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Asian Pacific Journal of Cancer... Dec 2017Background: Angiogenic activity has been considered to reflect important molecular events during breast tumour development. The present study concerned cellular and...
Background: Angiogenic activity has been considered to reflect important molecular events during breast tumour development. The present study concerned cellular and molecular changes of MNU-induced breast tumours subjected to promotion and suppression of angiogenesis. Methods: Female Sprague Dawley rats at the age of 21 days received MNU at the dose 70 mg/kg of body weight by intraperitoneal injection. Three months post-carcinogen initiation, mammary tumours were palpated and their growth was monitored. When the tumour diameter reached 1.0 ± 0.05 cm, rats were given bFGF or PF4 intratumourally at a dose of 10 μg/tumour. Entire palpable tumour were subsequently excised and subjected to histology examination, IHC staining, and RT-PCR. Results: No critical morphological changes were observed between pro-angiogenic factor, bFGF, and control groups. However, increase of tumour size with more necrotic and diffuse areas was notable in tumours after anti-angiogenic PF4 intervention. ER and PR mRNA expression was significantly up- and down-regulated in bFGF and PF4 groups, respectively. The trends were significantly associated with peri- and intratumoural MVD counts. However, irrespective of whether we promoted or inhibited angiogenesis, the expression of EGFR and ERBB2 continued to be significantly increased but this was not significantly associated with the MVD score. No significant differences in E-cadherin and LR gene expression were noted between intervention and control groups. Conclusion: ER and PR receptor expression shows consistent responses when tumour angiogenesis is manipulated either positively or negatively. Our study adds to current understanding that not only do we need to target hormonal receptors, as presently practiced, but we also need to target endothelial receptors to successfully treat breast cancer.
Topics: Alkylating Agents; Angiogenesis Inhibitors; Animals; Female; Fibroblast Growth Factor 2; Injections, Intralesional; Mammary Neoplasms, Experimental; Methylnitrosourea; Neovascularization, Pathologic; Platelet Factor 4; Rats; Rats, Sprague-Dawley
PubMed: 29281877
DOI: 10.22034/APJCP.2017.18.12.3231 -
World Journal of Gastroenterology Jun 2017To investigate the inhibitory effect of Liuwei Dihuang Pill (LDP) on gastric tumorigenesis induced by N-methyl-N-nitrosourea (MNU) in diabetic mice.
AIM
To investigate the inhibitory effect of Liuwei Dihuang Pill (LDP) on gastric tumorigenesis induced by N-methyl-N-nitrosourea (MNU) in diabetic mice.
METHODS
Four-week-old mice were divided into four groups: A, 12 db/m mice treated with MNU and saline, as the non-diabetic control; B, 12 db/db mice treated with MNU and saline, as the diabetic control; C, 12 db/db mice treated with MNU and metformin, as the positive control; and D, 12 db/db mice treated with MNU and LDP. MNU was administrated for 20 wk to induce gastric carcinogenesis. LDP was administrated for 10 wk for improvement of insulin resistance. Body weight and food intake were measured every week. Blood samples were collected for assays of fasting blood glucose, insulin, insulin-like growth factor (IGF)-1, adiponectin and leptin. Stomach tissues were collected for histopathological analysis, immunohistochemical staining of Ki67, quantitative reverse transcription-polymerase chain reaction and western blotting.
RESULTS
The incidence of MNU-induced gastric dysplasia was significantly elevated in diabetic (db/db) mice relative to the control (db/m) mice. The incidence of gastric dysplasia was significantly reduced by LDP with suppression of cell proliferation, as demonstrated by a decrease in Ki67 staining. Hyperglycemia, hyperinsulinemia and serum IGF-1 were inhibited by LDP. Expression of IGF-1 and insulin receptor mRNAs was decreased, phosphorylation of IGF-1 receptor and AKT protein was reduced in the stomach tissues by LDP. In addition, adiponectin was increased and leptin was decreased in the serum by LDP.
