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Abrogating endocrine resistance by targeting ERα and PI3K in breast cancer

Emily M Fox1, Carlos L Arteaga, Todd W Miller

  • 1Department of Medicine, Vanderbilt-Ingram Cancer Center, Vanderbilt University Nashville, TN, USA.

Frontiers in Oncology
|October 23, 2012
PubMed

Insights

Hyperactive phosphatidylinositol 3-kinase (PI3K) signaling drives resistance to antiestrogen therapies in estrogen receptor-positive (ER+) breast cancer. Combining PI3K inhibitors with ER-targeting drugs or ER downregulators may overcome this resistance.

Area of Science:

  • Oncology
  • Molecular Biology
  • Endocrinology

Background:

  • Estrogen receptor-alpha (ER) signaling is a key target in ER-positive breast cancer treatment.
  • Antiestrogen therapies are standard but face challenges with acquired resistance.
  • Hyperactivation of the phosphatidylinositol 3-kinase (PI3K) pathway is implicated in antiestrogen resistance.

Purpose of the Study:

  • To review the roles of PI3K and ER in the development of antiestrogen resistance.
  • To discuss current clinical trials combining PI3K and ER pathway inhibitors.
  • To highlight the potential of combining PI3K inhibitors with ER downregulators.

Main Methods:

  • Literature review of preclinical and clinical studies.
  • Analysis of mechanisms linking PI3K and ER signaling in breast cancer.
  • Examination of data from clinical trials investigating combination therapies.

Main Results:

  • PI3K pathway hyperactivation promotes both ligand-dependent and -independent ER signaling.
  • Ligand-independent ER signaling contributes to endocrine therapy resistance.
  • Models of resistant breast cancer remain sensitive to PI3K inhibition.

Conclusions:

  • Combination therapies targeting both PI3K and ER pathways are clinically warranted.
  • Investigating ER downregulators alongside PI3K inhibitors may offer new treatment strategies.
  • Targeting PI3K and ER pathways holds promise for overcoming antiestrogen resistance in breast cancer.
Keywords:
PI3Kantiestrogenaromatasebreast cancerestrogen receptorfulvestranttamoxifen

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