Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0149514 (bronchitis)
 6,902 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

K-ras mutation appears in about 60% of patients with non-small-cell lung cancer (NSCLC). This frequency and its presence in normal appearing tissues point to the potential of ras oncogene mutation to serve as a good biomarker. Using enriched PCR (EPCR), which enables the detection of one mutant allele in the presence of 10,000 normal alleles, we have determined the frequency of mutant ras alleles in the sputum samples of patients with or without lung cancer. Samples were collected from 17 patients with NSCLC and from 40 controls who suffered from non-oncological lung diseases, including bronchitis, asthma, and pneumonia. Of the 37 samples obtained from patients with lung cancer, 18 were found to harbor ras oncogene mutations (48%). Of the 40 cases that were free of lung cancer, five were found to harbor this mutation (12.5%). The difference between the two frequencies was found to be significant (P < 0.01). These findings indicate that (a) K-ras oncogene mutation can be identified in routinely obtained sputum samples of patients who may be at risk of developing lung cancer and (b) the higher frequency of these mutations in samples of patients with lung cancer points to the potential use of the ras mutation as a biomarker for either exogenous or endogenous exposure to carcinogens. Thus, the ability to examine sputum provides a powerful and convenient source of sampling and may be adapted for future large-scale screening.
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PMID:K-ras mutation in sputum of patients with or without lung cancer. 902 15

To examine the ability of ras to activate signal transduction pathways in the absence of lipid modifications, fusion proteins were constructed that target rasWT or activated ras61L to cellular membranes as integral membrane proteins, using the first transmembrane domain of the E1 protein of avian infectious bronchitis virus (IBV), which contains a cis-Golgi targeting signal. Golgi-targeted derivatives of activated ras were completely inactive in transformation assays. However, when examined in focus formation assays, transformation of NIH3T3 cells were seen with derivatives of ras61L containing a mutated E1 targeting sequence that results in plasma membrane localization. Removal of the lipid modification sites in and upstream of the CAAX motif did not abrogate the transforming activity of plasma membrane-localized ras61L derivatives, indicating that these lipid modifications are not essential for ras activity, as long as the protein is correctly localized to the plasma membrane. Interestingly, the activity of integral membrane versions of ras61L was strictly dependent on a minimum distance between the transmembrane domain anchor region and the coding sequence of ras. Derivatives with only a 3-amino acid linker were inactive, while linkers of either 11- or 22-amino acids were sufficient to restore transforming activity. These results demonstrate that: (1) activated ras targeted to Golgi membranes is unable to cause transformation; (2) lipid modifications at the C-terminus are not required for the transforming activity of plasma membrane-anchored ras61L derivatives, and serve primarily a targeting function; (3) a transmembrane domain can effectively substitute for C-terminal modifications that would normally target ras to the inner surface of the plasma membrane, indicating that ras61L does not need to reversibly dissociate from the membrane as might be allowed by the normal lipidation; and (4) in order to function properly, there exists a critical distance that the ras protein must reside from the plasma membrane.
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PMID:Derivatives of activated H-ras lacking C-terminal lipid modifications retain transforming ability if targeted to the correct subcellular location. 905 Sep 94