CONCLUSION
LDP decreased risk of gastric dysplasia in type 2 diabetic mice by down-regulation of IGF and insulin activity and correction of adipokines disorders.
Topics: Adiponectin; Animals; Blood Glucose; Body Weight; Carcinogenesis; Cell Transformation, Neoplastic; Diabetes Mellitus, Experimental; Drugs, Chinese Herbal; Immunohistochemistry; Insulin; Insulin Resistance; Insulin-Like Growth Factor I; Ki-67 Antigen; Leptin; Male; Methylnitrosourea; Mice; Stomach Neoplasms
PubMed: 28694663
DOI: 10.3748/wjg.v23.i23.4233 -
The American Journal of Pathology Mar 2021Nerve infiltration into the tumor is a common feature of the tumor microenvironment. The mechanisms of axonogenesis in breast cancer remain unclear. We hypothesized that...
Nerve infiltration into the tumor is a common feature of the tumor microenvironment. The mechanisms of axonogenesis in breast cancer remain unclear. We hypothesized that vascular endothelial growth factor (VEGF), as well as nerve growth factor (NGF), is involved in the axonogenesis of breast cancer. A N-methyl-N-nitrosourea (MNU)-induced rat model of breast cancer was used to explore the presence of axonogenesis in breast tumor and the involvement of VEGF, as well as NGF, in the axonogenesis of breast tumor. Nerve infiltration into the tumor was found in MNU-induced rat model of breast cancer including the sensory and sympathetic nerve fibers. Nerve density was increased following the growth of tumor. The sensory neurons innervating the thoracic and abdominal mammary tumors peaked at T5 to T6 and L1 to L2 dorsal root ganglions, respectively. Either VEGF receptor inhibitor or antibody against VEGF receptor 2, as well as NGF receptor inhibitor, apparently decreased both the nerve density and vascular density of breast tumor. The reduced nerve density was correlated with the decreased vascular density induced by these treatments. In cultured dorsal root ganglion neurons, phosphatidylinositol 3 (PI3K)/Akt, extracellular signal-regulated protein kinase (ERK), and p38 inhibitors significantly attenuated VEGF-induced neurite elongation. These findings provide direct evidence that VEGF, as well as NGF, may control the axonogenesis of breast cancer.
Topics: Alkylating Agents; Animals; Axons; Extracellular Signal-Regulated MAP Kinases; Female; MAP Kinase Signaling System; Mammary Neoplasms, Experimental; Methylnitrosourea; Neurites; Neurogenesis; Proto-Oncogene Proteins c-akt; Rats; Rats, Sprague-Dawley; Signal Transduction; Vascular Endothelial Growth Factor A
PubMed: 33345997
DOI: 10.1016/j.ajpath.2020.12.006 -
Journal of Korean Medical Science Feb 2017The present study investigated the temporal pattern and cellular localization of nestin in the adult mouse retina with pharmaceutically induced retinal degeneration...
The present study investigated the temporal pattern and cellular localization of nestin in the adult mouse retina with pharmaceutically induced retinal degeneration using N-methyl-N-nitrosourea (MNU). After a single intraperitoneal injection of MNU in 8-week-old C57BL/6 mice, the animals were sacrificed at 1, 3, 5, 7, and 21 days (n = 6, in each stage). The eyes were examined by means of immunohistochemical tests using nestin, ionized calcium-binding adaptor molecule (Iba-1), CD11b, F4/80, and glial fibrillary acidic protein (GFAP). Western blot analysis and manual cell counting were performed for quantification. Nestin expression was increased after MNU administration. Nestin+/Iba-1+ cells were migrated into outer nuclear layer (ONL) and peaked at day 3 post injection (PI). Nestin+/CD11b+ cells were also mainly identified in ONL at day 3 PI and peaked at day 5. Nestin+/F4/80+ cells were shown in the subretinal space and peaked at day 3 PI. Nestin+/GFAP+ cells were distinctly increased at day 1 PI and peaked at day 5 PI. The up-regulation of nestin expression after MNU administration in adult mouse retinal microglia, and monocyte/macrophage suggests that when retinal degeneration progresses, these cells may revert to a more developmentally immature state. Müller cells also showed reactive gliosis and differentiational changes.
