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Open Access Highly Accessed Research article

"A novel in vivo model for the study of human breast cancer metastasis using primary breast tumor-initiating cells from patient biopsies"

Carolyn G Marsden1, Mary Jo Wright2, Latonya Carrier3, Krzysztof Moroz4, Radhika Pochampally5 and Brian G Rowan6*

Author Affiliations

1 Department of Structural and Cellular Biology, Tulane University Health Sciences Center, The Louisiana Cancer Research Consortium, New Orleans, LA 70112, USA

2 Department of Surgery, Tulane University School of Medicine, The Louisiana Cancer Research Consortium, New Orleans, LA 70112, USA

3 Department of Structural and Cellular Biology, Tulane University Health Sciences Center, New Orleans, LA 70112, USA

4 Section of Surgical Pathology & Cytopathology, Tulane University School of Medicine, Louisiana Cancer Research Consortium, New Orleans, LA 70112, USA

5 Department of Pharmacology, Tulane University Health Sciences Center, Center for Gene Therapy, Louisiana Cancer Research Consortium, New Orleans, LA, 70,112, USA

6 Department of Structural and Cellular Biology, Tulane University Health Sciences Center, Louisiana Cancer Research Consortium, Center for Gene Therapy, New Orleans, LA 70112, USA

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BMC Cancer 2012, 12:10  doi:10.1186/1471-2407-12-10

Published: 10 January 2012

Abstract

Background

The study of breast cancer metastasis depends on the use of established breast cancer cell lines that do not accurately represent the heterogeneity and complexity of human breast tumors. A tumor model was developed using primary breast tumor-initiating cells isolated from patient core biopsies that would more accurately reflect human breast cancer metastasis.

Methods

Tumorspheres were isolated under serum-free culture conditions from core biopsies collected from five patients with clinical diagnosis of invasive ductal carcinoma (IDC). Isolated tumorspheres were transplanted into the mammary fat pad of NUDE mice to establish tumorigenicity in vivo. Tumors and metastatic lesions were analyzed by hematoxylin and eosin (H+E) staining and immunohistochemistry (IHC).

Results

Tumorspheres were successfully isolated from all patient core biopsies, independent of the estrogen receptor α (ERα)/progesterone receptor (PR)/Her2/neu status or tumor grade. Each tumorsphere was estimated to contain 50-100 cells. Transplantation of 50 tumorspheres (1-5 × 103 cells) in combination with Matrigel into the mammary fat pad of NUDE mice resulted in small, palpable tumors that were sustained up to 12 months post-injection. Tumors were serially transplanted three times by re-isolation of tumorspheres from the tumors and injection into the mammary fat pad of NUDE mice. At 3 months post-injection, micrometastases to the lung, liver, kidneys, brain and femur were detected by measuring content of human chromosome 17. Visible macrometastases were detected in the lung, liver and kidneys by 6 months post-injection. Primary tumors variably expressed cytokeratins, Her2/neu, cytoplasmic E-cadherin, nuclear β catenin and fibronectin but were negative for ERα and vimentin. In lung and liver metastases, variable redistribution of E-cadherin and β catenin to the membrane of tumor cells was observed. ERα was re-expressed in lung metastatic cells in two of five samples.

Conclusions

Tumorspheres isolated under defined culture conditions from patient core biopsies were tumorigenic when transplanted into the mammary fat pad of NUDE mice, and metastasized to multiple mouse organs. Micrometastases in mouse organs demonstrated a dormancy period prior to outgrowth of macrometastases. The development of macrometastases with organ-specific phenotypic distinctions provides a superior model for the investigation of organ-specific effects on metastatic cancer cell survival and growth.

Keywords:
Primary breast tumor-initiating cells; Metastasis; Dormancy; EMT