Rihet S, Vielh P, Camonis J, Goud B, Chevillard S, de Gunzburg J
Laboratoire de Signalisation Intracellulaire et Oncogènes, INSERM U-528, Institut Curie, Paris, France.
J Cancer Res Clin Oncol. 2001 Dec;127(12):733-8. doi: 10.1007/s004320100272.
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.
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.
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.
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.
通过点突变对Ras蛋白进行组成性激活是在人类恶性肿瘤中最常观察到的致癌基因激活方式。本研究的目的是调查由点突变导致的RhoA、Rac1和Cdc42蛋白的组成性激活（这可导致培养细胞的实验性转化）是否实际发生在一组浸润性结直肠癌和乳腺肿瘤中。
我们对通过逆转录和PCR扩增的RhoA转录本进行了变性梯度凝胶电泳和测序；我们使用PCR扩增的基因组DNA直接测序来寻找Rac1和Cdc42基因编码外显子中的突变。
尽管使用这些方法检测到了Kras4B和p53基因的突变，但在原发性以及相关转移灶中，未在RhoA、Rac1和Cdc42基因的编码序列中发现突变。
在浸润性乳腺和结直肠癌肿瘤中，编码RhoA、Rac1和Cdc42 GTPases的基因编码序列中的点突变并非高频发生。
