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Updated: Oct 3, 2026
Primary Tumor and MEF Cell Isolation to Study Lung Metastasis
Published on: May 20, 2015
Gene expression and metastasis of somatic cell hybrids between murine fibroblast cell lines of different malignant
A B Tuck1, S M Wilson, F R Sergovich
1London Regional Cancer Centre, Ontario, Canada.
Abstract:
We have used somatic cell hybrids to study the relationship between ras sensitivity, metastasis, and the expression of ras-responsive or "metastasis-associated" genes. We have previously shown that NIH 3T3 cells are nontumorigenic, but are made metastatic by transfection and expression of activated ras (i.e., they are ras-sensitive). LTA cells, however, are initially tumorigenic, but nonmetastatic, and are not altered in malignancy by ras (i.e., they are ras-resistant). We also have shown that patterns of expression of ras-responsive and "metastasis-associated" genes differ markedly between these two cell types. In the present work, we have constructed three sets of somatic cell hybrids: NIH 3T3 X LTA cells (designated NL), NIH 3T3 X ras-transfected LTA cells (designated NLR), and LTA X ras-transfected NIH 3T3 cells (designated LNR). In all three sets of cell hybrids, pooled clones were found to be highly metastatic in the chick embryo assay, suggesting complementation had occurred. Those cell hybrids that contained ras (NLR and LNR hybrids) were significantly more metastatic than those that did not (NL hybrids). Selected clones of low and high metastatic ability from both NL and LNR fusions were examined for tumorigenicity and "experimental" metastatic ability in nude mice, as well as for expression of several genes thought to be involved in ras-induced progression and malignancy. Patterns of expression of these genes showed a relationship to level of malignancy of the hybrids and demonstrated a responsiveness to the expression of activated ras. These results suggest that the complementation of phenotype observed in the hybrids may arise through a gene regulatory factor(s) supplied by the NIH 3T3- to the LTA-derived parent.
Insights
Somatic cell hybrids reveal that activated ras expression enhances metastasis. Gene expression patterns in hybrids correlate with malignancy, suggesting a gene regulatory factor from NIH 3T3 cells influences LTA cell metastasis.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- NIH 3T3 cells are non-tumorigenic but become metastatic with activated ras expression (ras-sensitive).
- LTA cells are tumorigenic but non-metastatic, and ras expression does not alter their malignancy (ras-resistant).
- Distinct expression patterns of ras-responsive and metastasis-associated genes exist between NIH 3T3 and LTA cells.
Purpose of the Study:
- To investigate the relationship between ras sensitivity, metastasis, and gene expression using somatic cell hybrids.
- To determine how ras expression influences metastasis and malignancy in hybrid cell lines.
- To identify potential gene regulatory factors involved in ras-induced cancer progression.
Main Methods:
- Construction of three sets of somatic cell hybrids: NIH 3T3 x LTA (NL), NIH 3T3 x ras-transfected LTA (NLR), and LTA x ras-transfected NIH 3T3 (LNR).
- Assessment of metastatic potential using the chick embryo assay and nude mouse models.
- Analysis of gene expression patterns in selected hybrid clones with varying metastatic abilities.
Main Results:
- All somatic cell hybrid sets exhibited high metastatic potential, indicating complementation.
- Hybrids containing activated ras (NLR, LNR) were significantly more metastatic than those without (NL).
- Gene expression patterns in hybrids correlated with malignancy levels and responded to activated ras expression.
Conclusions:
- Complementation of metastatic phenotype in hybrids may involve gene regulatory factors from NIH 3T3 cells transferred to LTA-derived parents.
- Activated ras expression plays a crucial role in enhancing metastasis and malignancy.
- Ras-responsive gene expression patterns are linked to cancer progression and metastasis.
