IMR Press / EJGO / Volume 40 / Issue 1 / DOI: 10.12892/ejgo4282.2019
Open Access Original Research
The pleiotropic factor Y-box binding protein-1 enhances the anti-proliferative efficacy of 4-hydroxytamoxifen and fulvestrant on breast cancer cells in vitro
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1 Dr. Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart, Germany
2 Department of Urology, University Medicine Greifswald, Greifswald, Germany
3 Department of Gynecology and Obstetrics, University Medicine Greifswald, Greifswald, Germany
4 Department of Gynecology and Obstetrics, University Medicine Tübingen, Tübingen, Germany
5 Institute for Laboratory and Transfusion Medicine, Heart and Diabetes Center North Rhine-Westphalia, Ruhr University Bochum, Bad Oeynhausen, Germany

†Contributed equally.

Eur. J. Gynaecol. Oncol. 2019, 40(1), 16–18;
Published: 10 February 2019

Purpose of investigation: The pleiotropic factor Y-box binding protein-1 (YB-1) is clinically correlated with breast cancer patients’ poor outcome. Due to the intereference of YB-1 with the estrogen receptor, the authors examined the antiproliferative efficacy of 4-hydroxytamoxifen (4-OHT) and fulvestrant (FUL) in the presence of low and high levels of YB-1. Materials and Methods: The human breast cancer cell line MCF-7 was transfected to overexpress YB-1 protein. 4-OHT and FUL incubation experiments were performed and cell growth behaviour of YB-1 overexpressing MCF-7 cells were compared to unmodified MCF-7 cells expressing endogenous YB-1 levels. Results: The incubation of MCF-7 cells with 100 nM 4-OHT and 1 nM FUL over a period of 120 hours clearly demonstrated the antiproliferative properties of both antiestrogens as expected. Notably, high levels of YB-1 led to an increase of antiproliferative properties in the presence of 4-OHT and FUL. Conclusion: The data presented here demonstrated YB-1 enhances the antiestrogenic efficacy of 4-OHT and FUL. Thus, the group of high level YB-1 mamma carcinoma patients might increasingly benefit from endocrine therapy.

Breast cancer
Endocrine therapy
Figure 1.
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