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Updated: Jun 16, 2026

Systems Biology of Metabolic Regulation by Estrogen Receptor Signaling in Breast Cancer
Published on: March 17, 2016
FKBPL regulates estrogen receptor signaling and determines response to endocrine therapy
Hayley D McKeen1, Christopher Byrne, Puthen V Jithesh
1School of Pharmacy, McClay Research Centre and Centre for Cancer Research and Cell Biology, Queen's University, Belfast, Northern Ireland BT9 7BL, United Kingdom.
Abstract:
The HSP90 chaperone and immunophilin FKBPL is an estrogen-responsive gene that interacts with estogen receptor alpha (ERalpha) and regulates its levels. In this study, we explored the effects of FKBPL on breast cancer proliferation. Breast cancer cells stably overexpressing FKBPL became dependent on estrogen for their growth and were dramatically more sensitive to the antiestrogens tamoxifen and fulvestrant, whereas FKBPL knockdown reverses this phenotype. FKBPL knockdown also decreased the levels of the cell cycle inhibitor p21WAF1 and increased ERalpha phosphorylation on Ser(118) in response to 17beta-estradiol and tamoxifen. In support of the likelihood that these effects explained FKBPL-mediated cell growth inhibition and sensitivity to endocrine therapies, FKBPL expression was correlated with increased overall survival and distant metastasis-free survival in breast cancer patients. Our findings suggest that FKBPL may have prognostic value based on its impact on tumor proliferative capacity and sensitivity to endocrine therapies, which improve outcome.
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