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Activation of the c-K-ras oncogene in a human pancreas carcinoma
Abstract:
The human pancreas carcinoma cell line T3M-4 contains activated c-Kirsten (K)-ras oncogene detectable by the DNA-mediated gene transfer technique using NIH/3T3 cells. DNA fragments containing coding lesions have been cloned, and nucleotide sequence analysis suggests that the T3M-4 oncogene has been activated by a single nucleotide transition from A to C in the second exon, which results in the substitution of histidine for glutamine in coden 61 of the predicted amino acid sequence. The quantity analysis of c-K-ras oncogene in the DNA and RNA of T3M-4 cells revealed that the c-K-ras gene was amplified and overexpressed in T3M-4 cells. These findings indicate that the T3M-4 c-K-ras oncogene is activated by different mutational events.
Insights
The T3M-4 pancreatic cancer cell line has an activated Kirsten ras (K-ras) oncogene. This oncogene shows a specific mutation and is amplified and overexpressed, indicating multiple activation events.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- Pancreatic cancer is a significant health concern with complex genetic underpinnings.
- The Kirsten ras (K-ras) oncogene is frequently implicated in various cancers, including pancreatic carcinoma.
- Understanding oncogene activation is crucial for developing targeted therapies.
Purpose of the Study:
- To investigate the specific genetic alterations and expression patterns of the K-ras oncogene in the T3M-4 human pancreatic carcinoma cell line.
- To identify the molecular mechanisms responsible for the activation of the K-ras oncogene in this cell line.
Main Methods:
- DNA-mediated gene transfer using NIH/3T3 cells to detect activated oncogenes.
- Cloning and nucleotide sequence analysis of DNA fragments containing coding lesions.
- Quantitative analysis of K-ras oncogene in both DNA and RNA from T3M-4 cells.
Main Results:
- The T3M-4 cell line harbors an activated K-ras oncogene.
- A single nucleotide transition (A to C) in the second exon of K-ras was identified, leading to a histidine substitution for glutamine at codon 61.
- Quantitative analysis revealed gene amplification and overexpression of the K-ras oncogene in T3M-4 cells.
Conclusions:
- The K-ras oncogene in the T3M-4 cell line is activated through distinct mutational events.
- The identified mutation and gene amplification/overexpression contribute to the oncogenic phenotype of T3M-4 cells.
- These findings provide insights into the molecular pathogenesis of pancreatic cancer.