stimulation of prostate epithelial cell proliferation by a sequential regimen of cyproterone acetate followed by testosterone propionate, male Wistar-Unilever rats received a single i.v. injection of N-methyl-N-nitrosourea (MNU) followed by chronic androgen stimulation via subcutaneous implantation of testosterone pellets. At 1 week post-MNU, groups of carcinogen-treated rats (39-44/group) were fed either a basal diet or a basal diet supplemented with l-selenomethionine (3 or 1.5 mg/kg diet; study 1), dl-alpha-tocopherol (vitamin E, 4,000 or 2,000 mg/kg diet; study 2), l-selenomethionine + vitamin E (3 + 2,000 mg/kg diet or 3 + 500 mg/kg diet; study 3), or selenized yeast (target selenium levels of 9 or 3 mg/kg diet; study 4). Each chemoprevention study was terminated at 13 months post-MNU, and prostate cancer incidence was determined by histopathologic evaluation. No statistically significant reductions in prostate cancer incidence were identified in any group receiving dietary supplementation with selenium and/or vitamin E. These data do not support the hypotheses that selenium and vitamin E are potent cancer chemopreventive agents in the prostate, and when considered with the recent clinical data reported in the Selenium and Vitamin E Cancer Prevention Trial (SELECT), show the predictive nature of this animal model for human prostate cancer chemoprevention.

78 FR 6357 - Submission for Renewal: New Information Collection, Fingerprint Chart Standard Form 87 (SF 87)

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-30

..., IPAC and MNU blocks support billing and processing enhancements. The printed ORI number is no longer necessary because SF 87 forms are converted to images and transmitted to the FBI electronically. The Public...

Quantitative Receptor-Based Imaging of Tumor Proliferation with the Sigma-2 Ligand [18F]ISO-1

PubMed Central

Shoghi, Kooresh I.; Xu, Jinbin; Su, Yi; He, June; Rowland, Douglas; Yan, Ying; Garbow, Joel R.; Tu, Zhude; Jones, Lynne A.; Higashikubo, Ryuji; Wheeler, Kenneth T.; Lubet, Ronald A.; Mach, Robert H.; You, Ming

2013-01-01

The sigma-2 receptor is expressed in higher density in proliferating (P) tumor cells versus quiescent (Q) tumor cells, thus providing an attractive target for imaging the proliferative status (i.e., P:Q ratio) of solid tumors. Here we evaluate the utility of the sigma-2 receptor ligand 2-(2-[18F]fluoroethoxy)-N-(4-(3,4-dihydro-6,7-dimethoxyisoquinolin-2(1H)-yl)butyl)-5-methyl-benzamide, [18F]ISO-1, in two different rodent models of breast cancer. In the first study, small animal Positron Emission Tomography (PET) imaging studies were conducted with [18F]ISO-1 and 18FDG in xenografts of mouse mammary tumor 66 and tracer uptake was correlated with the in vivo P:Q ratio determined by flow cytometric measures of BrdU-labeled tumor cells. The second model utilized a chemically-induced (N-methyl-N-nitrosourea [MNU]) model of rat mammary carcinoma to correlate measures of [18F]ISO-1 and FDG uptake with MR-based volumetric measures of tumor growth. In addition, [18F]ISO-1 and FDG were used to assess the response of MNU-induced tumors to bexarotene and Vorozole therapy. In the mouse mammary 66 tumors, a strong linear correlation was observed between the [18F]ISO-1 tumor: background ratio and the proliferative status (P:Q ratio) of the tumor (R = 0.87). Similarly, measures of [18F]ISO-1 uptake in MNU-induced tumors significantly correlated (R = 0.68, P<0.003) with changes in tumor volume between consecutive MR imaging sessions. Our data suggest that PET studies of [18F]ISO-1 provide a measure of both the proliferative status and tumor growth rate, which would be valuable in designing an appropriate treatment strategy. PMID:24073202

Topographic Quantification of the Transcorneal Electrical Stimulation (TES)-Induced Protective Effects on N-Methyl-N-Nitrosourea-Treated Retinas.

PubMed

Tao, Ye; Chen, Tao; Liu, Zhong-Yu; Wang, Li-Qiang; Xu, Wei-Wei; Qin, Li-Min; Peng, Guang-Hua; Yi-Fei, Huang

2016-09-01

To quantify the transcorneal electrical stimulation (TES)-induced effects on regional photoreceptors and visual signal pathway of N-methyl-N-nitrosourea (MNU)-treated retinas via topographic measurements. N-methyl-N-nitrosourea-administered mice received TES or sham stimulations and were subsequently subjected to electroretinography (ERG), multielectrode array (MEA), and histologic and immunohistochemistry examinations. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analyses were also performed to determine the mRNA levels of Bax, Bcl-2, Calpain-2, Caspase-3, brain-derived neurotrophic factor (BDNF), and ciliary neurotrophic factor (CNTF). Amplitudes of ERG b-wave in the TES-treated mice were significantly larger than those in the sham controls (P < 0.01). Microelectrode array examination revealed that the photoreceptors in TES-treated retina were efficiently preserved (P < 0.01). Morphologic measurements showed that the central retina region was more consolidated than the other areas in the TES-treated mice. Together with the disproportionate distribution of immunostaining in retinal flat mounts, these findings indicated that different rescuing kinetics existed among regional photoreceptors. Compared with the sham controls, a significantly increased signal-to-noise ratio was also found in the TES-treated mice (TES100: 2.02 ± 1.12; TES200: 4.42 ± 1.51; sham: 0.25 ± 0.13; P < 0.01). Moreover, qRT-PCR measurements suggested that the altered expression of several apoptotic factors and neurotrophic cytokines was correlated with TES-induced protection. Regional photoreceptors in the MNU-administered retinas exhibit different sensitivities to TES. Transcorneal electrical stimulation is capable of ameliorating MNU-induced photoreceptor degeneration and rectifying abnormalities in the inner visual signal pathways.

Analysis of the expression level and methylation of tumor protein p53, phosphatase and tensin homolog and mutS homolog 2 in N-methyl-N-nitrosourea-induced thymic lymphoma in C57BL/6 mice.

PubMed

Huo, Xueyun; Li, Zhenkun; Zhang, Shuangyue; Li, Changlong; Guo, Meng; Lu, Jing; Lv, Jianyi; Du, Xiaoyan; Chen, Zhenwen

2017-10-01

Tumorigenesis is often caused by somatic mutation or epigenetic changes in genes that regulate aspects of cell death, proliferation and survival. Although the functions of multiple tumor suppressor genes have been well studied in isolation, how these genes cooperate during the progression of a single tumor remains unclear in numerous cases. The present study used N-methyl-N-nitrosourea (MNU), one of the most potent mutagenic nitrosourea compounds, to induce thymic lymphoma in C57BL/6J mice. Subsequently, the protein expression levels of phosphatase and tensin homolog (PTEN), transformation protein 53 and mutS homolog 2 (MSH2) were evaluated concomitantly in the thymus, liver, kidney and spleen of MNU-treated mice by western blotting. To determine whether changes in expression level were due to aberrant epigenetic regulation, the present study further examined the methylation status of each gene by MassARRAY analysis. During the tumorigenesis process of an MNU-induced single thymic lymphoma, the expression level of PTEN was revealed to be reduced in thymic lymphoma samples but not in normal or non-tumor thymus tissue samples. Furthermore, a marked reduction of P53 expression levels were demonstrated in thymic lymphomas and spleens with a metastatic tumor. Conversely, MSH2 upregulation was identified only in liver, kidney, and spleen samples that were infiltrated by thymic lymphoma cells. Furthermore, the present study revealed that a number of 5'-C-phosphate-G-3' sites located in the promoter of aberrantly expressed genes had significantly altered methylation statuses. These results improve the understanding of the course of mutagen-induced cancer, and highlight that epigenetic regulation may serve an important function in cancer.

A Universal Shape of Empirical Mass Formula for all Leptons and Quarks

NASA Astrophysics Data System (ADS)

Królikowski, W.

2006-09-01

A specific {ITALIC universal} shape of empirical mass formula is proposed for all leptons nu 1, nu 2 , nu 3 and e-, mu -, tau - as well as all quarks u, c, t and d, s, b of three generations, parametrized by three free constants mu , \\varepsilon , xi assuming four different triplets of values. Four such triplets of parameter values are determined or estimated from the present data. Mass spectra in the four cases are related to each other by {ITALIC shifting} the triplet of parameters mu , \\varepsilon , xi . For charged leptons xi simeq 0 (but probably xi not =0). If for them xi is put to be exactly 0, then mtau = 1776.80 MeV is {ITALIC predicted} after the input of experimental me and mmu (the central value of experimental mtau = 1776.99+ 0.29-0.26 MeV corresponds to xi =1.8times 10-3not =0). For neutrinos 1/xi simeq 0 (but 1/xi not =0 in the case of normal hierarchy m2nu 1 ll m2nu 2 ll m2nu 3). If for neutrinos 1/xi is conjectured to be exactly 0, then (mnu 1, mnu 2, mnu 3) sim (1.5, 1.2, 5.1)times 10-2 eV are {ITALIC predicted} after the input of experimental estimates |m2nu 2 - m2nu 1| sim 8.0times 10-5mskip thickmuskip {eV}2 and |m2nu 3 - m2nu 2| sim 2.4times 10-3mskip thickmuskip {eV}2. Thus, the mass ordering of neutrino states 1 and 2 is then {ITALIC inverted}, while the position of state 3 is {ITALIC normal}.

Effect of an Extract of Withania somnifera Root on Estrogen Receptor-positive Mammary Carcinomas

PubMed Central

KHAZAL, KAMEL F.; SAMUEL, TEMESGEN; HILL, DONALD L.; GRUBBS, CLINTON J.

2013-01-01

The chemopreventive activity of an extract of Withania somnifera (WS) roots was examined in female Sprague-Dawley rats that received the mammary carcinogen methylnitrosourea (MNU). The dose of the extract, administered by gavage, was 150 mg/kg body weight daily for 155 days after injection of MNU. Rats in the treated group (N=15) had an average of 3.47 tumors, and rats in the control group (N=15) had 4.53, a reduction of 23%. The average weights of tumors were 4.98 g for rats in the treated group and 6.30 g for the controls, a difference of 21%. Labeling indices for Ki67 and proliferating cell nuclear antigen (PCNA) markers in cancers of the treated group were 42% and 38% lower, respectively, than those of the corresponding indices for the control group. These results indicate that the root extract significantly reduced the rate of cell division in the mammary tumors. PMID:23564793

Radiation-hardened MRAM-based LUT for non-volatile FPGA soft error mitigation with multi-node upset tolerance

NASA Astrophysics Data System (ADS)

Zand, Ramtin; DeMara, Ronald F.

2017-12-01

In this paper, we have developed a radiation-hardened non-volatile lookup table (LUT) circuit utilizing spin Hall effect (SHE)-magnetic random access memory (MRAM) devices. The design is motivated by modeling the effect of radiation particles striking hybrid complementary metal oxide semiconductor/spin based circuits, and the resistive behavior of SHE-MRAM devices via established and precise physics equations. The models developed are leveraged in the SPICE circuit simulator to verify the functionality of the proposed design. The proposed hardening technique is based on using feedback transistors, as well as increasing the radiation capacity of the sensitive nodes. Simulation results show that our proposed LUT circuit can achieve multiple node upset (MNU) tolerance with more than 38% and 60% power-delay product improvement as well as 26% and 50% reduction in device count compared to the previous energy-efficient radiation-hardened LUT designs. Finally, we have performed a process variation analysis showing that the MNU immunity of our proposed circuit is realized at the cost of increased susceptibility to transistor and MRAM variations compared to an unprotected LUT design.

Anticancer Potential of Nutraceutical Formulations in MNU-induced Mammary Cancer in Sprague Dawley Rats.

PubMed

Pitchaiah, Gummalla; Akula, Annapurna; Chandi, Vishala

2017-01-01

Nutraceuticals help in combating some of the major health problems of the century including cancer, and 'nutraceutical formulations' have led to the new era of medicine and health. To develop different nutraceutical formulations and to assess the anticancer potential of nutraceutical formulations in N-methyl-N-nitrosourea (MNU)-induced mammary cancer in Sprague Dawley rats. Different nutraceutical formulations were prepared using fine powders of amla, apple, garlic, onion, papaya, turmeric, and wheat grass with and without cow urine distillate. Total phenolic content, acute oral toxicity, and microbial load of nutraceutical formulations were assessed. The anticancer potential of nutraceutical formulations was evaluated against MNU-induced mammary cancer in female Sprague Dawley rats. Improvement in total phenolic content was significant ( P < 0.001) after self-fortification process. Toxicity studies showed that the nutraceutical formulations were safe to use in animals. Microbial load was within the limits. Significant longer tumor-free days ( P < 0.01), lower tumor incidence ( P < 0.01), lower tumor multiplicity ( P < 0.05) and tumor burden ( P < 0.01) were observed for nutraceutical formulation-treated groups. Combination of whole food-based nutraceuticals acted synergistically in the prevention of mammary cancer. Further, the process of fortification is novel and enhanced the anticancer potential of nutraceutical formulations. Nutraceuticals help in combating some of the major health problems of the century including cancer, and 'nutraceutical formulations' have led to the new era of medicine and health. In this study, different nutraceutical formulations using fine powders of amla, apple, garlic, onion, papaya, turmeric, and wheat grass with and without cow urine distillate. Total phenolic content, acute oral toxicity, and microbial load of nutraceutical formulations were assessed. The anticancer potential of nutraceutical formulations was evaluated against MNU-induced mammary cancer in female Sprague Dawley rats. Improvement in total phenolic content was observed after self-fortification process. Toxicity studies showed that the nutraceutical formulations were safe to use in animals. Microbial load was within the limits. Longer tumor-free days, lower tumor incidence, lower tumor multiplicity and tumor burden were observed for nutraceutical formulation-treated groups. This suggests that combination of whole food-based nutraceuticals acted synergistically in the prevention of mammary cancer. Further, the process of fortification enhanced the anticancer potential of nutraceutical formulations. Abbreviations used: HMNU: N-methyl-N-nitrosourea, CAM: Complementary and Alternative Medicine, NF: Nutraceutical Formulation, SFNF: Self-Fortitfied Nutraceutical Formulation, NFCUD: Nutraceutical Formulation fortified with Cow Urine Disstillate, SFNFCUD: Self-Fortified Nutraceutical Formulation fortified with Cow Urine Disstillate, CPCSEA: Committee for the Purpose of Control and Supervision of Experiments on Animals, OECD: Organisation for Economic Co-operation and Development, TPC: Total Phenolic Content, ANOVA: Analysis of Variance, GAE: Gallic Acid Equivalent, cfu/g: Colony forming unit per g.

KINETICS OF IN VIVO SISTER CHROMATID EXCHANGE INDUCTION IN MOUSE BONE MARROW CELLS IN ETHYLNITROSOUREA AND METHYLNITROSOUREA

EPA Science Inventory

Administration of ethylnitrosourea (ENU) (20, 25, 40, 50, and 60 mg/kg body weight) or methylnitrosourea (MNU) (25, 40, 50, 60, 75, and 80 mg/kg body weight) to male CD-1 mice 2 hours after subcutaneous implantation of 5-bromo-2'-deoxyurdine (BrdUrd) pellet (55 mg) resulted in a ...

Naval War College Research Guide, 1984-1985.

