Establishment and characterization of mouse mammary carcinoma cell lines expressing RET with a multiple endocrine
Kumi Kawai1, Mayumi Jijiwa, Yohei Shimono
1Department of Molecular Pathology, Center for Neural Disease and Cancer, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya 466-8550.
Abstract:
We recently generated transgenic mice expressing the RET proto-oncogene with a multiple endocrine neoplasia type 2A mutation (RET-MEN2A). Mammary tumors with frequent lung metastasis were developed in 22% of female transgenic mice in a stochastic fashion. In the current study, we established two cell lines (named MKK-f and MKK-s) from mammary tumors developed in RET-MEN2A transgenic mice. MKK-f and MKK-s were derived from well-differentiated ductal carcinoma and sarcomatous spindle cell carcinoma, respectively. MKK-f cells show epithelial-like morphology with a doubling time of 19 h, and MKK-s cells show spindle-shaped morphology with a doubling time of 15 h. When inoculated in immunodeficient mice, both cell lines were tumorigenic, metastasized to the lung and displayed histological features similar to those of the primary tumors. They maintained a high level of RET expression and activation of signaling molecules downstream of RET. Consistent with the histological phenotype, expression of E-cadherin was almost undetectable in MKK-s cells, whereas its expression was very high in MKK-f cells. When the difference of gene expression between the two cell lines was analyzed using cDNA microarrays including approximately 900 genes/ESTs, a total of 21 up- or down-regulated (> 2.0-fold) genes were identified. Differentially regulated genes included thymosin beta-10, fibroblast growth factor receptor 4, aldo-keto reductase and caspase 6 genes, which are known to be associated with tumor development and progression. These results may reflect the profiles of the transcriptional changes associated with dedifferentiation or progression of mammary carcinomas developed in genetically engineered mice.
Insights
Transgenic mice with a RET-MEN2A mutation developed mammary tumors that metastasized. Two cell lines derived from these tumors, MKK-f and MKK-s, retained tumorigenicity and metastatic potential, offering insights into mammary carcinoma progression.
Area of Science:
- Oncology
- Genetics
- Molecular Biology
Background:
- The RET proto-oncogene plays a role in various cancers, including Multiple Endocrine Neoplasia type 2A (MEN2A).
- Genetically engineered mouse models are crucial for studying cancer development and progression.
Purpose of the Study:
- To establish and characterize cell lines from mammary tumors in RET-MEN2A transgenic mice.
- To investigate the molecular mechanisms underlying mammary carcinoma dedifferentiation and progression.
Main Methods:
- Generation of RET-MEN2A transgenic mice and isolation of mammary tumor cell lines (MKK-f and MKK-s).
- In vitro characterization of cell morphology, doubling time, and tumorigenicity/metastasis in immunodeficient mice.
- Analysis of RET expression, downstream signaling, E-cadherin expression, and gene expression profiling using cDNA microarrays.
Main Results:
- MKK-f (ductal carcinoma) and MKK-s (spindle cell carcinoma) cell lines were established and demonstrated tumorigenicity and lung metastasis.
- Both cell lines maintained high RET expression and downstream signaling; MKK-f showed high E-cadherin, while MKK-s had undetectable levels.
- Gene expression analysis identified 21 differentially regulated genes, including thymosin beta-10 and fibroblast growth factor receptor 4, associated with tumor progression.
Conclusions:
- The established MKK-f and MKK-s cell lines serve as valuable models for studying RET-driven mammary carcinoma.
- Transcriptional changes identified in these cell lines may reflect the dedifferentiation and progression of mammary tumors in genetically engineered mice.
