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Updated: Jun 13, 2025
Orthotopic Injection of Breast Cancer Cells into the Mammary Fat Pad of Mice to Study Tumor Growth.
Published on: February 8, 2015
Innate immunity gene Nod2 protects mice from orthotopic breast cancer
Serdar Gurses1,2, Nivya Varghese1, Dipika Gupta3
1Indiana University School of Medicine-Northwest, Gary, IN, 46408, USA.
Background:
Nod2 is involved in innate immune responses to bacteria, regulation of metabolism, and sensitivity to cancer. A Nod2 polymorphism is associated with breast cancer, but the role of Nod2 in the development and progression of breast cancer is unknown.
Methods:
Here, we tested the hypothesis that Nod2 protects mice from breast cancer using the 4T1 orthotopic model of mammary tumorigenesis. WT and Nod2-/- mice were injected with 4T1 mammary carcinoma cells and the development of tumors was monitored. A detailed analysis of the tumor transcriptome was performed and genes that were differentially expressed and pathways that were predicted to be altered between WT and Nod2-/- mice were identified. The activation of key signaling molecules involved in metabolism and development of cancer was studied.
Results:
Our data demonstrate that Nod2-/- mice had a higher incidence and larger tumors than WT mice. Nod2-/- mice had increased expression of genes that promote DNA replication and cell division, and decreased expression of genes required for lipolysis, lipogenesis, and steroid biosynthesis compared with WT mice. Nod2-/- mice also had lower expression of genes required for adipogenesis and reduced levels of lipids compared with WT mice. The tumors in Nod2-/- mice had decreased expression of genes associated with PPARα/γ signaling, increased activation of STAT3, decreased activation of STAT5, and no change in the activation of ERK compared with WT mice.
Conclusions:
We conclude that Nod2 protects mice from the 4T1 orthotopic breast tumor, and that tumors in Nod2-/- mice are predicted to have increased DNA replication and cell proliferation and decreased lipid metabolism compared with WT mice.
Insights
Nucleotide-binding oligomerization domain-containing protein 2 (Nod2) protects against breast cancer development. Loss of Nod2 in mice led to increased tumor incidence, cell proliferation, and altered lipid metabolism, indicating a protective role.
Area of Science:
- Immunology
- Oncology
- Metabolism
Background:
- Nucleotide-binding oligomerization domain-containing protein 2 (Nod2) is implicated in innate immunity, metabolism, and cancer susceptibility.
- A specific Nod2 polymorphism is linked to breast cancer, but its precise role in tumorigenesis remains unclear.
Purpose of the Study:
- To investigate the protective role of Nod2 in breast cancer development and progression.
- To elucidate the molecular mechanisms underlying Nod2's influence on mammary tumorigenesis.
Main Methods:
- Utilized the 4T1 orthotopic mouse model of mammary carcinoma.
- Compared tumor development, transcriptome, and signaling pathway activation between wild-type (WT) and Nod2-deficient (Nod2-/-) mice.
- Analyzed gene expression related to DNA replication, cell division, lipid metabolism, and key signaling molecules (STAT3, STAT5, ERK).
Main Results:
- Nod2-/- mice exhibited higher tumor incidence and larger tumors compared to WT mice.
- Tumors in Nod2-/- mice showed increased expression of genes promoting DNA replication and cell division.
- Lipid metabolism pathways (lipolysis, lipogenesis, steroid biosynthesis, adipogenesis) and lipid levels were decreased in Nod2-/- mice.
- PPARα/γ signaling was downregulated, while STAT3 activation was increased in Nod2-/- tumors.
Conclusions:
- Nod2 confers protection against 4T1 orthotopic breast tumors in mice.
- Absence of Nod2 promotes increased DNA replication, cell proliferation, and altered lipid metabolism in breast tumors.
- These findings highlight Nod2 as a potential therapeutic target in breast cancer treatment.
