Research ArticleCancer

Nuclear Phospho-Akt Increase Predicts Synergy of PI3K Inhibition and Doxorubicin in Breast and Ovarian Cancer

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Science Translational Medicine  08 Sep 2010:
Vol. 2, Issue 48, pp. 48ra66
DOI: 10.1126/scitranslmed.3000630

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The phosphatidylinositol 3-kinase (PI3K)–Akt signaling pathway is frequently disrupted in cancer and implicated in multiple aspects of tumor growth and survival. In addition, increased activity of this pathway in cancer is associated with resistance to chemotherapeutic agents. Therefore, it has been hypothesized that PI3K inhibitors could help to overcome resistance to chemotherapies. We used preclinical cancer models to determine the effects of combining the DNA-damaging drug doxorubicin with GDC-0941, a class I PI3K inhibitor that is currently being tested in early-stage clinical trials. We found that PI3K inhibition significantly increased apoptosis and enhanced the antitumor effects of doxorubicin in a defined set of breast and ovarian cancer models. Doxorubicin treatment caused an increase in the amount of nuclear phospho-AktSer473 in cancer cells that rely on the PI3K pathway for survival. This increased phospho-AktSer473 response to doxorubicin correlates with the strength of GDC-0941’s effect to augment doxorubicin action. These studies predict that clinical use of combination therapies with GDC-0941 in addition to DNA-damaging agents will be effective in tumors that rely on the PI3K pathway for survival.


  • Citation: J. J. Wallin, J. Guan, W. W. Prior, K. A. Edgar, R. Kassees, D. Sampath, M. Belvin, L. S. Friedman, Nuclear phospho-Akt increase predicts synergy of PI3K inhibition and doxorubicin in breast and ovarian cancer. Sci. Transl. Med. 2, 48ra66 (2010).

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