Comparative proteomic analysis implicates eEF2 as a novel target of PI3Kγ in the MDA-MB-231 metastatic breast cancer cell line

Meizhi Niu, S McColl, Manuela Klingler-Hoffmann, Julie A Brazzatti, Briony Forbes, Chareeporn Akekawatchai, Peter Hoffmann

    Research output: Contribution to journalArticle

    7 Citations (Scopus)

    Abstract

    Background: Cancer cell migration is fundamentally required for breast tumour invasion and metastasis. The insulin-like growth factor 1 tyrosine kinase receptor (IGF-1R) and the chemokine G-protein coupled receptor, CXCR4 have been shown to play an important role in breast cancer metastasis. Our previous study has shown that IGF-1R can transactivate CXCR4 via a physical association in the human MDA-MB-231 metastatic breast cancer cell line and that this plays a key role in IGF-I-induced migration of these cells. In the present study we used pharmacological inhibition and RNAi to identify PI3Kγ as an important migration signalling molecule downstream of receptor transactivation in MDA-MB-231 cells. To identify PI3Kγ-regulated proteins upon transactivation of CXCR4 by IGF-I, we undertook a comparative proteomics approach using 2-D- Fluorescence Difference Gel Electrophoresis (DIGE) and identified the proteins by mass spectrometry.Results: These experiments identified eukaryotic elongation factor 2 (eEF2) as a novel downstream target of PI3Kγ after activation of the IGF-1R-CXCR4 heterodimer by IGF-I. Further analysis demonstrated that eEF2 is phosphorylated in MDA-MB-231 cells in response to IGF-I and that this is dependent on PI3Kγ activity.Conclusions: Our data imply a novel role for PI3Kγ in facilitating cell migration by regulating phosphorylation of eEF2.

    Original languageEnglish
    Article number4
    Pages (from-to)1-12
    Number of pages12
    JournalProteome Science
    Volume11
    Issue number1
    DOIs
    Publication statusPublished - 15 Jan 2013

    Keywords

    • 2D-DIGE
    • Cell migration
    • CXCR4
    • EEF2
    • IGF-I
    • PI3Kγ
    • Receptor transactivation

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