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Cooperative Effects of Akt-1 and Raf-1 on the Induction of Cellular Senescence in Doxorubicin or Tamoxifen Treated Breast Cancer Cells
Escape from cellular senescence induction is a potent mechanism for chemoresistance. Cellular senescence can be induced in breast cancer cell lines by the removal of estrogen signaling with tamoxifen or by the accumulation of DNA damage induced by the chemotherapeutic drug doxorubicin. Long term cul...
Autores principales: | , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Impact Journals LLC
2011
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3248208/ https://www.ncbi.nlm.nih.gov/pubmed/21881167 |
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author | Taylor, Jackson R. Lehmann, Brian D. Chappell, William H. Abrams, Stephen L. Steelman, Linda S. McCubrey, McCubrey |
author_facet | Taylor, Jackson R. Lehmann, Brian D. Chappell, William H. Abrams, Stephen L. Steelman, Linda S. McCubrey, McCubrey |
author_sort | Taylor, Jackson R. |
collection | PubMed |
description | Escape from cellular senescence induction is a potent mechanism for chemoresistance. Cellular senescence can be induced in breast cancer cell lines by the removal of estrogen signaling with tamoxifen or by the accumulation of DNA damage induced by the chemotherapeutic drug doxorubicin. Long term culturing of the hormone-sensitive breast cancer cell line MCF-7 in doxorubicin (MCF-7/DoxR) reduced the ability of doxorubicin, but not tamoxifen, to induce senescence. Two pathways that are often upregulated in chemo- and hormonal-resistance are the PI3K/PTEN/Akt/mTOR and Ras/Raf/MEK/ERK pathways. To determine if active Akt-1 and Raf-1 can influence drug-induced senescence, we stably introduced activated ΔAkt-1(CA) and ΔRaf-1(CA) into drug-sensitive and doxorubicin-resistant cells. Expression of a constitutively-active Raf-1 construct resulted in higher baseline senescence, indicating these cells possessed the ability to undergo oncogene-induced-senescence. Constitutive activation of the Akt pathway significantly decreased drug-induced senescence in response to doxorubicin but not tamoxifen in MCF-7 cells. However, constitutive Akt-1 activation in drug-resistant cells containing high levels of active ERK completely escaped cellular senescence induced by doxorubicin and tamoxifen. These results indicate that up regulation of the Ras/PI3K/PTEN/Akt/mTOR pathway in the presence of elevated Ras/Raf/MEK/ERK signaling together can contribute to drug-resistance by diminishing cell senescence in response to chemotherapy. Understanding how breast cancers containing certain oncogenic mutations escape cell senescence in response to chemotherapy and hormonal based therapies may provide insights into the design of more effective drug combinations for the treatment of breast cancer. |
format | Online Article Text |
id | pubmed-3248208 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2011 |
publisher | Impact Journals LLC |
record_format | MEDLINE/PubMed |
spelling | pubmed-32482082012-01-18 Cooperative Effects of Akt-1 and Raf-1 on the Induction of Cellular Senescence in Doxorubicin or Tamoxifen Treated Breast Cancer Cells Taylor, Jackson R. Lehmann, Brian D. Chappell, William H. Abrams, Stephen L. Steelman, Linda S. McCubrey, McCubrey Oncotarget Research Papers Escape from cellular senescence induction is a potent mechanism for chemoresistance. Cellular senescence can be induced in breast cancer cell lines by the removal of estrogen signaling with tamoxifen or by the accumulation of DNA damage induced by the chemotherapeutic drug doxorubicin. Long term culturing of the hormone-sensitive breast cancer cell line MCF-7 in doxorubicin (MCF-7/DoxR) reduced the ability of doxorubicin, but not tamoxifen, to induce senescence. Two pathways that are often upregulated in chemo- and hormonal-resistance are the PI3K/PTEN/Akt/mTOR and Ras/Raf/MEK/ERK pathways. To determine if active Akt-1 and Raf-1 can influence drug-induced senescence, we stably introduced activated ΔAkt-1(CA) and ΔRaf-1(CA) into drug-sensitive and doxorubicin-resistant cells. Expression of a constitutively-active Raf-1 construct resulted in higher baseline senescence, indicating these cells possessed the ability to undergo oncogene-induced-senescence. Constitutive activation of the Akt pathway significantly decreased drug-induced senescence in response to doxorubicin but not tamoxifen in MCF-7 cells. However, constitutive Akt-1 activation in drug-resistant cells containing high levels of active ERK completely escaped cellular senescence induced by doxorubicin and tamoxifen. These results indicate that up regulation of the Ras/PI3K/PTEN/Akt/mTOR pathway in the presence of elevated Ras/Raf/MEK/ERK signaling together can contribute to drug-resistance by diminishing cell senescence in response to chemotherapy. Understanding how breast cancers containing certain oncogenic mutations escape cell senescence in response to chemotherapy and hormonal based therapies may provide insights into the design of more effective drug combinations for the treatment of breast cancer. Impact Journals LLC 2011-08-30 /pmc/articles/PMC3248208/ /pubmed/21881167 Text en Copyright: © 2011 Taylor et al. http://creativecommons.org/licenses/by/2.5/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited |
spellingShingle | Research Papers Taylor, Jackson R. Lehmann, Brian D. Chappell, William H. Abrams, Stephen L. Steelman, Linda S. McCubrey, McCubrey Cooperative Effects of Akt-1 and Raf-1 on the Induction of Cellular Senescence in Doxorubicin or Tamoxifen Treated Breast Cancer Cells |
title | Cooperative Effects of Akt-1 and Raf-1 on the Induction of Cellular Senescence in Doxorubicin or Tamoxifen Treated Breast Cancer Cells |
title_full | Cooperative Effects of Akt-1 and Raf-1 on the Induction of Cellular Senescence in Doxorubicin or Tamoxifen Treated Breast Cancer Cells |
title_fullStr | Cooperative Effects of Akt-1 and Raf-1 on the Induction of Cellular Senescence in Doxorubicin or Tamoxifen Treated Breast Cancer Cells |
title_full_unstemmed | Cooperative Effects of Akt-1 and Raf-1 on the Induction of Cellular Senescence in Doxorubicin or Tamoxifen Treated Breast Cancer Cells |
title_short | Cooperative Effects of Akt-1 and Raf-1 on the Induction of Cellular Senescence in Doxorubicin or Tamoxifen Treated Breast Cancer Cells |
title_sort | cooperative effects of akt-1 and raf-1 on the induction of cellular senescence in doxorubicin or tamoxifen treated breast cancer cells |
topic | Research Papers |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3248208/ https://www.ncbi.nlm.nih.gov/pubmed/21881167 |
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