Background: The limited within-breed genetic heterogeneity and an enrichment of disease-predisposing alleles have made the dog a very suitable model for the identification of genes associated with risk for specific diseases. Canine mammary cancer is an example of such a disease. However, the underlying inherited risk factors for canine mammary tumours (CMTs) are still largely unknown. In this study, 52 single nucleotide polymorphisms (SNPs) in ten human cancer-associated genes were genotyped in two different datasets in order to identify genes/alleles associated with the development of CMTs. The first dataset consisted of English Springer Spaniel (ESS) CMT cases and controls. ESS is a dog breed known to be at increased risk of developing CMTs. In the second dataset, dogs from breeds known to have a high frequency of CMTs were compared to dogs from breeds with a lower occurrence of these tumours. Results: We found significant associations to CMT for SNPs and haplotypes in the estrogen receptor 1 (ESR1) gene in the ESS material (best P-Bonf = 0.021). A large number of SNPs, among them several SNPs in ESR1, showed significantly different allele frequencies between the high and low risk breed groups (best P-Bonf = 8.8E-32, best P-BPerm = 0.076). Conclusions: The identification of CMT-associated SNPs in ESR1 in two independent datasets suggests that this gene might be involved in CMT development. These findings also support that CMT may serve as a good model for human breast cancer research.

No description available.

No description available.

The activities of phosphohexose isomerase (EC. 5.3.1.9), isocitrate dehydrogenase (EC. 1.1.1.42) and lactate dehydrogenase (EC. 1.1.1.27) were measured in 14 normal and 21 tumorous mouse mammary tissue samples. Methods of tissue extraction and activity determination in this study employed equipment found in most clinical laboratories.For each of the three enzymes there was a statistically significant (p <.05) elevation of the tumor sample group's activities. The activities of the normal tissues were: PHI x = 9.6 and SD = 4.6, ICD x = 13.2 and SD = 5.3, and IDH x = 10.9 and SD = 5.3. The activities of the tumorous tissues were: PHI x = 55.2 and SD = 29.9, ICD x = 40.5 and SD = 23.8, and IDH x = 55.8 and SD = 31.4.Using values of 20, 27, and 21 for the upper limit of normal activity (x + 2SD) for PHI, ICD, and LDH respectively, the tissue samples can be divided into normal and tumorous groups with l00% sensitivity and 85% specificity.Ball State UniversityMuncie, IN 47306

Most members of the PAS (PER-ARNT-SIM) protein family are transcription factors, mediating development and adaptive responses to the environment, such as circadian rhythms and toxin responses. Because the PAS domain mediates protein-protein interactions and functional cross-talk between distinct biological processes, we hypothesized that PAS genes in the circadian clockworks, namely Per1 and Per2, may be involved in development and toxin responses, which are modulated by other PAS members. To explore the possible role of clock genes in development, we examined mammary epithelial cells in vitro and the mouse mammary gland in vivo for evidences of changes in clock gene expression during different stages of development and differentiation. Our results showed that Per1 and Bmal1 expression were up-regulated in differentiated HC-11 cells, whereas Per2 mRNA levels were higher in undifferentiated cells. A similar differentiation-dependent profile of clock gene expression was observed in mouse mammary glands; Per1 and Bmal1 mRNA levels were elevated in late pregnant and lactating mammary tissues, whereas Per2 expression was higher in proliferating virgin and early pregnant glands. These data suggest that circadian clock genes may play a role in mouse mammary gland development. To examine clock gene function in toxin responses, we evaluated whether disruption or inhibition of Per1 and/or Per2 alters toxin-induced activity of the AhR signaling pathway in the mouse mammary gland and liver. We assessed the activation of the AhR signaling pathway in response to 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), a prototypical AhR agonist, by analyzing the mRNA abundance of its two target genes, cytochrome P450, subfamily I, polypeptide 1 (Cyp1A1) and Cyp1B1. Our results showed that the targeted disruption of Per1, but not Per2, significantly increases the TCDD-induced p450 expression in the mammary gland and liver in vivo. Similar changes in TCDD-mediated p450 expression were observed in vitro using mammary primary cultures of mammary cells derived from from Per1ldc, Per2ldc and Per1ldc/Per2ldc mutant mice and Hepa1c1c7 cells subjected to siRNA-mediated inhibition of Per1 or Per2. These discoveries suggest that the clock gene Per1 may modulate toxin responses perhaps by functioning as a negative regulator for TCDD-mediated activation of the AhR signaling pathway.

Thesis (M.S.)--Rutgers University, 2009. / "Graduate Program in Microbiology and Molecular Genetics." Includes bibliographical references (p. 51-61).

Thesis (Ph. D.)--Case Western Reserve University, 2010. / [School of Medicine] Department of Pharmacology. Includes bibliographical references.

