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.
OBJECTIVE: Multidrug resistance (MDR) in humanB-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: Yo-Ting Tsai; Gerard Lozanski; Amy Lehman; Ellen J Sass; Erin Hertlein; Santosh B Salunke; Ching-Shih Chen; Michael R Grever; John C Byrd; David M Lucas Journal: Leuk Res Date: 2015-09-05 Impact factor: 3.156
Authors: K Morita; Y Masamoto; K Kataoka; J Koya; Y Kagoya; H Yashiroda; T Sato; S Murata; M Kurokawa Journal: Leukemia Date: 2015-06-08 Impact factor: 11.528
Authors: Amina Kariminia; Sabine M Ivison; Vivian M Leung; Susanna Sung; Nicole Couto; Jacob Rozmus; Nina Rolf; Aru Narendran; Sandra E Dunn; Gregor S D Reid; Kirk R Schultz Journal: Oncol Lett Date: 2016-11-28 Impact factor: 2.967
Authors: Sara Correia Marques; Maria Bach Laursen; Julie Støve Bødker; Malene Krag Kjeldsen; Steffen Falgreen; Alexander Schmitz; Martin Bøgsted; Hans Erik Johnsen; Karen Dybkaer Journal: Oncotarget Date: 2015-01-01