CBP-dependent Wnt/β-catenin signaling is crucial in regulation of MDR1 transcription

Author(s): Zanxian Xia, Mingquan Guo, Han Liu, Luwei Jiang, Qiaoxia Li, Jian Peng, Jia-Da Li, Baoen Shan, Pinghui Feng, Hong Ma.

Journal Name: Current Cancer Drug Targets

Volume 15 , Issue 6 , 2015

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Abstract:

Aberrant expression of the MDR1-encoded P-glycoprotein (P-gp) is often associated with clinical multi-drug resistance (MDR) leading to poor prognosis and failure of chemotherapy. However, the precise and cooperative molecular mechanism responsible for MDR1 transcription and expression in acquired MDR remains elusive. We, herein, demonstrate that Wnt/β-catenin signal pathway is constitutively activated in Doxorubicin-induced MDR cancer cells, in which nuclear β -catenin specifically interacts with the transcriptional coactivator CBP in a MEK1/2/ERK1/2 signaldependent manner. Specific knockdown of both β-catenin and CBP by RNAi-mediated depletion abrogates MDR1 transcription and expression resulting in a complete reversal of P-gp-dependent efflux function and restoration of sensitivity to the Doxorubincin-induced cytotoxicity. Moreover, following pharmacological disruption of CBP and β - catenin interaction through inhibition of the MEK1/2/ERK1/2 signal by the specific inhibitor PD98059, MDR1 transcription and its encoded P-gp-dependent function are abolished. These findings conclude that the CBP/β-catenin complex is a core component of the MDR1 transcriptional “enhancesome”.

Keywords: CBP, Chromatin Immunoprecipitation, MDR1, p300, RNAi, Wnt/β-catenin.

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Article Details

VOLUME: 15
ISSUE: 6
Year: 2015
Page: [519 - 532]
Pages: 14
DOI: 10.2174/1568009615666150506093643
Price: $58

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