title: Akt isoform-specific inhibition of MDA-MB-231 cell proliferation.
abstract: To dissect the isoform-specific roles of Akt in breast cancer cells, constitutively active Akt isoforms were introduced into MDA-MB-231 cells. Both Akt1 and Akt2 efficiently inhibited the growth of MDA-MB-231 cells. Overexpression of Akt1 down-regulated ERK activity inhibiting Ser 259 phosphorylation of c-Raf and subsequent downstream signaling. Akt2 overexpression up-regulated the cell cycle inhibitor p27. Cycloheximide decay assays showed that Akt2 increased the stability and nuclear localization of p27, thus inhibiting the cyclin E/CDK2 complex. These results suggest that the inhibition of cell proliferation by Akt1 and Akt2 is mediated by isoform-specific mechanisms.
authors.affiliation: Dept. of Life Science, Hanyang University, Seoul, Korea.
authors.forename: Wonseok
authors.initials: W
authors.lastname: Yang
authors.forename: Ji-hyun
authors.initials: JH
authors.lastname: Ju
authors.forename: Kyung-min
authors.initials: KM
authors.lastname: Lee
authors.forename: Incheol
authors.initials: I
authors.lastname: Shin
mesh_terms: D001943:Breast Neoplasms / Q000201:enzymology / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D019927:Cyclin E / Q000378:metabolism; D051357:Cyclin-Dependent Kinase 2 / Q000378:metabolism; D050760:Cyclin-Dependent Kinase Inhibitor p27 / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005260:Female; D006801:Humans; D010766:Phosphorylation; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism*; D019908:Proto-Oncogene Proteins c-raf / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D019927:Cyclin E; D020033:Protein Isoforms; D050760:Cyclin-Dependent Kinase Inhibitor p27; D051057:Proto-Oncogene Proteins c-akt; D019908:Proto-Oncogene Proteins c-raf; C495894:CDK2 protein, human; D051357:Cyclin-Dependent Kinase 2; D048049:Extracellular Signal-Regulated MAP Kinases