Altered methylation of the human MDR1 promoter is associated with acquired multidrug resistance

Phillip Kantharidis, Assam El-Osta, Michelle DeSilva, Dominic M P Wall, Xiu F. Hu, Alison Slater, Gabriella Nadalin, John D. Parkin, John R. Zalcberg

Research output: Contribution to journalArticleResearchpeer-review

Abstract

One of the most important forms of drug resistance in acute myeloid leukemia is the multidrug resistance (MDR) phenotype, which is characterized by the expression of the MDR1 gene product, P-glycoprotein. Although a number of factors affect MDR1 gene expression, the genetic events that 'switch on' the human MDR1 gene in tumor cells that were previously P-glycoprotein negative have remained elusive. Here, we report evidence that the methylation status of the human MDR1 promoter may serve as a basis for this 'switch.' Based on Southern analysis using methylation-sensitive and methylation- insensitive restriction enzymes, a tight correlation was found between MDR phenotype and demethylation of the 5' region of the MDR1 gene in a human T cell leukemia cell line. Similar results were obtained from the analysis of P-glycoprotein-positive and P-glycoprotein-negative samples of chronic lymphocytic leukemia. Treatment of the cell lines with the demethylating agent 5'-azadeoxycytidine altered the methylation pattern of the MDR1 promoter in P-glycoprotein-negative cells to resemble that of P-glycoprotein- positive cells and activated the promoter such that MDR1 mRNA was now detectable. Treatment also resulted in an increased resistance to epirubicin and decreased daunomycin accumulation, both of which were reversible by verapamil, a characteristic of the classical MDR phenotype in cells expressing P-glycoprotein. These results suggest that the MDR phenotype may be acquired as a result of changes in methylation of the MDR1 promoter.

Original languageEnglish
Pages (from-to)2025-2032
Number of pages8
JournalClinical Cancer Research
Volume3
Issue number11
Publication statusPublished - Nov 1997
Externally publishedYes

Cite this

Kantharidis, Phillip ; El-Osta, Assam ; DeSilva, Michelle ; Wall, Dominic M P ; Hu, Xiu F. ; Slater, Alison ; Nadalin, Gabriella ; Parkin, John D. ; Zalcberg, John R. / Altered methylation of the human MDR1 promoter is associated with acquired multidrug resistance. In: Clinical Cancer Research. 1997 ; Vol. 3, No. 11. pp. 2025-2032.
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abstract = "One of the most important forms of drug resistance in acute myeloid leukemia is the multidrug resistance (MDR) phenotype, which is characterized by the expression of the MDR1 gene product, P-glycoprotein. Although a number of factors affect MDR1 gene expression, the genetic events that 'switch on' the human MDR1 gene in tumor cells that were previously P-glycoprotein negative have remained elusive. Here, we report evidence that the methylation status of the human MDR1 promoter may serve as a basis for this 'switch.' Based on Southern analysis using methylation-sensitive and methylation- insensitive restriction enzymes, a tight correlation was found between MDR phenotype and demethylation of the 5' region of the MDR1 gene in a human T cell leukemia cell line. Similar results were obtained from the analysis of P-glycoprotein-positive and P-glycoprotein-negative samples of chronic lymphocytic leukemia. Treatment of the cell lines with the demethylating agent 5'-azadeoxycytidine altered the methylation pattern of the MDR1 promoter in P-glycoprotein-negative cells to resemble that of P-glycoprotein- positive cells and activated the promoter such that MDR1 mRNA was now detectable. Treatment also resulted in an increased resistance to epirubicin and decreased daunomycin accumulation, both of which were reversible by verapamil, a characteristic of the classical MDR phenotype in cells expressing P-glycoprotein. These results suggest that the MDR phenotype may be acquired as a result of changes in methylation of the MDR1 promoter.",
author = "Phillip Kantharidis and Assam El-Osta and Michelle DeSilva and Wall, {Dominic M P} and Hu, {Xiu F.} and Alison Slater and Gabriella Nadalin and Parkin, {John D.} and Zalcberg, {John R.}",
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Kantharidis, P, El-Osta, A, DeSilva, M, Wall, DMP, Hu, XF, Slater, A, Nadalin, G, Parkin, JD & Zalcberg, JR 1997, 'Altered methylation of the human MDR1 promoter is associated with acquired multidrug resistance' Clinical Cancer Research, vol. 3, no. 11, pp. 2025-2032.

