Estrogen-mediated post transcriptional down-regulation of breast cancer resistance protein/ABCG2

Yasuo Imai, Etsuko Ishikawa, Sakiyo Asada, Yoshikazu Sugimoto

Research output: Contribution to journalArticle

129 Citations (Scopus)

Abstract

Breast cancer resistance protein (BCRP)/ABCG2 mediates concurrent resistance to chemotherapeutic agents, such as 7-ethyl-10-hydroxycamptothecin (SN-38), mitoxantrone, and topotecan, by pumping them out of cells. We previously reported that BCRP transports sulfated estrogens. In the present study, we show that at physiologic levels, estrogens markedly decrease endogenous BCRP expression in the estrogen-responsive and estrogen receptor α (ERα)-positive human breast cancer MCF-7 cells, but not in estrogen-nonresponsive human cancer cells. 17 β-Estradiol (E2) also significantly reduces exogenous BCRP expression, driven by a constitutive promoter, in BCRP-transduced estrogen-responsive and ERα-positive MCF-7 (MCF-7/BCRP) and T-47D cells, but not in BCRP-transduced estrogen-nonresponsive MDA-MB-231 and SKOV-3 cells. E2 potentiates the cytotoxicity of SN-38, but not vincristine, in MCF-7/BCRP cells significantly, and increases cellular topotecan uptake in MCF-7 and MCF-7/ BCRP cells. Antiestrogen tamoxifen partially reverses E2-mediated BCRP down-regulation in MCF-7 and MCF-7/ BCRP cells and treatment of MCF-7/BCRP cells with an ERα small interfering RNA abolished E2-mediated BCRP down-regulation, suggesting that interaction of E2 and ERα is necessary for BCRP down-regulation. E2 does not affect endogenous BCRP mRNA levels in MCF-7 cells or exogenous BCRP mRNA levels in MCF-7/BCRP cells. The results from pulse-chase labeling experiments with MCF-7/BCRP cells suggest that decreased protein biosynthesis and maturation, but not alterations in protein turnover, might underlie E2-mediated BCRP down-regulation. These data indicate that estrogen down-regulates BCRP expression by novel posttranscriptional mechanisms. This is the first report of small molecules that can affect BCRP protein expression in cells and may therefore assist in establishing new strategies for regulating BCRP expression.

Original languageEnglish
Pages (from-to)596-604
Number of pages9
JournalCancer Research
Volume65
Issue number2
Publication statusPublished - 2005 Jan 15

Fingerprint

Estrogens
Down-Regulation
Breast Neoplasms
Proteins
irinotecan
Estrogen Receptors
ATP Binding Cassette Transporter, Sub-Family G, Member 2
MCF-7 Cells
Topotecan
Mitoxantrone
Messenger RNA
Estrogen Receptor Modulators
Protein Biosynthesis
Vincristine
Protein Transport
Tamoxifen

ASJC Scopus subject areas

  • Cancer Research
  • Oncology

Cite this

Estrogen-mediated post transcriptional down-regulation of breast cancer resistance protein/ABCG2. / Imai, Yasuo; Ishikawa, Etsuko; Asada, Sakiyo; Sugimoto, Yoshikazu.

In: Cancer Research, Vol. 65, No. 2, 15.01.2005, p. 596-604.

Research output: Contribution to journalArticle

Imai, Yasuo ; Ishikawa, Etsuko ; Asada, Sakiyo ; Sugimoto, Yoshikazu. / Estrogen-mediated post transcriptional down-regulation of breast cancer resistance protein/ABCG2. In: Cancer Research. 2005 ; Vol. 65, No. 2. pp. 596-604.
@article{35cfd2087cb9494c9f8bd353ccb0224d,
title = "Estrogen-mediated post transcriptional down-regulation of breast cancer resistance protein/ABCG2",
abstract = "Breast cancer resistance protein (BCRP)/ABCG2 mediates concurrent resistance to chemotherapeutic agents, such as 7-ethyl-10-hydroxycamptothecin (SN-38), mitoxantrone, and topotecan, by pumping them out of cells. We previously reported that BCRP transports sulfated estrogens. In the present study, we show that at physiologic levels, estrogens markedly decrease endogenous BCRP expression in the estrogen-responsive and estrogen receptor α (ERα)-positive human breast cancer MCF-7 cells, but not in estrogen-nonresponsive human cancer cells. 17 β-Estradiol (E2) also significantly reduces exogenous BCRP expression, driven by a constitutive promoter, in BCRP-transduced estrogen-responsive and ERα-positive MCF-7 (MCF-7/BCRP) and T-47D cells, but not in BCRP-transduced estrogen-nonresponsive MDA-MB-231 and SKOV-3 cells. E2 potentiates the cytotoxicity of SN-38, but not vincristine, in MCF-7/BCRP cells significantly, and increases cellular topotecan uptake in MCF-7 and MCF-7/ BCRP cells. Antiestrogen tamoxifen partially reverses E2-mediated BCRP down-regulation in MCF-7 and MCF-7/ BCRP cells and treatment of MCF-7/BCRP cells with an ERα small interfering RNA abolished E2-mediated BCRP down-regulation, suggesting that interaction of E2 and ERα is necessary for BCRP down-regulation. E2 does not affect endogenous BCRP mRNA levels in MCF-7 cells or exogenous BCRP mRNA levels in MCF-7/BCRP cells. The results from pulse-chase labeling experiments with MCF-7/BCRP cells suggest that decreased protein biosynthesis and maturation, but not alterations in protein turnover, might underlie E2-mediated BCRP down-regulation. These data indicate that estrogen down-regulates BCRP expression by novel posttranscriptional mechanisms. This is the first report of small molecules that can affect BCRP protein expression in cells and may therefore assist in establishing new strategies for regulating BCRP expression.",
author = "Yasuo Imai and Etsuko Ishikawa and Sakiyo Asada and Yoshikazu Sugimoto",
year = "2005",
month = "1",
day = "15",
language = "English",
volume = "65",
pages = "596--604",
journal = "Cancer Research",
issn = "0008-5472",
publisher = "American Association for Cancer Research Inc.",
number = "2",

