Open Access

Combining AZD8931, a novel EGFR/HER2/HER3 signalling inhibitor, with AZD5363 limits AKT inhibitor induced feedback and enhances antitumour efficacy in HER2-amplified breast cancer models

  • Authors:
    • Claire Crafter
    • John P. Vincent
    • Eric Tang
    • Phillippa Dudley
    • Neil H. James
    • Teresa Klinowska
    • Barry R. Davies
  • View Affiliations

  • Published online on: June 22, 2015     https://doi.org/10.3892/ijo.2015.3062
  • Pages: 446-454
  • Copyright: © Crafter et al. This is an open access article distributed under the terms of Creative Commons Attribution License [CC BY_NC 3.0].

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Abstract

The phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) signalling network is frequently de-regulated in breast cancer and has been shown to mediate resistance to anti-HER2 agents. Whilst constitutive activation of this pathway is emerging as a marker of sensitivity to various PI3K pathway inhibitors, activity of these agents in the clinic may be limited by the presence of feedback loops, leading to reactivation of receptor tyrosine kinases, such as HER2/HER3. To determine whether inhibition of HER2 could increase the efficacy of AZD5363, a novel AKT inhibitor, a panel of breast cancer cells was dosed with AZD5363 in combination with AZD8931, an inhibitor of EGFR/HER2/HER3 signalling. We show that the combined treatment resulted in synergistic growth inhibition and enhanced cell death, specifically in the HER2-amplified cell lines. Investigation of the mechanism by western blot analysis revealed that the addition of AZD8931 prevented the induction of HER2/HER3 phosphorylation induced by AZD5363 and resulted in concomitant inhibition of both the PI3K/AKT/mTOR and ERK signalling pathways and induction of apoptosis. Using the HCC1954 xenograft model, which is resistant to trastuzumab, we show that the combination of AZD5363 and AZD8931 is more efficacious than either agent alone, resulting in profound tumour regressions. We conclude that the activity of AZD5363 in HER2-amplified breast cancer cells is enhanced by the addition of AZD8931 and that dual targeting of AKT and EGFR/HER2/HER3 signalling is an attractive treatment option to be explored in the clinic.
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August-2015
Volume 47 Issue 2

Print ISSN: 1019-6439
Online ISSN:1791-2423

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Spandidos Publications style
Crafter C, Vincent JP, Tang E, Dudley P, James NH, Klinowska T and Davies BR: Combining AZD8931, a novel EGFR/HER2/HER3 signalling inhibitor, with AZD5363 limits AKT inhibitor induced feedback and enhances antitumour efficacy in HER2-amplified breast cancer models. Int J Oncol 47: 446-454, 2015.
APA
Crafter, C., Vincent, J.P., Tang, E., Dudley, P., James, N.H., Klinowska, T., & Davies, B.R. (2015). Combining AZD8931, a novel EGFR/HER2/HER3 signalling inhibitor, with AZD5363 limits AKT inhibitor induced feedback and enhances antitumour efficacy in HER2-amplified breast cancer models. International Journal of Oncology, 47, 446-454. https://doi.org/10.3892/ijo.2015.3062
MLA
Crafter, C., Vincent, J. P., Tang, E., Dudley, P., James, N. H., Klinowska, T., Davies, B. R."Combining AZD8931, a novel EGFR/HER2/HER3 signalling inhibitor, with AZD5363 limits AKT inhibitor induced feedback and enhances antitumour efficacy in HER2-amplified breast cancer models". International Journal of Oncology 47.2 (2015): 446-454.
Chicago
Crafter, C., Vincent, J. P., Tang, E., Dudley, P., James, N. H., Klinowska, T., Davies, B. R."Combining AZD8931, a novel EGFR/HER2/HER3 signalling inhibitor, with AZD5363 limits AKT inhibitor induced feedback and enhances antitumour efficacy in HER2-amplified breast cancer models". International Journal of Oncology 47, no. 2 (2015): 446-454. https://doi.org/10.3892/ijo.2015.3062