Altered methylation of the human MDR1 promoter is associated with acquired multidrug resistance. / Kantharidis, Phillip; El-Osta, Assam; DeSilva, Michelle; Wall, Dominic M P; Hu, Xiu F.; Slater, Alison; Nadalin, Gabriella; Parkin, John D.; Zalcberg, John R.

In: Clinical Cancer Research, Vol. 3, No. 11, 11.1997, p. 2025-2032.

Research output: Contribution to journalArticleResearchpeer-review

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T1 - Altered methylation of the human MDR1 promoter is associated with acquired multidrug resistance

AU - Kantharidis, Phillip

AU - El-Osta, Assam

AU - DeSilva, Michelle

AU - Wall, Dominic M P

AU - Hu, Xiu F.

AU - Slater, Alison

AU - Nadalin, Gabriella

AU - Parkin, John D.

AU - Zalcberg, John R.

PY - 1997/11

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N2 - One of the most important forms of drug resistance in acute myeloid leukemia is the multidrug resistance (MDR) phenotype, which is characterized by the expression of the MDR1 gene product, P-glycoprotein. Although a number of factors affect MDR1 gene expression, the genetic events that 'switch on' the human MDR1 gene in tumor cells that were previously P-glycoprotein negative have remained elusive. Here, we report evidence that the methylation status of the human MDR1 promoter may serve as a basis for this 'switch.' Based on Southern analysis using methylation-sensitive and methylation- insensitive restriction enzymes, a tight correlation was found between MDR phenotype and demethylation of the 5' region of the MDR1 gene in a human T cell leukemia cell line. Similar results were obtained from the analysis of P-glycoprotein-positive and P-glycoprotein-negative samples of chronic lymphocytic leukemia. Treatment of the cell lines with the demethylating agent 5'-azadeoxycytidine altered the methylation pattern of the MDR1 promoter in P-glycoprotein-negative cells to resemble that of P-glycoprotein- positive cells and activated the promoter such that MDR1 mRNA was now detectable. Treatment also resulted in an increased resistance to epirubicin and decreased daunomycin accumulation, both of which were reversible by verapamil, a characteristic of the classical MDR phenotype in cells expressing P-glycoprotein. These results suggest that the MDR phenotype may be acquired as a result of changes in methylation of the MDR1 promoter.

AB - One of the most important forms of drug resistance in acute myeloid leukemia is the multidrug resistance (MDR) phenotype, which is characterized by the expression of the MDR1 gene product, P-glycoprotein. Although a number of factors affect MDR1 gene expression, the genetic events that 'switch on' the human MDR1 gene in tumor cells that were previously P-glycoprotein negative have remained elusive. Here, we report evidence that the methylation status of the human MDR1 promoter may serve as a basis for this 'switch.' Based on Southern analysis using methylation-sensitive and methylation- insensitive restriction enzymes, a tight correlation was found between MDR phenotype and demethylation of the 5' region of the MDR1 gene in a human T cell leukemia cell line. Similar results were obtained from the analysis of P-glycoprotein-positive and P-glycoprotein-negative samples of chronic lymphocytic leukemia. Treatment of the cell lines with the demethylating agent 5'-azadeoxycytidine altered the methylation pattern of the MDR1 promoter in P-glycoprotein-negative cells to resemble that of P-glycoprotein- positive cells and activated the promoter such that MDR1 mRNA was now detectable. Treatment also resulted in an increased resistance to epirubicin and decreased daunomycin accumulation, both of which were reversible by verapamil, a characteristic of the classical MDR phenotype in cells expressing P-glycoprotein. These results suggest that the MDR phenotype may be acquired as a result of changes in methylation of the MDR1 promoter.

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SP - 2025

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JO - Clinical Cancer Research

JF - Clinical Cancer Research

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