DTIC Science & Technology

1984-08-01

Washington: 1980. OECD N 4. Organization for Economic Cooperation and Develop- ment, Economic Surveys: Greece (Paris: 1983), p. 50. B Organization for...Amr, i iCa-In naItI ()n SC ca 1no t , mnU St 1not and Will not pefrmit beP es--tablishment o)f ano1()ther 1 Comm111U nis:t r- ;mcn t inr t hef Wes t

A Riboproteomic Platform to Identify Novel Targets for Prostate Cancer Therapy

DTIC Science & Technology

2015-10-01

cell lines derived from RWPE1 prostatic epithelial cells after exposure to N-methyl-N- nitrosourea (MNU) (these cell lines are commercially available...is well established that the malignancy of cells is strongly linked to and dependent on aberrant protein synthesis . Current knowledge clearly...highlights deregulation of protein synthesis , in the development of prostate cancer, through aberrant activation of classical signaling pathways. It has

Creating Space for God in the Lives of Millennials by Leveraging Technology to Practice a Spiritual Discipline Modeled by Christ

ERIC Educational Resources Information Center

St. John, Kelvin Wesley

2013-01-01

Today's Millennials, the first generation to reach their majority in this millennium, often compartmentalize their faith lives from their social and work lives. MidAmerica Nazarene University (MNU) offers a course in Spiritual Formation once each spring. The enrollment for this elective course ranges from twelve to eighteen students per class.…

Disease Subtype–Independent Biomarkers of Breast Cancer Chemoprevention by the Ayurvedic Medicine Phytochemical Withaferin A

PubMed Central

Samanta, Suman K.; Sehrawat, Anuradha; Kim, Su-Hyeong; Hahm, Eun-Ryeong; Shuai, Yongli; Roy, Ruchi; Pore, Subrata K.; Singh, Krishna B.; Christner, Susan M.; Beumer, Jan H.; Davidson, Nancy E.; Singh, Shivendra V.

2017-01-01

Abstract Background A nontoxic chemopreventive intervention efficacious against different subtypes of breast cancer is still a clinically unmet need. The present study was undertaken to determine the efficacy of an Ayurvedic medicine phytochemical (Withaferin A, [WA]) for chemoprevention of breast cancer and to elucidate its mode of action. Methods Chemopreventive efficacy of WA (4 and 8 mg/kg body weight) was determined using a rat model of breast cancer induced by N-methyl-N-nitrosourea (MNU; n = 14 for control group, n = 15 for 4 mg/kg group, and n = 18 for 8 mg/kg group). The mechanisms underlying breast cancer chemoprevention by WA were elucidated by immunoblotting, biochemical assays, immunohistochemistry, and cytokine profiling using plasma and tumors from the MNU-rat (n = 8–12 for control group, n = 7–11 for 4 mg/kg group, and n = 8–12 for 8 mg/kg group) and/or mouse mammary tumor virus-neu (MMTV-neu) models (n = 4–11 for control group and n = 4–21 for 4 mg/kg group). Inhibitory effect of WA on exit from mitosis and leptin-induced oncogenic signaling was determined using MCF-7 and/or MDA-MB-231 cells. All statistical tests were two-sided. Results Incidence, multiplicity, and burden of breast cancer in rats were decreased by WA administration. For example, the tumor weight in the 8 mg/kg group was lower by about 68% compared with controls (8 mg/kg vs control, mean = 2.76 vs 8.59, difference = –5.83, 95% confidence interval of difference = −9.89 to –1.76, P = .004). Mitotic arrest and apoptosis induction were some common determinants of breast cancer chemoprevention by WA in the MNU-rat and MMTV-neu models. Cytokine profiling showed suppression of plasma leptin levels by WA in rats. WA inhibited leptin-induced oncogenic signaling in cultured breast cancer cells. Conclusion WA is a promising chemopreventative phytochemical with the ability to inhibit at least two different subtypes of breast cancer. PMID:28040797

Raw starch conversion by Saccharomyces cerevisiae expressing Aspergillus tubingensis amylases

PubMed Central

2013-01-01

Background Starch is one of the most abundant organic polysaccharides available for the production of bio-ethanol as an alternative transport fuel. Cost-effective utilisation of starch requires consolidated bioprocessing (CBP) where a single microorganism can produce the enzymes required for hydrolysis of starch, and also convert the glucose monomers to ethanol. Results The Aspergillus tubingensis T8.4 α-amylase (amyA) and glucoamylase (glaA) genes were cloned and expressed in the laboratory strain Saccharomyces cerevisiae Y294 and the semi-industrial strain, S. cerevisiae Mnuα1. The recombinant AmyA and GlaA displayed protein sizes of 110–150 kDa and 90 kDa, respectively, suggesting significant glycosylation in S. cerevisiae. The Mnuα1[AmyA-GlaA] and Y294[AmyA-GlaA] strains were able to utilise 20 g l-1 raw corn starch as sole carbohydrate source, with ethanol titers of 9.03 and 6.67 g l-1 (0.038 and 0.028 g l-1 h-1), respectively, after 10 days. With a substrate load of 200 g l-1 raw corn starch, Mnuα1[AmyA-GlaA] yielded 70.07 g l-1 ethanol (0.58 g l-1 h-1) after 120 h of fermentation, whereas Y294[AmyA-GlaA] was less efficient at 43.33 g l-1 ethanol (0.36 g l-1 h-1). Conclusions In a semi-industrial amylolytic S. cerevisiae strain expressing the A. tubingensis α-amylase and glucoamylase genes, 200 g l-1 raw starch was completely hydrolysed (saccharified) in 120 hours with 74% converted to released sugars plus fermentation products and the remainder presumably to biomass. The single-step conversion of raw starch represents significant progress towards the realisation of CBP without the need for any heat pretreatment. Furthermore, the amylases were produced and secreted by the host strain, thus circumventing the need for exogenous amylases. PMID:24286270

Raw starch conversion by Saccharomyces cerevisiae expressing Aspergillus tubingensis amylases.

PubMed

Viktor, Marko J; Rose, Shaunita H; van Zyl, Willem H; Viljoen-Bloom, Marinda

2013-11-29

Starch is one of the most abundant organic polysaccharides available for the production of bio-ethanol as an alternative transport fuel. Cost-effective utilisation of starch requires consolidated bioprocessing (CBP) where a single microorganism can produce the enzymes required for hydrolysis of starch, and also convert the glucose monomers to ethanol. The Aspergillus tubingensis T8.4 α-amylase (amyA) and glucoamylase (glaA) genes were cloned and expressed in the laboratory strain Saccharomyces cerevisiae Y294 and the semi-industrial strain, S. cerevisiae Mnuα1. The recombinant AmyA and GlaA displayed protein sizes of 110-150 kDa and 90 kDa, respectively, suggesting significant glycosylation in S. cerevisiae. The Mnuα1[AmyA-GlaA] and Y294[AmyA-GlaA] strains were able to utilise 20 g l-1 raw corn starch as sole carbohydrate source, with ethanol titers of 9.03 and 6.67 g l-1 (0.038 and 0.028 g l-1 h-1), respectively, after 10 days. With a substrate load of 200 g l-1 raw corn starch, Mnuα1[AmyA-GlaA] yielded 70.07 g l-1 ethanol (0.58 g l-1 h-1) after 120 h of fermentation, whereas Y294[AmyA-GlaA] was less efficient at 43.33 g l-1 ethanol (0.36 g l-1 h-1). In a semi-industrial amylolytic S. cerevisiae strain expressing the A. tubingensis α-amylase and glucoamylase genes, 200 g l-1 raw starch was completely hydrolysed (saccharified) in 120 hours with 74% converted to released sugars plus fermentation products and the remainder presumably to biomass. The single-step conversion of raw starch represents significant progress towards the realisation of CBP without the need for any heat pretreatment. Furthermore, the amylases were produced and secreted by the host strain, thus circumventing the need for exogenous amylases.

Chemoprevention of Prostate Cancer by Phenethyl Isothiocyanate

DTIC Science & Technology

2007-03-01

AD cells were exposed to PEITC, protein synthesis inhibitor cycloheximide (CHX), or proteasome inhibitor MG-132 alone, or to the combination of...The results indicated that down-regulation of Sp1 may require protein synthesis for a proteasome activity, thereby enhancing Sp1 protein degradation...carcinogen N- methyl-N- nitrosourea (MNU) for the formation of prostate tumors. The experimental group of rats was provided with PEITC, to evaluate the

Chemoprevention of rat prostate carcinogenesis by soy isoflavones and by Bowman-Birk inhibitor.

PubMed

McCormick, David L; Johnson, William D; Bosland, Maarten C; Lubet, Ronald A; Steele, Vernon E

2007-01-01

Epidemiology studies suggest that soy consumption confers protection against human prostate cancer. To identify the soy component(s) that may be responsible for this chemopreventive activity, studies were conducted to determine the influence of a soy isoflavone mixture (PTI G-2535; 45% genistein, 22% daidzein, 2% glycitein) and a soy-derived protease inhibitor (Bowman-Birk Inhibitor Concentrate; BBIC) on prostate carcinogenesis in rats. Prostate cancers were induced in male Wistar-Unilever rats by a sequential regimen of cyproterone acetate and testosterone propionate, followed by a single intravenous injection of N-methyl-N-nitrosourea (MNU) and chronic androgen stimulation. In separate studies, PTI G-2535 and BBIC were administered continuously at 0 (control), 200, or 2000 mg/kg diet, beginning 1 wk post-MNU. PTI G-2535 and BBIC both conferred modest, but statistically significant and dose-related protection against carcinogenesis in the dorsolateral+anterior prostate. These data demonstrate that both the isoflavone and protein (protease inhibitor) components of soy can inhibit prostate carcinogenesis in the rat. However, the modest individual activities of soy isoflavones and BBIC suggest that while both components may contribute to the chemopreventive activity of soy, combination administration (or exposure to whole soy) may be more effective in prostate cancer prevention than is administration of either component alone.

Null effect of dietary restriction on prostate carcinogenesis in the Wistar-Unilever rat.

PubMed

McCormick, David L; Johnson, William D; Haryu, Todd M; Bosland, Maarten C; Lubet, Ronald A; Steele, Vernon E

2007-01-01

Chronic dietary restriction inhibits carcinogenesis in several sites in laboratory animals. To determine the effects of dietary restriction on prostate carcinogenesis, prostate cancers were induced in male Wistar-Unilever rats by a sequential regimen of cyproterone acetate (50 mg/day; 21 days); testosterone propionate (100 mg/kg/day; 3 days); N-methyl-N-nitrosourea [MNU; 30 mg/kg; single dose]; and testosterone (subcutaneous implants of 2 pellets containing 40 mg each). Dietary restriction (0% [ad libitum control], 15%, or 30%) was initiated 2 wk post-MNU, and continued until study termination at 12 mo. Dietary restriction induced a rapid suppression of body weight gain but conferred no protection against prostate carcinogenesis. 74% of carcinogen-treated ad libitum controls developed accessory sex gland cancers, versus cancer incidences of 64% and 72% in groups restricted by 15% and 30%, respectively. Similarly, 44% of dietary controls developed cancers limited to the dorsolateral/prostate, versus incidences of 45% and 53% in groups restricted by 15% and 30%. The results of the present study do not support the hypothesis that prostate carcinogenesis can be prevented by reducing caloric intake. Reducing mean body weight by up to 25% through chronic dietary restriction has no effect on the induction of prostate cancers in the Wistar-Unilever rat model.

Prevention and Treatment of Breast Cancer

DTIC Science & Technology

2016-08-01

naturally occurring protein of pregnancy (α- fetoprotein) which is largely responsible for the lifetime reduction in risk of breast cancer that occurs as a...result of pregnancy . The scope of this translational project entails essential work that will move AFPep beyond discovery and position it to enter...side effect.  For the MNU/SD model, we treated rats for only 23 days, a duration chosen to mimic pregnancy . Because AFPep has its origins in

Effects of Recurrent Stress and a Music Intervention on Tumor Progression and Indices of Distress in an MNU-induced Mammary Cancer in Rats

DTIC Science & Technology

2011-03-04

through negative emotions, behavioral disruptions, and/or physiological reactions (Grunberg & Singer, 1990; Baum, Gatchel, & Krantz, 1997; Park...biological responses that range from activation of the HPA axis to 14 altering the physiology of internal organs and organ systems (Kvetnansky, Weise...Females consistently show greater physiological response to both acute and chronic stressors, which many investigators attribute to sex hormone

A Theoretical Study of the Mechanism of the Alkylation of Guanine by N- Nitroso Compounds.

DTIC Science & Technology

1992-01-01

Later, Loveless isolated an 0 6 - methylated product from treatment with MNU and was the first to suggest a relevance of O6 alkylation 11 to the...replication. The ultimate metabolite involved in the alkylation reaction has generally been thought to be an alkyldiazonium ion or, its decomposition... Methylation of Formamide by the Methyldiazonium Ion .................... 60 Table 3.10: Intrinsic Barriers for Degenerate SN 2 Reactions .......... 66 Table

Activation of Poly(ADP-Ribose) Polymerase by Sulfur Mustard in Hela Cell Cultures

DTIC Science & Technology

1993-05-13

i O : DUTiC-TID INTRODUCTION Sulfur mustard ( 2,2’-dichlorodiethyl sulfide or HD) is a bifunctional alkylating agent which reacts with a wide variety...of biological molecules. It is a strong alkylating agent of purine bases in DNA (Kohn 1983). Early studies strongly implicate DNA as a principal...cells have previously demonstrated stimulation of PADPRP activity following exposure to a monofunctional alkylating agent , methylnitrosourea (MNU

Carcinogen-induced mutations in the mouse c-Ha-ras gene provide evidence of multiple pathways for tumor progression.

PubMed Central

Brown, K; Buchmann, A; Balmain, A

1990-01-01

A number of mouse skin tumors initiated by the carcinogens N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), methylnitrosourea (MNU), 3-methylcholanthrene (MCA), and 7,12-dimethylbenz[a]anthracene (DMBA) have been shown to contain activated Ha-ras genes. In each case, the point mutations responsible for activation have been characterized. Results presented demonstrate the carcinogen-specific nature of these ras mutations. For each initiating agent, a distinct spectrum of mutations is observed. Most importantly, the distribution of ras gene mutations is found to differ between benign papillomas and carcinomas, suggesting that molecular events occurring at the time of initiation influence the probability with which papillomas progress to malignancy. This study provides molecular evidence in support of the existence of subsets of papillomas with differing progression frequencies. Thus, the alkylating agents MNNG and MNU induced exclusively G ---- A transitions at codon 12, with this mutation being found predominantly in papillomas. MCA initiation produced both codon 13 G ---- T and codon 61 A ---- T transversions in papillomas; only the G ---- T mutation, however, was found in carcinomas. These findings provide strong evidence that the mutational activation of Ha-ras occurs as a result of the initiation process and that the nature of the initiating event can affect the probability of progression to malignancy. Images PMID:2105486

Variance components of short-term biomarkers of manganese exposure in an inception cohort of welding trainees.

PubMed

Baker, Marissa G; Simpson, Christopher D; Sheppard, Lianne; Stover, Bert; Morton, Jackie; Cocker, John; Seixas, Noah

2015-01-01

Various biomarkers of exposure have been explored as a way to quantitatively estimate an internal dose of manganese (Mn) exposure, but given the tight regulation of Mn in the body, inter-individual variability in baseline Mn levels, and variability in timing between exposure and uptake into various biological tissues, identification of a valuable and useful biomarker for Mn exposure has been elusive. Thus, a mixed model estimating variance components using restricted maximum likelihood was used to assess the within- and between-subject variance components in whole blood, plasma, and urine (MnB, MnP, and MnU, respectively) in a group of nine newly-exposed apprentice welders, on whom baseline and subsequent longitudinal samples were taken over a three month period. In MnB, the majority of variance was found to be between subjects (94%), while in MnP and MnU the majority of variance was found to be within subjects (79% and 99%, respectively), even when controlling for timing of sample. While blood seemed to exhibit a homeostatic control of Mn, plasma and urine, with the majority of the variance within subjects, did not. Results presented here demonstrate the importance of repeat measure or longitudinal study designs when assessing biomarkers of Mn, and the spurious associations that could result from cross-sectional analyses. Copyright © 2014 Elsevier GmbH. All rights reserved.

