3-phosphoinositide dependent protein kinase-1 (PDK1), a transducer protein that functions downstream of PI3K, is responsible for the regulation of cell proliferation and migration and it also has been found to play a key role in different cancers, pancreatic and breast cancer amongst others.
In summary, these results suggest that PDK1 may contribute to breast cancer, even in the absence of PI3K oncogenic mutations and through both Akt-dependent and Akt-independent mechanisms.
In severe combined immunodeficiency mice, PDK1-depleted human breast cancer cells formed more slowly growing tumors and were defective in extravasation to mouse lungs after i.v. injection.
The phosphorylation of FAK, mTOR, p70S6K, and PDK-1 were elevated in both breast cancer cell lines, whereas the phosphorylation of AKT, EGFR, ErbB2/Her2, PDGFR, Shc, and Stat3 were elevated in only one breast cancer line compared to normal primary mammary epithelial cells and telomerase-immortalised breast epithelial cells.