Topics: Animals; Blotting, Western; Calcium-Binding Proteins; Disease Models, Animal; Female; Glial Fibrillary Acidic Protein; Immunohistochemistry; Leukocyte Count; Methylnitrosourea; Mice; Mice, Inbred C57BL; Microfilament Proteins; Microscopy, Fluorescence; Nestin; Retina; Retinal Degeneration; Up-Regulation
PubMed: 28049248
DOI: 10.3346/jkms.2017.32.2.343 -
Physiology & Behavior Feb 2017Epidemiological evidence indicates that physical activity between menarche and first pregnancy is associated with a lower risk of breast cancer among women with at least...
Epidemiological evidence indicates that physical activity between menarche and first pregnancy is associated with a lower risk of breast cancer among women with at least 20years between these reproductive events. The mechanism by which physical activity during this interval confers protection is unknown. This study used a novel animal model to assess potentially protective effects of physical activity on tumor development in delayed parity. Thirty-six female Sprague Dawley rats received an i.p. injection of 50mg/kg N-methyl-N-nitrosourea (MNU) at 5weeks of age. Estrogen and progesterone pellets were implanted subcutaneously 1week (early parity, EP, n=8) or 4weeks (delayed parity, DP, n=11) following MNU injection. An additional group of DP rats were progressively exercise trained (Ex+DP, n=9) on a treadmill following MNU injection for 7weeks (up to 20m/min at 15% incline for 30min). We observed the greatest tumor latency and smallest tumor burden in Ex+DP animals. Ductal hyperplasia and inflammation of non-tumor bearing mammary glands were only found in DP, and we detected a significant increase in collagen for DP and Ex+DP compared to EP. Exercise induced differential gene expression of cyclin-dependent kinase-inhibitor 1C (Cdkn1c) and urokinase-plasminogen activator (Plau) in mammary tissue of Ex+DP animals compared to DP alone. While there are delayed parity-induced changes in mammary gland collagen and gene expression levels, Ex+DP animals had longer tumor latency, smaller tumor burden, and glandular tissue resistant to ductal hyperplasia. Exercise may induce protection through beneficial regulation of gene expression profiles.
Topics: Alkylating Agents; Animals; Breast Neoplasms; Collagen Type V; Cyclin-Dependent Kinase Inhibitor p57; Disease Models, Animal; Female; Gene Expression; Gene Expression Regulation, Neoplastic; Methylnitrosourea; Parity; Physical Conditioning, Animal; Pregnancy; Pregnancy, Animal; Rats; Rats, Sprague-Dawley; Reaction Time; Time Factors; Urokinase-Type Plasminogen Activator
PubMed: 27884590
DOI: 10.1016/j.physbeh.2016.11.026 -
Journal of Cancer Prevention Sep 2016The aim of this study was to investigate the effect of N-methyl-N-nitrosourea (MNU) treatment followed by chronic SS1 and colonization on the stomachs of C57BL/6 mice....
BACKGROUND
The aim of this study was to investigate the effect of N-methyl-N-nitrosourea (MNU) treatment followed by chronic SS1 and colonization on the stomachs of C57BL/6 mice. The role of MNU and species in gastric carcinogenesis was also elucidated.
METHODS
A total of 69 C57BL/6 mice at 4 weeks of age were divided into 6 groups according to MNU treatment and SS1 or infection. The mice were sacrificed at 21 and 50 weeks. The degree of inflammation was determined by histopathology. The levels of gastric mucosal myeloperoxidase, TNF-α, and interleukin-1β (IL-1β) were measured by ELISA.