Mutagenic synergism detected between dimethyl sulfate and X-rays but not found between N-methyl-N-nitrosourea and X-rays in the stamen hairs of Tradescantia clone BNL 4430.

PubMed

Shima, N; Ichikawa, S

1995-09-01

Mutagenic interactions with X-rays of two monofunctional alkylating agents, dimethyl sulfate (DMS) and N-methyl-N-nitrosourea (MNU), were studied in the stamen hairs of Tradescantia clone BNL 4430, a blue/pink heterozygote. The young inflorescence-bearing shoots with roots cultivated in the nutrient solution circulating growth chamber were used as tester plants. Synergism between two different mutagens was judged to have occurred when the mutation frequency observed after applying the two mutagens concurrently was statistically significantly higher than the mutation frequency expected from the additive effects of the two mutagens. Clear synergistic effects in inducing somatic pink mutations were detected with all combinations of doses of DMS and X-rays examined, even in a relatively low X-ray dose range (down to 299 mGy), resembling those confirmed earlier between ethyl methanesulfonate (EMS) and X-rays, but somewhat differing from the synergisms observed earlier between methyl methanesulfonate (MMS) and X-rays. On the other hand, no mutagenic synergism was detected between MNU and X-rays, even in a relatively high X-ray dose range (up to 862 mGy). The presence or absence of mutagenic synergisms of these alkylating agents with X-rays could be related to the action mechanism of each alkylating agent.

Investigation of J-shaped dose-responses induced by exposure to the alkylating agent N-methyl-N-nitrosourea.

PubMed

Chapman, Katherine E; Hoffmann, George R; Doak, Shareen H; Jenkins, Gareth J S

2017-07-01

Hormesis is defined as a biphasic dose-response where biological effects of low doses of a stressor demonstrate the opposite effect to high-dose effects of the same stressor. Hormetic, or J-shaped, dose-response relationships are relatively rarely observed in toxicology, resulting in a limited understanding and even some skepticism of the concept. Low dose-response studies for genotoxicity endpoints have been performed at Swansea University for over a decade. However, no statistically significant decreases below control genotoxicity levels have been detected until recently. A hormetic-style dose-response following a 24h exposure to the alkylating agent N-methyl-N-nitrosourea (MNU) was observed in a previous study for HPRT mutagenesis in the human lymphoblastoid cell line AHH-1. A second recent study demonstrated a J-shaped dose-response for the induction of micronuclei by MNU in a 24h treatment in a similar test system. Following mechanistic investigations, it was hypothesized that p53 may be responsible for the observed hormetic phenomenon. As genotoxic carcinogens are a major causative factor of many cancers, consideration of hormesis in carcinogenesis could be important in safety assessment. The data examined here offer possible insights into hormesis, including its estimated prevalence, underlying mechanisms and lack of generalizability. Copyright © 2017 Elsevier B.V. All rights reserved.

Differences in sensitivity of murine spermatogonia and somatic cells in vivo to sister-chromatid exchange induction by nitrosoureas.

PubMed

Morales-Ramírez, P; Cruz-Vallejo, V; Rodríguez-Reyes, R

2001-07-01

Previously published data indicate that spermatogonia (SPG) are less sensitive to a sister-chromatid exchange (SCE) induction for different mutagens. In an earlier study, we have observed that bromodeoxyuridine (BrdU) substituted murine SPG are less sensitive to SCE induction by gamma ray in cells, than bone marrow (BM) and salivary gland (SG) cells in vivo. This was interpreted to mean that SPG are more efficient in DNA repair or are less prone to SCE induction. That the lower induction of SCE could be due to a reduced accessibility of mutagens to the SPG by virtue of a physiological barrier, was discarded by using gamma radiation. The aim of the present study was to establish whether or not there are differences in SCE induction by nitrosoureas among SPG, SG and BM cells with BrdU substituted or unsubstituted DNA. It was observed that SCE induction by methylnitrosourea (MNU) or by ethylnitrosourea (ENU) in SPG was, respectively, five and two times lower than in SG, and ten and three times lower than in BM. In SPG after BrdU incorporation, there was no increase in efficiency of SCE induction; in fact, there was even a slight decrease by exposure to MNU or ENU. BM and SG cells showed an increased efficiency in SCE induction after BrdU incorporation. This implies that SPG are also less sensitive to SCE induction by nitrosoureas, which cause a different kind of damage from previously assayed mutagens.

Exploiting for Breast Cancer Control a Proposed Unified Mechanism for Reduction of Human Breast Cancer Risk by the Hormones of Pregnancy

DTIC Science & Technology

2008-05-01

associated hormones or hCG to virgin female rats either before or after MNU treatment elicits persistent serum AFP levels, thereby explaining why breast...cancer appearance is inhibited when employing either treatment sequence; (2) Giving hCG to estrogenized SCID mice bearing human breast cancer...that is elicited by injection of the animals with high E3 doses. (3) In an “all-human” in vitro system, hCG elicits hAFP from cultured HepG2 human

Influence of live tularemia vaccine on chemical mutagenesis in white rats

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zil'fyan, V.N.; Nersesyan, A.K.; Kumkumadzhyan, V.A.

1986-03-01

The influence of a single cutaneous immunization of live dry tularemia vaccine (TV) on mutagenesis induced by cyclophosphamide (CP), methyl nitrosourea (MNU), benzopyrene(BP), chloroprene (ChP), and 1,2,3,4-tetrachlorobutane (TCB) is studied for the first time on rats of the Wistar line. It is established that in rats immunized with TV, significant reduction in number of aberrant myelokaryocytes is noted on the 15th day after vaccination as compared to unimmunized animals which received the mutagens indicated. Possible mechanisms of the effect obtained are discussed.

Toxicity, Mutagenicity, and Mutational Spectra of Vinyl Chloride, 2- Chloroethylene Oxide, and Chloracetaldehyde in a Human Lymphoblastoid Line Expressing Cytochrome P450IIE1.

DTIC Science & Technology

1992-01-01

concluded that CEO was the alkylating agent involved in conversion of adenosine to l,N 6 -ethenoadenosine. 1,N6 - Ethenoadenosine was not produced by CEO...guanines as nearest neighbors upon the alkylation of a guanine residue in DNA. N-methyl-N- nitrosourea (MNU) was reacted with a synthetic polynucleotide...the alkylating agent MNNG or the intercalating agent ICR-191. In the study they determined that mutants comprising at least one percent of the total

Potential of amphiphilic graft copolymer α-tocopherol succinate-g-carboxymethyl chitosan in modulating the permeability and anticancer efficacy of tamoxifen.

PubMed

Jena, Sunil K; Samal, Sanjaya K; Kaur, Shamandeep; Chand, Mahesh; Sangamwar, Abhay T

2017-04-01

Recent studies showed an enhanced oral bioavailability of tamoxifen (TMX) by hydrophobically modified α-tocopherol succinate-g-carboxymethyl chitosan (Cmc-TS) micelles. As a continued effort, here we evaluated TMX-loaded polymeric micelles (TMX-PMs) for its enhanced permeability with increased anticancer efficacy and decreased hepatotoxicity. We employed co-solvent evaporation technique to encapsulate TMX into Cmc-TS. Apparent permeability assay of TMX-PMs was performed on Caco-2 cell line. The absorptive transport of TMX increased significantly about 3.8-fold when incorporated into Cmc-TS PMs. Cytotoxicity of Cmc-TS PMs was studied on MCF-7 cell line by MTT and; confocal microscopy was used for cellular uptake. Confocal microscopy revealed that Cmc-TS PMs could effectively accumulate in the cytosol of MCF-7 cell lines. In vitro data was further validated using N-methyl-N-nitrosourea (MNU)-induced mammary carcinogenesis model in Sprague-Dawley rats. Hepatotoxicity profiles of TMX-PMs at three different doses were also evaluated against the free drug TMX. TMX-PMs were more effective in suppressing breast tumor in MNU-induced mammary carcinoma model than free TMX with better safety profile. In addition, histological data shows that tumors are "benign" in TMX-PMs treated group compared with "malignant" tumors in free TMX treated and control groups. Overall, the results implicate that our Cmc-TS PMs may serve as a promising carrier for the intracellular delivery of anticancer drug molecules via oral route. Copyright © 2017. Published by Elsevier B.V.

Overexpression of the DNA mismatch repair factor, PMS2, confers hypermutability and DNA damage tolerance.

PubMed

Gibson, Shannon L; Narayanan, Latha; Hegan, Denise Campisi; Buermeyer, Andrew B; Liskay, R Michael; Glazer, Peter M

2006-12-08

Inherited defects in genes associated with DNA mismatch repair (MMR) have been linked to familial colorectal cancer. Cells deficient in MMR are genetically unstable and demonstrate a tolerance phenotype in response to certain classes of DNA damage. Some sporadic human cancers also show abnormalities in MMR gene function, typically due to diminished expression of one of the MutL homologs, MLH1. Here, we report that overexpression of the MutL homolog, human PMS2, can also cause a disruption of the MMR pathway in mammalian cells, resulting in hypermutability and DNA damage tolerance. A mouse fibroblast cell line carrying a recoverable lambda phage shuttle vector for mutation detection was transfected with either a vector designed to express hPMS2 or with an empty vector control. Cells overexpressing hPMS2 were found to have elevated spontaneous mutation frequencies at the cII reporter gene locus. They also showed an increase in the level of mutations induced by the alkylating agent, methynitrosourea (MNU). Clonogenic survival assays demonstrated increased survival of the PMS2-overexpressing cells following exposure to MNU, consistent with the induction of a damage tolerance phenotype. Similar results were seen in cells expressing a mutant PMS2 gene, containing a premature stop codon at position 134 and representing a variant found in an individual with familial colon cancer. These results show that dysregulation of PMS2 gene expression can disrupt MMR function in mammalian cells and establish an additional carcinogenic mechanism by which cells can develop genetic instability and acquire resistance to cytotoxic cancer therapies.

Determining neutrino mass from the cosmic microwave background alone.

PubMed

Kaplinghat, Manoj; Knox, Lloyd; Song, Yong-Seon

2003-12-12

Distortions of cosmic microwave background temperature and polarization maps caused by gravitational lensing, observable with high angular resolution and high sensitivity, can be used to measure the neutrino mass. Assuming two massless species and one with mass m(nu), we forecast sigma(m(nu))=0.15 eV from the Planck satellite and sigma(m(nu))=0.04 eV from observations with twice the angular resolution and approximately 20 times the sensitivity. A detection is likely at this higher sensitivity since the observation of atmospheric neutrino oscillations requires Deltam(2)(nu) greater, similar (0.04 eV)(2).

Neem leaf extract inhibits mammary carcinogenesis by altering cell proliferation, apoptosis, and angiogenesis

PubMed Central

Arumugam, Arunkumar; Agullo, Pamela; Boopalan, Thiyagarajan; Nandy, Sushmita; Lopez, Rebecca; Gutierrez, Christina; Narayan, Mahesh; Rajkumar, Lakshmanaswamy

2014-01-01

Plant-based medicines are useful in the treatment of cancer. Many breast cancer patients use complementary and alternative medicine in parallel with conventional treatments. Neem is historically well known in Asia and Africa as a versatile medicinal plant with a wide spectrum of biological activities. The experiments reported herein determined whether the administration of an ethanolic fraction of Neem leaf (EFNL) inhibits progression of chemical carcinogen-induced mammary tumorigenesis in rat models. Seven-week-old female Sprague Dawley rats were given a single intraperitoneal injection of N-methyl-N-nitrosourea (MNU). Upon the appearance of palpable mammary tumors, the rats were divided into vehicle-treated control groups and EFNL-treated groups. Treatment with EFNL inhibited MNU-induced mammary tumor progression. EFNL treatment was also highly effective in reducing mammary tumor burden and in suppressing mammary tumor progression even after the cessation of treatment. Further, we found that EFNL treatment effectively upregulated proapoptotic genes and proteins such as p53, B cell lymphoma-2 protein (Bcl-2)-associated X protein (Bax), Bcl-2-associated death promoter protein (Bad) caspases, phosphatase and tensin homolog gene (PTEN), and c-Jun N-terminal kinase (JNK). In contrast, EFNL treatment caused downregulation of anti-apoptotic (Bcl-2), angiogenic proteins (angiopoietin and vascular endothelial growth factor A [VEGF-A]), cell cycle regulatory proteins (cyclin D1, cyclin-dependent kinase 2 [Cdk2], and Cdk4), and pro-survival signals such as NFκB, mitogen-activated protein kinase 1 (MAPK1). The data obtained in this study demonstrate that EFNL exert a potent anticancer effect against mammary tumorigenesis by altering key signaling pathways. PMID:24146019

CDB-4124, a progesterone receptor modulator, inhibits mammary carcinogenesis by suppressing cell proliferation and inducing apoptosis.

PubMed

Wiehle, Ronald; Lantvit, Daniel; Yamada, Tohru; Christov, Konstantin

2011-03-01

CDB-4124 (Proellex or telapristone acetate) is a modulator of progesterone receptor (PR) signaling, which is currently employed in preclinical studies for prevention and treatment of breast cancer and has been used in clinical studies for treatment of uterine fibroids and endometriosis. Here we provide evidence for its action on steroid hormone-signaling, cell cycle-regulated genes and in vivo on mammary carcinogenesis. When CDB-4124 is given to rats at 200 mg/kg for 24 months, it prevents the development of spontaneous mammary hyperplastic and premalignant lesions. Also, CDB-4124 given as subcutaneous pellets at two different doses suppressed, dose dependently, N-methyl-N-nitrosourea (MNU)-induced mammary carcinogenesis. The high dose (30 mg, over 84 days) increased tumor latency from 66 ± 24 days to 87 ± 20 days (P < 0.02), decreased incidence from 85% to 35% (P < 0.001), and reduced multiplicity from 3.0 to 1.1 tumors/animal (P < 0.001). Tumor burden decreased from 2.6 g/animal to 0.26 g/animal (P < 0.01). CDB-4124 inhibited cell proliferation and induced apoptosis in MNU-induced mammary tumors, which correlated with a decreased proportion of PR(+) tumor cells and with decreased serum progesterone. CDB-4124 did not affect serum estradiol. In a mechanistic study employing T47D cells we found that CDB-4124 suppressed G(1)/G(0)-S transition by inhibiting CDK2 and CDK4 expressions, which correlated with inhibition of estrogen receptor (ER) expression. Taken together, these data indicate that CDB-4124 can suppress the development of precancerous lesions and carcinogen-induced ER(+) mammary tumors in rats, and may have implications for prevention and treatment of human breast cancer.

Twenty-six-week oral carcinogenicity study of 3-monochloropropane-1,2-diol in CB6F1-rasH2 transgenic mice.

