High estrogen receptor alpha activation confers resistance to estrogen deprivation and is required for therapeutic response to estrogen in breast cancer. Oncogene 2021 May;40(19):3408-3421
Date
04/21/2021Pubmed ID
33875787Pubmed Central ID
PMC8122072DOI
10.1038/s41388-021-01782-wScopus ID
2-s2.0-85104865418 (requires institutional sign-in at Scopus site) 11 CitationsAbstract
Estrogen receptor alpha (ER)-positive breast cancer is commonly treated with endocrine therapies, including antiestrogens that bind and inhibit ER activity, and aromatase inhibitors that suppress estrogen biosynthesis to inhibit estrogen-dependent ER activity. Paradoxically, treatment with estrogens such as 17b-estradiol can also be effective against ER+ breast cancer. Despite the known efficacy of estrogen therapy, the lack of a predictive biomarker of response and understanding of the mechanism of action have contributed to its limited clinical use. Herein, we demonstrate that ER overexpression confers resistance to estrogen deprivation through ER activation in human ER+ breast cancer cells and xenografts grown in mice. However, ER overexpression and the associated high levels of ER transcriptional activation converted 17b-estradiol from a growth-promoter to a growth-suppressor, offering a targetable therapeutic vulnerability and a potential means of identifying patients likely to benefit from estrogen therapy. Since ER+ breast cancer cells and tumors ultimately developed resistance to continuous estrogen deprivation or continuous 17b-estradiol treatment, we tested schedules of alternating treatments. Oscillation of ER activity through cycling of 17b-estradiol and estrogen deprivation provided long-term control of patient-derived xenografts, offering a novel endocrine-only strategy to manage ER+ breast cancer.
Author List
Traphagen NA, Hosford SR, Jiang A, Marotti JD, Brauer BL, Demidenko E, Miller TWAuthor
Todd W. Miller PhD Professor in the Pharmacology and Toxicology department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
AnimalsBreast Neoplasms
Cell Line, Tumor
Drug Resistance, Neoplasm
Estradiol
Estrogen Antagonists
Estrogen Receptor alpha
Estrogens
Female
Humans
Mice
Mice, Inbred NOD
Mice, SCID
Signal Transduction
Xenograft Model Antitumor Assays