RESULTS
In the groups with or without MNU, the incidence of gastric tumors was 21.1% and 35.0% at 21 and 50 weeks, respectively. No gastric tumors were observed in all control mice. At 50 weeks, 37.5% of gastric adenoma cases were observed in the alone and MNU + groups. Furthermore, 12.5% of gastric adenocarcinoma cases were observed in the MNU alone and MNU + groups. The gastric mucosal IL-1β level was significantly higher in the MNU + group at 21 weeks and group at 50 weeks, respectively, than that for control mice ( < 0.05). However, the effect of MNU on SS1-induced gastric carcinogenesis was low compared to that on .
CONCLUSIONS
Administration of MNU before infection provokes severe inflammation through IL-1β, and eventually induces gastric cancer. However, the role of MNU in SS1-induced gastric carcinogenesis model is minor.
PubMed: 27722144
DOI: 10.15430/JCP.2016.21.3.182 -
International Journal of... 2022Angiogenesis is the process of new vascular formation, which is derived from various factors. For suppressing cancer cell growth, targeting angiogenesis is one of the...
Angiogenesis is the process of new vascular formation, which is derived from various factors. For suppressing cancer cell growth, targeting angiogenesis is one of the therapeutic approaches. Vascular endothelial growth factor family receptors, including Flt-1, Flk-1 and Flt-4, have been found to play an essential role in regulating angiogenesis. Rapamycin is a macrolide compound with anti-proliferative properties, while platelet factor-4 (PF-4) is an antiangiogenic ELR-negative chemokine. Rapamycin inhibits mTOR ligands activation, thus suppressing cell proliferation, while PF-4 inhibits cell proliferation through several mechanisms. In the present study, we evaluated the effects of rapamycin and platelet factor-4 toward breast carcinoma at the proteomic and genomic levels. A total of 60 N-Methyl-N-Nitrosourea-induced rat breast carcinomas were treated with rapamycin, platelet factor-4 and rapamycin+platelet factor-4. The tumours were subsequently subjected to immunohistochemical protein analysis and polymerase chain reaction gene analysis. Protein analysis was performed using a semiquantitative scoring method, while the mRNA expression levels were analysed based on the relative expression ratio. There was a significant difference in the protein and mRNA expression levels for the selected markers. In the rapamycin+platelet factor-4-treated group, the Flt-4 marker was downregulated, whereas there were no differences in the expression levels of other markers, such as Flt-1 and Flk-1. On the other hand, platelet factor-4 did not exhibit a superior angiogenic inhibiting ability in this study. Rapamycin is a potent antiangiogenic drug; however, platelet factor-4 proved to be a less effective drug of anti-angiogenesis on rat breast carcinoma model.
Topics: Angiogenesis Inhibitors; Animals; Female; Mammary Glands, Animal; Mammary Neoplasms, Experimental; Methylnitrosourea; Platelet Factor 4; Rats, Sprague-Dawley; Receptors, Vascular Endothelial Growth Factor; Sirolimus; Rats
PubMed: 35037503
DOI: 10.1177/20587384211059673 -
BMC Cancer Mar 2017Recent 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...
BACKGROUND
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 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.
METHODS
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.
RESULTS
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).
CONCLUSIONS
A novel role for rat NAT2 in mammary cancer was discovered unrelated to carcinogen metabolism, suggesting a role for human NAT1 in breast cancer.
