Nuclear and nucleolar image analysis of human breast epithelial cells transformed by benzo[a]pyrene and transfected with the c-Ha-ras oncogene

Changes in nuclear and nucleolar morphometric parameters were investigated by image analysis procedures in human breast MCF-10F epithelial cells expressing different stages of the tumourigenic progression after benzo[a]pyrene (BP) transformation (BP1, BP1-E, and BP1-E1 cell lines), and additionally transfected with the c-Ha-ras oncogene (BP1-Tras cell line). Nuclear pleomorphism was evident in all the transformed cells. The analysis of different morphometric parameters did not show a clear relationship between specific nuclear and nucleolar changes and the expression of the different stages of the tumourigenesis, with the exception of the nucleolar size, which could be associated to the expression of the tumourigenic phenotype, and a nucleolar area/nuclear area ratio, which discriminated,the immortalized, the transformed, and the tumourigenic phenotypes from one another. The nuclear morphometric data established for the BP-transformed cells and for the cells additionally transfected with the c-Ha-ras oncogene were suggestive of complex and distinct morphofunctional mechanisms. involving the in vitro transformation of the MCF-10F cells. The nuclear changes found in the BP1-Tras:cell line were assumed to be related to the additional effects and/or enhanced genomic instability induced by transfection with the ras oncogene.16419319

Apoptosis and catastrophic cell death in benzo[a]pyrene-transformed human breast epithelial cells

Apoptosis and mitotic death, bi- and multinucleation, giant cells and micronucleation were investigated in human breast epithelial cell lines transformed by benzo[a]pyrene (BP) (BP1, BP1-E and BP1-E1 cells) and in BP1 cells transfected with the c-aa-ras oncogene (BP1-Tras cells). Since BP induces apoptosis and the abnormal expression of ras genes elicits catastrophic mitosis, both cell death phenomena were expected to occur in this system, especially in BP1-Tras cells. Regardless of the cell line considered, single-nucleate cells were found to be eliminated preferentially through apoptosis, while bi- and multinucleate cells were eliminated through catastrophic mitosis. Apoptosis and catastrophic mitosis were observed in all cell lines but were significantly more frequent in BP1-Tras cells. The abnormal expression of Ha-ras in the latter cells may enhance in this system the effects of the BP apoptosis path reported for BP-transformed Hepa 1c1c7 hepatoma cells. Transfection with the ras oncogene also enhanced the mitotic disturbances, which produced multi- and micronucleation and mitotic death, possibly because of the genomic instability promoted by this oncogene in the BP-transformed cell line. (C) 1999 Elsevier Science B.V. All rights reserved.431113313

RNA relocation at mitosis in transformed and tumorigenic human breast epithelial cells

The fate of RNA revealed by metachromatic staining after a critical electrolyte concentration assay using toluidine blue and Mg2+ ions as competitors for the substrate dye binding sites was followed at mitosis in human breast epithelial cells transformed by benzo[a]pyrene and transfected with the c-Ha-ras oncogene. The aim was to detect changes in RNA distribution during mitosis in human transformed/tumorigenic cells exhibiting increased nucleolar sizes and rRNA production while in interphase. RNA relocation in association with the mitotic spindle fibers was observed from metaphase to telophase not to vary in all the cell lines studied. RNA-containing nucleolus-like bodies persistent during mitosis were found to decrease in frequency in the transformed and tumorigenic cells in comparison with control non-transformed cells simultaneously to the previously reported increase in nucleolar areas for the same cells while in interphase. It is suggested that an improved use of RNA transcripts has been developed with cell transformation and tumorigenesis in this particular model. (C) 1999 Academic Press.23212512