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Vitamin E is a group of naturally occurring fat soluble compounds which consists of eight distinct forms of tocopherols and tocotrienols. Although a well-defined physiological function of vitamin E is as an antioxidant, beneficial effects of individual vitamin E compounds on chronic human diseases such as cancer need to be better understood. Studies in this dissertation investigated potential application of gamma-tocopherol (gamma-T), gamma-tocotrienol (gamma-T3) or synthetic derivatives of tocotrienols as anticancer agents in comparison to alpha-tocopherol (alpha-T), its redox-silent acetic acid derivative (alpha-TEA) or alpha-tocotrienol (alpha-T3). Redox-silent derivatives of alpha- and gamma-T3; namely alpha-T3EA and gamma-T3EA exhibited potent anti-proliferative and proapoptotic activities in a murine mammary cancer cell line as well as in human breast cancer cell lines. Moreover, studies using human vascular endothelial cells in cell culture showed that the tocotrienol derivatives exhibited strong antiangiogenic activities which were markedly improved over those of the parent compounds. An antitumor efficacy study using the 66cl-4-GFP syngeneic mouse mammary tumor model showed that each tocotrienol derivative, when delivered in the diet, significantly suppressed mammary tumor growth; however serum and tissue concentrations of these novel compounds were lower than those of alpha-TEA, suggesting that the next generation of vitamin E derivatives will need to be modified to improve bioavailability. On the other hand, some natural-source vitamin E forms, especially gamma-forms, display anticancer activities without any chemical modification in both in vitro cell culture studies and in vivo animal models. Dietary delivery of gamma-T3 suppressed tumor growth in a syngeneic implantation mouse mammary cancer model by inhibiting cell proliferation and inducing apoptosis. Cell culture studies using human breast cancer cells showed that gamma-T3 triggered apoptosis by inducing endoplasmic reticulum (ER)-stress mediated by acid sphingomyelinase (ASMase) action. Activation of stress-activated mitogen-activated protein kinases (MAPKs), JNK and p38, was associated with gamma-T3-induced ER stress followed by upregulation of extrinsic death receptor-5 (DR5) expression in a CHOP transcription factor dependent manner. Gamma-T also triggered extrinsic apoptosis signaling by increasing DR5 mRNA, protein and cell surface expression levels followed by mitochondria-dependent apoptotic signaling. In agreement with in vitro studies, gamma-T delivered in the diet suppressed the tumor growth of MDA-MB-231-GFP human breast cancer cells in a xenograft model but the antitumor activity of gamma-T was hampered by co-administration of alpha-T. The preferential tissue retention of alpha-T over gamma-T could be overcome by use of sesamin, a dietary source of human cytochrome P450 inhibitor. Based on data presented, gamma-T and gamma-T3 show preclinical potential for cancer treatment either as single agents or in combination with other agents. / text

Se estudiaron 136 carcinomas mamarios de perras y sus linfonódulos satélites. Se evaluaron la proliferación celular (mediante la marcación inmunohistoquímica del antígeno nuclear de proliferación celular) y la actividad angiogénica (mediante la inmunomarcación del receptor para el factor de crecimiento de endotelios vasculares 2 -VEGFR-2- y el recuento de microvasos). Se relacionaron ambos procesos y su repercusión en el estado del linfonódulo. Se estableció la asociación entre estas características y el tipo y grado histológicos, y la presencia de émbolos neoplásicos en los vasos tumorales. Para determinar su significación en el pronóstico, estos parámetros se relacionaron con el estado del linfonódulo (merced a la observación de cortes procesados mediante la técnica histopatológica de rutina y a la marcación inmunohistoquìmica de citoqueratinas) y con la supervivencia de un grupo de pacientes. Los tipos histológicos pudieron clasificarse en dos grupos teniendo en cuenta su comportamiento proliferativo, angiogénico e invasivo: uno constituido por carcinomas complejos, simples tubulares y de células escamosas, y el otro por carcinomas simples papilares, sólidos y anaplásicos y carcinosarcomas. A menor diferenciación histológica correspondieron mayores actividades proliferativa, invasiva y angiogénica. Con respecto a esta última, en neoplasias con mayor expresión del VEGFR-2, la densidad de microvasos y la proliferación fueron mayores. La mayor densidad de vasos favorece la invasión vascular. La presencia de émbolos, el grado histológico, el índice de proliferación, la expresión del VEGFR- 2 y la densidad de microvasos permitieron predecir la capacidad metastásica. El tipo histológico no se relacionó con la supervivencia de manera independiente. Los carcinosarcomas y los carcinomas simples anaplásicos presentaron mayor riesgo de metástasis que los carcinomas simples tubulares, complejos y de células escamosas. La probabilidad de supervivencia a 18 meses fue alta y estuvo influenciada por el estado del linfonódulo y la presencia de émbolos neoplásicos. / One hundred and thirty six canine mammary carcinomas and their satellite lymph nodes were studied. Proliferation and angiogenic activities were evaluated by means of immunohistochemical procedures. For the former, proliferating cell nuclear antigen was labelled. Vascular endothelial growth factor receptor-2 (VEGFR-2) expression and microvessel density were measured to estimate angiogenesis. Both processes were related and their influence on the status of the lymph nodes was investigated. An association was established between these characteristics and the histological type and grade, and the presence of neoplastic cells within tumor vessels. In order to determine their prognostic significance, these parameters were related to the lymph node status (defined after histopathological and immunohistochemical studies with anticytokeratin antibodies) and survival of a group of patients. According to their proliferative, angiogenic, and invasive behavior, histological types could be classified into two groups: one comprising complex, simple tubular, and squamous cell carcinomas, and the other comprising simple papillary, solid, and anaplastic carcinomas, and carcinosarcomas. A lower histological differentiation corresponded to higher proliferative, invasive, and angiogenic activities. Tumors with higher expression of VEGFR-2 exhibited more density of microvessels and higher proliferation rates. Vascular density favored vascular invasion. Metastatic potential could be predicted according to the presence of emboli, histological grade, proliferation index, expression of VEGFR-2, and density of microvessels. Independent correlation between histological type and survival was not found. Carcinosarcomas and simple anaplastic carcinomas presented a higher risk of metastasis than simple tubular, complex, or squamous cell carcinomas.Probability of survival at 18 months was high and was influenced by the status of the lymph node and the presence of neoplastic emboli.