}

TY - JOUR

T1 - Estrogen-mediated post transcriptional down-regulation of breast cancer resistance protein/ABCG2

AU - Imai, Yasuo

AU - Ishikawa, Etsuko

AU - Asada, Sakiyo

AU - Sugimoto, Yoshikazu

PY - 2005/1/15

Y1 - 2005/1/15

N2 - Breast cancer resistance protein (BCRP)/ABCG2 mediates concurrent resistance to chemotherapeutic agents, such as 7-ethyl-10-hydroxycamptothecin (SN-38), mitoxantrone, and topotecan, by pumping them out of cells. We previously reported that BCRP transports sulfated estrogens. In the present study, we show that at physiologic levels, estrogens markedly decrease endogenous BCRP expression in the estrogen-responsive and estrogen receptor α (ERα)-positive human breast cancer MCF-7 cells, but not in estrogen-nonresponsive human cancer cells. 17 β-Estradiol (E2) also significantly reduces exogenous BCRP expression, driven by a constitutive promoter, in BCRP-transduced estrogen-responsive and ERα-positive MCF-7 (MCF-7/BCRP) and T-47D cells, but not in BCRP-transduced estrogen-nonresponsive MDA-MB-231 and SKOV-3 cells. E2 potentiates the cytotoxicity of SN-38, but not vincristine, in MCF-7/BCRP cells significantly, and increases cellular topotecan uptake in MCF-7 and MCF-7/ BCRP cells. Antiestrogen tamoxifen partially reverses E2-mediated BCRP down-regulation in MCF-7 and MCF-7/ BCRP cells and treatment of MCF-7/BCRP cells with an ERα small interfering RNA abolished E2-mediated BCRP down-regulation, suggesting that interaction of E2 and ERα is necessary for BCRP down-regulation. E2 does not affect endogenous BCRP mRNA levels in MCF-7 cells or exogenous BCRP mRNA levels in MCF-7/BCRP cells. The results from pulse-chase labeling experiments with MCF-7/BCRP cells suggest that decreased protein biosynthesis and maturation, but not alterations in protein turnover, might underlie E2-mediated BCRP down-regulation. These data indicate that estrogen down-regulates BCRP expression by novel posttranscriptional mechanisms. This is the first report of small molecules that can affect BCRP protein expression in cells and may therefore assist in establishing new strategies for regulating BCRP expression.

AB - Breast cancer resistance protein (BCRP)/ABCG2 mediates concurrent resistance to chemotherapeutic agents, such as 7-ethyl-10-hydroxycamptothecin (SN-38), mitoxantrone, and topotecan, by pumping them out of cells. We previously reported that BCRP transports sulfated estrogens. In the present study, we show that at physiologic levels, estrogens markedly decrease endogenous BCRP expression in the estrogen-responsive and estrogen receptor α (ERα)-positive human breast cancer MCF-7 cells, but not in estrogen-nonresponsive human cancer cells. 17 β-Estradiol (E2) also significantly reduces exogenous BCRP expression, driven by a constitutive promoter, in BCRP-transduced estrogen-responsive and ERα-positive MCF-7 (MCF-7/BCRP) and T-47D cells, but not in BCRP-transduced estrogen-nonresponsive MDA-MB-231 and SKOV-3 cells. E2 potentiates the cytotoxicity of SN-38, but not vincristine, in MCF-7/BCRP cells significantly, and increases cellular topotecan uptake in MCF-7 and MCF-7/ BCRP cells. Antiestrogen tamoxifen partially reverses E2-mediated BCRP down-regulation in MCF-7 and MCF-7/ BCRP cells and treatment of MCF-7/BCRP cells with an ERα small interfering RNA abolished E2-mediated BCRP down-regulation, suggesting that interaction of E2 and ERα is necessary for BCRP down-regulation. E2 does not affect endogenous BCRP mRNA levels in MCF-7 cells or exogenous BCRP mRNA levels in MCF-7/BCRP cells. The results from pulse-chase labeling experiments with MCF-7/BCRP cells suggest that decreased protein biosynthesis and maturation, but not alterations in protein turnover, might underlie E2-mediated BCRP down-regulation. These data indicate that estrogen down-regulates BCRP expression by novel posttranscriptional mechanisms. This is the first report of small molecules that can affect BCRP protein expression in cells and may therefore assist in establishing new strategies for regulating BCRP expression.

UR - http://www.scopus.com/inward/record.url?scp=12544251673&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=12544251673&partnerID=8YFLogxK

M3 - Article

C2 - 15695404

AN - SCOPUS:12544251673

VL - 65

SP - 596

EP - 604

JO - Cancer Research

JF - Cancer Research

SN - 0008-5472

IS - 2

ER -