Reproductive effects in male rats exposed to diuron

Diuron is a ureic herbicide considered to have very low toxicity. The present study evaluated several aspects of reproductive toxicity of diuron in adult male rats. Diuron was diluted in corn oil and administered by oral gavage to groups of 18-20 rats at doses of 0, 125 or 250 mg/kg per day for 30 days; the control group received only the corn oil vehicle. At the end of the treatment period, approximately half the animals from each group were assigned to one of two terminal assessment lines: (1) reproductive organ, liver and kidney weights; measurement of diuron concentrations in liver and kidney; plasma testosterone determinations; evaluation of daily sperm production per testis; sperm number and sperm transit time in the epididymis; or (2) sexual behavior assessment during cohabitation with a receptive female; fertility and pregnancy outcome after natural mating; testicular, epididymal, kidney and liver histopathology; sperm morphology. After 30 days of oral diuron treatment, there were no treatment-related changes in body weights, but dose-related diuron residues were detected in the liver of all treated rats and absolute and relative liver weights were increased in both groups. There were no statistically significant differences between the treated and control groups obtained in plasma testosterone concentrations, or in parameters of daily sperm production, sperm reserves in the epididymis, sperm morphology or measured components of male sexual behavior. On the other hand, the number of fetuses in the litters from diuron-treated rats was slightly smaller than litters from control rats. Therefore, although the results did not indicate that diuron exposure resulted in direct male reproductive toxicity in the rat, they suggest that additional studies should be undertaken to investigate the possible effects on fertility and reproductive performance. (c) 2006 Elsevier Inc. All rights reserved.23110611

Assessment of Female Reproductive Endpoints in Sprague-Dawley Rats Developmentally Exposed to Diuron: Potential Ovary Toxicity

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)BACKGROUND: Diuron is widely used in agriculture but its deleterious effects on the reproductive system and mammary gland are still poorly understood. This study evaluated whether early-life-stage exposure to Diuron alters puberty onset or susceptibility to mammary carcinogenesis in female Sprague-Dawley rats. METHODS AND RESULTS: Pregnant rats received basal diet or diet containing Diuron at 500, 750, and 1,250 ppm, from gestational day 12 to the end of lactation (postnatal day 21 [PND21]). After weaning, female offspring continued receiving basal diet or diet containing Diuron until PND 51. At PND 51, female Sprague-Dawley offspring received a single dose of 50 mg/kg b.w. of 7,12-dimethylbenz(a) anthracene (DMBA) for initiation of mammary carcinogenesis. The animals were sacrificed on PND 51, 75, and 226 to 233 (week 25) for mammary gland morphology, reproductive organs and tumor analysis, respectively. There were no significant differences among groups on vaginal opening, estrous cycle, mammary morphology, or carcinogenesis. However, reductions in ovary weight and corpora lutea were observed at PND 75 in the group treated with Diuron at 1,250 ppm. CONCLUSIONS: The findings suggesting that Diuron exposure (1,250 ppm) may have been potentially toxic to the ovaries. Birth Defects Res (Part B) 92:478-486, 2011. (C) 2011 Wiley Periodicals, Inc.925SI478486Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP [2006/01330-0

Indole-3-carbinol attenuates the deleterious gestational effects of bisphenol A exposure on the prostate gland of male F1 rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Bisphenol A (BPA) is a chemical that has been investigated for it potential to cause prostate diseases. In this study, pregnant Sprague-Dawley rats were treated with 25 or 250 mu g/kg BPA from gestational day (GD) 10 to GD21 with or without concurrent indole-3-carbinol (I3C) feeding. I3C is a phytochemical, and it affords chemoprotection against many types of neoplasia. Male F1 rats from different litters were euthanized on post-natal day (PND) 21 and PND180. BPA-treated groups showed a significant increase in histopathological lesions, but I3C feeding reversed many of these changes, mainly at PND180. Maternal I3C feeding increased prostate epithelial apoptosis in the BPA-treated groups and across age groups. Furthermore, I3C induced partial normalization of the prostate histoarchitecture. The results pointed to a protective effect of maternal I3C feeding during pregnancy in the BPA-exposed male offspring, thereby indicating reduction in the harmful effects of gestational BPA imprinting on the prostate. (C) 2013 Elsevier Inc. All rights reserved.435666Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [2010/17262-0, 2011/01954-2, 2010/14110-4]CNPq [471646/2011-3