Article

Abnormal expression of bcl-2 and bax in rat tongue mucosa during the development of squamous cell carcinoma induced by 4-nitroquinoline 1-oxide.

Department of Pathology, Center for Genotoxins and Carcinogens Evaluation, TOXICAN, Botucatu Medical School, UNESP, SP, Brazil.
International Journal of Experimental Pathology (Impact Factor: 2.05). 12/2005; 86(6):375-81. DOI: 10.1111/j.0959-9673.2005.00444.x
Source: PubMed

ABSTRACT 4-Nitroquinoline 1-oxide (4NQO)-induced rat tongue carcinogenesis is a useful model for studying oral squamous cell carcinoma. The aim of this study was to investigate the expression of bcl-2 and bax during tongue carcinogenesis induced by 4NQO. Male Wistar rats were distributed into three groups of 10 animals each and treated with 50 ppm 4NQO solution through their drinking water for 4, 12 or 20 weeks. Ten animals were used as negative control. Although no histological changes were induced in the epithelium after 4 weeks of carcinogen exposure, bcl-2 and bax were over-expressed (P < 0.01) in all layers of the 'normal' epithelium. The expression levels were the same in all layers of epithelium for both the antibodies used (bcl-2 or bax). In dysplastic lesions at 12 weeks following carcinogen administration, the levels of bcl-2 and bax expression did not increase when compared to negative control with the immunoreactivity for bcl-2 being restricted to the superficial layer of epithelium. In well-differentiated squamous cell carcinoma induced after 20 weeks of treatment with 4NQO, bcl-2 was expressed in some cells of tumour islands. On the other hand, immunostaining for bax was widely observed at the tumour nests. The labelling index for bcl-2 and bax showed an increase (P < 0.05) after only 4 weeks of 4NQO administration. In conclusion, our results suggest that abnormalities in the apoptosis pathways are associated with the development of persistent clones of mutated-epithelial cells in the oral mucosa. Bcl-2 and bax expression appears to be associated with a risk factor in the progression of oral cancer.

0 Bookmarks
 · 
90 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The goal of this study was to investigate the expression of some metalloendopeptidases in squamous cell carcinomas of the oropharynx as well as its relation to histological differentiation, staging of disease, and prognosis. Paraffin blocks from 21 primary tumors were obtained from archives of the Department of Pathology, Paulista Medical School, Federal University of Sao Paulo, UNIFESP/EPM. Immunohistochemistry was used to detect the expression of EP24.15 and EP24.16 by means of tissue microarrays. Expression of EP24.15 or EP24.16 was not correlated with the stage of disease, histopathological grading or recurrence in squamous cell carcinomas of the oropharynx. In summary, our results support the notion that EP24.15 and EP24.16 are expressed in carcinoma of the oropharynx; however, these do not appear to be suitable biomarkers for histological grading, disease stage or recurrence as depicted by tissue microarrays and immunohistochemistry. Head and neck neoplasms are the sixth most common type of cancer worldwide (1). About 90% of these tumors are squamous cell carcinoma (SCC) and the oropharynx is a site commonly involved (2). This neoplasm arises from accumulated damage to genes that control cellular proliferation, invasion, motility and survival (3). These genetic alterations most often occur as the result of exposure to tobacco, alcohol and other carcinogens. In particular, prolonged exposure to these agents results in irreversible damage to the DNA of the oropharyngeal mucosa which leads to alterations in the coding and regulatory regions of cell cycle regulatory genes. To date, a few studies have demonstrated the expression of such genes in SCC of the oropharynx, especially
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: SUMMARY Odontogenic myxoma is a rare benign neoplasm occurring in the jaws. Microscopically, it is composed of spindle or stellate- shaped cells arranged in a mucinous matrix. In some cases (20%), odontogenic epithelial islands may be found. The Authors evaluated p53, MIB-1, and Bcl-2 expressed by the epithelial and stromal elements in 12 cases of odontogenic myxoma of the jaws. The cells of the odontogenic epithelium were positive for Bcl-2, p53 and MIB-1. The stromal cell showed a high positiv- ity for MIB-1. Proliferation of both the epithelial and stromal components could be related to the growth of this odontogenic tumour.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The aim of this study was to evaluate overall genetic damage induced by total sleep deprivation in obese, female Zucker rats of differing ages. Lean and obese Zucker rats at 3, 6, and 15 months old were randomly distributed into two groups for each age group: home-cage control and sleep-deprived (N = 5/group). The sleep-deprived groups were deprived sleep by gentle handling for 6 hours, whereas the home-cage control group was allowed to remain undisturbed in their home-cage. At the end of the sleep deprivation period, or after an equivalent amount of time for the home-cage control groups, the rats were brought to an adjacent room and decapitated. The blood, brain, and liver tissue were collected and stored individually to evaluate DNA damage. Significant genetic damage was observed only in 15-month-old rats. Genetic damage was present in the liver cells from sleep-deprived obese rats compared with lean rats in the same condition. Sleep deprivation was associated with genetic damage in brain cells regardless of obesity status. DNA damage was observed in the peripheral blood cells regardless of sleep condition or obesity status. Taken together, these results suggest that obesity was associated with genetic damage in liver cells, whereas sleep deprivation was associated with DNA damage in brain cells. These results also indicate that there is no synergistic effect of these noxious conditions on the overall level of genetic damage. In addition, the level of DNA damage was significantly higher in 15-month-old rats compared to younger rats.
    Clinics (São Paulo, Brazil) 03/2013; 68(3):385-9. · 1.59 Impact Factor

Full-text (2 Sources)

Download
13 Downloads
Available from
May 30, 2014