Anjos Vanessa Abelaira, Sandrini Juliana Zomer, Martinez Cláudia Bueno Reis, Souza Marta Marques
Programa de Pós-Graduação em Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande, Rio Grande, Rio Grande do Sul, Brazil.
Programa de Pós-Graduação em Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande, Rio Grande, Rio Grande do Sul, Brazil; Instituto de Ciências Biológicas, Universidade Federal do Rio Grande, Rio Grande, Rio Grande, do Sul, Brazil.
Comp Biochem Physiol C Toxicol Pharmacol. 2017 Nov;202:12-18. doi: 10.1016/j.cbpc.2017.07.003. Epub 2017 Jul 25.
Transmembrane proteins of the ABC family contribute to a multiple xenobiotic resistance (MXR) phenotype in cells, driving the extrusion of toxic substances. This phenotype promotes a high degree of protection against xenobiotics. The present study provides a better understanding of the MXR activity in the podal disk cells of Bunodosoma cangicum exposed to copper, and further establishes the relationship between protein activity (measured by accumulation of rhodamine-B) and bioaccumulation of copper in these cells. Sea anemone cells were exposed for 24h to copper (0, 7.8 and 15.6μg/L) in presence and absence of MXR blocker (verapamil 50μM). Results indicate that copper exposure increases intracellular metal content when ABC proteins were blocked, causing an increase in cellular death. The present study also verified the relationship between MXR activity, ATP depletion, and general metabolic activity (by MTT). MXR activity decreased in treatment groups exposed to copper concentrations of 15.6μg/L and 10mM energy depleting potassium cyanide. Metabolic activity increased in cells exposed to 7.8μgCu/L, but 15.6μgCu/L was similar to 0 and 7.8μg/L. The presence of copper decreased the ABC proteins expression. The present study improves the knowledge of MXR in anemone cells and shows that this activity is closely associated with copper extrusion. Also, the copper exposure is able to modify the metabolic state and to lead to cytotoxicity when cells cannot defend themselves.
ABC家族的跨膜蛋白有助于细胞产生多重异生素抗性（MXR）表型，推动有毒物质的排出。这种表型能提供高度的异生素防护。本研究能更好地理解暴露于铜的仓氏 Bunodosoma cangicum 足盘细胞中的MXR活性，并进一步确立了蛋白活性（通过罗丹明-B的积累来衡量）与这些细胞中铜生物积累之间的关系。海葵细胞在存在和不存在MXR阻断剂（50μM维拉帕米）的情况下，暴露于铜（0、7.8和15.6μg/L）24小时。结果表明，当ABC蛋白被阻断时，铜暴露会增加细胞内金属含量，导致细胞死亡增加。本研究还验证了MXR活性、ATP消耗和一般代谢活性（通过MTT）之间的关系。在暴露于15.6μg/L铜浓度和10mM能消耗能量的氰化钾的处理组中，MXR活性降低。暴露于7.8μg铜/L的细胞中代谢活性增加，但15.6μg/L与0和7.8μg/L相似。铜的存在会降低ABC蛋白的表达。本研究增进了对海葵细胞中MXR的了解，并表明这种活性与铜的排出密切相关。此外，当细胞无法自我防御时，铜暴露能够改变代谢状态并导致细胞毒性。
