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Updated: Jun 26, 2026
A Portal Vein Injection Model to Study Liver Metastasis of Breast Cancer
Published on: December 26, 2016
Altered gene expression in breast cancer liver metastases
Nuray Erin1, Ning Wang, Ping Xin
1Department of Pathology, Gittlen Cancer Research Foundation, Hershey Medical Center, Pennsylvania State University, Hershey, PA 17033, USA.
Abstract:
We previously developed a highly aggressive cell line from heart metastases of 4T1 breast carcinoma (designated 4THM), which produced liver metastases (designated 4TLM). In this study, gene array analysis (GAEA) compared gene expression profiles in 4TLM with profiles in 4T1 and 4THM primary tumors. GAEA demonstrated that 4T1 and 4THM tumors differed in about 250 genes. Over 1,000 genes, however, were expressed differently in 4TLM compared with primary tumors. A cohort of 16 genes showed significantly decreased expression in 4THM tumors, which decreased even further in 4TLM. Many of these genes have been implicated in breast cancer, and many are involved in cell adhesion and junctional complexes. Expression of multiple tight and adherence junction proteins was either downregulated or disappeared in 4TLM; downregulation of claudin 4, claudin 7 and gamma-catenin was confirmed by quantitative polymerase chain reaction, immunoblot, and immunocytochemical (ICC) analyses. At the protein level, intact ZO-1 was also observed in 4T1 tumors, but was not expressed in 4THM or 4TLM tumors. ICC demonstrated expression of gamma-catenin at the plasma membrane with 4T1 tumors, whereas staining appeared to be nuclear/perinuclear in 4THM tumors. Claudin 7 staining was also seen in monocyte/pmacrophage-like cells in liver around metastatic lesions by ICC, and it appeared that larger 4TLM tumors apparently reexpressed claudin 7 RNA and protein. Our results demonstrate that decreased or abnormal expression of a number of cell adhesion/junctional proteins, including claudin 4, 7, ZO-1 and gamma-catenin, correlates with liver metastases, and that cell adhesion molecules in the microenvironment are also altered.
Insights
Decreased expression of cell adhesion proteins like claudin 4, 7, ZO-1, and gamma-catenin correlates with liver metastases in aggressive breast cancer models. These changes impact cell junctions and the tumor microenvironment.
Area of Science:
- Oncology
- Molecular Biology
- Genomics
Background:
- A highly aggressive 4T1 breast carcinoma cell line (4THM) was developed from heart metastases.
- This cell line produced liver metastases (4TLM), serving as a model for metastatic progression.
Purpose of the Study:
- To compare gene expression profiles of liver metastases (4TLM) with primary tumors (4T1 and 4THM).
- To identify genes and proteins associated with breast cancer liver metastasis.
- To investigate the role of cell adhesion and junctional proteins in metastasis.
Main Methods:
- Gene array analysis (GAEA) was used to compare gene expression in 4T1, 4THM, and 4TLM tumors.
- Quantitative polymerase chain reaction (qPCR), immunoblotting, and immunocytochemistry (ICC) were employed to validate gene expression changes at the protein level.
- Expression of specific proteins including claudin 4, claudin 7, gamma-catenin, and ZO-1 was analyzed.
Main Results:
- GAEA revealed significant differences in gene expression between primary tumors and liver metastases (>1,000 genes).
- A cohort of 16 genes showed decreased expression in 4THM and further decreased in 4TLM, many linked to cell adhesion.
- Downregulation or loss of tight and adherence junction proteins (claudin 4, claudin 7, gamma-catenin, ZO-1) was observed in 4TLM, correlating with metastatic progression.
- Altered expression patterns of gamma-catenin and reexpression of claudin 7 were noted in metastatic lesions and surrounding cells.
Conclusions:
- Decreased or abnormal expression of cell adhesion/junctional proteins (claudin 4, 7, ZO-1, gamma-catenin) is associated with breast cancer liver metastasis.
- Changes in these proteins likely contribute to the development and progression of liver metastases.
- The tumor microenvironment, including cell adhesion molecules, is altered during metastatic spread.