Anastrozole has an Association between Degree of Estrogen Suppression and Outcomes in Early Breast Cancer and is a Ligand for Estrogen Receptor α

Ingle JN, Cairns J, Suman VJ, Shepherd LE, Fasching P, Hoskin TL, Singh RJ, Desta Z, Kalari KR, Ellis MJ, Goss PE, Chen BE, Volz B, Barman P, Carlson EE, Haddad T, Goetz MP, Goodnature B, Cuellar ME, Walters MA, Correia C, Kaufmann SH, Weinshilboum RM, Wang L (2020)

Publication Type: Journal article

Publication year: 2020

Journal

Clinical Cancer Research American Association for Cancer Research

Book Volume: 26

Pages Range: 2986-2996

Journal Issue: 12

DOI: 10.1158/1078-0432.CCR-19-3091

Abstract

PURPOSE: To determine if the degree of estrogen suppression with aromatase inhibitors (AI: anastrozole, exemestane, letrozole) is associated with efficacy in early-stage breast cancer, and to examine for differences in the mechanism of action between the three AIs. EXPERIMENTAL DESIGN: Matched case-control studies [247 matched sets from MA.27 (anastrozole vs. exemestane) and PreFace (letrozole) trials] were undertaken to assess whether estrone (E1) or estradiol (E2) concentrations after 6 months of adjuvant therapy were associated with risk of an early breast cancer event (EBCE). Preclinical laboratory studies included luciferase activity, cell proliferation, radio-labeled ligand estrogen receptor binding, surface plasmon resonance ligand receptor binding, and nuclear magnetic resonance assays. RESULTS: Women with E1 ≥1.3 pg/mL and E2 ≥0.5 pg/mL after 6 months of AI treatment had a 2.2-fold increase in risk (P = 0.0005) of an EBCE, and in the anastrozole subgroup, the increase in risk of an EBCE was 3.0-fold (P = 0.001). Preclinical laboratory studies examined mechanisms of action in addition to aromatase inhibition and showed that only anastrozole could directly bind to estrogen receptor α (ERα), activate estrogen response element-dependent transcription, and stimulate growth of an aromatase-deficient CYP19A1-/- T47D breast cancer cell line. CONCLUSIONS: This matched case-control clinical study revealed that levels of estrone and estradiol above identified thresholds after 6 months of adjuvant anastrozole treatment were associated with increased risk of an EBCE. Preclinical laboratory studies revealed that anastrozole, but not exemestane or letrozole, is a ligand for ERα. These findings represent potential steps towards individualized anastrozole therapy.

Authors with CRIS profile

Peter Fasching Professur für Translationale Frauenheilkunde und Geburtshilfe

Involved external institutions

Mayo Clinic US United States (USA) (US) Canadian Cancer Trials Group (CCTG) CA Canada (CA) Indiana University – Purdue University Indianapolis US United States (USA) (US) Baylor College of Medicine US United States (USA) (US) Harvard University US United States (USA) (US) Hochschule Ansbach DE Germany (DE) University of Minnesota (UMN) US United States (USA) (US)

How to cite

APA:

Ingle, J.N., Cairns, J., Suman, V.J., Shepherd, L.E., Fasching, P., Hoskin, T.L.,... Wang, L. (2020). Anastrozole has an Association between Degree of Estrogen Suppression and Outcomes in Early Breast Cancer and is a Ligand for Estrogen Receptor α. Clinical Cancer Research, 26(12), 2986-2996. https://doi.org/10.1158/1078-0432.CCR-19-3091

MLA:

Ingle, James N., et al. "Anastrozole has an Association between Degree of Estrogen Suppression and Outcomes in Early Breast Cancer and is a Ligand for Estrogen Receptor α." Clinical Cancer Research 26.12 (2020): 2986-2996.

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