Molecular mechanisms of phytoestrogens Indole-3-carbinol and Genistein chemoprotective on the prostate in rats exposed to bisphenol A and subjected to hormonal carcinogenesis

Abstract

Gestational and lactational exposure, prostate development critical periods, to endocrine disruptors may increase the risk of prostate cancer (PCa) in adulthood. Bisphenol A (BPA) is a component of products based on epoxy resins and polycarbonate plastics and has been investigated for its probable carcinogenic activity for breast and prostate. Phytoestrogens such as indole-3-carbinol (I3C) and genistein (GEN), alone or synergistically, may increase the efficacy in the prevention of cancer through mechanisms such as the activation of apoptosis molecular signaling pathways and antiproliferative. The aim of this study is to evaluate the chemoprotective mechanisms of phytoestrogens (I3C and GEN) isolated and/or associated male rats from litters of dams exposed to BPA and subsequently subjected to a hormonal carcinogenic test. Pregnant dams from strain Fisher (n = 10) will be divided into 5 groups: G1: Control; G2: BPA (10 ¼g/Kg); G2: BPA (10¼g/Kg) + I3C (20mg/kg); G3: BPA (10¼g/Kg) + GEN (5mg/kg); G4: BPA (10¼g/Kg) + I3C + GEN, at the same doses the groups 3 and 4. The dams will be treated orally, by gavage, from the gestational day (GD) 17 until postnatal day (PND) 21. During the experiment, the animals will receive basal diet and filtered water ad libitum. The selected males (2/litter) will be euthanized in two moments: DPN22 and DPN240. At 90 days of age (DPN90) a capsule of testosterone and estradiol will be subcutaneously implanted in concentrations of 3ng/mL and 75pg/ml respectively. After euthanasia, the right ventral and dorsolateral prostate hemilobos will be used for histological analyzes after fixation in methacarn while left hemilobos will be frozen in liquid nitrogen for molecular analysis. Blood will be collected by the rupture of the cervical vessels for hormonal measurements. In DPN22, the pattern of development of the prostate will be assessed compared to different treatments focusing on rates of proliferation and cell death and inflammatory processes. In DPN240, fragments addressed to histopathological analyzes will be evaluated by standard methods and will also be held incidence and multiplicity of lesions. In DPN240 the gene expression will also be assessed by RT-qPCR and TaqMan Low Density Arrays (TLDA) for 96 genes expressed by prostate cells. The selected genes are related to the ways of maintenance, proliferation, death, stress and autophagy, and anti and proinflammatory interleukins. After identification of genes with altered expression, the study of protein expression will be done by Western Blot for the protein, target of major importance in these processes.