Contrasting expression of thrombospondin-1 and osteopontin correlates with absence or presence of metastatic phenotype in an isogenic model of spontaneous human breast cancer metastasis.
Clin Cancer Res
; 8(1): 61-74, 2002 Jan.
Article
em En
| MEDLINE
| ID: mdl-11801541
ABSTRACT
Knowledge of the molecular mechanisms involved in metastatic spread is needed to facilitate advances in prognostic evaluation for individual patients and in the design of therapeutic interventions to inhibit the process. In an effort to establish a methodological framework for analysis of molecules and mechanisms involved in this complex multistep process, we have developed a well defined experimental system, in which the role of candidate genes can be screened and tested. By serial dilution cloning of the MDA-MB-435 breast tumor cell line and screening by orthotopic implantation into the mammary fat pad of athymic mice, we have derived a pair of breast tumor cell lines (M-4A4 and NM-2C5) that originate from the same breast tumor but have diametrically opposite metastatic capabilities. In 74% of inoculated athymic mice, clone M-4A4 metastasized consistently to the lungs, mimicking a major dissemination route of human breast cancer. Conversely, although equally tumorigenic, clone NM-2C5 did not metastasize to any distal site. We have confirmed that the cell lines originate from a single genetic source by spectral karyotyping and evaluated the expression of a number of proteins previously implicated in cellular transformation and metastasis. The ability of M-4A4 to metastasize was not associated with increased angiogenesis, as measured by immunohistochemical microvessel density analysis. However, RNA and protein analyses revealed that two secreted proteins were differentially expressed osteopontin expression was increased approximately 30-fold in clone M-4A4 and thrombospondin-1 expression was increased approximately 15-fold in clone NM-2C5. These cell lines constitute a stable and accessible model for the identification of genes involved in the multistep process of breast tumor metastasis. Manipulation of candidate genes in these cells will permit evaluation of their functional significance in the geometric progression of breast cancer.
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Base de dados:
MEDLINE
Assunto principal:
Sialoglicoproteínas
/
Neoplasias da Mama
/
Regulação Neoplásica da Expressão Gênica
/
Trombospondina 1
/
Neoplasias Pulmonares
/
Proteínas de Neoplasias
Tipo de estudo:
Prognostic_studies
Limite:
Animals
/
Female
/
Humans
Idioma:
En
Revista:
Clin Cancer Res
Assunto da revista:
NEOPLASIAS
Ano de publicação:
2002
Tipo de documento:
Article
País de afiliação:
Estados Unidos