PDK1-SGK1 signaling sustains AKT-independent mTORC1 activation and confers resistance to PI3Kα inhibition Journal Article


Authors: Castel, P.; Ellis, H.; Bago, R.; Toska, E.; Razavi, P.; Carmona, F. J.; Kannan, S.; Verma, C. S.; Dickler, M.; Chandarlapaty, S.; Brogi, E.; Alessi, D. R.; Baselga, J.; Scaltriti, M.
Article Title: PDK1-SGK1 signaling sustains AKT-independent mTORC1 activation and confers resistance to PI3Kα inhibition
Abstract: PIK3CA, which encodes the p110α subunit of PI3K, is frequently mutated and oncogenic in breast cancer. PI3Kα inhibitors are in clinical development and despite promising early clinical activity, intrinsic resistance is frequent among patients. We have previously reported that residual downstream mTORC1 activity upon treatment with PI3Kα inhibitors drives resistance to these agents. However, the mechanism underlying this phenotype is not fully understood. Here we show that in cancer cells resistant to PI3Kα inhibition, PDK1 blockade restores sensitivity to these therapies. SGK1, which is activated by PDK1, contributes to the maintenance of residual mTORC1 activity through direct phosphorylation and inhibition of TSC2. Targeting either PDK1 or SGK1 prevents mTORC1 activation, restoring the antitumoral effects of PI3Kα inhibition in resistant cells. © 2016 The Author(s)
Journal Title: Cancer Cell
Volume: 30
Issue: 2
ISSN: 1535-6108
Publisher: Cell Press  
Date Published: 2016-08-08
Start Page: 229
End Page: 242
Language: English
DOI: 10.1016/j.ccell.2016.06.004
PROVIDER: scopus
PMCID: PMC4982440
PUBMED: 27451907
DOI/URL:
Notes: Article -- Export Date: 2 November 2016 -- Source: Scopus
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MSK Authors
  1. Maura N Dickler
    262 Dickler
  2. Edi Brogi
    515 Brogi
  3. Pau Castel
    25 Castel
  4. Jose T Baselga
    484 Baselga
  5. Maurizio Scaltriti
    169 Scaltriti
  6. Haley Lynn Ellis
    7 Ellis
  7. Pedram Razavi
    172 Razavi
  8. Eneda   Toska
    30 Toska