PubMed

Lee, Byoung-Seok; Park, Sang-Jin; Kim, Yong-Bum; Han, Ji-Seok; Jeong, Eun Ju; Son, Hwa-Young; Moon, Kyoung-Sik

2017-01-01

The carcinogenic potential of 3-monochloro-1,2-propanediol (3-MCPD) was evaluated in a short-term carcinogenicity testing study using CB6F1 rasH2-Tg (rasH2-Tg) mice. 3-MCPD is found in many foods and food ingredients as a result of storage or processing and is regarded as a carcinogen since it is known to induce Leydig cell and kidney tumors in rats. Male and female rasH2-Tg mice were administered 3-MCPD once daily by oral gavage at doses of 0, 10, 20, and 40 mg/kg body weight (bw) per day for 26 weeks. As a positive control, N-methyl-N-nitrosourea (MNU) was administered as a single intraperitoneal injection (75 mg/kg). In 3-MCPD-treated mice, there was no increase in the incidence of neoplastic lesions compared to the incidence in vehicle control mice. However, 3-MCPD treatment resulted in an increased incidence of tubular basophilia in the kidneys and germ cell degeneration in the testes, with degenerative germ cell debris in the epididymides of males at 20 and 40 mg/kg bw per day. In 3-MCPD-treated females, vacuolation of the brain and spinal cord was observed at 40 mg/kg bw per day; however, only one incidence of vacuolation was observed in males. Forestomach and cutaneous papilloma and/or carcinoma and lymphoma were observed in most rasH2 mice receiving MNU treatment. We concluded that 3-MCPD did not show carcinogenic potential in the present study using rasH2-Tg mice. The findings of this study suggest that the carcinogenic potential of 3-MCPD is species specific.

[Importance of Helicobacter pylori in the pathogenesis of gastric cancer. Experimental models in rodents].

PubMed

Barreto-Zúñiga, R; Kato, Y; Bobadilla, D J; Okuyama, M; Maruyama, M; Ohta, H; Takekoshi, T; Shigematsu, A

2000-01-01

We found that the seroprevalence in Cancer Institute of H. pylori infection was significantly more frequent in gastric cancer than in age- and gender-matched controls. This study suggested an epidemiological link between H. pylori infection and gastric cancer. H. pylori exhibits a complex system of enzymes which serve a range of functions. Toxic effects are produced by urease (UR), phospholipase (PL) and alcohol dehydrogenase (ADH). We embarked on an exploration of the enzyme activities of H. pylori infected patients using a TLC-autoradioluminography. This method has a wide dynamic range and could offer an analytical technique for studying a radioactive compound and its enzymes in H. pylori infected mucosa. Biopsies samples taken from 21 gastric cancer patients and 95 controls were studied. Although high activity of UR indicates well the presence of H. pylori impairment, activities of ADH and PL reflects more the chronicity of mucosal damage in both groups. Clearly, the enzyme profile showed in our study reflects the "physiological" adaptations behind chronic injured mucosal changes but its relation to gastric cancer and H. pylori needs further study. There is an urgent need to understand the carcinogenesis process using animal models. We performed previous study for to explore the effect of H. pylori infection on N- methyl-N-nitrosourea-induced (MNU) gastric carcinogenesis in mice C57BL/6 mice were administered broth culture of H. pylori and given MNU in drinking water. In terms of the incidence of neoplasms development was increase in the MNU group pre-infected with H. pylori. That findings showed that C57BL/6 mice-infected model is well suited for investigating the bacteria promoter effect in the gastric carcinogenesis. Finally another rodent model study (still in process) showed rapid development of hyperplastic gastritis with gastric erosions in H. pylori-infected MTH1 knockout mice. We sought to further evaluate MTH1 knockout mice as potential test animal for carcinogenesis. It is suggested that H. pylori infection is an important risk factor for the development of gastric cancer. The possibility that this organism acts etiologically, exerting its effect over long period of time, is biologically plausible. However, the role of H. pylori per se in that process is still a matter of discussion. The various enzymes of H. pylori discussed in this paper support colonization, and are perhaps important for epithelial damage, they could contribute to the stimulation and modulation of the chronic inflammatory response, but its relation to gastric cancer and H. pylori needs further study. Finally H. pylori in C57BL/6 and knockout mice showed excellent colonization at two months and six months after infection there was adenomatous, hyperplastic and ulcerative changes. Those findings showed that both mice-infected models are well suited for investigating the bacteria promoter effect in the gastric carcinogenesis.

Interrelationships among angiogenesis, proliferation, and apoptosis in the tumor microenvironment during N-methyl-N-nitrosourea androgen-induced prostate carcinogenesis in rats.

PubMed

Liao, Zhiming; Boileau, Thomas W-M; Erdman, John W; Clinton, Steven K

2002-10-01

Proliferation, apoptosis and angiogenesis are critical biologic processes altered during carcinogenesis. Surrogate biomarkers of these processes represent potential intermediate endpoints for short-term intervention studies with preventive and therapeutic agents. We examined the interrelationships among these processes during prostate carcinogenesis induced by N-methyl-N-nitrosourea (MNU) in male Wistar-Unilever rats. Immunohistochemical and digital image analysis techniques were used to evaluate the proliferation index, the apoptotic index and microvessel density (MVD) in tissue representing stages of prostate carcinogenesis. The proliferation index in the normal glandular epithelium of the prostate is lower than that observed in hyperplastic foci and atypical hyperplasia (P < 0.01) and is further increased in carcinoma (P < 0.01). Apoptosis in the normal prostate epithelium or hyperplastic lesions is lower than in adenocarcinoma (P < 0.01). In parallel to proliferation index, MVD increases as prostate cancer progresses. As tumors enlarge, we observed a predictable change in biomarker expression within the tumor microenvironment. We examined prostate tumors vertical line 1 cm in diameter and biomarker expression was quantified within the peripheral (outer 1-2 mm), central (perinecrotic) and intermediate (remaining) areas of each tumor. The proliferation index is higher (P < 0.01) in the intermediate area than either in the peripheral area or central area. Similarly, the vascular density in the intermediate area is higher (P < 0.01) than either in the peripheral or central area. The apoptotic index is higher (P < 0.05) in the central perinecrotic core than that in either the intermediate or the peripheral area. In conclusion, we observe that angiogenesis, proliferation and apoptosis are linked biological processes predictably altered temporally and spatially during prostate carcinogenesis in the MNU model. These biomarker changes are similar to those reported in human prostate carcinogenesis and represent potential biomarkers for the assessment of dietary, chemopreventive and therapeutic agents.

Exact results for quench dynamics and defect production in a two-dimensional model.

PubMed

Sengupta, K; Sen, Diptiman; Mondal, Shreyoshi

2008-02-22

We show that for a d-dimensional model in which a quench with a rate tau(-1) takes the system across a (d-m)-dimensional critical surface, the defect density scales as n approximately 1/tau(mnu/(znu+1)), where nu and z are the correlation length and dynamical critical exponents characterizing the critical surface. We explicitly demonstrate that the Kitaev model provides an example of such a scaling with d = 2 and m = nu = z = 1. We also provide the first example of an exact calculation of some multispin correlation functions for a two-dimensional model that can be used to determine the correlation between the defects. We suggest possible experiments to test our theory.

Manganese in plasma: a promising biomarker of exposure to Mn in welders. A pilot study.

PubMed

Hoet, Perrine; Vanmarcke, Els; Geens, Tom; Deumer, Gladys; Haufroid, Vincent; Roels, Harry A

2012-08-13

There is raising concern about the potential neurotoxic effects of manganese (Mn) inhalation exposure in welders. Because most of the airborne particles in welding fume are in the respirable fraction, their bioavailability is likely to be higher than for coarser dust exposure. No well-validated biomarker for Mn exposure is available. To investigate the interest of measuring Mn in plasma (Mn-P) and urine (Mn-U) as biomarkers of exposure in a group of 28 welders whose tasks were only welding-related. Ambient air exposure to Mn (Mn-air) was determined by personal full-shift measurements on Monday and Tuesday. On the same days, blood and urine samples were collected before and after the shift. Mn-air varied from 1.3 to 729 μg/m(3) (GM 27.7). For Mn-U 65% of the values in welders were below the LOQ (0.20 μg/L). Compared to controls, the welders' Mn-P averaged 33% higher (1.5 vs 2.0 μg/L). In welders, the after-shift Mn-P values correlated well with Mn-air above 10 μg/m(3). In spite of similar Mn-air exposure on Monday and Tuesday, the relationships between Mn-air and after-shift Mn-P strikingly differed on Tuesday in that the inflection in the relationship was less obvious and the slope of the regression line (Mn-P after-shift/logMn-air) for a doubling of logMn-air was 2.3 times lower than on Monday. On Monday (the first day of the workweek), a Mn-P value of 2 μg/L could distinguish Mn-air exposure above or below 20 μg/m(3) with a sensitivity of 69% and a specificity of 82%. This preliminary study indicates that Mn-P is a promising biomarker of current exposure to Mn in welders and lends biological plausibility to the intended change for the Mn TLV-TWA of 20 μg/m(3) proposed by ACGIH for respirable Mn particulate. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Breast cancer amelioration by Butea monosperma in-vitro and in-vivo.

PubMed

Karia, Prachi; Patel, Kirti V; Rathod, Shri S P

2018-05-10

Butea monosperma belonging to family Fabaceae is used in the Indian traditional medicine (Ayurveda) for various ailments including abdominal tumors and possess anti-estrogenic activity. The present study is aimed at investigating the chemo-preventive potential of Butea monosperma in breast cancer and elucidating it's mechanism of action by assessing its effect on key processes like apoptosis, angiogenesis and metastasis. Cytotoxic potential of methanol extract of Butea monosperma flower (MEBM) was tested in MCF-7 (estrogen receptor positive), MDA-MB-231 (triple negative) and MDA-MB-453 (HER2 positive) human breast cancer cells by MTT assay. Chemo-preventive potential was evaluated in-vivo in Methylnitrosourea (MNU) induced mammary cancer in nulliparous Sprague-Dawley rats. The mechanism for anticancer potential was screened by in-vitro studies involving Annexin V- FITC assay (apoptosis), Chick Chorioallantoic Membrane assay (angiogenesis) and Migration assay (metastasis). Statistical analysis was done by one way and two way ANOVA (for Growth Rate and feed consumption efficiency) followed by post hoc Bonferroni's test with P value < 0.05. It is observed that the exposure of MEBM, at various concentrations and time intervals to different cell lines, resulted in decreased cell proliferation. The IC 50 value of MCF-7 cells was found significantly less than that of MDA-MB-231 and MDA-MB-453 cells, which indicated that the extract of said medicinal plant were more potent inhibitors of estrogen positive breast cancer cells than other types of breast cancer cells in vitro. Corroborative evidences were acquired in MNU actuated mammary carcinogenesis where MEBM constricted tumor parameters, decreased expression of estrogen and progesterone, nucleic acid content and increased latency period. MEBM also induced apoptosis, inhibited angiogenesis and metastasis in-vitro. Selective cytotoxic activity in MCF-7 estrogen positive breast cancer cells and inhibition of growth of mammary carcinoma in-vivo by methanol extract of Butea monosperma flowers (MEBM) suggests chemo-prevention through modulation of estrogen and progesterone receptor, apoptotic, anti-angiogenesis and anti-metastatic activity. Copyright © 2017 Elsevier B.V. All rights reserved.

Mutagenicity and clastogenicity of extracts of Helicobacter pylori detected by the Ames test and in the micronucleus test using human lymphoblastoid cells.

PubMed

Arimoto-Kobayashi, Sakae; Ohta, Kaori; Yuhara, Yuta; Ayabe, Yuka; Negishi, Tomoe; Okamoto, Keinosuke; Nakajima, Yoshihiro; Ishikawa, Takeshi; Oguma, Keiji; Otsuka, Takanao

2015-07-01

Epidemiological studies have demonstrated a close association between infection with Helicobacter pylori (H.pylori) and the development of gastric carcinoma. Chronic H.pylori infection increases the frequency of mutation in gastric epithelial cells. However, the mechanism by which infection of H.pylori leads to mutation in gastric epithelial cells is unclear. We suspected that components in H.pylori may be related to the mutagenic response associated with DNA alkylation, and could be detected with the Ames test using a more sensitive strain for alkylating agents. Our investigation revealed that an extract of H.pylori was mutagenic in the Ames test with Salmonella typhimurium YG7108, which is deficient in the DNA repair of O(6)-methylguanine. The extract of H.pylori may contain methylating or alkylating agents, which might induce O (6)-alkylguanine in DNA. Mutagenicity of the alkylating agents N-methyl-N-nitrosourea (MNU) and N-methyl-N'-nitro-N-nitrosoguanidine in the Ames test with S.typhimurium TA1535 was enhanced significantly in the presence of the extract of H.pylori. The tested extracts of H.pylori resulted in a significant induction of micronuclei in human-derived lymphoblastoid cells. Heat instability and dialysis resistance of the extracts of H.pylori suggest that the mutagenic component in the extracts of H.pylori is a heat-unstable large molecule or a heat-labile small molecule strongly attached or adsorbed to a large molecule. Proteins in the extracts of H.pylori were subsequently fractionated using ammonium sulphate precipitation. However, all fractions expressed enhancing effects toward MNU mutagenicity. These results suggest the mutagenic component is a small molecule that is absorbed into proteins in the extract of H.pylori, which resist dialysis. Continuous and chronic exposure of gastric epithelial cells to the alkylative mutagenic component from H.pylori chronically infected in the stomach might be a causal factor in the gastric carcinogenesis associated with H.pylori. © The Author 2015. Published by Oxford University Press on behalf of the UK Environmental Mutagen Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Nardilysin regulates inflammation, metaplasia, and tumors in murine stomach.

PubMed

Kimura, Yuto; Ikuta, Kozo; Kimura, Takeshi; Chiba, Tsutomu; Oshima, Hiroko; Oshima, Masanobu; Nishi, Eiichiro; Seno, Hiroshi

2017-02-23

Chronic inflammation contributes to a wide variety of human disorders. In the stomach, longstanding gastritis often results in structural alterations in the gastric mucosa, including metaplastic changes and gastric cancers. Therefore, it is important to elucidate factors that are involved in gastric inflammation. Nardilysin (N-arginine dibasic convertase; Nrdc) is a metalloendopeptidase of the M16 family that promotes ectodomain shedding of the precursor forms of various growth factors and cytokines by enhancing the protease activities of a disintegrin and metalloproteinase (ADAM) proteins. Here, we have demonstrated that Nrdc crucially regulates gastric inflammation caused by Helicobacter felis infection or forced expression of prostaglandin E 2 in K19-C2mE mice. Metaplastic changes following gastric inflammation were suppressed by the deletion of Nrdc. Furthremore, the deletion of Nrdc significantly suppressed N-methyl-N-nitrosourea (MNU)-induced gastric tumorigenesis in the murine stomach. These data may lead to a global therapeutic approach against various gastric disorders by targeting Nrdc.

Evaluation of the mutagenicity of alkylating agents, methylnitrosourea and temozolomide, using the rat Pig-a assay with total red blood cells or reticulocytes.

PubMed

Muto, Shigeharu; Yamada, Katsuya; Kato, Tatsuya; Ando, Masamitsu; Inoue, Yoshimi; Iwase, Yumiko; Uno, Yoshifumi

2016-11-15

A collaborative study of the endogenous phosphatidylinositol glycan class A (Pig-a) gene mutation assay was conducted by the Japanese Environmental Mutagen Society/Mammalian Mutagenicity Study Group with a single-dosing regimen of test chemicals administered to male rats. As a part of the study, two DNA alkylating agents, methylnitrosourea (MNU) and temozolomide (TMZ), were dosed by single oral gavage at 25, 50, and 100mg/kg body weight. Pig-a mutant analysis of total red blood cells (RBCs; RBC Pig-a assay) and reticulocytes (RETs; PIGRET assay) was performed on Days 8, 15 and 29 after the administration. Both chemicals increased Pig-a mutants among RBCs and RETs with dose dependency on all days examined. The mutant frequencies were higher among RETs compared with RBCs, indicating that the PIGRET assay could detect mutagenicity more sensitively than the RBC Pig-a assay after a single dose of test chemicals. Copyright © 2016 Elsevier B.V. All rights reserved.

