Upregulation of mdr1 gene is related to activation of the MAPK/ERK signal transduction pathway and YB-1 nuclear translocation in B-cell lymphoma.

Abstract

OBJECTIVE:

Multidrug resistance (MDR) in human B-cell lymphoma constitutes a major obstacle to the effectiveness of chemotherapy. The aim of this study was to investigate the molecular mechanism of MDR in B-cell lymphoma.

MATERIALS AND METHODS:

The B-cell lymphoma MDR sublines were developed by exposing the parental Daudi cells to stepwise increasing concentrations of doxorubicin. Interaction of Y-box binding protein-1 (YB-1) with the Y-box motif of the mdr1 gene promoters was studied by electrophoretic mobility shift assay. The effects of YB-1 on mdr1 promoter activity were examined by luciferase assay. After silencing of YB-1 gene by shRNA, the role of YB-1 nuclear translocation in the formation of induced MDR was examined. Expression of mdr1 and YB-1 was examined further after Daudi cells were pretreated with mitogen-activated protein kinase (MAPK) inhibitor PD98059 for 1 hour.

RESULTS:

Doxorubicin-resistant sublines was generated from the Daudi cell line by stepwise selection in doxorubicin. We found that acquisition of MDR is associated with enhanced YB-1 nuclear translocation and MAPK/extracellular signal-regulated kinase (ERK) activity. Electrophoretic mobility shift assay revealed that doxorubicin increased binding of YB-1 to the Y-box of mdr1 promoter. Luciferase reporter assays demonstrated that the Y-box region is essential for YB-1 regulation of mdr1 expression. The introduction of exogenous YB-1 shRNA into Daudi cells resulted in decreased levels of the expression of mdr1 gene and P-glycoprotein induced by doxorubicin. When Daudi cells were pretreated with MAPK inhibitor PD98059, the phosphorylation of ERK was effectively inhibited as well as the nuclear translocation of YB-1 and the expression of mdr1 gene.

CONCLUSION:

Doxorubicin can increase expression of mdr1/P-glycoprotein through activating MAPK/ERK transduction pathway, then increasing expression of YB-1, inducing YB-1 nuclear translocation, and enhancing DNA-binding activity of YB-1.

• Authors: Huiling Shen, Wenlin Xu, Wenjuan Luo, Leilei Zhou, Wei Yong, Fang Chen, Chaoyang Wu, Qiaoyun Chen, Xiao Han
• Journal: Experimental hematology (Exp Hematol) Vol. 39 Issue 5 Pg. 558-69 (May 2011) ISSN: 1873-2399 [Electronic] Netherlands
• PMID: 21300134 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2011 ISEH - Society for Hematology and Stem Cells. Published by Elsevier Inc. All rights reserved.

Chemical References

• ABCB1 protein, human
• ATP Binding Cassette Transporter, Subfamily B
• ATP Binding Cassette Transporter, Subfamily B, Member 1
• DNA-Binding Proteins
• Nuclear Proteins
• Y-Box-Binding Protein 1
• YBX1 protein, human
• Doxorubicin

Topics

• ATP Binding Cassette Transporter, Subfamily B
• ATP Binding Cassette Transporter, Subfamily B, Member 1 (genetics, metabolism)
• Cell Nucleus (drug effects, genetics, metabolism)
• DNA-Binding Proteins (genetics, metabolism)
• Doxorubicin (pharmacology)
• Humans
• Lymphoma, B-Cell (genetics, metabolism)
• MAP Kinase Signaling System (genetics)
• Nuclear Proteins (genetics, metabolism)
• Signal Transduction (genetics)
• Transfection
• Tumor Cells, Cultured
• Up-Regulation (genetics)
• Y-Box-Binding Protein 1