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Percorrer por autor "Carvalho, Tiago Miguel Amaral"

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  • The “ins and outs” of prostate metabolism towards carcinogenesis: the case of methoxychlor
    Publication . Carvalho, Tiago Miguel Amaral; Socorro, Sílvia Cristina da Cruz Marques; Vaz, Cátia Alexandra Vicente
    The last years have witnessed the emergence of metabolic reprogramming as a hallmark of cancer. The changes in cancer cell metabolism include, among others, a shift in glucose metabolism from oxidative phosphorylation to aerobic glycolysis, which culminates in an increased lactate production and acidification of microenvironment favoring tumor progression. We and others previous work have shown that steroid hormones play a relevant role driven the metabolic changes associated with development and progression of prostate cancer. Nevertheless, the panoply of metabolic (de)regulators linked with prostate cancer remains poorly known. Endocrine-disrupting chemicals are a group of compounds that interfere with the synthesis, secretion, and metabolism of natural hormones, which have also been implicated in carcinogenesis. Methoxychlor (MXC) is a chlorinated pesticide widely dispersed in the environment by its use in agricultural activities, and several reports have demonstrated its estrogenic properties. However, the MXC effects inducing metabolic alterations in prostate cells are largely unknown. This study aimed to analyze the effect of MXC on cell viability, apoptosis and glycolytic metabolism of neoplastic (LNCaP and PC3) and non-neoplastic (PNT1A) human prostate cells. For this purpose, LNCaP, PC3, and PNT1A cells were cultured in the presence or absence of a range of MXC concentrations (0, 0.1, 1, 10 and 100 µM) for 48 and 72 hours. MTT assays performed for all experimental conditions demonstrated that MXC diminished the viability of both neoplastic and non-neoplastic prostate cells in a time- and concentration-dependent manner. The 100 µM concentration and a treatment period of 48 hours were the conditions selected for evaluation of the effect of MXC on apoptosis and glycolytic metabolism of all cell lines under study. Protein expression and activity of target modulators of these biological processes were assessed by means of Western blot analysis and biochemical assays. The obtained results showed that MXC-treatment decreased the apoptotic rate of PNT1A cells, despite the observed decrease in cell proliferation. Curiously, in LNCaP- and PC3-treated cells MXC had an opposite effect increasing caspase-3 activity, the effector protein of apoptosis, and up-regulating the expression of apoptotic regulators. Regarding metabolism, measurement of glucose and lactate levels by spectrophotometric assays showed that MXC stimulated the glycolytic flux in both non-neoplastic and neoplastic human prostate cell lines, as indicated by the enhanced glucose consumption and lactate production. This metabolic response was underpinned by the increased expression of glucose transporters and activity of glycolytic enzymes. The present findings demonstrated that MXC may have a role in the development and progression of prostate cancer by suppressing apoptosis in non-neoplastic prostate epithelial cells and stimulating the glycolytic pathway in both non-neoplastic and neoplastic cells. Moreover, the evidence gathered herein highlights for the impact of MXC in other human diseases, such as diabetes, obesity, and infertility, since they are all associated with alterations in apoptosis and metabolism also.
    2017-10-26Dissertação de mestrado Acesso aberto Ver mais