RESUMEN
Selenium (Se) is an essential micronutrient modulating several physiopathological processes in the human body. The aim of the study is to characterize the molecular effects determined by Se-supplementation in thyroid follicular cells, using as model the well-differentiated rat thyroid follicular cell line FRTL5. Experiments have been performed to evaluate the effects of Se on cell growth, mortality and proliferation and on modulation of pro- and antiapoptotic pathways. The results indicate that Se-supplementation improves FRTL5 growth rate. Furthermore, Se reduces the proportion of cell death and modulates both proapoptotic (p53 and Bim) and antiapoptotic (NF-kB and Bcl2) mRNA levels. In addition, incubation with high doses of Na-Se might prevent the ER-stress apoptosis induced by tunicamycin, as assessed by membrane integrity maintenance, reduction in caspase 3/7 activities, and reduction in Casp-3 and PARP cleavage. Taken together, these results provide molecular evidences indicating the role of Se supplementation on cell death and apoptosis modulation in thyroid follicular cells. These observations may be useful to understand the effects of this micronutrient on the physiopathology of the thyroid gland. © 2016 BioFactors, 43(3):415-423, 2017.
Asunto(s)
Apoptosis/efectos de los fármacos , Estrés del Retículo Endoplásmico/efectos de los fármacos , Regulación de la Expresión Génica/efectos de los fármacos , Selenio/farmacología , Células Epiteliales Tiroideas/efectos de los fármacos , Animales , Apoptosis/genética , Proteína 11 Similar a Bcl2/genética , Proteína 11 Similar a Bcl2/metabolismo , Caspasa 3/genética , Caspasa 3/metabolismo , Caspasa 7/genética , Caspasa 7/metabolismo , Línea Celular , Proliferación Celular/efectos de los fármacos , Estrés del Retículo Endoplásmico/genética , FN-kappa B/genética , FN-kappa B/metabolismo , Poli(ADP-Ribosa) Polimerasas/genética , Poli(ADP-Ribosa) Polimerasas/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2/genética , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Ratas , Transducción de Señal , Células Epiteliales Tiroideas/citología , Células Epiteliales Tiroideas/metabolismo , Proteína p53 Supresora de Tumor/genética , Proteína p53 Supresora de Tumor/metabolismo , Tunicamicina/farmacologíaRESUMEN
Oncolytic viruses represent a novel therapeutic approach for aggressive tumors, such as glioblastoma multiforme, which are resistant to available treatments. Autophagy has been observed in cells infected with oncolytic viruses; however, its role in cell death/survival is unclear. To elucidate the potential therapeutic use of autophagy modulators in association with viral therapy, we analyzed autophagy induction in human glioma cell lines U373MG and U87MG infected with the oncolytic adenovirus dl922-947. dl922-947 infection triggered an autophagic cellular response, as shown by the development of acidic vesicular organelles, LC3-IâLC3-II conversion, and reduction of p62 levels. However, on infection, the Akt/mTOR/p70s6k pathway, which negatively regulates autophagy, was activated, whereas the ERK1/2 pathway, a positive regulator of autophagy, was inhibited. Accordingly, MEK inhibition by PD98059 sensitized glioma cells to dl922-947 effects, whereas autophagy induction by rapamycin protected cells from dl922-947-induced death. Treatment with two inhibitors of autophagy, chloroquine and 3-methyladenine, increased the cytotoxic effects of dl922-947 in vitro. In vivo, the growth of U87MG-induced xenografts was further reduced by adding chloroquine to the dl922-947 treatment. In conclusion, autophagy acts as a survival response in glioma cells infected with dl922-947, thus suggesting autophagy inhibitors as adjuvant/neoadjuvant drugs in oncolytic virus-based treatments.