Inclusion of dietary β-mannanase improves performance and ileal digestibility and reduces ileal digesta viscosity of broilers fed corn-soybean meal based diet.

PubMed

Balasubramanian, B; Ingale, S L; Park, J Hong; Rathi, P C; Shanmugam, S; Kim, I H

2018-05-16

This study was aimed to evaluate the influence of dietary β-mannanase inclusion on growth performance, apparent ileal digestibility, digesta viscosity, blood metabolites and excreta noxious gas emissions in broilers fed corn-soybean meal based diet. A total of 600 conventional healthy 1-d-old ROSS 308 broilers with body weight 45 ± 0.50 g (mean ± SD) were randomly assigned to 4 dietary treatments with 10 replicates cages, with 15 broilers in each and fed basal diet supplemented to corn-SBM based diets with 0, 2400, 4800, and 7200 MNU β-mannanase/kg for 35 d feeding trial period. Significant results were observed on improved average daily gain and reduced feed conversion ratio during trial period and also reduced ileal digesta viscosity and improved apparent ileal digestibility of dry matter, nitrogen and energy. However, no significant effects were found on blood urea nitrogen and creatinine, excreta noxious gas emissions. In conclusion, the inclusion of dietary β-mannanase had potential to improve daily gain and feed efficiency and apparent ileal digestibility while decreasing digesta viscosity of broiler.

DuCLOX-2/5 Inhibition Attenuates Inflammatory Response and Induces Mitochondrial Apoptosis for Mammary Gland Chemoprevention

PubMed Central

Gautam, Swetlana; Rawat, Atul K.; Sammi, Shreesh R.; Roy, Subhadeep; Singh, Manjari; Devi, Uma; Yadav, Rajnish K.; Singh, Lakhveer; Rawat, Jitendra K.; Ansari, Mohd N.; Saeedan, Abdulaziz S.; Kumar, Dinesh; Pandey, Rakesh; Kaithwas, Gaurav

2018-01-01

The present study is a pursuit to define implications of dual cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX) (DuCLOX-2/5) inhibition on various aspects of cancer augmentation and chemoprevention. The monotherapy and combination therapy of zaltoprofen (COX-2 inhibitor) and zileuton (5-LOX inhibitor) were validated for their effect against methyl nitrosourea (MNU) induced mammary gland carcinoma in albino wistar rats. The combination therapy demarcated significant effect upon the cellular proliferation as evidenced through decreased in alveolar bud count and restoration of the histopathological architecture when compared to toxic control. DuCLOX-2/5 inhibition also upregulated levels of caspase-3 and caspase-8, and restored oxidative stress markers (GSH, TBARs, protein carbonyl, SOD and catalase). The immunoblotting and qRT-PCR studies revealed the participation of the mitochondrial mediated death apoptosis pathway along with favorable regulation of COX-2, 5-LOX. Aforementioned combination restored the metabolic changes to normal when scrutinized through 1H NMR studies. Henceforth, the DuCLOX-2/5 inhibition was recorded to import significant anticancer effects in comparison to either of the individual treatments. PMID:29681851

Nuclear physics and cosmology

NASA Technical Reports Server (NTRS)

Schramm, David N.

1989-01-01

Nuclear physics has provided one of two critical observational tests of all Big Bang cosmology, namely Big Bang Nucleosynthesis. Furthermore, this same nuclear physics input enables a prediction to be made about one of the most fundamental physics questions of all, the number of elementary particle families. The standard Big Bang Nucleosynthesis arguments are reviewed. The primordial He abundance is inferred from He-C and He-N and He-O correlations. The strengthened Li constraint as well as D-2 plus He-3 are used to limit the baryon density. This limit is the key argument behind the need for non-baryonic dark matter. The allowed number of neutrino families, N(nu), is delineated using the new neutron lifetime value of tau(n) = 890 + or - 4s (tau(1/2) = 10.3 min). The formal statistical result is N(nu) = 2.6 + or - 0.3 (1 sigma), providing a reasonable fit (1.3 sigma) to three families but making a fourth light (m(nu) less than or equal to 10 MeV) neutrino family exceedly unlikely (approx. greater than 4.7 sigma). It is also shown that uncertainties induced by postulating a first-order quark-baryon phase transition do not seriously affect the conclusions.

DNA replication after mutagenic treatment in Hordeum vulgare.

PubMed

Kwasniewska, Jolanta; Kus, Arita; Swoboda, Monika; Braszewska-Zalewska, Agnieszka

2016-12-01

The temporal and spatial properties of DNA replication in plants related to DNA damage and mutagenesis is poorly understood. Experiments were carried out to explore the relationships between DNA replication, chromatin structure and DNA damage in nuclei from barley root tips. We quantitavely analysed the topological organisation of replication foci using pulse EdU labelling during the S phase and its relationship with the DNA damage induced by mutagenic treatment with maleic hydrazide (MH), nitroso-N-methyl-urea (MNU) and gamma ray. Treatment with mutagens did not change the characteristic S-phase patterns in the nuclei; however, the frequencies of the S-phase-labelled cells after treatment differed from those observed in the control cells. The analyses of DNA replication in barley nuclei were extended to the micronuclei induced by mutagens. Replication in the chromatin of the micronuclei was rare. The results of simultanous TUNEL reaction to identify cells with DNA strand breaks and the labelling of the S-phase cells with EdU revealed the possibility of DNA replication occurring in damaged nuclei. For the first time, the intensity of EdU fluorescence to study the rate of DNA replication was analysed. Copyright © 2016 Elsevier B.V. All rights reserved.

Quantitative assessment of the dose-response of alkylating agents in DNA repair proficient and deficient ames tester strains.

PubMed

Tang, Leilei; Guérard, Melanie; Zeller, Andreas

2014-01-01

Mutagenic and clastogenic effects of some DNA damaging agents such as methyl methanesulfonate (MMS) and ethyl methanesulfonate (EMS) have been demonstrated to exhibit a nonlinear or even "thresholded" dose-response in vitro and in vivo. DNA repair seems to be mainly responsible for these thresholds. To this end, we assessed several mutagenic alkylators in the Ames test with four different strains of Salmonella typhimurium: the alkyl transferases proficient strain TA1535 (Ogt+/Ada+), as well as the alkyl transferases deficient strains YG7100 (Ogt+/Ada-), YG7104 (Ogt-/Ada+) and YG7108 (Ogt-/Ada-). The known genotoxins EMS, MMS, temozolomide (TMZ), ethylnitrosourea (ENU) and methylnitrosourea (MNU) were tested in as many as 22 concentration levels. Dose-response curves were statistically fitted by the PROAST benchmark dose model and the Lutz-Lutz "hockeystick" model. These dose-response curves suggest efficient DNA-repair for lesions inflicted by all agents in strain TA1535. In the absence of Ogt, Ada is predominantly repairing methylations but not ethylations. It is concluded that the capacity of alkyl-transferases to successfully repair DNA lesions up to certain dose levels contributes to genotoxicity thresholds. Copyright © 2013 Wiley Periodicals, Inc.

Curcumin inhibits urothelial tumor development by suppressing IGF2 and IGF2-mediated PI3K/AKT/mTOR signaling pathway.

PubMed

Tian, Binqiang; Zhao, Yingmei; Liang, Tao; Ye, Xuxiao; Li, Zuowei; Yan, Dongliang; Fu, Qiang; Li, Yonghui

2017-08-01

We have previously reported that curcumin inhibits urothelial tumor development in a rat bladder carcinogenesis model. In this study, we report that curcumin inhibits urothelial tumor development by suppressing IGF2 and IGF2-mediated PI3K/AKT/mTOR signaling pathway. Curcumin inhibits IGF2 expression at the transcriptional level and decreases the phosphorylation levels of IGF1R and IRS-1 in bladder cancer cells and N-methyl-N-nitrosourea (MNU)-induced urothelial tumor tissue. Ectopic expression of IGF2 and IGF1R, but not IGF1, in bladder cancer cells restored this process, suggesting that IGF2 is a target of curcumin. Moreover, introduction of constitutively active AKT1 abolished the inhibitory effect of curcumin on cell proliferation, migration, and restored the phosphorylation levels of 4E-BP1 and S6K1, suggesting that curcumin functions via suppressing IGF2-mediated AKT/mTOR signaling pathway. In summary, our results reveal that suppressing IGF2 and IGF2-mediated PI3K/AKT/mTOR signaling pathway is one of the mechanisms of action of curcumin. Our findings suggest a new therapeutic strategy against human bladder cancer caused by aberrant activation of IGF2, which are useful for translational application of curcumin.

Manganese in exhaled breath condensate: a new marker of exposure to welding fumes.

PubMed

Hulo, Sébastien; Chérot-Kornobis, Nathalie; Howsam, Mike; Crucq, Sébastien; de Broucker, Virginie; Sobaszek, Annie; Edme, Jean-Louis

2014-04-07

To evaluate manganese in exhaled breath condensate (Mn-EBC) as an indicator of exposure to fumes from metal inert gas welding process. We collected EBC and urine from 17 welders and 16 unexposed control subjects after 5 days exposure. Concentrations of manganese (Mn), nickel (Ni), iron (Fe) and chromium (Cr) were measured in EBC and urine samples and correlated with cumulative exposure indices for the working week (CIW) and for the total welding years (WY), based on duration of welding activity and atmospheric metal measurements. Concentrations of Mn and Ni in EBC were significantly higher among welders than controls whereas this difference was not significant for Mn in urine. Levels of Mn and Ni in EBC were not correlated with their respective levels in urine. The linear regressions found significant positive coefficients between Mn-EBC, Ni-EBC, Ni-U and Cr-U concentrations and the cumulative exposure indices. Taking into account tobacco use, statistical analysis showed the same trends except for the relationship between Mn-U and CIW. This pilot study showed that Mn-EBC, as well as Ni-EBC, can serve as reliable indices of occupational exposure to welding fumes and provide complimentary toxicokinetic information to that provided by urine analyses. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Alkylarylnitrosoureas--stability in aqueous solution, partition coefficient, alkylating activity and its relationship to SCE induction in Chinese hamster V 79-E cells.

PubMed

Mendel, J; Thust, R; Schwarz, H

1982-01-01

The alkylating activity, chemical stability in aqueous solution (pH 7.0; 37 degrees C), and partition coefficient (octanol/water) of the following compounds were determined: 1-methyl-3-phenyl-1-nitrosourea (MPNU), 1-ethyl-3-phenyl-1-nitrosourea (EPNU), 1-isopropyl-3-phenyl-1-nitrosourea (i-PrPNU), 1-methyl-3-(p-fluorophenyl)-1-nitrosourea (F-MPNU), 1-methyl-3-(p-chlorophenyl)-1-nitrosourea (Cl-MPNU), 1-methyl-3-(p-bromophenyl)-1-nitrosourea (Br-MPNU), 1,3-dimethyl-3-phenyl-1-nitrosourea (DMPNU), and 1-methyl-3-naphthyl-1-nitrosocarbamate (NCA). 1-Methyl-1-nitrosourea (MNU) and 1-ethyl-1-nitrosourea (ENU) were used for the comparison. THe rate of decomposition in aqueous solution is discussed concerning the influences of the substituents at the 1- and 3-N-atom. The mono- and disubstituted N-nitrosoureas showed a coarse correlation between alkylating activity and SCE induction in Chinese hamster V 79-E cells. On the other hand, this correlation is missing in the case of NCA, which is a potent SCE inducer despite relatively low alkylating activity. DMPNU is the strongest SCE inducer, but this compound shows a high stability in aqueous solution and, consequently, we were not able to detect an alkylating activity.

Rat medium-term multi-organ carcinogenesis bioassay of Agaricus blazei Murrill fruit-body extract.

PubMed

Doi, Yuko; Furukawa, Fumio; Suguro, Mayuko; Ito, Hikaru; Imai, Norio; Nabae, Kyoko; Toda, Yosuke; Inatomi, Satoshi; Kinugasa, Satomi; Kobayashi, Hitoshi

2010-01-01

The modifying potential of Agaricus blazei Murrill fruit-body extract (ABFE) on tumor development was investigated in a medium-term multi-organ carcinogenesis bioassay. Male 6-week-old F344 rats were treated with N-nitrosodiethylamine (DEN), N-methyl-N-nitrosourea (MNU), 1,2-dimethylhydrazine dihydrochloride (DMH), N-butyl-N-(hydroxybutyl)-nitrosamine (BBN), and diisopropanolnitrosamine (DHPN) for initiation (DMBDD treatment). After a 1-week withdrawal period, the animals received distilled water (vehicle control) or ABFE A, gamma-amino butyric acid (GABA) at 0.8 mg/kg, ABFE B (GABA level of 3.0mg/kg) or ABFE C (GABA level of 12.0mg/kg) by gavage for 24 weeks. There were no effects of ABFE on survival rate, general condition, body weight, food and water consumption, and organ weights. The multiplicity of large intestinal nodules, smaller than 2mm was significantly increased in the ABFE C group with DMBDD treatment. However, there were no significantly inter-group differences in incidences of hyperplastic or neoplastic lesions in colon or other organs, or in immunohistochemically identified preneoplastic lesions in the liver. In conclusion, A. blazei Murrill fruit-body extract, even at a GABA level up to 12 mg/kg, did not exert modifying potential in the present medium-term multi-organ carcinogenesis bioassay in male F344 rats (DMBDD method). Copyright 2009 Elsevier Ltd. All rights reserved.

[Chemotherapeutic characterization of new nitrosourea compounds].

PubMed

Zeller, W J; Berger, M R; Eisenbrand, G; Petru, E

1988-01-01

The development of new nitrosoureas is described using selected examples. Results obtained with water-soluble analogs and with compounds linked to biomolecules as for instance amino acids, oligopeptides and steroids, are presented. The pronounced antineoplastic effect of some water-soluble analogs is paralleled by an increased rate of DNA-interstrand cross-links and by an increased suppression of hematopoietic stem cells. The suppression of bone marrow stem cells is followed by their rapid regeneration. Water-soluble nitrosoureas induce significant less inhibition of glutathione reductase as compared with established compounds. With regard to long-term toxicity and carcinogenicity water-soluble are superior to established compounds as for instance BCNU. Linking of the nitrosourea moiety to amino acids and oligopeptides led to some analogs with outstanding therapeutic ratio. Out of a group of steroid-linked nitrosoureas, CNC-L-alanine-estradiol-17-ester (CNC-ala-17-E2) is chosen to demonstrate the possibility of reducing bone marrow toxicity despite unchanged or increased therapeutic activity by attachment of the nitrosourea moiety to a steroid. Results of a comparative interspecies in vitro evaluation of CNC-ala-17-E2 in transplanted MXT mammary carcinoma of the mouse, MNU-induced autochthonous rat mammary carcinoma and primary human mammary carcinomas are presented and the question is discussed to what extent in vitro activity of such receptor agents using the tumor stem cell assay reflects their in vivo activity.

Progesterone receptor antagonism inhibits progestogen-related carcinogenesis and suppresses tumor cell proliferation.

