Linked Life Data

9537449

Source:http://linkedlifedata.com/resource/pubmed/id/9537449

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1998-4-16
pubmed:abstractText
Mouse liver tumors frequently harbor activating ras gene mutations. Downstream effector molecules of p21Ras include Raf-1 kinase which mediates external signals via kinase signaling pathways to nuclear transcription factors including c-Fos and c-Jun. Mouse liver tumors with differing ras-mutational status were analyzed for alterations in Ras/Raf-1 signal transduction. Tumors were characterized with respect to the presence of base substitutions in the 3 known hot-spot positions at codons 12, 13, and 61 of Ha-ras, Ki-ras, and N-ras. Ha-ras codon 61 or Ki-ras codon 13 mutations, but no N-ras mutations, were detected in 23 out of 33 tumors analyzed, while no ras-mutations were found in 10 of the tumors. There was no significant difference in the expression of p21RaS proteins between ras-mutated tumors and tumors without detectable ras mutations. To allow for determination of Raf-1 kinase activity in tumors, a sensitive and specific assay was developed for measurements with tissue homogenates. Raf-1 kinase activity was increased about four-fold in liver tumors as compared with normal liver tissue. No significant differences in kinase activity, however, were evident between ras-mutated and ras-wild-type tumors. The same was true with respect to the levels of c-fos and c-jun mRNAs. Moreover, there were no significant differences in cell division (5-bromo-2'-deoxyuridine-labeling indices) of hepatocytes from ras-mutated and ras-wild-type tumors. The similar degree of constitutive activation of the Ras/Raf-1 signaling pathway in liver tumors, with and without detectable ras mutations, suggests that other molecules within the signaling pathway may substitute for ras-mutations during oncogenic conversion of ras-wild-type hepatocytes.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0270-9139
pubmed:author
pubmed:issnType
Print
pubmed:volume
27
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1081-8
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
p21Ras downstream effectors are increased in activity or expression in mouse liver tumors but do not differ between ras-mutated and ras-wild-type lesions.
pubmed:affiliation
Institute of Toxicology, University of Tübingen, Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't