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Updated: Jul 25, 2026
RhoC GTPase Activation Assay
Published on: August 22, 2010
Mutation status of genes encoding RhoA, Rac1, and Cdc42 GTPases in a panel of invasive human colorectal and breast
1Laboratoire de Signalisation Intracellulaire et Oncogènes, INSERM U-528, Institut Curie, Paris, France.
Purpose:
The constitutive activation of Ras proteins by point mutation is the most frequently observed oncogene activation in human malignancies. The goal of this study was to investigate whether the constitutive activation of RhoA, Rac1, and Cdc42 proteins by point mutations, which can lead to experimental transformation of cultured cells, actually occurred in a panel of invasive colorectal and breast tumors.
Methods:
We performed denaturing gradient gel electrophoresis and sequencing of transcripts amplified by reverse transcription and PCR for RhoA; we used direct sequencing of PCR-amplified genomic DNA to search for mutations in coding exons of the Rac1 and Cdc42 genes.
Results:
Although mutations of the Kras4B and the p53 genes were detected using these methods, no mutation was found in the coding sequences of RhoA, Rac1, and Cdc42 genes, in primary as well as in associated metastasis.
Conclusions:
Point mutations in the coding sequences of genes encoding RhoA, Rac1, and Cdc42 GTPases do not occur at high frequency in invasive breast and colorectal tumors.
Insights
Point mutations in RhoA, Rac1, and Cdc42 genes are not common in invasive colorectal and breast tumors. Researchers found no such mutations, despite detecting others like Kras4B and p53.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- Ras protein activation by point mutation is a common oncogene activation in human cancers.
- RhoA, Rac1, and Cdc42 proteins, when constitutively activated by point mutations, can experimentally transform cultured cells.
Purpose of the Study:
- To investigate the occurrence of constitutive activation of RhoA, Rac1, and Cdc42 proteins via point mutations in invasive colorectal and breast tumors.
- To determine if these specific gene mutations are a frequent event in these cancer types.
Main Methods:
- Denaturing gradient gel electrophoresis and transcript sequencing were used for RhoA.
- Direct sequencing of PCR-amplified genomic DNA was employed to detect mutations in Rac1 and Cdc42 coding exons.
Main Results:
- Mutations in Kras4B and p53 genes were detected in the tumor samples.
- No mutations were identified in the coding sequences of RhoA, Rac1, and Cdc42 genes, neither in primary tumors nor in metastases.
Conclusions:
- Constitutive activation of RhoA, Rac1, and Cdc42 GTPases through point mutations is infrequent in invasive breast and colorectal tumors.
- These specific mutations do not appear to be a major driver of tumorigenesis in these cancers.
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