PubMed

Lee, Oukseub; Choi, Mi-Ran; Christov, Konstantin; Ivancic, David; Khan, Seema A

2016-07-01

Blockade of the progestogen-progesterone receptor (PR) axis is a novel but untested strategy for breast cancer prevention. We report preclinical data evaluating telapristone acetate (TPA), ulipristal acetate (UPA), and mifepristone. Tumors were induced with medroxyprogesterone acetate (MPA) plus 7,12-dimethylbenz[a]anthracene (DMBA) in mice, and MPA or progesterone plus N-methyl-N-nitrosourea (MNU) in rats. Mammary gland histology, tumor incidence, latency, multiplicity, burden and histology were evaluated, along with immunohistochemical labeling of pHH3 (proliferation), CD34 (angiogenesis), and estrogen and progesterone receptors (ER and PR). A concentration gradient of TPA, UPA, and mifepristone was tested for growth inhibition of T47D spheroids. In mouse mammary glands, no tumors formed, but TPA opposed the pro-hyperplastic effects of MPA (p = 0.002). In rats, TPA decreased tumor incidence (p = 0.037 for MPA + TPA vs. MPA, and p = 0.032 for progesterone + TPA vs. progesterone) and tumor burden (p = 0.042 for progesterone + TPA vs. progesterone), with significant decreases in pHH3 and CD34 positive cells. TPA and UPA were superior to mifepristone in growth inhibition of T47D spheroids. TPA has consistent anti-tumorigenic effects in several models, which are accompanied by decreases in cell proliferation, angiogenesis, and hormone receptor expression. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

CMB and the elementary particles structure deduced from QFT of non-dot model

NASA Astrophysics Data System (ADS)

Chen, Shao-Guang

In my paper ‘Planck Constant Deduced from Metrical Results of Doppler Effect of Moving Particle —Uncertainty Principle Caused by Collision of a Particle with CMB Photons and Virtual Photons (H05-0036-10)’ the absolute velocity is decided by CMB which as a mark of the vacuum. CMB come from the thermal radiation of stars via gravitational redshift about 10 (13) year (E14- 0032-08). In my paper ‘Quanta turn-advance ism, China Science && Technology Overview 131 192-210 (2011)’, QFT four-dimensional uncertainty principle and momentum-energy conservation law had been generalized as a five-dimensional equations: de Broglie wavelength as a position vector \\underline{q}= (i c t, r, s), momentum \\underline{P} = (i E / c, P, U c), \\underline{q} = i h / \\underline{P}, \\underline{q} \\underline{q} = 0, \\underline{P} \\underline{P} = 0, Sigma∑ \\underline{P} = \\underline{P} (0) . The five-dimensional time-space-spin had been quantized as a non-dot model basic cell, the lowest energy state vertical polarized left spin 1/2 neutrino and right spin 1/2 antineutrino are just the left, right advance unit quanta _{0}nuυ, nuυ _{0} and left, right back unit quanta (0) nuυ, nuυ (0) , it again compose into spin 1 unit advance photons _{0}nuυnuυ _{0} and back (0) nuυnuυ (0) , spin 0 unit rest mass nuυ _{0}nuυ (0) and anti-mass _{0}nuυ (0) nuυ, spin 0 unit positive charge _{0}nuυnuυ (0) and negative charge nuυ _{0} (0) nuυ. It accord to the high energy physics experimental results of the transformation among the photons, masses quanta and charges quanta. The physical vacuum is the even collocation of non-combinational nuυ _{0} or _{0}nuυ. QFT is no longer with divergence difficulty by the non-dot model. It is mathematically easy that from five-dimensional equations deduce out the Dirac, Klein-Gordan, Maxwell equations and Lorentz force formula, but appear some new results. The interactions between _{0}nuυ, nuυ _{0}, (0) nuυ, nuυ (0) , i.e., force f = ± ( h c / 2 r (3) ) r cos thetaθ for r not equal to 0 and f = 0 for r = 0, f as the magnetic force makes the photons, rest mass and charge quanta automatically come into being and stabilize. CMB photon can be produced from many spin 1 unit photons by its statistical attraction. In the quantized inconsecutive time-space-spin using momentum and turn-quantity as the coordinates drawing the momentum-turn graphics are some points with certain distance. The rest mass m _{0} is the lowest energy state advance-back neutrinos pair nuυ _{0}nuυ (0) , when j direction have 2n nuυ_{0} the i , k directions must have (2n-1), (2n+1) nuυ_{0} for i, j, k three directions all matching into pair to eliminate the external interaction of electric quantity q(0) in nuυ_{0}. The spatial rest mass is quanta (n) m _{0} = (2n - 1) 2n (2n +1) m (0) = 6, 60, 210, 504, 990, 1716 m (0) , m (0) is the rest mass of nuυ_{0} (also anti-mass (n) \\underline{m}_{0} and \\underline{m}(0) ). According to the uncertainty principle n large rest mass layer is more little and at the inside layer of particle. The spatial unit charge quanta e or \\underline{e} is constituted by nine one-dimensional unit charge quanta nuυ_{0}(0) nuυ or _{0}nuυnuυ (0) because of the vertical polarization at each spatial direction there is only three states: the left, the right and the middle of left-right balance. Via photons, rest mass and charge quanta all elementary particles come from _{0}nuυ, nuυ_{0}, (0) nuυ, nuυ (0) . The particle’s momentum is constituted by the photons _{0}nuυnuυ _{0} or (0) nuυnuυ (0) and a few nuυ _{0} or _{0}nuυ. The particle’s charge is constituted by one e or \\underline{e} and one nuυ _{0} or _{0}nuυ. The particle’s rest mass is constituted by one or several (n) m _{0} or (n) \\underline{m} _{0}. According to the uncertainty principle n large rest mass layer is more little and at the inside layer of particle. The left spin 1/2 nu υ _{mu}: 1 _{0}nuυ + 1 (n) \\underline{m} _{0}, right spin 1/2 nuυ _{mu}: 1 nuυ _{0} +1 (n) m _{0}. The e (+) :1 nuυ _{0 } +1 \\underline{e} (9 _{0} nuυnuυ (0) ) + 1 (5) \\underline{m} _{0} + 6 (2) \\underline{m} _{0} , with one positive electron charge q (+) (9.5 _{0}nuυnuυ (0) ) and rest anti- mass (990+6*60)= 1350 \\underline{m} _{nu}. The e (-) : 1 _{0}nuυ +1 e (9 nuυ_{0} (0) nuυ) + (5) m _{0} + 6 (2) m_{0} with one electron charge q (-) (9.5 nuυ}_{0}(0) nuυ) and rest mass (990+6*60)=1350 m_{nu}. The electronic mass m_{e} = 1+18+1350 = 1369 m _{nu} , V = m_{nu} c /m = 219 km/s which accord to the solar system speed of astronomy observation and as a reason of the electronic stabilization. The neutral electron nuυ_{mu} (0) ( (0) nuυ_{mu}): 1 nuυ _{0} ( _{0} nuυ) + 3 (1) m _{0} (18 m _{nu}) + 6 (2) m _{0} + (5) m _{0} =1369 m_{nu} (\\underline{m} _{nu}). They are as the nu υ _{mu} and \\underline{nu υ}_{mu} with electronic mass and only in the weak interaction which maybe had been observed in the neutrinos but in the dark. With (0) nuυ_{mu} and nuυ_{mu} (0) as new unit compose the elementary particles. The (n) m ((n) \\underline{m}) = (2n-1) 2n (2n+1) m_{e} (\\underline{m}_{e}). The piπ (0) meson: (1) m + (2) m (66 m _{e}) is the flat shape, for the spatial symmetry two superposition to ({2) -1} m (2) (132 m _{e}), again with ({2) -1} \\underline{m} (2) (132 \\underline{m} _{e}) compose into piπ (0) meson with rest mass 264 m _{e}. The mu (-) and mu (+) : (3) m ( (3) \\underline{m}) outside layer i, j, k each direction one nuυ _{mu} (0) ( (0) nuυ_{mu}) to be replaced by one _{0} nuυ and e (nuυ _{0} and \\underline{e}), its rest mass is ( 210 - 3 + (19/1369)) m _{e} (\\underline{m}_{e}) = 207.02 m_{e} (\\underline{m}_{e}). The piπ (-) and piπ (+) : muμ (-) + ({2) -1} m = piπ (-) with 273.02 m _{e}, muμ (+) + ({2) -1} m _{e} =piπ (+) with 273.02 m _{e} (n) m _{e} = 6, 60, 210, 504, 990, 1716 m _{e} (\\underline{m} _{e}) still come into existent, m _{e} is the rest mass of electron. The p (+) and p (-) : (5) m + (4) m + ({3) }m + ({2) -1}m(2) = 1836 m_{e}, its outside layer is (2) m_{0} ({2) }(120 m _{nu}), \\underline{e} (18 m _{nu}) and one _{0} nuυ with 139 m_{nu} = (139/1369) m _{e} = 0.1 m_{e}, it is just the proton p (+) with 1836.10 m_{e}. The antiproton p (-) : with 1836.10 \\underline{m}_{e}, one e and one nuυ_{0}. The n and \\underline{n} : In p (+) outside layer the _{0} nuυ (1 m _{nu} ), e (18 m_{nu}) and (2) m_{0} (2) (120 m _{nu}) are replaced by two nuυ_{mu}(0) and one sub-nuυ_{mu} (0) which (5) m_{0} exchange into (4) m_{0}) become 1838.64 m_{e}), again absorb one vacuum nuυ_{0} become the neutron n. The anti-neutron n has 1838.64 \\underline{m}_{e} and one _{0}nuυ. The essence of strangeness is that: one left turn anti-mass ({2) -1} \\underline{m}(2) (132 m_{e}) interfuse in great right mass particle then the strange number S = -1, such as K (0) , LambdaΛ(0) , Sigma∑(0,+,-) , two (2-1) \\underline{m}(2) then S = -2 such as XiΞ(0,-) ; one right turn mass ({2) -1}m(2) (132 m_{e}) interfuse in great left turn anti-mass particle then the strange number S = + 1 such as \\underline{K}(0) , \\underline{LambdaΛ} (0) , \\underline{Sigma∑}(0,+,-) , two ({2) -1}m(2) then S = + 2 such as \\underline{XiΞ}(0,-) . All strange particles as positive -negative pair to be produced from the particle’s momentum in accelerator, on the fountainhead, all come from the neutral microwave photons. Only from the collective structure of the photons, rest mass and charge quanta we can understand the strange particles producing process and the strange number invariable law. From the structure of elementary particles it may be obtained that the gravitational constant is likely dependent on the absolute velocity of galaxy.

Genomic phenotyping by barcode sequencing broadly distinguishes between alkylating agents, oxidizing agents, and non-genotoxic agents, and reveals a role for aromatic amino acids in cellular recovery after quinone exposure.

PubMed

Svensson, J Peter; Quirós Pesudo, Laia; McRee, Siobhan K; Adeleye, Yeyejide; Carmichael, Paul; Samson, Leona D

2013-01-01

Toxicity screening of compounds provides a means to identify compounds harmful for human health and the environment. Here, we further develop the technique of genomic phenotyping to improve throughput while maintaining specificity. We exposed cells to eight different compounds that rely on different modes of action: four genotoxic alkylating (methyl methanesulfonate (MMS), N-Methyl-N-nitrosourea (MNU), N,N'-bis(2-chloroethyl)-N-nitroso-urea (BCNU), N-ethylnitrosourea (ENU)), two oxidizing (2-methylnaphthalene-1,4-dione (menadione, MEN), benzene-1,4-diol (hydroquinone, HYQ)), and two non-genotoxic (methyl carbamate (MC) and dimethyl sulfoxide (DMSO)) compounds. A library of S. cerevisiae 4,852 deletion strains, each identifiable by a unique genetic 'barcode', were grown in competition; at different time points the ratio between the strains was assessed by quantitative high throughput 'barcode' sequencing. The method was validated by comparison to previous genomic phenotyping studies and 90% of the strains identified as MMS-sensitive here were also identified as MMS-sensitive in a much lower throughput solid agar screen. The data provide profiles of proteins and pathways needed for recovery after both genotoxic and non-genotoxic compounds. In addition, a novel role for aromatic amino acids in the recovery after treatment with oxidizing agents was suggested. The role of aromatic acids was further validated; the quinone subgroup of oxidizing agents were extremely toxic in cells where tryptophan biosynthesis was compromised.

Genomic Phenotyping by Barcode Sequencing Broadly Distinguishes between Alkylating Agents, Oxidizing Agents, and Non-Genotoxic Agents, and Reveals a Role for Aromatic Amino Acids in Cellular Recovery after Quinone Exposure

PubMed Central

Svensson, J. Peter; Quirós Pesudo, Laia; McRee, Siobhan K.; Adeleye, Yeyejide; Carmichael, Paul; Samson, Leona D.

2013-01-01

Toxicity screening of compounds provides a means to identify compounds harmful for human health and the environment. Here, we further develop the technique of genomic phenotyping to improve throughput while maintaining specificity. We exposed cells to eight different compounds that rely on different modes of action: four genotoxic alkylating (methyl methanesulfonate (MMS), N-Methyl-N-nitrosourea (MNU), N,N′-bis(2-chloroethyl)-N-nitroso-urea (BCNU), N-ethylnitrosourea (ENU)), two oxidizing (2-methylnaphthalene-1,4-dione (menadione, MEN), benzene-1,4-diol (hydroquinone, HYQ)), and two non-genotoxic (methyl carbamate (MC) and dimethyl sulfoxide (DMSO)) compounds. A library of S. cerevisiae 4,852 deletion strains, each identifiable by a unique genetic ‘barcode’, were grown in competition; at different time points the ratio between the strains was assessed by quantitative high throughput ‘barcode’ sequencing. The method was validated by comparison to previous genomic phenotyping studies and 90% of the strains identified as MMS-sensitive here were also identified as MMS-sensitive in a much lower throughput solid agar screen. The data provide profiles of proteins and pathways needed for recovery after both genotoxic and non-genotoxic compounds. In addition, a novel role for aromatic amino acids in the recovery after treatment with oxidizing agents was suggested. The role of aromatic acids was further validated; the quinone subgroup of oxidizing agents were extremely toxic in cells where tryptophan biosynthesis was compromised. PMID:24040048

Dual action of high estradiol doses on MNU-induced prostate neoplasms in a rodent model with high serum testosterone: Protective effect and emergence of unstable epithelial microenvironment.

PubMed

Gonçalves, Bianca F; de Campos, Silvana G P; Góes, Rejane M; Scarano, Wellerson R; Taboga, Sebastião R; Vilamaior, Patricia S L

2017-06-01

Estrogens are critical players in prostate growth and disease. Estrogen therapy has been the standard treatment for advanced prostate cancer for several decades; however, it has currently been replaced by alternative anti-androgenic therapies. Additionally, studies of its action on prostate biology, resulting from an association between carcinogens and estrogen, at different stages of life are scarce or inconclusive about its protective and beneficial role on induced-carcinogenesis. Thus, the aim of this study was to determine whether estradiol exerts a protective and/or stimulatory role on N-methyl-N-nitrosurea-induced prostate neoplasms. We adopted a rodent model that has been used to study induced-prostate carcinogenesis: the Mongolian gerbil. We investigated the occurrence of neoplasms, karyometric patterns, androgen and estrogen receptors, basal cells, and global methylation status in ventral and dorsolateral prostate tissues. Histopathological analysis showed that estrogen was able to slow tumor growth in both lobes after prolonged treatment. However, a true neoplastic regression was observed only in the dorsolateral prostate. In addition to the protective effects against neoplastic progression, estrogen treatment resulted in an epithelium that exhibited features distinctive from a normal prostate, including increased androgen-insensitive basal cells, high androgens and estrogen receptor positivity, and changes in DNA methylation patterns. Estrogen was able to slow tumor growth, but the epithelium exhibited features distinct from a normal prostatic epithelium, and this unstable microenvironment could trigger lesion recurrence over time. © 2017 Wiley Periodicals, Inc.

