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The Serine Protease Inhibitor Elafin Maintains Normal Growth Control by Opposing the Mitogenic Effects of Neutrophil Elastase
The serine protease inhibitor, elafin, is a critical component of the epithelial barrier against neutrophil elastase (NE). Elafin is downregulated in the majority of breast cancer cell lines compared to normal human mammary epithelial cells (HMECs). Here, we evaluated the role of elafin and NE on pr...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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2014
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4362782/ https://www.ncbi.nlm.nih.gov/pubmed/25195861 http://dx.doi.org/10.1038/onc.2014.284 |
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author | Caruso, Joseph A. Akli, Said Pageon, Laura Hunt, Kelly K. Keyomarsi, Khandan |
author_facet | Caruso, Joseph A. Akli, Said Pageon, Laura Hunt, Kelly K. Keyomarsi, Khandan |
author_sort | Caruso, Joseph A. |
collection | PubMed |
description | The serine protease inhibitor, elafin, is a critical component of the epithelial barrier against neutrophil elastase (NE). Elafin is downregulated in the majority of breast cancer cell lines compared to normal human mammary epithelial cells (HMECs). Here, we evaluated the role of elafin and NE on proliferation and tumorigenesis. Elafin is induced in growth factor deprived HMECs as they enter a quiescent (G0) state, suggesting that elafin is a counterbalance against the mitogenic effects of NE in G0 HMECs. Stable knockdown of elafin compromises the ability of HMECs to maintain G0-arrest during long-term growth factor deprivation; this effect can be reversed by re-expression of wild-type elafin, but not elafin-M25G lacking protease inhibitory function. These results suggest that NE, which is largely contributed by activated neutrophils in the tumor microenvironment, may be negatively regulating the ability of elafin to arrest cells in G0. In fact when purified NE was added to elafin knockdown HMECs, these cells demonstrated greater sensitivity to the growth promoting effects of purified NE. Activation of ERK signaling, downstream of toll-like receptor 4, was essential to the mitogenic effect of NE on HMECs. These findings were next translated to patient samples, and immunohistochemical analysis of normal breast tissue revealed robust elafin expression in the mammary epithelium; however, elafin expression was dramatically downregulated in a significant proportion of human breast tumor specimens. The loss of elafin expression during breast cancer progression may promote tumor growth as a consequence of increased NE-activity. To address the role of NE in mammary tumorigenesis, we next examined if deregulated NE-activity enhances mammary tumor growth. NE knockout in the C3(1)TAg mouse model of mammary tumorigenesis suppressed proliferation and reduced the kinetics of tumor growth. Overall, the imbalance between NE and its inhibitors, such as elafin, presents an important therapeutic target in breast cancer. |
format | Online Article Text |
id | pubmed-4362782 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2014 |
record_format | MEDLINE/PubMed |
spelling | pubmed-43627822016-01-01 The Serine Protease Inhibitor Elafin Maintains Normal Growth Control by Opposing the Mitogenic Effects of Neutrophil Elastase Caruso, Joseph A. Akli, Said Pageon, Laura Hunt, Kelly K. Keyomarsi, Khandan Oncogene Article The serine protease inhibitor, elafin, is a critical component of the epithelial barrier against neutrophil elastase (NE). Elafin is downregulated in the majority of breast cancer cell lines compared to normal human mammary epithelial cells (HMECs). Here, we evaluated the role of elafin and NE on proliferation and tumorigenesis. Elafin is induced in growth factor deprived HMECs as they enter a quiescent (G0) state, suggesting that elafin is a counterbalance against the mitogenic effects of NE in G0 HMECs. Stable knockdown of elafin compromises the ability of HMECs to maintain G0-arrest during long-term growth factor deprivation; this effect can be reversed by re-expression of wild-type elafin, but not elafin-M25G lacking protease inhibitory function. These results suggest that NE, which is largely contributed by activated neutrophils in the tumor microenvironment, may be negatively regulating the ability of elafin to arrest cells in G0. In fact when purified NE was added to elafin knockdown HMECs, these cells demonstrated greater sensitivity to the growth promoting effects of purified NE. Activation of ERK signaling, downstream of toll-like receptor 4, was essential to the mitogenic effect of NE on HMECs. These findings were next translated to patient samples, and immunohistochemical analysis of normal breast tissue revealed robust elafin expression in the mammary epithelium; however, elafin expression was dramatically downregulated in a significant proportion of human breast tumor specimens. The loss of elafin expression during breast cancer progression may promote tumor growth as a consequence of increased NE-activity. To address the role of NE in mammary tumorigenesis, we next examined if deregulated NE-activity enhances mammary tumor growth. NE knockout in the C3(1)TAg mouse model of mammary tumorigenesis suppressed proliferation and reduced the kinetics of tumor growth. Overall, the imbalance between NE and its inhibitors, such as elafin, presents an important therapeutic target in breast cancer. 2014-09-08 2015-07 /pmc/articles/PMC4362782/ /pubmed/25195861 http://dx.doi.org/10.1038/onc.2014.284 Text en http://www.nature.com/authors/editorial_policies/license.html#terms Users may view, print, copy, and download text and data-mine the content in such documents, for the purposes of academic research, subject always to the full Conditions of use:http://www.nature.com/authors/editorial_policies/license.html#terms |
spellingShingle | Article Caruso, Joseph A. Akli, Said Pageon, Laura Hunt, Kelly K. Keyomarsi, Khandan The Serine Protease Inhibitor Elafin Maintains Normal Growth Control by Opposing the Mitogenic Effects of Neutrophil Elastase |
title | The Serine Protease Inhibitor Elafin Maintains Normal Growth Control by Opposing the Mitogenic Effects of Neutrophil Elastase |
title_full | The Serine Protease Inhibitor Elafin Maintains Normal Growth Control by Opposing the Mitogenic Effects of Neutrophil Elastase |
title_fullStr | The Serine Protease Inhibitor Elafin Maintains Normal Growth Control by Opposing the Mitogenic Effects of Neutrophil Elastase |
title_full_unstemmed | The Serine Protease Inhibitor Elafin Maintains Normal Growth Control by Opposing the Mitogenic Effects of Neutrophil Elastase |
title_short | The Serine Protease Inhibitor Elafin Maintains Normal Growth Control by Opposing the Mitogenic Effects of Neutrophil Elastase |
title_sort | serine protease inhibitor elafin maintains normal growth control by opposing the mitogenic effects of neutrophil elastase |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4362782/ https://www.ncbi.nlm.nih.gov/pubmed/25195861 http://dx.doi.org/10.1038/onc.2014.284 |
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