To characterize the role of BRCA1 in mammary gland development and tumor suppression, a transgenic mouse model of BRCA1 overexpression was developed. Using the mouse mammary tumor virus (MMTV) promoter/enhancer, transgenic mice expressing human BRCA1 or select mutant controls were generated. Transgenic animals examined during adolescence were shown to express the human transgene in their mammar...

Pulmonary metastases in C3H/He mice bearing spontaneous mammary tumors were detected and characterized by histological criteria and immunocytochemical staining for mouse mammary tumor virus antigens. The same lungs containing metastases were also positive when assayed for a specific subset of mouse mammary tumor virus proviral DNA sequences. These sequences, termed tumor-associated sequences, h...

Mus musculus subsp. musculus (Czech II) mammary tumor DNA frequently contains an integrated proviral genome of the mouse mammary tumor virus (MMTV) within a specific 0.5-kilobase-pair region of the cellular genome (designated int-3). Viral integration at this site results in activation of expression of an adjacent cellular gene. We mapped int-3 to mouse chromosome 17 by analysis of PstI-restric...

The effect of 1,3,5(i 0)-estratriene-3,1 6a,i 7f@-triol(estriol), i ,3,5(i O)-estratriene-2,3-diol-i 7-one (2-hydroxyestrone), and 1,3,5(i 0)-estratriene-2,3,i 7$-triol (2-hydroxyestradiol) on the growth of dirnethylbenz(a)anthracene-induced mammary tumor and of R3230AC-transplantable mammary tumor was corn pared with that produced by estradiol benzoate treatment. Estriol showed minimal inhibit...

A comparisonof the transferRNA(tRNA)methyltransferases from rat mammary gland and mammary tumors was carried out to explore possible tumor-specific differences in enzyme activ ity, substrate specificity, and capacity to methylatebacterial tRNA substrates. Enzymes from 9,10-dimethyl-1,2-benzan thracene-induced mammary tumors had specific activities 2to 3-fold higher than those from normal mammar...

Type 2 diabetes increases breast cancer risk and mortality, and hyperinsulinemia is a major mediator of this effect. The mammalian target of rapamycin (mTOR) is activated by insulin and is a key regulator of mammary tumor progression. Pharmacological mTOR inhibition suppresses tumor growth in numerous mammary tumor models in the non-diabetic setting. However, the role of the mTOR pathway in typ...

The tumorigenicity of dexamethasone-treated tissue-cultured mammary tumor cells was compared to that of untreated mammary tumor cells. The dexamethasone-induced cells progressed faster in normal syngeneic animals than did untreated mammary tumor cells. The fact that the growth rate differential was also observed in athymic mice suggests that T-lymphocyte-mediated immunity was not a factor in t...

Following subcutaneous inoculation of newborn Wistar-Furth rats with human adenovirus type 9 (Ad9), 16 of 16 female and 0 of 11 male rats developed mammary tumors. Tumor-positive animals usually developed tumors in multiple glands. Histopathological analyses indicated that three general categories of tumor could be identified. Mammary fibroadenomas were the most common tumor type encountered, b...

Administration of kefir and a kefir cell-free fraction (KF) to mice injected with breast tumor cells produced, locally in the mammary gland, different profiles of cells secreting cytokines. Here, the immune cell populations in mammary glands affected by the cyclic consumption of kefir or KF for 2 or 7 d were evaluated using a breast tumor model. Apoptosis was also assayed as another mechanism i...

The effect of 1,3,5(10)-estratriene-3, 16 alpha, 17 beta-triol (estriol), 1, 3, 5(10)-estratriene-2,3-diol-17-one (2-hydroxyestrone), and 1,3,5(10)-estratriene-2,3,17 beta-triol (2-hydroxyestradiol) on the growth of dimethylbenz(a)anthracene-induced mammary tumor and of R3230AC-transplantable mammary tumor was compared with that produced by estradiol benzoate treatment. Estriol showed minimal i...