Metformin Accumulation Correlates with Organic Cation Transporter 2 Protein Expression and Predicts Mammary Tumor Regression in Vivo

PubMed Central

Checkley, L. Allyson; Rudolph, Michael C.; Wellberg, Elizabeth A.; Giles, Erin D.; Wahdan-Alaswad, Reema S.; Houck, Julie A.; Edgerton, Susan M.; Thor, Ann D.; Schedin, Pepper; Anderson, Steven M.; MacLean, Paul S.

2017-01-01

Several epidemiological studies have associated metformin treatment with a reduction in breast cancer incidence in pre-diabetic and type II diabetic populations. Uncertainty exists regarding which patient populations and/or tumor subtypes will benefit from metformin treatment, and most preclinical in vivo studies have given little attention to the cellular pharmacology of intratumoral metformin uptake. Epidemiological reports consistently link western-style high fat diets, which drive overweight and obesity, with increased risk of breast cancer. We used a rat model of high fat diet (HFD) induced overweight and mammary carcinogenesis to define intratumoral factors that confer metformin sensitivity. Mammary tumors were initiated with N-methyl-N-nitrosourea (MNU), and rats were randomized into metformin-treated (2 mg/ml drinking water) or control groups (water only) for 8 weeks. Two-thirds of existing mammary tumors responded to metformin treatment with decreased tumor volumes (p<0.05), reduced proliferative index (p<0.01), and activated AMPK (p<0.05). Highly responsive tumors accumulated 3-fold greater metformin amounts (p<0.05) that were positively correlated with organic cation transporter-2 (OCT2) protein expression (r=0.57, P=0.038). Importantly, intratumoral metformin concentration negatively associated with tumor volume (P=0.03), and each 10 pmol increase in intratumoral metformin predicted >0.11 cm3 reduction in tumor volume. Metformin treatment also decreased proinflammatory arachidonic acid >1.5 fold in responsive tumors (P=0.023). Collectively, these preclinical data provide evidence for a direct effect of metformin in vivo and suggest that OCT2 expression may predict metformin uptake and tumor response. PMID:28154203

Expression in mammalian cells of the Escherichia coli O6 alkylguanine-DNA-alkyltransferase gene ogt reduces the toxicity of alkylnitrosoureas.

PubMed Central

Harris, L. C.; Margison, G. P.

1993-01-01

V79 Chinese hamster cells expressing either the O6-alkylguanine-DNA-alkyltransferase (ATase) encoded by the E. coli ogt gene or a truncated version of the E. coli ada gene have been exposed to various alkylnitrosoureas to investigate the contribution of ATase repairable lesions to the toxicity of these compounds. Both ATases are able to repair O6-alkylguanine (O6-AlkG) and O4-alkylthymine (O4-AlkT) but the ogt ATase is more efficient in the repair of O4-methylthymine (O4-MeT) and higher alkyl derivatives of O6-AlkG than is the ada ATase. Expression of the ogt ATase provided greater protection against the toxic effects of the alkylating agents then the ada ATase particularly with N-ethyl-N-nitrosourea (ENU) and N-butyl-N-nitrosourea (BNU) to which the ada ATase expressing cells were as sensitive as parent vector transfected cells. Although ogt was expressed at slightly higher levels than the truncated ada in the transfected cells, this could not account for the differential protection observed. For-N-methyl-N-nitrosourea (MNU) the increased protection in ogt-transfected cells is consistent with O4-MeT acting as a toxic lesion. For the longer chain alkylating agents and chloroethylating agents, the protection afforded by the ogt protein may be a consequence of the more efficient repair of O6-AlkG, O4-AlkT or both of these lesions in comparison with the ada-encoded ATase. Images Figure 2 Figure 3 PMID:8512805

Analysis of genes involved in the PI3K/Akt pathway in radiation- and MNU-induced rat mammary carcinomas

PubMed Central

Showler, Kaye; Nishimura, Mayumi; Imaoka, Tatsuhiko; Nishimura, Yukiko; Morioka, Takamitsu; Blyth, Benjamin J.; Kokubo, Toshiaki; Takabatake, Masaru; Fukuda, Maki; Moriyama, Hitomi; Kakinuma, Shizuko; Fukushi, Masahiro

2017-01-01

Abstract The PI3K/AKT pathway is one of the most important signaling networks in human breast cancer, and since it was potentially implicated in our preliminary investigations of radiation-induced rat mammary carcinomas, our aim here was to verify its role. We included mammary carcinomas induced by the chemical carcinogen 1-methyl-1-nitrosourea to determine whether any changes were radiation-specific. Most carcinomas from both groups showed activation of the PI3K/AKT pathway, but phosphorylation of AKT1 was often heterogeneous and only present in a minority of carcinoma cells. The negative pathway regulator Inpp4b was significantly downregulated in both groups, compared with in normal mammary tissue, and radiation-induced carcinomas also showed a significant decrease in Pten expression, while the chemically induced carcinomas showed a decrease in Pik3r1 and Pdk1. Significant upregulation of the positive regulators Erbb2 and Pik3ca was observed only in chemically induced carcinomas. However, no genes showed clear correlations with AKT phosphorylation levels, except in individual carcinomas. Only rare carcinomas showed mutations in PI3K/AKT pathway genes, yet these carcinomas did not exhibit stronger AKT phosphorylation. Thus, while AKT phosphorylation is a common feature of rat mammary carcinomas induced by radiation or a canonical chemical carcinogen, the mutation of key genes in the pathways or permanent changes to gene expression of particular signaling proteins do not explain the pathway activation in the advanced cancers. Although AKT signaling likely facilitates cancer development and growth in rat mammary carcinomas, it is unlikely that permanent disruption of the PI3K/AKT pathway genes is a major causal event in radiation carcinogenesis. PMID:27738081

CHEMOPREVENTIVE EFFICACY OF NAPROXEN AND NO-NAPROXEN IN RODENT MODELS OF COLON, URINARY BLADDER, AND MAMMARY CANCERS

PubMed Central

Steele, Vernon E.; Rao, Chinthalapally V.; Zhang, Yuting; Patlolla, Jagan; Boring, Daniel; Kopelovich, Levy; Juliana, M. Margaret; Grubbs, Clinton J.; Lubet, Ronald A.

2009-01-01

Nonsteroidal anti-inflammatory drugs (NSAIDs) have been highly effective in preventing colon, urinary bladder, and skin cancer preclinically; and also in clinical trials of colon adenoma formation. However, certain NSAIDs cause gastrointestinal (GI) ulceration and may increase cardiovascular (CV) events. Naproxen appears to cause the lowest CV events of the common NSAIDs other than aspirin. NO-naproxen was tested based on the finding that adding a nitric oxide (NO) group to NSAIDs may help alleviate GI toxicity. In the azoxymethane (AOM)-induced rat colon aberrant crypt foci (ACF) model, naproxen administered at 200 and 400 ppm in the diet reduced mean ACFs in the colon by about 45–60%, respectively. NO-naproxen was likewise administered in the diet at roughly equimolar doses (300 and 600 ppm), and reduced total ACF by 20–40%, respectively. In the hydroxybutyl (butyl) nitrosamine (OH-BBN) rat urinary bladder cancer model, NO-naproxen was given at 183 ppm or 550 ppm in the diet, and naproxen at 128 ppm. The NO-naproxen groups had 77% and 73% decreases, respectively, in the development of large urinary bladder tumors, while the 128 ppm naproxen group also showed a strong decrease (69%). If treatments were started three months after OH-BBN, NO-naproxen (550 ppm) and naproxen (400 ppm) were also highly effective (86–94% decreases). In the methylnitrosourea (MNU)-induced mammary cancer model in rats, NO-naproxen and naproxen showed non-significant inhibitions (12 and 24%) at 550 and 400 ppm, respectively. These data show that both naproxen and NO-naproxen are effective agents against urinary bladder and colon, but not mammary, carcinogenesis. PMID:19892664

Tumor-associated macrophages recruit CCR6+ regulatory T cells and promote the development of colorectal cancer via enhancing CCL20 production in mice.

PubMed

Liu, Jinlin; Zhang, Ning; Li, Qun; Zhang, Weiwei; Ke, Fang; Leng, Qibin; Wang, Hong; Chen, Jinfei; Wang, Honglin

2011-04-29

Tumor-associated macrophages (TAMs) remodel the colorectal cancer (CRC) microenvironment. Yet, findings on the role of TAMs in CRC seem to be contradictory compared with other cancers. FoxP3(+) regulatory T (Treg)-cells dominantly infiltrate CRC. However, the underlying molecular mechanism in which TAMs may contribute to the trafficking of Treg-cells to the tumor mass remains unknown. CRC was either induced by N-methyl-N-nitrosourea (MNU) and H. pylori or established by subcutaneous injection of mouse colorectal tumor cell line (CMT93) in mice. CMT93 cells were co-cultured with primary macrophages in a transwell apparatus. Recruitment of FoxP3 green fluorescence protein positive (FoxP3(GFP+)) Treg-cells was assessed using the IVIS Imaging System or immunofluorescence staining. A role for macrophages in trafficking of Treg-cells and in the development of CRC was investigated in CD11b diphtheria toxin receptor (CD11b-DTR) transgenic C57BL/6J mice in which macrophages can be selectively depleted. Treg-cells remarkably infiltrated solid tumor, and predominantly expressed the homing chemokine receptor (CCR) 6 in the induced CRC model. Both CMT93 cancer cells and macrophages produced a large amount of CCL20, the sole ligand of CCR6 in vitro and in vivo. Injection of recombinant mouse CCL20 into tumor sites promoted its development with a marked recruitment of Treg-cells in the graft CRC model. Conditional macrophage ablation decreased CCL20 levels, blocked Treg-cell recruitment and inhibited tumor growth in CD11b-DTR mice grafted with CMT93. TAMs recruit CCR6(+) Treg-cells to tumor mass and promote its development via enhancing the production of CCL20 in a CRC mouse model.

Nitric oxide donors attenuate clongenic potential in rat C6 glioma cells treated with alkylating chemotherapeutic agents.

PubMed

Yang, Jir-Jei; Yin, Jiu-Haw; Yang, Ding-I

2007-05-11

1,3-Bis(2-chloroethyl)-1-nitrosourea (BCNU) kills tumor cells via multiple actions including alkylation and carbamoylation. Previously, we have reported that formation of S-nitrosoglutathione (GSNO) in glioma cells overexpressing inducible nitric oxide synthase (iNOS) contributed to nitric oxide (NO)-dependent carbamoylating chemoresistance against BCNU. To further characterize the effects of NO on alkylating cytotoxicity, colony formation assay was applied to evaluate the effects of various NO donors on rat C6 glioma cells challenged with alkylating agents. We demonstrate that NO donors including GSNO, diethylamine NONOate (DEA/NO), and sodium nitroprusside (SNP) substantially reduced the extent of colony formation in glioma cells treated with alkylating agents, namely methyl methanesulfonate (MMS), N-methyl-N-nitrosourea (MNU), and N-ethyl-N-nitrosourea (ENU). Without alkylating agents these NO-releasing agents alone had no effects on clongenic potential of rat C6 glioma cells. Among these three NO donors used, the effectiveness in potentiating alkylating cytotoxicity is in the order of "GSNO>DEA/NO>SNP" when applied at the same dosages. GSNO also exerted similar synergistic actions reducing the extents of colony formation when co-administrated with 1,2-bis(methylsulfonyl)-1-(2-chloroethyl)-hydrazine (compound #1), another alkylating agent that mimics the chloroethylating action of BCNU. Together with our previous findings, we propose that NO donors may be used as adjunct chemotherapy with alkylating agents for such malignant brain tumors as glioblastoma multiforme (GBM). In contrast, production of NO as a result of iNOS induction, such as that occurring after surgical resection of brain tumors, may compromise the efficacy of carbamoylating chemotherapy.

Distinct pathways for repairing mutagenic lesions induced by methylating and ethylating agents

PubMed Central

Negishi, Tomoe

2013-01-01

DNA alkylation damage can be repaired by nucleotide excision repair (NER), base excision repair (BER) or by direct removal of alkyl groups from modified bases by O 6-alkylguanine DNA alkyltransferase (AGT; E.C. 2.1.1.63). DNA mismatch repair (MMR) is also likely involved in this repair. We have investigated alkylation-induced mutagenesis in a series of NER- or AGT-deficient Escherichia coli strains, alone or in combination with defects in the MutS, MutL or MutH components of MMR. All strains used contained the Fʹprolac from strain CC102 (FʹCC102) episome capable of detecting specifically lac GC to AT reverse mutations resulting from O 6-alkylguanine. The results showed the repair of O 6-methylguanine to be performed by AGT ≫ MMR > NER in order of importance, whereas the repair of O 6-ethylguanine followed the order NER > AGT > MMR. Studies with double mutants showed that in the absence of AGT or NER repair pathways, the lack of MutS protein generally increased mutant frequencies for both methylating and ethylating agents, suggesting a repair or mutation avoidance role for this protein. However, lack of MutL or MutH protein did not increase alkylation-induced mutagenesis under these conditions and, in fact, reduced mutagenesis by the N-alkyl-N-nitrosoureas MNU and ENU. The combined results suggest that little or no alkylation damage is actually corrected by the mutHLS MMR system; instead, an as yet unspecified interaction of MutS protein with alkylated DNA may promote the involvement of a repair system other than MMR to avoid a mutagenic outcome. Furthermore, both mutagenic and antimutagenic effects of MMR were detected, revealing a dual function of the MMR system in alkylation-exposed cells. PMID:23446177

Analysis of genes involved in the PI3K/Akt pathway in radiation- and MNU-induced rat mammary carcinomas.

PubMed

Showler, Kaye; Nishimura, Mayumi; Daino, Kazuhiro; Imaoka, Tatsuhiko; Nishimura, Yukiko; Morioka, Takamitsu; Blyth, Benjamin J; Kokubo, Toshiaki; Takabatake, Masaru; Fukuda, Maki; Moriyama, Hitomi; Kakinuma, Shizuko; Fukushi, Masahiro; Shimada, Yoshiya

2017-03-01

The PI3K/AKT pathway is one of the most important signaling networks in human breast cancer, and since it was potentially implicated in our preliminary investigations of radiation-induced rat mammary carcinomas, our aim here was to verify its role. We included mammary carcinomas induced by the chemical carcinogen 1-methyl-1-nitrosourea to determine whether any changes were radiation-specific. Most carcinomas from both groups showed activation of the PI3K/AKT pathway, but phosphorylation of AKT1 was often heterogeneous and only present in a minority of carcinoma cells. The negative pathway regulator Inpp4b was significantly downregulated in both groups, compared with in normal mammary tissue, and radiation-induced carcinomas also showed a significant decrease in Pten expression, while the chemically induced carcinomas showed a decrease in Pik3r1 and Pdk1. Significant upregulation of the positive regulators Erbb2 and Pik3ca was observed only in chemically induced carcinomas. However, no genes showed clear correlations with AKT phosphorylation levels, except in individual carcinomas. Only rare carcinomas showed mutations in PI3K/AKT pathway genes, yet these carcinomas did not exhibit stronger AKT phosphorylation. Thus, while AKT phosphorylation is a common feature of rat mammary carcinomas induced by radiation or a canonical chemical carcinogen, the mutation of key genes in the pathways or permanent changes to gene expression of particular signaling proteins do not explain the pathway activation in the advanced cancers. Although AKT signaling likely facilitates cancer development and growth in rat mammary carcinomas, it is unlikely that permanent disruption of the PI3K/AKT pathway genes is a major causal event in radiation carcinogenesis. © The Author 2016. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

The rice endosperm ADP-glucose pyrophosphorylase large subunit is essential for optimal catalysis and allosteric regulation of the heterotetrameric enzyme.

