2022-12-122022-12-122016-07-15Eskiler, G. G. vd. (2016). "An in vitro model for the development of acquired tamoxifen resistance". Cell Biology and Toxicology, 32(6), 563-581.0742-20911573-6822https://doi.org/10.1007/s10565-016-9355-8https://link.springer.com/article/10.1007/s10565-016-9355-8http://hdl.handle.net/11452/29828The development of resistance to tamoxifen (Tam) remains a challenging clinical problem for ER+ breast cancer patients. To understand the mechanisms underlying of resistance, previous studies have driven the acquisition of Tam resistance by exposing cells to varying concentration of drug for varying lengths of time. However, a detailed protocol for the establishment of Tam-resistant cells remains to be clarified. In the present study, we aimed to determine and compare the effect of different in vitro protocols on the degree of resistance to 4-hydroxytamoxifen (4-OH Tam) for MCF7 cells. For this purpose, MCF7-Tam resistance (MCF7-TamR) cells were developed by treated with different concentrations (100, 200, 400, 600, 800 and 1000 nM) of 4-OH Tam over 3 months. The relative resistance was measured by WST-1 analysis. Studies characterizing of the 4-OH Tam resistance of MCF7-TamR cells were performed by 17 beta-oestradiol (E2) and Annexin V/PI analysis. In addition, the expression levels of ABCC1, ABCG2 and ABCG1 were detected by RT-PCR, any changes in morphological of each resistance group were observed at the end of each month and compared with parental MCF7 cells. Consequently, exposure time and concentration can affect the degree of resistance to 4-OH Tam; thus, dose and treatment duration should be chosen according to the desired degree of resistance. This work presents a novel procedure for the generation of MCF7-TamR cells, thus enabling the identification and characterization of MCF7-TamR cells.eninfo:eu-repo/semantics/closedAccessCell biologyToxicologyBreast cancerTamoxifenDrug resistanceMCF7 cellsBreast-cancer cellsDrug-resistanceReceptorMechanismsApoptosisInductionExpressionLineE2f1Analysis of varianceAntigen peptide transporter-1ApoptosisCell shapeCell survivalDrug resistance, neoplasmEstradiolGene expression regulation, neoplasticHumansMCF-7 cellsModels, biologicalMultidrug resistance-associated proteinsP-glycoproteinsRNA, messengerTamoxifenArticle0003875952000082-s2.0-8498485099156358132627585693Cell biologyToxicologyBreast Neoplasms; Aromatase Inhibitors; Estrogen ReceptorsABC transporter G1AfimoxifeneBreast cancer resistance proteinEstradiolEstrogenLipocortin 5Multidrug resistance associated protein 1TamoxifenABCB1 protein, humanEstradiolMessenger RNAMultidrug resistance proteinMultidrug resistance-associated protein 1TamoxifenTAP1 protein, humanTransporter associated with antigen processing 1ApoptosisArticleCancer modelCancer resistanceCell structureConcentration responseControlled studyGene expression profilingHumanHuman cellIn vitro studyMCF-7 cell linePriority jourbiological modelnalProtein expressionReverse transcription polymerase chain reactionTreatment durationAnalysis of varianceBiological modelCell shapeCell survivalDrug resistanceGene expression regulationGeneticsMCF-7 cell lineMetabolismDrug effects