RESUMO
P-glycoprotein (Pgp) and breast cancer resistance protein (BCRP) are ATP binding cassette (ABC) transporters that are overexpressed in different drug-resistant cancer cell lines. In this study, we investigated whether doxorubicin promotes Pgp and/or BCRP expression to induce drug resistance in colon cancer cells under hypoxic conditions. We analyzed HIF-1α activity via ELISA, Pgp, and BCRP expression by qRT-PCR and the relationship between doxorubicin uptake and ABC transporter expression via confocal microscopy in HT-29WT and HT-29 doxorubicin-resistant colon cancer cells (HT-29DxR). These cells were treated with doxorubicin and/or CoCl2 (chemical hypoxia), and reactive oxygen species inductors. We found that the combination of chemically induced hypoxia and doxorubicin promoted Pgp mRNA expression within 24 h in HT-29WT and HT-29DxR cells. Both doxorubicin and CoCl2 alone or in combination induced Pgp and BCRP expression, as demonstrated via confocal microscopy in each of the above two cell lines. Thus, we surmised that Pgp and BCRP expression may result from synergistic effects exerted by the combination of doxorubicin-induced ROS production and HIF-1α activity under hypoxic conditions. However, HIF-1α activity disruption via the administration of E3330, an APE-1 inhibitor, downregulated Pgp expression and increased doxorubicin delivery to HT-29 cells, where it served as a substrate for Pgp, indicating the existence of an indirect relationship between Pgp expression and doxorubicin accumulation. Thus, we concluded that Pgp and BCRP expression can be regulated via cross-talk between doxorubicin and hypoxia, promoting drug resistance in HT-29 WT, and HT-29DxR cells and that this process may be ROS dependent. J. Cell. Biochem. 118: 1868-1878, 2017. © 2017 Wiley Periodicals, Inc.
Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Membro 2 da Subfamília G de Transportadores de Cassetes de Ligação de ATP/metabolismo , Hipóxia Celular/fisiologia , Neoplasias do Colo/metabolismo , Doxorrubicina/farmacologia , Proteínas de Neoplasias/metabolismo , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Membro 2 da Subfamília G de Transportadores de Cassetes de Ligação de ATP/genética , Hipóxia Celular/genética , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/genética , Neoplasias do Colo/genética , DNA Liase (Sítios Apurínicos ou Apirimidínicos)/genética , DNA Liase (Sítios Apurínicos ou Apirimidínicos)/metabolismo , Ensaio de Imunoadsorção Enzimática , Células HT29 , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Microscopia Confocal , Proteínas de Neoplasias/genética , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/genética , Espécies Reativas de Oxigênio/metabolismoRESUMO
Los sistemas educativos tradicionales han convertido a los estudiantes en entidades pasivas que guardan información transitoriamente, sin mayores capacidades para procesarla y aplicarla a la solución de situaciones de la vida diaria. La discusión generalizada entre los investigadores de la educación plantea la necesidad de cambiar las estrategias pedagógicas que han favorecido esas situaciones, para permitir una formación integral del individuo como ser capaz de razonar, crear, innovar y desarrollarse autónomamente. Las exigencias gubernamentales, institucionales e incluso las políticas de la globalización y el desarrollo del ser humano basado en la economía del conocimiento reclaman ese cambio de estrategias en el sistema pedagógico de enseñanza-aprendizaje; pues aunque éste se encuentre amenazado por la resistencia natural que ofrece el enfrentamiento con una cultura establecida, debe darse desde el aula de una manera inmediata. Como respuesta a esa necesidad, la Unidad de Bioquímica del Instituto de Ciencias Básicas de la Facultad de Medicina (Universidad del Rosario) plantea una estrategia no tradicional en pos del cambio.
Traditional educative systems, had convert students in passive recipient, who are keeping information without any possibility to process and apply it for the solution of daily problems. General discussion between educative researchers, had been establish the necessity to change the educative strategies that have been supporting those situations, looking for an integral education of the individual in terms of the capacity to argue, to create, to innovate, to develop by him self with independence. Governments, institutions and the politics requirements, that handle the globalization and the human development based in the knowledge economy, demand changes in the pedagogical system strategies in spite of the barriers from the traditional educative system. Responding to these necessity, the Biochemistry Department belong to the Basic Sciences Institute from the Medicine Faculty in the University of Rosario, is applying a different pedagogical strategy.