PubMed

Tuncel, Aytug; Kawaguchi, Joe; Ihara, Yasuharu; Matsusaka, Hiroaki; Nishi, Aiko; Nakamura, Tetsuhiro; Kuhara, Satoru; Hirakawa, Hideki; Nakamura, Yasunori; Cakir, Bilal; Nagamine, Ai; Okita, Thomas W; Hwang, Seon-Kap; Satoh, Hikaru

2014-06-01

Although an alternative pathway has been suggested, the prevailing view is that starch synthesis in cereal endosperm is controlled by the activity of the cytosolic isoform of ADPglucose pyrophosphorylase (AGPase). In rice, the cytosolic AGPase isoform is encoded by the OsAGPS2b and OsAGPL2 genes, which code for the small (S2b) and large (L2) subunits of the heterotetrameric enzyme, respectively. In this study, we isolated several allelic missense and nonsense OsAGPL2 mutants by N-methyl-N-nitrosourea (MNU) treatment of fertilized egg cells and by TILLING (Targeting Induced Local Lesions in Genomes). Interestingly, seeds from three of the missense mutants (two containing T139I and A171V) were severely shriveled and had seed weight and starch content comparable with the shriveled seeds from OsAGPL2 null mutants. Results from kinetic analysis of the purified recombinant enzymes revealed that the catalytic and allosteric regulatory properties of these mutant enzymes were significantly impaired. The missense heterotetramer enzymes and the S2b homotetramer had lower specific (catalytic) activities and affinities for the activator 3-phosphoglycerate (3-PGA). The missense heterotetramer enzymes showed more sensitivity to inhibition by the inhibitor inorganic phosphate (Pi) than the wild-type AGPase, while the S2b homotetramer was profoundly tolerant to Pi inhibition. Thus, our results provide definitive evidence that starch biosynthesis during rice endosperm development is controlled predominantly by the catalytic activity of the cytoplasmic AGPase and its allosteric regulation by the effectors. Moreover, our results show that the L2 subunit is essential for both catalysis and allosteric regulatory properties of the heterotetramer enzyme. © The Author 2014. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Ginkgo biloba L. leaf extract offers multiple mechanisms in bridling N-methylnitrosourea - mediated experimental colorectal cancer.

PubMed

Ahmed, Hanaa H; El-Abhar, Hanan S; Hassanin, Elsayed Abdul Khalik; Abdelkader, Noha F; Shalaby, Mohamed B

2017-11-01

In Egypt, colorectal cancer (CRC) is the 6th cancer in both gender and CRC rates are high in subjects under 40 years of age. This study goaled to determine the development of CRC using relevant biochemical markers and to elucidate the potent mechanism of Ginkgo biloba L. leaf extract in retrogression of experimental CRC. Adult male Sprague-Dawley rats were administered N-methylnitrosourea (N-MNU; 2mg in 0.5ml water/rat) intrarectally thrice a week for five weeks to induce CRC, followed by treatment with either 5-fluorouracil (5-FU; 12.5mg/kg, i.p.) or Ginkgo biloba L. leaf extract in a dose of 0.675 and 1.35g/kg, p.o. respectively. The developed tumor enhanced plasma TGF-β, and Bcl 2 , serum EGF, CEA, CCSA, and MMP-7 significantly. Also, gene expression analysis showed significant upregulation of colonic β-Catenin, K-ras and C-myc genes. Besides, immunohistochemical findings revealed significant increase in COX-2, cyclin D1 and survivin content in colon tissue. These data were further supported by the histological observations. Ginkgo biloba L. leaf extract-treated rats; particularly those treated with dose of 1.35g/kg, exhibited significant reduction in the aforementioned parameters and improvement in the histological organization of the colon tissue. The therapeutic effect of Ginkgo biloba L. leaf extract was comparable with that mediated by 5-FU. The current research proved that Ginkgo biloba L. leaf extract could suppress tumor cell proliferation, promote apoptosis, and mitigat inflammation in vivo. The amelioration of these key events might be linked with the inhibition of Wnt/β-Catenin signaling module. The outcomes of the present investigation encourage the use of Ginkgo biloba L. leaf extract as a complementary and alternative therapeutic approach to abate CRC. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

High local carcinogenic activity of 1,3-dimethyl-3-phenyl-1-nitrosourea and its inactivation by intravenous application in rats: comparison of in vivo findings with the in vitro direct and a combined in vivo/in vitro sister chromatid exchange assay in V79-E cells.

PubMed

Thust, R; Martin, J; Mendel, J; Schreiber, D

1987-02-01

1,3-Dimethyl-3-phenyl-1-nitrosourea (DMPNU) is a very potent local carcinogen in rats and induces a 100% frequency of forestomach carcinomas when applied i.g. in two different dosages (10 applications of 0.3 or 0.03 mmol/kg body wt, respectively, at 14-day intervals), but it is inactive upon i.v. administration (10 applications of 0.03 mmol/kg body wt at 14-day intervals). By means of the direct sister chromatid exchange (SCE) assay in V79-E cells in the presence of rat blood, serum or plasma, respectively, as well as by a 'host-mediated' SCE assay (in which the agent was given i.v. to rats, and blood taken from the animal was checked for the recovery of genotoxic activity in cell cultures), we tried to elucidate the unexpected lack of carcinogenic activity of i.v. DMPNU. The direct SCE assay revealed a drastic reduction of DMPNU genotoxicity by rat blood, serum or plasma, respectively, which is abolished by the esterase inhibitor diisopropylfluorophosphate. In the 'host-mediated' SCE assay a genotoxic activity of DMPNU was only recoverable after a very high i.v. dose and when the blood added to the cell cultures had been taken from the rat heart within 1 min after DMPNU administration in vivo. 1-Methyl-1-nitrosourea (MNU) and 1-methyl-3-phenyl-1-nitrosourea (MPNU) were used as positive controls in these experiments and also gave a lower response than theoretically expected, but the relative loss of activity with the latter compounds was much lower than with DMPNU. It is assumed that an esterase in rat blood effectively decomposes this trisubstituted nitrosourea. Problems of the novel 'host-mediated' SCE assay are discussed.

Tumor-Associated Macrophages Recruit CCR6+ Regulatory T Cells and Promote the Development of Colorectal Cancer via Enhancing CCL20 Production in Mice

PubMed Central

Li, Qun; Zhang, Weiwei; Ke, Fang; Leng, Qibin; Wang, Hong; Chen, Jinfei; Wang, Honglin

2011-01-01

Background Tumor-associated macrophages (TAMs) remodel the colorectal cancer (CRC) microenvironment. Yet, findings on the role of TAMs in CRC seem to be contradictory compared with other cancers. FoxP3+ regulatory T (Treg)-cells dominantly infiltrate CRC. However, the underlying molecular mechanism in which TAMs may contribute to the trafficking of Treg-cells to the tumor mass remains unknown. Methodology/Principal Findings CRC was either induced by N-methyl-N-nitrosourea (MNU) and H. pylori or established by subcutaneous injection of mouse colorectal tumor cell line (CMT93) in mice. CMT93 cells were co-cultured with primary macrophages in a transwell apparatus. Recruitment of FoxP3 green fluorescence protein positive (FoxP3GFP+) Treg-cells was assessed using the IVIS Imaging System or immunofluorescence staining. A role for macrophages in trafficking of Treg-cells and in the development of CRC was investigated in CD11b diphtheria toxin receptor (CD11b-DTR) transgenic C57BL/6J mice in which macrophages can be selectively depleted. Treg-cells remarkably infiltrated solid tumor, and predominantly expressed the homing chemokine receptor (CCR) 6 in the induced CRC model. Both CMT93 cancer cells and macrophages produced a large amount of CCL20, the sole ligand of CCR6 in vitro and in vivo. Injection of recombinant mouse CCL20 into tumor sites promoted its development with a marked recruitment of Treg-cells in the graft CRC model. Conditional macrophage ablation decreased CCL20 levels, blocked Treg-cell recruitment and inhibited tumor growth in CD11b-DTR mice grafted with CMT93. Conclusions/Significance TAMs recruit CCR6+ Treg-cells to tumor mass and promote its development via enhancing the production of CCL20 in a CRC mouse model. PMID:21559338

Inducible DNA-repair systems in yeast: competition for lesions.

PubMed

Mitchel, R E; Morrison, D P

1987-03-01

DNA lesions may be recognized and repaired by more than one DNA-repair process. If two repair systems with different error frequencies have overlapping lesion specificity and one or both is inducible, the resulting variable competition for the lesions can change the biological consequences of these lesions. This concept was demonstrated by observing mutation in yeast cells (Saccharomyces cerevisiae) exposed to combinations of mutagens under conditions which influenced the induction of error-free recombinational repair or error-prone repair. Total mutation frequency was reduced in a manner proportional to the dose of 60Co-gamma- or 254 nm UV radiation delivered prior to or subsequent to an MNNG exposure. Suppression was greater per unit radiation dose in cells gamma-irradiated in O2 as compared to N2. A rad3 (excision-repair) mutant gave results similar to wild-type but mutation in a rad52 (rec-) mutant exposed to MNNG was not suppressed by radiation. Protein-synthesis inhibition with heat shock or cycloheximide indicated that it was the mutation due to MNNG and not that due to radiation which had changed. These results indicate that MNNG lesions are recognized by both the recombinational repair system and the inducible error-prone system, but that gamma-radiation induction of error-free recombinational repair resulted in increased competition for the lesions, thereby reducing mutation. Similarly, gamma-radiation exposure resulted in a radiation dose-dependent reduction in mutation due to MNU, EMS, ENU and 8-MOP + UVA, but no reduction in mutation due to MMS. These results suggest that the number of mutational MMS lesions recognizable by the recombinational repair system must be very small relative to those produced by the other agents. MNNG induction of the inducible error-prone systems however, did not alter mutation frequencies due to ENU or MMS exposure but, in contrast to radiation, increased the mutagenic effectiveness of EMS. These experiments demonstrate that in this lower eukaryote, mutagen exposure does not necessarily result in a fixed risk of mutation, but that the risk can be markedly influenced by a variety of external stimuli including heat shock or exposure to other mutagens.

Carcinogenicity of antioxidants BHA, caffeic acid, sesamol, 4-methoxyphenol and catechol at low doses, either alone or in combination, and modulation of their effects in a rat medium-term multi-organ carcinogenesis model.

PubMed

Hirose, M; Takesada, Y; Tanaka, H; Tamano, S; Kato, T; Shirai, T

1998-01-01

The carcinogenicity of low dietary levels of the antioxidants butylated hydroxyanisole (BHA), caffeic acid, sesamol, 4-methoxyphenol (4-MP) and catechol, known to target the forestomach or glandular stomach, were examined alone or in combination in a 2-year long-term experiment and their modifying effects assessed in a medium-term multiorgan model. In the carcinogenicity study, groups of 30-31 male F344 rats were treated with 0.4% BHA, 0.4% caffeic acid, 0.4% sesamol, 0.4% 4-MP and 0.16% catechol either alone or in combination for up to 104 weeks and then killed. In the medium-term multi-organ model, groups of 10 to 15 male F344 rats were given diethylnitrosamine (DEN), N-methylnitrosourea (MNU), 1,2-dimethylhydrazine (DMH), N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) and 2,2'-dihydroxy-di-n-propylnitrosamine (DHPN) for a total multiple initiation period of 4 weeks (DMBDD treatment). BHA, caffeic acid, sesamol and 4-MP, each at doses of 0.4% or 0.08%, and catechol at doses of 0.16% or 0.032% were administered in the diet either alone or in combination after completion of the initiation regimen. All surviving animals were killed at the end of week 28, and major organs were examined histopathologically. In the carcinogenicity study, slightly increased incidences of forestomach papillomas were found in the sesamol- (15.8%), caffeic acid- (14.8%), catechol- (3%) and 4-MP- (11.5%) treated groups as compared with basal diet (0%), and a significant increase was observed with the five antioxidants in combination (42.9%, P < 0.001). In a medium-term multiorgan carcinogenesis model, incidences of forestomach papillomas and/or carcinomas were increased in each high dose group, but additive or synergistic effects were not found in the combination group. In the low dose case, the incidence of forestomach papillomas was significantly increased only in the combination group. With regard to other organs, the incidence of colon tumors was significantly decreased only in the high dose combination group. The results indicate that even at low dose levels phenolic compounds can exert additive/synergistic effect on carcinogenesis.

The nervous system effects of occupational exposure on workers in a South African manganese smelter.

PubMed

Myers, Jonathan E; Thompson, Mary Lou; Ramushu, Suzan; Young, Taryn; Jeebhay, Mohamed F; London, Leslie; Esswein, Eric; Renton, Kevin; Spies, Adri; Boulle, Andrew; Naik, Inakshi; Iregren, Anders; Rees, David J

2003-12-01

Five hundred and nine production workers at a manganese (Mn) smelting works comprising eight production facilities and 67 external controls were studied cross-sectionally for Mn related neuroehavioural effects. Exposure measures from personal sampling included Mn in inhalable dust as cumulative exposure indices (CEI) and average intensity (INT). Biological exposure and biological effect measures included blood (MnB), urine (MnU) manganese and serum prolactin. Endpoints included items from the Swedish nervous system questionnaire (Q16), World Health Organisation neurobehavioural core test battery (WHO NCTB), Swedish performance evaluation system (SPES), Luria-Nebraska (LN), and Danish product development (DPD) test batteries, and a brief clinical examination. Potential confounders and effect modifiers included age, educational level, alcohol and tobacco consumption, neurotoxic exposures in previous work, past medical history, previous head injury and home language. Associations were evaluated by multiple linear and logistic regression modelling. Modelling assumptions were tested. Average exposure intensity across all jobs ranged from near 0 (0.06 microg/m3) for external controls to 5.08 mg/m3 for inhalable Mn, and was greater than the ACGIH TLV for 69% of subjects. Results from the large number of tests performed resolved into three groups. Group 1 shows differences between external unexposed referents and all the exposed and/or differences between internal low exposed referents and the rest of the exposed but no further exposure-response relationships. It includes the Santa Ana, Benton and digit-span tests from the WHO NCTB; the hand tapping and endurance tapping tests from the SPES; Luria-Nebraska item 2L; questionnaire items tired, depressed, irritated, having to take notes in order to remember things, and subjects' perception that they had sex less often than normal; a test of clinical abnormality; and increased sway under two conditions (eyes open without foot insulation, eyes open with foot insulation). Group 2 shows the presence of a more substantive exposure-response relationship. It consists of only two tests: and includes the WHO digit-symbol test (although the major impact is at low exposure and therefore counterintuitive, arguably placing this test in group 3) and the LN item 1R which has a step to a poorer score at high exposure. Group 3 contains the overwhelming majority of test results (almost all the questionnaire items, almost all the DPD tests including tremor, sway and diadochokinesia, and serum prolactin) which were either null or counterintuitive (did not make sense). The CEI was the strongest predictor of test abnormalities, except for the clinical test which was more strongly associated with blood manganese. Despite a comprehensive range of endpoints, and levels of exposure ranging from environmental to industrial, this large study of Mn workers found little convincing evidence for a continuum of effects, contributing further questions to current debates about the adequacy of the current ACGIH TLV.