Topics: 9,10-Dimethyl-1,2-benzanthracene; Animals; Arylamine N-Acetyltransferase; Carcinogens; Disease Susceptibility; Female; Inactivation, Metabolic; Mammary Neoplasms, Animal; Rats; Rats, Inbred F344; Rats, Inbred WKY
PubMed: 28359264
DOI: 10.1186/s12885-017-3221-9 -
Oncotarget May 2017We previously demonstrated that chemopreventive methylselenocysteine (MSC) prevents N-Nitroso-N-methylurea (NMU)-induced mammary carcinogenesis in the susceptible... (Comparative Study)
Comparative Study
We previously demonstrated that chemopreventive methylselenocysteine (MSC) prevents N-Nitroso-N-methylurea (NMU)-induced mammary carcinogenesis in the susceptible Fischer 344 (F344) rats by enhancing NAD+-dependent SIRT1 activity, restoring circadian expression of Period 2 (Per2) and circadian controlled genes. Here, we show that compared to the genetically resistant Copenhagen (COP) rat strain, mammary glands of the F344 rats have a 4-hour phase delay in circadian expression of Per2. Consequently, F344 rats failed to increase SIRT1 activity and circadian expression of Per2 and DDRR genes after exposure to NMU. Exposure of COP rats to NMU had the opposite effect, enhancing SIRT1 activity, increasing circadian expression of Per2 and DDRR genes. Significantly, SIRT1 activity and circadian expression of Per2 and DDRR genes in NMU-treated F344 rats on a chemopreventive regimen of MSC approximated those in NMU-treated COP rats. These results indicated that COP rats have an increased capacity to maintain NAD+-dependent SIRT1 activity under genotoxic stress. This contention was supported by increased stability of the period and phase of circadian locomotor activity in COP vs F344 rats exposed to changing light conditions. The increased sensitivity and rapid response of COP to changing light were correlated with the enhanced circadian response of this strain to carcinogen. Disturbance of circadian rhythm by jet lag also disrupted circadian expression of Per2 and DDRR genes, and accelerated mammary tumorigenesis in rodent models. These results suggested that uncoupling of DDRR responses from circadian control by environmental stresses and endogenous factors increases susceptibility to mammary carcinogenesis, possibly by inducing a promutagenic state.
Topics: Animals; Cell Transformation, Neoplastic; Circadian Rhythm; DNA Repair; Disease Models, Animal; Female; Jet Lag Syndrome; Mammary Glands, Animal; Mammary Neoplasms, Experimental; Methylnitrosourea; Period Circadian Proteins; Rats; Rats, Inbred F344; Sirtuin 1
PubMed: 28427145
DOI: 10.18632/oncotarget.15678 -
Molecular Biology Reports Sep 2022In this study, two main research objectives were examined: (1) the cytotoxic and anticancer activities of the aqueous methanol extract from Acacia nilotica flowers on...
PURPOSE
In this study, two main research objectives were examined: (1) the cytotoxic and anticancer activities of the aqueous methanol extract from Acacia nilotica flowers on three human cancer cells, namely lung A549, breast MCF-7, and leukemia THP-1 cells, and (2) the genotoxic effects of A. nilotica extract and its influence on DNA damage induced by N-methyl-N-nitrosourea (MNU) in mice.
METHODS
Mice were orally treated with A. nilotica extract (200, 500, and 800 mg/kg for 4 days) with or without MNU (80 mg/kg intraperitoneally for 24 h).
RESULTS
In vitro experiments showed that A549 cells were the most sensitive to A. nilotica extract among the tested cell lines. A. nilotica extract inhibited A549 cell proliferation by blocking the cell cycle at the G/M phase and accumulating apoptotic cells in the sub-G/G phase in A549 cells. In vivo experiments showed that MNU induced positive and negative genotoxicity in bone marrow cells and spermatocytes, respectively. Negative genotoxicity was observed in A. nilotica extract-treated groups only. However, A. nilotica extract (800 mg/kg) remarkably increased comet tail formation in bone marrow cells. Unexpectedly, the absence of antigenotoxicity was observed in three cotreated groups with A. nilotica extract and MNU compared with the MNU-treated group. Astonishingly, cotreatment with MNU and A. nilotica extract at a dose above 200 mg/kg remarkably increased micronucleus and comet tail formation in bone marrow cells compared with the MNU-treated group.
CONCLUSIONS
A. nilotica extract possessed anticancer activity with relative genotoxic effects at high doses.
Topics: Acacia; Animals; Antineoplastic Agents; DNA Damage; Flowers; Humans; Male; Methylnitrosourea; Mice; Plant Extracts
PubMed: 35934768
DOI: 10.1007/s11033-022-07662-0