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Cytogenetic characterization and H-ras associated transformation of immortalized human mammary epithelial cells

INTRODUCTION: Immortalization is a key step in malignant transformation, but immortalization alone is insufficient for transformation. Human mammary epithelial cell (HMEC) transformation is a complex process that requires additional genetic changes beyond immortalization and can be accomplished in v...

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Autores principales: Rao, Krishna, Alper, Özge, Opheim, Kent E, Bonnet, George, Wolfe, Kristine, Bryant, Eileen, Larivee, Siobhan O'Hara, Porter, Peggy, McDougall, James K
Formato: Texto
Lenguaje:English
Publicado: BioMed Central 2006
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1524989/
https://www.ncbi.nlm.nih.gov/pubmed/16729884
http://dx.doi.org/10.1186/1475-2867-6-15
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author Rao, Krishna
Alper, Özge
Opheim, Kent E
Bonnet, George
Wolfe, Kristine
Bryant, Eileen
Larivee, Siobhan O'Hara
Porter, Peggy
McDougall, James K
author_facet Rao, Krishna
Alper, Özge
Opheim, Kent E
Bonnet, George
Wolfe, Kristine
Bryant, Eileen
Larivee, Siobhan O'Hara
Porter, Peggy
McDougall, James K
author_sort Rao, Krishna
collection PubMed
description INTRODUCTION: Immortalization is a key step in malignant transformation, but immortalization alone is insufficient for transformation. Human mammary epithelial cell (HMEC) transformation is a complex process that requires additional genetic changes beyond immortalization and can be accomplished in vitro by accumulation of genetic changes and expression of H-ras. METHODS: HMEC were immortalized by serial passaging and transduction with the catalytic subunit of the human telomerase gene (hTERT). The immortalized cells were passaged in vitro and studied by a combination of G- banding and Spectral Karyotyping (SKY). H-ras transduced, hTERT immortalized cells were cloned in soft agar and injected into nude mice. Extensive analysis was performed on the tumors that developed in nude mice, including immunohistochemistry and western blotting. RESULTS: Immortal HMEC alone were not tumorigenic in γ-irradiated nude mice and could not grow in soft agar. Late passage hTERT immortalized HMEC from a donor transduced with a retroviral vector containing the mutant, autoactive, human H-ras61L gene acquired anchorage independent growth properties and the capacity for tumorigenic growth in vivo. The tumors that developed in the nude mice were poorly differentiated epithelial carcinomas that continued to overexpress ras. These cells were resistant to doxorubicin mediated G1/S phase arrest but were sensitive to treatment with a farnesyltransferase inhibitor. CONCLUSION: Some of the cytogenetic changes are similar to what is observed in premalignant and malignant breast lesions. Despite these changes, late passage immortal HMEC are not tumorigenic and could only be transformed with overexpression of a mutant H-ras oncogene.
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spelling pubmed-15249892006-08-01 Cytogenetic characterization and H-ras associated transformation of immortalized human mammary epithelial cells Rao, Krishna Alper, Özge Opheim, Kent E Bonnet, George Wolfe, Kristine Bryant, Eileen Larivee, Siobhan O'Hara Porter, Peggy McDougall, James K Cancer Cell Int Primary Research INTRODUCTION: Immortalization is a key step in malignant transformation, but immortalization alone is insufficient for transformation. Human mammary epithelial cell (HMEC) transformation is a complex process that requires additional genetic changes beyond immortalization and can be accomplished in vitro by accumulation of genetic changes and expression of H-ras. METHODS: HMEC were immortalized by serial passaging and transduction with the catalytic subunit of the human telomerase gene (hTERT). The immortalized cells were passaged in vitro and studied by a combination of G- banding and Spectral Karyotyping (SKY). H-ras transduced, hTERT immortalized cells were cloned in soft agar and injected into nude mice. Extensive analysis was performed on the tumors that developed in nude mice, including immunohistochemistry and western blotting. RESULTS: Immortal HMEC alone were not tumorigenic in γ-irradiated nude mice and could not grow in soft agar. Late passage hTERT immortalized HMEC from a donor transduced with a retroviral vector containing the mutant, autoactive, human H-ras61L gene acquired anchorage independent growth properties and the capacity for tumorigenic growth in vivo. The tumors that developed in the nude mice were poorly differentiated epithelial carcinomas that continued to overexpress ras. These cells were resistant to doxorubicin mediated G1/S phase arrest but were sensitive to treatment with a farnesyltransferase inhibitor. CONCLUSION: Some of the cytogenetic changes are similar to what is observed in premalignant and malignant breast lesions. Despite these changes, late passage immortal HMEC are not tumorigenic and could only be transformed with overexpression of a mutant H-ras oncogene. BioMed Central 2006-05-26 /pmc/articles/PMC1524989/ /pubmed/16729884 http://dx.doi.org/10.1186/1475-2867-6-15 Text en Copyright © 2006 Rao et al; licensee BioMed Central Ltd. http://creativecommons.org/licenses/by/2.0 This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( (http://creativecommons.org/licenses/by/2.0) ), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Primary Research
Rao, Krishna
Alper, Özge
Opheim, Kent E
Bonnet, George
Wolfe, Kristine
Bryant, Eileen
Larivee, Siobhan O'Hara
Porter, Peggy
McDougall, James K
Cytogenetic characterization and H-ras associated transformation of immortalized human mammary epithelial cells
title Cytogenetic characterization and H-ras associated transformation of immortalized human mammary epithelial cells
title_full Cytogenetic characterization and H-ras associated transformation of immortalized human mammary epithelial cells
title_fullStr Cytogenetic characterization and H-ras associated transformation of immortalized human mammary epithelial cells
title_full_unstemmed Cytogenetic characterization and H-ras associated transformation of immortalized human mammary epithelial cells
title_short Cytogenetic characterization and H-ras associated transformation of immortalized human mammary epithelial cells
title_sort cytogenetic characterization and h-ras associated transformation of immortalized human mammary epithelial cells
topic Primary Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1524989/
https://www.ncbi.nlm.nih.gov/pubmed/16729884
http://dx.doi.org/10.1186/1475-2867-6-15
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