Collagen density promotes mammary tumor initiation and progression

<p>Abstract</p> <p>Background</p> <p>Mammographically dense breast tissue is one of the greatest risk factors for developing breast carcinoma. Despite the strong clinical correlation, breast density has not been causally linked to tumorigenesis, largely because no anima...

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Main Authors: Knittel Justin G, Eliceiri Kevin W, Inman David R, Provenzano Paolo P, Yan Long, Rueden Curtis T, White John G, Keely Patricia J
Format: Article
Language:English
Published: BMC 2008-04-01
Series:BMC Medicine
Online Access:http://www.biomedcentral.com/1741-7015/6/11
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author Knittel Justin G
Eliceiri Kevin W
Inman David R
Provenzano Paolo P
Yan Long
Rueden Curtis T
White John G
Keely Patricia J
author_facet Knittel Justin G
Eliceiri Kevin W
Inman David R
Provenzano Paolo P
Yan Long
Rueden Curtis T
White John G
Keely Patricia J
author_sort Knittel Justin G
collection DOAJ
description <p>Abstract</p> <p>Background</p> <p>Mammographically dense breast tissue is one of the greatest risk factors for developing breast carcinoma. Despite the strong clinical correlation, breast density has not been causally linked to tumorigenesis, largely because no animal model has existed for studying breast tissue density. Importantly, regions of high breast density are associated with increased stromal collagen. Thus, the influence of the extracellular matrix on breast carcinoma development and the underlying molecular mechanisms are not understood.</p> <p>Methods</p> <p>To study the effects of collagen density on mammary tumor formation and progression, we utilized a bi-transgenic tumor model with increased stromal collagen in mouse mammary tissue. Imaging of the tumors and tumor-stromal interface in live tumor tissue was performed with multiphoton laser-scanning microscopy to generate multiphoton excitation and spectrally resolved fluorescent lifetimes of endogenous fluorophores. Second harmonic generation was utilized to image stromal collagen.</p> <p>Results</p> <p>Herein we demonstrate that increased stromal collagen in mouse mammary tissue significantly increases tumor formation approximately three-fold (<it>p </it>< 0.00001) and results in a significantly more invasive phenotype with approximately three times more lung metastasis (<it>p </it>< 0.05). Furthermore, the increased invasive phenotype of tumor cells that arose within collagen-dense mammary tissues remains after tumor explants are cultured within reconstituted three-dimensional collagen gels. To better understand this behavior we imaged live tumors using nonlinear optical imaging approaches to demonstrate that local invasion is facilitated by stromal collagen re-organization and that this behavior is significantly increased in collagen-dense tissues. In addition, using multiphoton fluorescence and spectral lifetime imaging we identify a metabolic signature for flavin adenine dinucleotide, with increased fluorescent intensity and lifetime, in invading metastatic cells.</p> <p>Conclusion</p> <p>This study provides the first data causally linking increased stromal collagen to mammary tumor formation and metastasis, and demonstrates that fundamental differences arise and persist in epithelial tumor cells that progressed within collagen-dense microenvironments. Furthermore, the imaging techniques and signature identified in this work may provide useful diagnostic tools to rapidly assess fresh tissue biopsies.</p>
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spelling doaj.art-6e6fa549d7574d7daddda1e48bdb7cb32022-12-21T23:12:52ZengBMCBMC Medicine1741-70152008-04-01611110.1186/1741-7015-6-11Collagen density promotes mammary tumor initiation and progressionKnittel Justin GEliceiri Kevin WInman David RProvenzano Paolo PYan LongRueden Curtis TWhite John GKeely Patricia J<p>Abstract</p> <p>Background</p> <p>Mammographically dense breast tissue is one of the greatest risk factors for developing breast carcinoma. Despite the strong clinical correlation, breast density has not been causally linked to tumorigenesis, largely because no animal model has existed for studying breast tissue density. Importantly, regions of high breast density are associated with increased stromal collagen. Thus, the influence of the extracellular matrix on breast carcinoma development and the underlying molecular mechanisms are not understood.</p> <p>Methods</p> <p>To study the effects of collagen density on mammary tumor formation and progression, we utilized a bi-transgenic tumor model with increased stromal collagen in mouse mammary tissue. Imaging of the tumors and tumor-stromal interface in live tumor tissue was performed with multiphoton laser-scanning microscopy to generate multiphoton excitation and spectrally resolved fluorescent lifetimes of endogenous fluorophores. Second harmonic generation was utilized to image stromal collagen.</p> <p>Results</p> <p>Herein we demonstrate that increased stromal collagen in mouse mammary tissue significantly increases tumor formation approximately three-fold (<it>p </it>< 0.00001) and results in a significantly more invasive phenotype with approximately three times more lung metastasis (<it>p </it>< 0.05). Furthermore, the increased invasive phenotype of tumor cells that arose within collagen-dense mammary tissues remains after tumor explants are cultured within reconstituted three-dimensional collagen gels. To better understand this behavior we imaged live tumors using nonlinear optical imaging approaches to demonstrate that local invasion is facilitated by stromal collagen re-organization and that this behavior is significantly increased in collagen-dense tissues. In addition, using multiphoton fluorescence and spectral lifetime imaging we identify a metabolic signature for flavin adenine dinucleotide, with increased fluorescent intensity and lifetime, in invading metastatic cells.</p> <p>Conclusion</p> <p>This study provides the first data causally linking increased stromal collagen to mammary tumor formation and metastasis, and demonstrates that fundamental differences arise and persist in epithelial tumor cells that progressed within collagen-dense microenvironments. Furthermore, the imaging techniques and signature identified in this work may provide useful diagnostic tools to rapidly assess fresh tissue biopsies.</p>http://www.biomedcentral.com/1741-7015/6/11
spellingShingle Knittel Justin G
Eliceiri Kevin W
Inman David R
Provenzano Paolo P
Yan Long
Rueden Curtis T
White John G
Keely Patricia J
Collagen density promotes mammary tumor initiation and progression
BMC Medicine
title Collagen density promotes mammary tumor initiation and progression
title_full Collagen density promotes mammary tumor initiation and progression
title_fullStr Collagen density promotes mammary tumor initiation and progression
title_full_unstemmed Collagen density promotes mammary tumor initiation and progression
title_short Collagen density promotes mammary tumor initiation and progression
title_sort collagen density promotes mammary tumor initiation and progression
url http://www.biomedcentral.com/1741-7015/6/11
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