Akt isoforms regulate intermediate filament protein levels in epithelial carcinoma cells.
Keratin 8 and 18 are simple epithelial intermediate filament (IF) proteins, whose expression is differentiation- and tissue-specific, and is maintained during tumorigenesis. Vimentin IF is often co-expressed with keratins in cancer cells. Recently, IF have been proposed to be involved in signaling pathways regulating cell growth, death and motility. The PI3K/Akt pathway plays a pivotal role in these processes. Thus, we investigated the role of Akt (1 and 2) in regulating IF expression in different epithelial cancer cell lines. Over-expression of Akt1 increases K8/18 proteins. Akt2 up-regulates K18 and vimentin expression by an increased mRNA stability. To our knowledge, these results represent the first indication that Akt isoforms regulate IF expression and support the hypothesis that IFs are involved in PI3K/Akt pathway.
Fortier
Anne-Marie
AM
Department of Chemistry-Biology, University of Quebec at Trois-Rivieres, Trois-Rivieres, Quebec, Canada G9A 5H7.
Van Themsche
Céline
C
Asselin
Eric
E
Cadrin
Monique
M
D015153:Blotting, Western; D045744:Cell Line, Tumor; D005455:Fluorescent Antibody Technique; D006367:HeLa Cells; D006801:Humans; D007328:Insulin / Q000494:pharmacology; D007381:Intermediate Filament Proteins / Q000235:genetics / Q000378:metabolism*; D053538:Keratin-18 / Q000235:genetics / Q000378:metabolism; D053533:Keratin-8 / Q000235:genetics / Q000378:metabolism; D007633:Keratins / Q000235:genetics / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D053773:Transforming Growth Factor beta1 / Q000494:pharmacology; D014746:Vimentin / Q000235:genetics / Q000378:metabolism
D007328:Insulin; D007381:Intermediate Filament Proteins; D053538:Keratin-18; D053533:Keratin-8; D020033:Protein Isoforms; D053773:Transforming Growth Factor beta1; D014746:Vimentin; D007633:Keratins; D019869:Phosphatidylinositol 3-Kinases; C494918:AKT1 protein, human; C494921:AKT2 protein, human; D051057:Proto-Oncogene Proteins c-akt