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Phosphatidylinositol 3-kinase and antiestrogen resistance in breast cancer

Todd W Miller1, Justin M Balko, Carlos L Arteaga

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

Journal of Clinical Oncology : Official Journal of the American Society of Clinical Oncology
|October 20, 2011
PubMed

Insights

Antiestrogen therapies for hormone-dependent breast cancer can fail due to resistance. Targeting the phosphatidylinositol 3-kinase (PI3K) pathway alongside estrogen receptor (ER) signaling shows promise for overcoming this resistance.

Area of Science:

  • Oncology
  • Molecular Biology
  • Endocrinology

Background:

  • Estrogen receptor (ER) α signaling is a key target in hormone-dependent breast cancer treatment.
  • Antiestrogen therapies are effective but face challenges with de novo or acquired resistance.
  • ERBB2 (HER2) amplification/overexpression and phosphatidylinositol 3-kinase (PI3K) pathway hyperactivation are implicated in endocrine resistance.

Purpose of the Study:

  • To review alterations in the PI3K pathway linked to endocrine therapy resistance in breast cancer.
  • To discuss the clinical development status of PI3K inhibitors.
  • To outline strategies for investigating PI3K inhibitors in hormone receptor-positive breast cancer.

Main Methods:

  • Review of experimental and clinical evidence on PI3K pathway involvement in antiestrogen resistance.
  • Analysis of PI3K as a signaling hub downstream of HER2 and other receptor tyrosine kinases.
  • Examination of PI3K's role in promoting ER transcriptional activity in breast cancer cells.

Main Results:

  • PI3K pathway hyperactivation promotes resistance to antiestrogen therapies.
  • Preclinical models suggest sensitivity to both estrogens and PI3K inhibition in resistant breast cancer.
  • Simultaneous targeting of PI3K and ER pathways may offer a more effective therapeutic strategy.

Conclusions:

  • Alterations in the PI3K pathway are significantly associated with endocrine therapy resistance.
  • PI3K inhibitors are under clinical development for breast cancer treatment.
  • Combined targeting of PI3K and ER pathways warrants further clinical investigation for hormone receptor-positive breast cancer.

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