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Expression of Drug Resistance Genes in VP‐16 and mAMSA‐selected Human Carcinoma Cells

The cell lines described in the present study were isolated as part of an effort to understand resistance to topoisomerase (topo) II inhibitors. To that end, 50 sublines were isolated from four human breast cancer cell lines, i.e., MCF‐7, T47D, MDA‐MB‐231, and ZR‐75B. As an initial step, a concentra...

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Autores principales: Matsumoto, Yoshihito, Takano, Hiroshi, Kunishio, Katsuzo, Nagao, Seigo, Fojo, Tito
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Blackwell Publishing Ltd 2001
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5926780/
https://www.ncbi.nlm.nih.gov/pubmed/11473729
http://dx.doi.org/10.1111/j.1349-7006.2001.tb01161.x
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author Matsumoto, Yoshihito
Takano, Hiroshi
Kunishio, Katsuzo
Nagao, Seigo
Fojo, Tito
author_facet Matsumoto, Yoshihito
Takano, Hiroshi
Kunishio, Katsuzo
Nagao, Seigo
Fojo, Tito
author_sort Matsumoto, Yoshihito
collection PubMed
description The cell lines described in the present study were isolated as part of an effort to understand resistance to topoisomerase (topo) II inhibitors. To that end, 50 sublines were isolated from four human breast cancer cell lines, i.e., MCF‐7, T47D, MDA‐MB‐231, and ZR‐75B. As an initial step, a concentration that would be lethal to the majority of cells (IC99) was selected for both VP‐16 and mAMSA, for each cell line. The identification of an increasing number of putative drug resistance‐related proteins provided the opportunity to examine expression of the corresponding genes in the selected cell lines. Northern blot analysis revealed different responses to the selecting agents in the different cell lines. Previous studies examining expression of multidrug resistance (MDR)‐l in resistant cell lines had found undetectable levels in all cells. In the ZR‐75B sublines, increased expression of MDR‐associated protein (MRP) and canalicular multispecific organic anion transporter (cMOAT) was observed, and when the relative levels of overexpression were compared, a high correlation was found. In contrast, increased expression of MRP was observed in some of the MDA‐MB‐231 sublines, without a concomitant increase in cMOAT expression. Finally, in both T47D and MCF‐7 sublines, increased expression of cMOAT or MRP was observed infrequently, and where it occurred, was of a much smaller magnitude. In the analysis of expression of MRP, the highest levels were found in the ZR‐75B and MDA‐MB‐231 sublines, with lower levels in the MCF‐7 and T47D clones. Similarly, differences in the expression of topo IIα were observed among the sublines. Although the differences in expression appear to depend on the parental cell line from which the resistant sublines were derived, a strong correlation was observed between the expression of MRP and the levels of topo IIα. Cell lines with low levels of MRP had lower levels of topo IIα, while those with high levels of MRP maintained higher levels of topo IIα. While a reduced topo IIα level was common, there did not appear to be a compensating increase in the expression of topo IIβ or topo I or casein kinase (CK) IIα in any of the cell lines. While the possibility that such compensation could occur has been discussed and even reported in some cell lines, such an adaptation was not observed in the present study, suggesting that it is not common.
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spelling pubmed-59267802018-05-11 Expression of Drug Resistance Genes in VP‐16 and mAMSA‐selected Human Carcinoma Cells Matsumoto, Yoshihito Takano, Hiroshi Kunishio, Katsuzo Nagao, Seigo Fojo, Tito Jpn J Cancer Res Article The cell lines described in the present study were isolated as part of an effort to understand resistance to topoisomerase (topo) II inhibitors. To that end, 50 sublines were isolated from four human breast cancer cell lines, i.e., MCF‐7, T47D, MDA‐MB‐231, and ZR‐75B. As an initial step, a concentration that would be lethal to the majority of cells (IC99) was selected for both VP‐16 and mAMSA, for each cell line. The identification of an increasing number of putative drug resistance‐related proteins provided the opportunity to examine expression of the corresponding genes in the selected cell lines. Northern blot analysis revealed different responses to the selecting agents in the different cell lines. Previous studies examining expression of multidrug resistance (MDR)‐l in resistant cell lines had found undetectable levels in all cells. In the ZR‐75B sublines, increased expression of MDR‐associated protein (MRP) and canalicular multispecific organic anion transporter (cMOAT) was observed, and when the relative levels of overexpression were compared, a high correlation was found. In contrast, increased expression of MRP was observed in some of the MDA‐MB‐231 sublines, without a concomitant increase in cMOAT expression. Finally, in both T47D and MCF‐7 sublines, increased expression of cMOAT or MRP was observed infrequently, and where it occurred, was of a much smaller magnitude. In the analysis of expression of MRP, the highest levels were found in the ZR‐75B and MDA‐MB‐231 sublines, with lower levels in the MCF‐7 and T47D clones. Similarly, differences in the expression of topo IIα were observed among the sublines. Although the differences in expression appear to depend on the parental cell line from which the resistant sublines were derived, a strong correlation was observed between the expression of MRP and the levels of topo IIα. Cell lines with low levels of MRP had lower levels of topo IIα, while those with high levels of MRP maintained higher levels of topo IIα. While a reduced topo IIα level was common, there did not appear to be a compensating increase in the expression of topo IIβ or topo I or casein kinase (CK) IIα in any of the cell lines. While the possibility that such compensation could occur has been discussed and even reported in some cell lines, such an adaptation was not observed in the present study, suggesting that it is not common. Blackwell Publishing Ltd 2001-07 /pmc/articles/PMC5926780/ /pubmed/11473729 http://dx.doi.org/10.1111/j.1349-7006.2001.tb01161.x Text en
spellingShingle Article
Matsumoto, Yoshihito
Takano, Hiroshi
Kunishio, Katsuzo
Nagao, Seigo
Fojo, Tito
Expression of Drug Resistance Genes in VP‐16 and mAMSA‐selected Human Carcinoma Cells
title Expression of Drug Resistance Genes in VP‐16 and mAMSA‐selected Human Carcinoma Cells
title_full Expression of Drug Resistance Genes in VP‐16 and mAMSA‐selected Human Carcinoma Cells
title_fullStr Expression of Drug Resistance Genes in VP‐16 and mAMSA‐selected Human Carcinoma Cells
title_full_unstemmed Expression of Drug Resistance Genes in VP‐16 and mAMSA‐selected Human Carcinoma Cells
title_short Expression of Drug Resistance Genes in VP‐16 and mAMSA‐selected Human Carcinoma Cells
title_sort expression of drug resistance genes in vp‐16 and mamsa‐selected human carcinoma cells
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5926780/
https://www.ncbi.nlm.nih.gov/pubmed/11473729
http://dx.doi.org/10.1111/j.1349-7006.2001.tb01161.x
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