Overexpression of the proto-oncogene/translation factor 4E in breast-carcinoma cell lines

Int J Cancer. 1996 Mar 15;65(6):858-63. doi: 10.1002/(SICI)1097-0215(19960315)65:6<858::AID-IJC25>3.0.CO;2-Z.

Abstract

The expression of the proto-oncogene, translation factor elF-4E, was examined in breast-cell lines: 5 carcinomas and 2 normal. At the protein level, elF-4E was 10 times higher in the carcinoma lines than in normal cells, which is comparable to the level found in breast-cancer biopsies. The elevation appears to be due to increased transcription, since the elF-4E mRNA was correspondingly increased. These results demonstrate that cells isolated from naturally occurring breast carcinomas maintain an elevated expression of the factor. Turnover rates for elF-4E (mRNA and protein) were determined for normal and cancer cells. We found that elF-4e mRNA is relatively stable during an 8-hr incubation with Actinomycin D, but the half-life of the protein is fairly short (approximately 4.5 hr). This suggests that, in proliferating cells, elF-4E may be turning over rapidly, possibly to fine-tune the changes in translation rates which occur during the cell cycle.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Blotting, Western
  • Breast / metabolism
  • Breast Neoplasms / metabolism*
  • Cells, Cultured
  • Epithelium / metabolism
  • Eukaryotic Initiation Factor-4E
  • Female
  • Gene Expression
  • Humans
  • Molecular Sequence Data
  • Peptide Initiation Factors / biosynthesis*
  • Peptide Initiation Factors / genetics
  • Peptide Initiation Factors / metabolism
  • Precipitin Tests
  • Proto-Oncogene Mas
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Reference Values
  • Tumor Cells, Cultured

Substances

  • Eukaryotic Initiation Factor-4E
  • MAS1 protein, human
  • Peptide Initiation Factors
  • Proto-Oncogene Mas
  • RNA, Messenger