Avaliação do efeito carcinogênico do bromazepam em Drosophila melanogaster / Evaluation of carcinogen bromazepam effect in Drosophila melanogaster

Introdução: embora o câncer seja um dos maiores problemas de saúde pública enfrentados mundialmente, diversas substâncias presentes no meio, como os fármacos, não estão muito bem elucidadas sobre seu possível potencial carcinogênico. Entre eles, estão os benzodiazepínicos, fármacos que possuem crescente aumento do consumo desde o século XX e, principalmente, na segunda década do século XXI, por suas ações ansiolíticas, sedativas e anticonvulsivantes. Objetivo: avaliar o efeito carcinogênico do bromazepam por meio do teste para detecção de tumores epiteliais (ETT) em Drosophila melanogaster. Metodologia: para realização do ETT foram utilizadas duas linhagens mutantes de D. melanogaster: wts (fêmeas) e mwh (machos). As larvas descendentes desse cruzamento foram tratadas isoladamente com cinco concentrações de bromazepam, sendo elas: 0,0375; 0,075; 0,15; 0,30 e 0,60 mM. A Doxorrubicina foi utilizada como controle positivo e a água ultrapura como controle negativo. Após tratamento, coleta e armazenamento, as moscas foram analisadas, identificando-se as frequências tumorais, por região corporal, em cada concentração testada. Resultados: o bromazepam não apresentou efeito carcinogênico em nenhuma das concentrações experimentadas neste estudo, não havendo diferença estatisticamente significativa nas frequências tumorais observadas nos indivíduos tratados com bromazepam quando comparadas à frequência obtida nos indivíduos tratados com o controle negativo. Conclusão: Nas presentes condições experimentais, o bromazepam não apresentou atividade carcinogênica, no entanto, há a necessidade de novos estudos, com diferentes metodologias e diferentes organismos testes, para a maior compreensão da ação do bromazepam no organismo.

Introduction: although cancer is one of the biggest public health problems faced worldwide, several substances present in the environment, such as drugs are not very well understood about its possible carcinogenic potential. Among them are benzodiazepines, drugs that have increased their consumption since the 20th century and, mainly, in the second decade of the 21st century, due to their anxiolytic, sedative and anticonvulsant actions. Objective: Evaluate the carcinogenic effect of bromazepam through the test to detect epithelial tumor clones (ETT) in Drosophila melanogaster. Methodology: to perform the ETT, two mutant strains of D. melanogaster were used: wts (female) and mwh (male). The descending larves of this cross were treated separately with five concentrations of bromazepam, namely: 0.0375; 0.075; 0.15; 0.30 and 0.60 mM. Doxorubicin was used as a positive control and ultrapure water as a negative control. After treatment, collection and storage, the flies were analyzed, identifying the tumor frequencies, by body region, at each concentration tested. Results: bromazepam did not have a carcinogenic effect at any of the concentrations experienced in this study, with no statistically significant difference in tumor frequencies observed in individuals treated with bromazepam when compared to the frequency obtained in individuals treated with the negative control. Conclusion: In the present experimental conditions, bromazepam did not show carcinogenic activity, however, there is a need for further studies with different methodologies and different test organisms to better understand the action of bromazepam in the body.

Gastric Leptin and Tumorigenesis: Beyond Obesity.

Leptin, an adipocyte-derived hormone and its receptor (ObR) expressed in the hypothalamus are well known as an essential regulator of appetite and energy expenditure. Obesity induces abundant leptin production, however, reduced sensitivity to leptin leads to the development of metabolic disorders, so called leptin resistance. The stomach has been identified as an organ that simultaneously expresses leptin and ObR. Accumulating evidence has shown gastric leptin to perform diverse functions, such as those in nutrient absorption and carcinogenesis in the gastrointestinal system, independent of its well-known role in appetite regulation and obesity. Overexpression of leptin and phosphorylated ObR is implicated in gastric cancer in humans and in murine model, and diet-induced obesity causes precancerous lesions in the stomach in mice. While the underlying pathomechanisms remain unclear, leptin signaling can affect gastric mucosal milieu. In this review, we focus on the significant role of the gastric leptin signaling in neoplasia and tumorigenesis in stomach in the context of hereditary and diet-induced obesity.

Anti-oxidative, anti-tumor-promoting, and anti-carcinogensis activities of nitroastaxanthin and nitrolutein, the reaction products of astaxanthin and lutein with peroxynitrite.

Astaxanthin captured peroxynitrite to form nitroastaxanthins. 15-Nitroastaxanthin was a major reaction product of astaxanthin with peroxynitrite. Here, the anti-oxidative, anti-tumor-promoting, and anti-carcinogensis activities of 15-nitroastaxanthin were investigated. In addition to astaxanthin, 15-nitroastaxanthin showed excellent singlet oxygen quenching activity. Furthermore, 15-nitroastaxanthin showed inhibitory effects of in vitro Epstein-Barr virus early antigen activation and two-stage carcinogensis on mouse skin papillomas. These activities were slightly higher than those of astaxanthin. Similar results were obtained for the 15-nitrolutein, a major reaction product of lutein with peroxynitrite.