Increased nuclear localization of transcription factor Y-box binding protein 1 accompanied by up-regulation of P-glycoprotein in breast cancer pretreated with paclitaxel.
Clin Cancer Res
; 11(24 Pt 1): 8837-44, 2005 Dec 15.
Article
em En
| MEDLINE
| ID: mdl-16361573
ABSTRACT
PURPOSE:
The Y-box binding protein 1 (YB-1) regulates expression of P-glycoprotein encoded by the MDR1 gene. There have been no previous studies regarding the involvement of YB-1 in the development of resistance to paclitaxel. The present study was done to examine how paclitaxel affects the localization and expression of YB-1 in breast cancer. EXPERIMENTALDESIGN:
We evaluated the expression and localization of YB-1 and P-glycoprotein in breast cancer tissues obtained from 27 patients before and after treatment with paclitaxel. The effect of paclitaxel on localization of cellular YB-1 was examined by using GFP-YB-1. Interaction of YB-1 with the Y-box motif of the MDR1 promoters was studied by electrophoretic mobility shift assay. The effects of paclitaxel on MDR1 promoter activity were examined by luciferase assay.RESULTS:
Of 27 breast cancer tissues treated with paclitaxel, nine (33%) showed translocation of YB-1 from the cytoplasm to the nucleus together with increased expression of P-glycoprotein during the course of treatment. Twelve breast cancer tissues (44%) showed neither translocation of YB-1 nor increased expression of P-glycoprotein. Nuclear translocation of YB-1 was correlated significantly with increased expression of P-glycoprotein (P=0.0037). Confocal analysis indicated that paclitaxel induced nuclear translocation of green fluorescent fused YB-1 in MCF7 cells. Furthermore, binding of YB-1 to the Y-box of MDR1 promoter was increased in response to treatment with paclitaxel. In addition, MDR1 promoter activity was significantly up-regulated by paclitaxel in MCF7 cells (P<0.001).CONCLUSIONS:
The results of the present study suggested that YB-1 may be involved in the development of resistance to paclitaxel in breast cancer.
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Base de dados:
MEDLINE
Assunto principal:
Neoplasias da Mama
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Núcleo Celular
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Paclitaxel
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Membro 1 da Subfamília B de Cassetes de Ligação de ATP
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Proteína 1 de Ligação a Y-Box
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Antineoplásicos Fitogênicos
Idioma:
En
Ano de publicação:
2005
Tipo de documento:
Article